Change search
Refine search result
1234567 1 - 50 of 1597
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Alanne, Kari
    et al.
    Aalto University.
    Schade, Jutta
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Martinac, Ivo
    Kungliga tekniska högskolan, KTH.
    Saari, Arto J.
    Aalto University.
    Jokisalo, Juha
    Aalto University.
    Kalamees, Targo
    Tallinn University of Technology.
    Economic viability of energy-efficiency measures in educational buildings in Finland2013In: Advances in Building Energy Research, ISSN 1751-2549, E-ISSN 1756-2201, Vol. 7, no 1, 120-127 p.Article in journal (Refereed)
    Abstract [en]

    The economic viability of novel energy-efficient design concepts has been evaluated in Finnish educational buildings. The total energy consumption of representative target buildings with each design concept has been found using the whole-building simulation tool IDA Indoor Climate and Energy 4.0, and the financial viability has been assessed using the discounted payback period method. Different thermal insulation and air tightness properties of the building envelope, and different ventilation's heat recovery efficiency assumptions and heat distribution options have been investigated. The results suggest that a prudent attitude should be taken toward the investments in ultra-low-energy designs. Total energy-saving potential of 25-32% can be obtained. The payback periods varied from 15 to more than 40 years. The results can be generalized in cold climates and techno-economic conditions similar to Finland

  • 2.
    Al-Emrani, Mohammad
    et al.
    Chalmers University of Technology.
    Lukic, Mladen
    CTICM.
    Nilsson, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bridge fatigue guidance: a European research project2009In: Sustainable infrastructure: environment friendly, safe and resource efficient ; proceedings of IABSE symposium, Bangkok, Thailand, Sept. 9 - 11, 2009 / [ed] Mahāvidyālăy Culālaṅkărṇ, Zürich: International Association for Bridge and Structural Engineering, 2009Conference paper (Refereed)
  • 3.
    Al-Gburi, Majid
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Restraint Calculation in Concrete Culvert First Casting2014Report (Other academic)
  • 4.
    Al-Gburi, Majid
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Restraint Calculation in Concrete Culvert Second Casting2014Report (Other academic)
  • 5.
    Al-Gburi, Majid
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Restraint Effects in Early Age Concrete Structures2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of the widespread issues in concrete structures is cracks occurring at early age. Cracks that appear in the young concrete may cause early start of corrosion of rebars or early penetration of harmful liquids or gases into the concrete body. These situations could result in reduced service life and in significantly increased maintenance cost of structures. Therefore it is important for construction companies to avoid these cracks.Volumetric deformations in early age concrete are caused by changes in temperature and/or the moisture state. If such movements are restrained, stresses will occur. If the tensile stresses are high enough, there will be a damage failure in tension and visible cracks arise. These stresses are always resulting from a self-balancing of forces, either within the young concrete bodyalone, i.e. without structural joints to other structures, or from the young concrete in combination with adjacent structures through structural joints.The decisive situation within a young concrete body alone is typically high stresses at the surface when the temperature is near the peak temperature within the body. This situation occur rather early for ordinary structures, say within a few days after casting for structures up to about some meters thickness, but for very massive structures like large concrete dams, it might take months and even years to reach the maximum tensile stresses at the surface. Usually this type of cracks is denoted "surface cracks", and in some cases only a temperature calculation may give a good perception to make decisions of the risk of surface cracking.On the other hand, the decisive situation within a young concrete body connected to adjacent structures, might include both risk of surface cracking at some distance away from the structural joint and risk of through cracking starting in the neighborhood of the structural joint. If the young concrete body is small in accordance to the adjacent structure, or, in other words, if thereis an overall high restraint situation in the young concrete, the risk of early surface cracking might be out of question. So, restraint from adjacent structures represents one of the main sources of thermal and shrinkage stresses in a young concrete body.This study is mainly concentrated on establishing the restraint inside the young concrete body counteracted by adjacent structures, and how to estimate the risk of through cracking based on such restraint distributions. The restraint values in the young concrete are calculated with use of the finite element method, FEM. Any spatial structure may be analyzed with respect to the level of restraint. Calculations of risk of cracking are demonstrated with use of existing compensation plane methods, and a novel method denoted equivalent restraint method, ERM, is developed for the use of restraint curves. ERM enables the use of both heating ofthe adjacent structure and/or cooling of the young concrete, which are the most common measures used on site to reduce the risk of early cracking.In a design situation many parameters are to be considered, like type of cement, different concrete mixes, temperature in the fresh concrete, surrounding temperatures, temperature in the adjacent structure, measures on site (heating/cooling/insulation), sequence order of casting.Therefore, in general a lot of estimations concerning risks of cracking are to be performed. The main objective with the present study is to develop methods speeding up and shorten the design process.Furthermore, established restraint curves have been applied to the method of artificial neural networks (ANN) to model restraint in the slab, wall, and roof for the typical structure Tunnel. It has been shown that ANN is capable of modeling the restraint with good accuracy. The usage of the neural network has been demonstrated to give a clear picture of the relative importance of the input parameters. Further, results from the neural network can be represented by a series of basic weight and response functions, which enables that the restraint curves easily can be made available to any engineer without use of complicated software.A new casting technique is proposed to reduce restraint in the newly cast concrete with a new arrangement of the structural joint to the existing old concrete. The proposed technique is valid for the typical structure wall-on-slab using one structural joint. This casting method means that the lower part of the wall is cast together with the slab, and that part is called a kicker. It hasbeen proven by the beam theory and demonstrated by numerical calculations that there is a clear reduction in the restraint from the slab to the wall using kickers.Restraint is affected by casting sequence as well as boundary conditions and joint position between old and new concrete elements. This study discusses the influence of different possible casting sequences for the typical structure wall-on-slab and slab-on-ground. The aim is to identify the sequence with the lowest restraint to reduce the risk of cracking.

  • 6.
    Al-Gburi, Majid
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Restraint formulation for wall on slab at early age concrete structures by using ANN2012Report (Other academic)
    Abstract [en]

    Existing restraint curves have been applied to the method of artificial neural networks (ANN) to model restraint in the wall for the typical structure wall-on-slab. It has been proven that ANN is capable of modeling the restraint with good accuracy. The usage of the neural network has been demonstrated to give a clear picture of the relative importance of the input parameters. Further, it is shown that the results from the neural network can be represented by a series of basic weight and response functions. Thus, the results can easily be made available to any engineer without use of complicated software.

  • 7.
    Al-Gburi, Majid
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Restraint in structures with young concrete: Tools and estimations for practical use2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    One of the widespread issues in concrete structures is cracks occurring at early age. Cracks that appear in the young concrete may cause early start of corrosion of rebars or early penetration of harmful liquids or gases into the concrete body. These situations could result in reduced service life and in significantly increased maintenance cost of structures. Therefore it is important for construction companies to avoid these cracks. Restraint represents one of the main sources of thermal and shrinkage stresses at early age concrete. Paper I, deals with both the compensation plane method, CPM, and local restraint method, LRM, as alternative methods studying crack risks for early age concrete. It is shown that CPM can be used both for cooling and heating, but basic LRM cannot be applied to heating. This paper presents an improved equivalent restraint method, ERM, which easily can be applied both for usage of heating and cooling for general structures. Restraint curves are given for two different infrastructures, one founded on frictional materials and another on rock. Such curves might be directly applied in design using LRM and ERM.In Paper II, existing restraint curves have been applied to the method of artificial neural networks (ANN) to model restraint in the wall for the typical structure wall-on-slab. It has been proven that ANN is capable of modeling the restraint with good accuracy. The usage of the neural network has been demonstrated to give a clear picture of the relative importance of the input parameters. Further, it is shown that the results from the neural network can be represented by a series of basic weight and response functions. Thus, the results can easily be made available to any engineer without use of complicated software.Paper III, discusses the influence of five casting sequences for the typical structure slab-on-ground. The aim is to map restraints from adjacent structures for a number of possible casting sequences, and to identify the sequence with the lowest restraint. The paper covers both continuous and jumped casting sequences, which include one, two and three contact edges. The result shows that the best casting sequence is the continuous technique with one contact edge.

  • 8.
    Al-Gburi, Majid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jonasson, Jan-Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Effect of casting sequences on the restraint in slab-on-ground2014Conference paper (Refereed)
    Abstract [en]

    One of the widespread issues in concrete structures is cracks occurring at early age. Cracks that appear in the young concrete may cause early start of corrosion of rebars or early penetration of harmful liquids or gases into the concrete body. These situations could result in reduced service life and in significantly increased maintenance cost of structures. Therefore it is important for construction companies to avoid these cracks. Restraint represents one of the main sources of thermal and shrinkage stresses at early age concrete. The casting sequence is affected by the restraint from adjacent structures. The present study discusses the influence of five casting sequences for the typical structure slab-on-ground. The aim is to map restraints for a number of possible casting sequences, and to identify the sequence with the lowest restraint. The study covers both continuous and jumped casting sequences, which include one, two and three contact edges. The result shows that the best casting sequence is the continuous technique with one contact edge

  • 9.
    Al-Gburi, Majid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jonasson, Jan-Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Effect of the boundary conditions on the crack distribution in early age concrete2014In: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, 347-351 p.Article in journal (Refereed)
    Abstract [en]

    Restrained movement in early age concrete may cause cracking. The boundary conditions – restraint – influence the possible crack distribution. This study aims at highlighting the effect of such restraint on the crack distribution. This is done by using the “Cracking Model for Concrete” in ABAQUS/Explicit simulating the non-linear behaviour under and after cracking. In the study the typical case wall-on-slab was in focus using a structure previously been tested in laboratory with both fixed and free bottom slab. The result of the modelling shows fairly good agreement with the cracks observed in the tests.

  • 10.
    Al-Gburi, Majid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jonasson, Jan-Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Reduction of Early Age Crack Risks in Concrete Walls by Using a New Casting Technique2016In: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 26, no 3, 216-224 p.Article in journal (Refereed)
    Abstract [en]

    Volumetric changes in early age concrete that are restrained might lead to cracks. The degree of restraint is influenced by the casting sequence and the dimensions of the castings. In the current study a new casting technique is proposed to reduce restraint in the newly cast concrete with a new arrangement of the structural joint to the existing old concrete. The proposed technique is valid for the typical structure wall-on-slab using one structural joint. This casting method means that lower part of the wall is cast together with the slab, and that part is called a kicker. Hereby, the behavior of the structure changes from a typical case wall-on-slab to a typical case wall-on-wall. It has been proven by the beam theory and demonstrated by numerical calculations that there is a clear reduction in the restraint from the slab to the wall using kickers. In the paper different kicker heights are studied with the aim of determining the minimum restraint in the upper part of the wall cast in contact with the kicker. The technique using kickers is compared with common measures used in the field to avoid cracking, such as cooling pipes in the new casting and/or heating cables in the adjoining old concrete. The presented method is both cost and time effective, as it opens the possibility to use larger structural length of each casting sequence.

  • 11.
    Al-Gburi, Majid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jonasson, Jan-Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Using Artificial Neural Network to Predict the Restraint in Concrete Culvert at Early Age2015In: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 25, no 3, 258-265 p.Article in journal (Refereed)
    Abstract [en]

    Estimation of restraint is very important for accurate prediction of the risk of concrete cracking at early age. The present study predicts the restraint in 324 walls and 972 roofs for a concrete culvert. A parametric study included the thickness and width of the roofs, thickness and height of the walls, thickness and width of the slab, and length of the structures. Each parameter increased or decreased the restraint in the walls and the roofs. The calculation of the restraint was done elastically by the finite-element method (FE). The results were used by an artificial neural network (ANN) tool, where firstly an influential percentage was investigated as input parameters on the restraint prediction. Equations have been derived by the ANN model to calculate the restraint in the walls and the roofs. It was then used in an Excel sheet to calculate the restraint and compare the result with the result from the finite-element calculations giving high accuracy between the ANN model and the FE calculations

  • 12.
    Al-Gburi, Majid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jonasson, Jan-Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Hedlund, Hans
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Hösthagen, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Simplified methods for crack risk analyses of early age concrete: Part 1: Development of Equivalent Restraint Method2012In: Nordic Concrete Research, ISSN 0800-6377, Vol. 46, no 2, 17-38 p.Article in journal (Refereed)
    Abstract [en]

    The present study deals with both the compensation plane method, CPM, and local restraint method, LRM, as alternative methods studying crack risks for early age concrete. It is shown that CPM can be used both for cooling and heating, but basic LRM cannot be applied to heating. This paper presents an improved equivalent restraint method, ERM, which easily can be applied both for usage of heating and cooling for general structures. Restraint curves are given for two different infrastructures, one founded on frictional materials and another on rock. Such curves might be directly applied in design using LRM and ERM.

  • 13.
    Al-Gburi, Majid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Jonasson, Jan-Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Yousif, Salim T
    Mosul University.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Simplified methods for crack risk analyses of early age concrete: Part 2: Restraint factors for typical case wall-on-slab2012In: Nordic Concrete Research, ISSN 0800-6377, Vol. 46, no 2, 39-56 p.Article in journal (Refereed)
    Abstract [en]

    Existing restraint curves have been applied to the method of artificial neural networks (ANN) to model restraint in the wall for the typical structure wall-on-slab. It has been proven that ANN is capable of modeling the restraint with good accuracy. The usage of the neural network has been demonstrated to give a clear picture of the relative importance of the input parameters. Further, it is shown that the results from the neural network can be represented by a series of basic weight and response functions. Thus, the results can easily be made available to any engineer without use of complicated software.

  • 14.
    Alm, Ove
    et al.
    Luleå tekniska universitet.
    Norin, Jonas
    Luleå tekniska universitet.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Experimentella bestämningar av mekaniska egenskaper för hårdmetallpulver: slutrapport över pilotstudie1982Report (Other academic)
  • 15.
    Alm, Ove
    et al.
    Luleå tekniska universitet.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Attempt to make accurate measurements of deformations of compressible soilds at high pressure and different states of stress1982In: High pressure in research and industry: 8th AIRAPT Conference, 19th EHPRG Conference, 17 - 22 August 1981, Institte of Physical Chemistry, University of Uppsala, Sweden ; proceedings / [ed] C.-M. Backman, Uppsala: Fysikalisk-kemiska inst., Univ , 1982, 619-622 p.Conference paper (Refereed)
  • 16.
    Al-Taie, Entidhar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Al-Ansari, Nadhir
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Saaed, Tarek Edrees
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Foundation assessment in different parts of Iraq using STAAD Pro v8i2013In: Journal of Civil Engineering and Architecture, ISSN 1934-7359, E-ISSN 1934-7367, Vol. 7, no 3, 273-281 p.Article in journal (Refereed)
    Abstract [en]

    Foundation is considered as one of the main parts of any structure such as buildings, railways, bridges, etc. The type of foundation used is highly dependent on the type and properties of soil. The design of foundations requires many factors that should be defined such as the load that the foundation is going to hold, geological conditions of the soil under the foundation, type of soil and the local building code criteria.There are number of differences in the geological and soil conditions in Iraq. As a consequence, these differences are reflected on the type of foundation to be used. Despite these differences, same materials and style of buildings are used all over Iraq. The main problems of Iraqi soil are high gypsum content, salinity and shallow water table depth. These factors that influence the foundations are the soil properties and the amount of loads that transmitted by the superstructure.The situation had been analysed through a case study which illustrated the link between soil and foundation types in three different parts of Iraq (Mosul, Baghdad and Basra). One building was analysed using STAAD. Pro software in these regions. It is evident that Iraqi designers and engineers require local code to define all the loads, materials and design of the foundation to be used. The use of local materials might be very effective from both engineering and economic perspectives.

  • 17.
    Andersson, Jörgen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Veljkovic, Milan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Design Guide: Dimensionering av ekonomiska och långsiktigt hållbara samverkansbroar med integrerade landfästen.2011Report (Other academic)
    Abstract [sv]

    Denna dimensioneringshandbok är ett resultat av forskningsprojektet RFS-PR-04120 INTAB “Economic and Durable Design of Composite Bridges with Integreral Abutments” (Feldmann, et al., 2010) och det efterföljande disseminationsprojektet RFS – P2 - 08065 INTAB+ “Economic and Durable Design of Composite Bridges with Integreral Abutments” (Feldmann, et al., 2012), som varit delfinansierat av EU:s forskningsfond ”Research Fund for Coal and Steel” (RFCS) samt Svenska Byggbranschens Utvecklingsfond (SBUF). Inom forskningsprojektet har väsentlig kunskap inhämtats för att skapa möjlighet att öka konkurrenskraften hos samverkansbroar med integrerade landfästen. Denna kunskap har inarbetats i denna dimensioneringshandbok, vars engelska version har presenterats vid ett antal internationella seminarier och workshops.

  • 18.
    Andrade, Pedro António Pimenta de
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Innovative Construction of Student Residences: Frameup Project2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the majority of university cities in Sweden, a strong demand for student accommodations has initiated various development and research projects focusing on costs reduction and fast execution. The present thesis brings up a solution based on the development of a feasible assembly concept and process, for a Modular Building erection, where prefabricated 3D Modules are assembled into a sway steel frame. The concept has been initiated within FRAMEUP project: Optimization of Frames for Effective Assembling (RFCS contract RFS-PR-10121). One of the main project objectives was to investigate and develop a competitive structural system suitable for fast in-situ execution and dismounting. Thus, in order to streamline the construction process, the use of optimized prefabricated frames and room 3D modules has become a very attractive alternative. The building is designed considering a six-story building, as it has been seen as the suitable choice of industrial partners in the project on market demands for the optimal payoff time. The use of Intensive Use of Steel together with Modular Construction enhances the conditions for industrialization of the construction process towards the cost reduction.The development of the whole concept is described and followed up by a 4D construction sequence. The concept is based on the original structural system for which calculations, drawings and feasibility test at full scale are made to prove the credibility of the system. The 3D Modules are designed by Norrbotten based SME, which has influenced the global concept design. In addition, development of a novel joint, by means of laboratory tests and finite element models, is shown in the thesis. It is believed that its use in the frame, for the column splice connection, may be advantageous for the execution process. The issue of execution tolerances has been addressed by advanced FEA, which has been validated by experiments.

  • 19.
    Andrade, Pedro
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Monteiro, Safira
    Gervásio, Helena
    University of Coimbra, Faculty of Science and Technology, Coimbra, Portugal.
    Veljkovic, Milan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Assessment and monitoring of a student residential building using an innovative execution solution2013In: Proceedings of SB13 Portugal: Contribution of Sustainable Building to Meet EU 20-20-20 Targets / [ed] Luís Bragança; Ricardo Mateus; Manuel Pinheiro, Guimarães, Portugal, 2013, 403-410 p.Conference paper (Refereed)
    Abstract [en]

    The construction, fit-out, operation and the final demolition of buildings contributes to a large-scale negative impacts on the environment, even at the level of material and energy consumption, or even because the inefficient infrastructure. This document is based on a thorough study that encompasses the design phase, construction, use and, finally,the end of life. This work it is followed by an innovative modular building and execution process, within theFRAMEUP project, which will take place in Lulea, Sweden. The aim of this study is to analyze the sustainability of this future building; first from an energy point of view so as to know the specific energy consumption using specific software, and on the other hand from an environmental stand point by leading a complete life-cycle assessment (cradle-to-grave).

  • 20.
    Andrade, Pedro
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Pavlovic, Marko
    Faculty of Civil Engineering, University of Belgrade.
    Heistermann, Christine
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Veljkovic, Milan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Heistermann, Tim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Structural Behaviour of a Novel Column-Splice Joint: Finger Connection2015In: The 13th Nordic Steel Construction Conference: NSCC-2015 / [ed] Markku Heinisuo; Jari Mäkinen, Tampere: Tampere University of Technology, Department of Civil Engineering , 2015, 215-216 p.Conference paper (Refereed)
    Abstract [en]

    The novel joint presented in this paper is a friction connection used for column-splice connections of modular buildings as part of the innovative construction method introduced in the research project Optimization of frames for effective assembling - FRAMEUP. This type of joint provides a quick assembly and can deal with misalignments by introducing a connection gap. A filler and finger plate are welded to the upper part of the column to this end.The gap between finger plates and lower column faces is closed during tightening of the bolts and, thus, establishes a slip-resistant connection. The efficiency of the joint resistance based on different connection gaps subjected to uniform compression is assessed.The column-splice is composed of four slip-resistant connections, one at each side of the tube. Each finger plate consists of three long slotted holes and is welded to the upper column face. Long slotted holes are used to accommodate vertical misalignments and, therefore, allow fitting the bolts which are pre-installed in the lower column. Filler plates with different thicknesses (4, 6 and 8 mm) welded between the finger plate and upper column face are used to create a connection gap which allows balancing horizontal misalignments. The lower column faces consist of each nine holes with no clearance in order to pre-fit the bolts in a workshop. Thus, the assembling process on the construction site can be speeded up as once the lowercolumns are in place all bolts can be tightened immediately.

  • 21.
    Andrade, Pedro
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Veljkovic, Milan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Feldmann, Markus
    Institute for Steel Structures, RWTH Aachen University.
    Pak, Daniel
    Institute for Steel Structures, RWTH Aachen University.
    Pyschny, Dominik
    Institute for Steel Structures, RWTH Aachen University.
    Lundholm, John
    Part Construction AB.
    Design and execution of a 3D modular building2014In: Eurosteel 2014: 7th European Conference on Steel and Composite Structures / [ed] Raffaele Landolfo; Frederico M. Mazzolani, Brussels, Belgium: European Convention for Constructional Steelwork, ECCS , 2014, 103-104 p.Conference paper (Refereed)
  • 22.
    Andrade, Pedro
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Veljkovic, Milan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lundholm, John
    Part Construction AB.
    Heistermann, Tim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Innovative Construction of Student Residences: Frameup concept2015In: The 13th Nordic Steel Construction Conference: NSCC-2015 / [ed] Markku Heinisuo; Jari Mäkinen, Tampere: Tampere University of Technology, Department of Civil Engineering , 2015, 199-200 p.Conference paper (Refereed)
    Abstract [en]

    Sweden has a strong demand on the construction of student accommodations and therefore significant efforts have been taken towards an affordable and easy solution of the problem. A concept combining these requirements may be based on the use of structural steel frames in combination with prefabricated 3D modules fully equipped and suitable for student accommodations. Therefore, the need to investigate and develop a system suitable for an effective assembly of student residences is considered in this paper, as part of an international project, Optimization of the frames for effective assembling - FRAMEUP. The Fig. 1 reveals an overview of the system within the execution process.The Frameup system introduces a new approach in terms of execution technique which consists of the execution of a building starting from the roof to the 1st floor. The existence of a lifting system constituted of a horizontal rigid frame - grid - in combination with lifting towers - pylons - permits the erection of the building, promoting each time the building is lifted, a clearance of one-floor-height plus tolerances at the ground level. This creates room enough for the assembly of the lower floor from below the previously assembled floor. The procedure is repeated several times according to the number of floors until the 1st floor of the building, the last floor of the execution sequence, is assembled. Moreover the Frameup system introduces an innovation, the Frameup conveyor system, which streamlines the assembly process so to move/slide the elements, as they come, directly from the lorry to their final position in the building.The development of the Frameup system benefits from a stepwise detailed 3D modeling and structural analysis and design tools. However, when it comes to attest the reliability and efficiency of the system, a full scale feasibility test is essential and it is performed on the majority of the sequences of construction.

  • 23.
    Andren, Henrik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Wennström, Joakim
    Luleå tekniska universitet.
    Analysis of replication casting of ice surfaces2007In: Proceeding of the 8th International Symposium on Cold Region Development, Tampere University of Technology, 2007Conference paper (Refereed)
    Abstract [en]

    The microscopic analysis of an ice surface is very difficult, due to the nature of the ice. The optically transparent, brittle and very environmentally sensitive surface is hard to analyze in a manner that does not render the results useless from damage or errors in measurements.The ice surface is ill suited for contact microscopy, like Atomic Force Microscopy (AFM) or other methods of sliding a probe over the surface. Furthermore the ice surface is transparent, so even cold room optical microscopy is not feasible. Due to the vacuous atmosphere Scanning Electron Microscope (SEM) is not an option. In this paper the authors look at some casting techniques to try and reproduce the surface with a substance much better suited for optical and mechanical measurements, as well as having a longer shelf life and being easier to handle. Different evaluations have been considered, where the frequency information is used as a measure of resolution, comparing the resolution loss of different casting materials.The casting materials used are different products from the dental industry, as well as polyvinyl formvar, a dissolved polymer that is very useful for casting of ice surfaces.

  • 24.
    André, Alann
    et al.
    Swerea SICOMP AB.
    Johnsson, Helena
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Flax fibre-reinforced glued-laminated timber in tension perpendicular to the grain: experimental study and probabilistic analysis2010In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 22, no 9, 827-835 p.Article in journal (Refereed)
    Abstract [en]

    The weak mechanical properties of wood in tension perpendicular to the grain are often the origin of catastrophic brittle failure. In order to enhance the tension strength perpendicular to the grain and achieve a more ductile failure, flax fibre and glass fibre reinforced polymer (FRP) composites were used to strengthen glued-laminated (glulam) timber specimens. Three series of specimen of glulam timber (flax fibre reinforced, glass fibre reinforced and unreinforced), with a grand total of 28 specimens, were tested in tension perpendicular to the grain. For an approximate amount of FRP reinforcement of 1.2- in volume (thickness ~ 0.7 mm), an increase of the tensile strength up to 74- was shown, with a stiffness increase up to 41-. For all reinforced specimens, semi-ductile failures were observed. A parametric study was carried out using both the Monte Carlo method (MC) and the First Order Second Moment method (FOSM). It is shown that the mean values obtained during experiments are in agreement with those from the MC simulation. However, the standard deviations from the MC simulation are larger. From the FOSM analysis, it is demonstrated that the variation in glulam stiffness perpendicular to the grain is not the first parameter driving the variation for the reinforced system. The variation in mechanical properties of the flax fibres appeared to be the driving parameters for the strength of the system.

  • 25. Apleberger, Lennart
    et al.
    Cederwall, Krister
    Luleå tekniska universitet.
    Emborg, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Massiva betongkonstruktioner i varmt klimat: fältmätningar och teoretisk analys av väggsektioner : D. 1 Rapportdel1985Report (Other academic)
  • 26. Apleberger, Lennart
    et al.
    Cederwall, Krister
    Luleå tekniska universitet.
    Emborg, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Massiva betongkonstruktioner i varmt klimat: fältmätningar och teoretisk analys av väggsektioner : D. 2 Tabelldel1985Report (Other academic)
  • 27. Arwidson, Claes
    et al.
    Bernspång, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Kaplan, Alexander
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Verification of numerical forming simulation in high strength steels2004In: Proceedings of the Conference Innovations in metal forming, 2004Conference paper (Refereed)
  • 28.
    Atashipour, Seyed Abdolrahim
    et al.
    Department of Civil, Chemical and Environmental Engineering, Genoa University.
    Sburlati, R.
    Department of Civil, Chemical and Environmental Engineering, Genoa University.
    Atashipour, Seyed Rasoul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elastic analysis of thick-walled pressurized spherical vessels coated with functionally graded materials2014In: Meccanica (Milano. Print), ISSN 0025-6455, E-ISSN 1572-9648, Vol. 49, no 12, 2965-2978 p.Article in journal (Refereed)
    Abstract [en]

    In recent years, functionally graded material (FGM) has been widely explored in coating technology amongst both academic and industry communities. FGM coatings are suitable substitutes for many typical conventional coatings which are susceptible to cracking, debonding and eventual functional failure due to the mismatch of material properties at the coating/substrate interface. In this study, a thick spherical pressure vessel with an inner FGM coating subjected to internal and external hydrostatic pressure is analyzed within the context of three-dimensional elasticity theory. Young’s modulus of the coating is assumed to vary linearly or exponentially through the thickness, while Poisson’s ratio is considered as constant. A comparative numerical study of FGM versus homogeneous coating is conducted for the case of vessel under internal pressure, and the dependence of stress and displacement fields on the type of coating is examined and discussed.

  • 29.
    Atashipour, Seyed Rasoul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Structural Analysis of Deep Composite Box-Type Components with application to a proprietary stabilising timber wall element2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The stabilising wall element of the Trä8-system is a deep box-type beam/column element which is made of different types of timber composites including framing members of gluedlaminated timber (glulam) and sheathings of laminated veneer lumber (LVL). This element is used as a ―shear wall‖ in multi-storey buildings up to four storeys. To be able to optimise thecomposite stabilising element and use its maximum potential and efficiency, it is necessary to have sufficient fundamental knowledge and information about the structural behaviour and influences of different mechanical properties and geometrical parameters and dimensions of the sub-elements.In this thesis, structural analysis and design principles of the Trä8 stabilising wall element are discussed, including the early stage of erection during assembly to the final usage and residence. A list of required fundamental basic analyses are presented, including accurate deflection analysis for the serviceability limit state, local pre- and post-buckling of the LVL sheathings, global buckling as well as the lateral-torsional buckling of the stabilising element in different design situations. This thesis is then focused on deformations and local instability. For each type of structural problem, accurate, but simple and general methodology is employed to incorporate a large number of effective geometric and property parameters. In this way, a fast evaluation of the influence of different parameters is possible for a wide range of values without needing several time-consuming 3-D finite element (FE) simulations. In several cases, the accuracy and validity of the obtained solutions and formulae are examined and confirmed by comparing their results to those based on the 3-D FE simulations. First, different composite beam theories including shear effects are employed for deflection analysis of the stabilising timber element. Next, an accurate energy-based methodology isdeveloped rendering an explicit formula that gives accurate predictions for the deflection of the stabilising element within a medium range of sheathing or web thicknesses and/or stiffnesses. For weak shear webs, however, this model is not sufficient. Therefore, another new model based on the partial composite interaction theory is developed for accurate deflection predictions of the element having weak shear webs. This model contains simple but accurate formulae for deflection analysis of any similar composite box-type of element with an arbitrary range of geometry and property parameters.Next, shear buckling of the rectangular LVL-panel between the framing members are analysed using differential quadrature (DQ) numerical technique as well as an explicit analytical solution and a formula is established for accurate and fast prediction of the shear pre-buckling of the LVL. This study is extended by considering the effect of each individual lamina of the LVL as well as general orthotropic material properties using a laminated theoryand the DQ solution approach. Further, the post-buckling of the LVL panel is studied based on a simple analytical method with rotating stress fields together with the accurate 3-D FE simulations. A simple formula is then proposed for accurate prediction of the shear post-buckling resistance of the LVL-panel in the stabilising element. As a result of the thesis concerning the two main focus areas, deformations and local instability, explicit analytical formulae are presented for the design of the box-type stabilisingelement with respect to deflections including shear effects in the serviceability limit state and with respect to local shear buckling of the sheathings of the stabilising element including the post-critical area in the ultimate limit state.

  • 30.
    Atashipour, Seyed Rasoul
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Girhammar, Ulf Arne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    On the Shear Buckling of Clamped Narrow Rectangular Orthotropic Plates2015In: Mathematical problems in engineering (Print), ISSN 1024-123X, E-ISSN 1563-5147, Vol. 2015, 569356Article in journal (Refereed)
    Abstract [en]

    This paper deals with stability analysis of clamped rectangular orthotropic thin plates subjected to uniformly distributed shear load around the edges. Due to the nature of this problem, it is impossible to present mathematically exact analytical solution for the governing differential equations. Consequently, all existing studies in the literature have been performed by means of different numerical approaches. Here, a closed-form approach is presented for simple and fast prediction of the critical buckling load of clamped narrow rectangular orthotropic thin plates. Next, a practical modification factor is proposed to extend the validity of the obtained results for a wide range of plate aspect ratios. To demonstrate the efficiency and reliability of the proposed closed-form formulas, an accurate computational code is developed based on the classical plate theory (CPT) by means of differential quadrature method (DQM) for comparison purposes. Moreover, several finite element (FE) simulations are performed via ANSYS software. It is shown that simplicity, high accuracy, and rapid prediction of the critical load for different values of the plate aspect ratio and for a wide range of effective geometric and mechanical parameters are the main advantages of the proposed closed-form formulas over other existing studies in the literature for the same problem.

  • 31.
    Atashipour, Seyed Rasoul
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Girhammar, Ulf Arne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Challamel, Noël
    University of Europeenne Bretagne, Laboratory Genie Civil & Genie Mecan, Université Européenne de Bretagne, Mechanics Division, Department of Mathematics, University of Oslo, LIMATB, Université Européenne de Bretagne, University of South Brittany, Lorient.
    The effect of weak shear webs on the deformations of timber box type beams2015In: Proceedings of the Fifteenth International Conference on Civil, Structural and Environmental Engineering Computing / [ed] J. Kruis; Y. Tsompanakis; B.H.V. Topping, Stirlingshire: Civil-Comp Press , 2015, 259Conference paper (Refereed)
    Abstract [en]

    This paper deals with deflection analysis of a deep composite box beam due to inplane shear deformations, especially the modelling of the shear deformations in the webs is considered. The beam is composed of three framing members with sheathings on both sides. The sheathings or webs between the framing members are modelled as shear media with equivalent slip moduli corresponding to the partially composite beam model with three separated layers and two interlayer slip areas. The minimum total potential energy principle is employed to obtain the governing equilibrium equations and corresponding boundary conditions. The coupled set of governing equations is recast into an uncoupled form and solved explicitly together with the corresponding boundary conditions. The closed-form solutions obtained are compared to those based on the conventional beam theories. It is shown that the model is capable of predicting accurately the deflections for a wide range of geometry and property parameters, especially for small shear stiffness (slip modulus) values for the webs. The formula for the deflection is reduced to the Timoshenko formula for full composite interaction when the shear slip modulus of the web approaches infinity. Comparative numerical results are presented to show the influence of bending deformations, shear deformations in the framing layers and the in-plane shear deformations in the sheathings

  • 32.
    Axelsson, Kennet B. E.
    et al.
    Högskolan i Luleå, Luleå tekniska universitet, Luleå University of Technology.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Grennberg, Torsten
    Luleå tekniska universitet.
    Horrigmoe, Geir
    Luleå tekniska universitet.
    Johansson, Bernt
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Institutionen för Anläggningsteknik, Verksamhetsberättelse 1988/891989Report (Other (popular science, discussion, etc.))
  • 33.
    Axelsson, Kennet B. E.
    et al.
    Högskolan i Luleå, Luleå tekniska universitet, Luleå University of Technology.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Grennberg, Torsten
    Luleå tekniska universitet.
    Horrigmoe, Geir
    Luleå tekniska universitet.
    Johansson, Bernt
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Institutionen för Anläggningsteknik. Verksamhetsberättelse 1989/901990Report (Other (popular science, discussion, etc.))
  • 34.
    Axelsson, Kennet B. E.
    et al.
    Högskolan i Luleå, Luleå tekniska universitet, Luleå University of Technology.
    Johansson, Bernt
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Grennberg, Torsten
    Luleå tekniska universitet.
    Horrigmoe, Geir
    Luleå tekniska universitet.
    Institutionen för Anläggningsteknik. Verksamhetsberättelse 1990/911991Report (Other (popular science, discussion, etc.))
  • 35.
    Axelsson, Kenneth
    et al.
    Luleå tekniska universitet.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bro1990In: Nationalencyclopedin, Höganäs: Bra Böcker , 1990, 320-324 p.Chapter in book (Other academic)
  • 36.
    Babic, N.C.
    et al.
    University of Maribor.
    Rebolj, D.
    University of Maribor.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Schumacher, S.
    P3 Ingenieurgesellschaft.
    InPro training environment and model based working in construction2009In: Improving Construction and Use through Integrated Design Solutions: First International Conference on CIB IDS 2009 / [ed] Kaisa Belloni; Jun Kojima; Isabel Pinto Seppä, Espoo: Valtion teknillinen tutkimuskeskus. Tie- ja liikennelaboratorio , 2009, 72-86 p.Conference paper (Refereed)
    Abstract [en]

    InPro project is European initiative which is developing a model based and collaborative way of working in early design phase in construction. To support project goals and facilitate the industrial transformation and industrial technology take-up, the project implemented tools and developed curricula and materials for training and education of management, architects, engineers, and construction workers, as well as university students. The paper presents training environment architecture with BIM laboratory that was developed to support training on model based work practices and enhancement of hands-on skills. Development process, technical solutions and experiences are described. Content of training courses and curricula is based on experiences from live project demonstrations and use cases. The paper presents one of the answers that address the problem of insufficient skills in construction industry that prevent adoption of novel methods of working and technology.

  • 37.
    Bagge, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Assessment of Concrete Bridges: Models and Tests for Refined Capacity Estimates2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Optimising the strategy for repairing, upgrading and replacing bridges in the European Union, and elsewhere, is becoming increasingly important due to ageing of the bridge stock, continuously increasing load requirements and budgetary limitations. Thus, there is a clear need to identify or develop, and implement, refined methods for assessing existing bridges in order to determine the most cost-effective options and actions to extend their lives, increase their capacities or replace them.Thus, the objective of the research project partly reported in this licentiate thesis is to verify and calibrate methods for refined assessment of existing bridges, using information acquired in an extensive program of experimental studies. In addition to describing parts of the project, the thesis is intended to provide a basis for suggestions and a discussion of the author’s future research in the area. It includes presentations of two experimental studies designed to evaluate, and calibrate, assessment methods:1. A laboratory-based experimental study of 12 two-span continuous reinforced concrete beams conducted in Dublin, Ireland, in 2012. The tests particularly focused on the beams’ nonlinear overall behaviour and related redistribution of internal forces.2. A full-scale test of a 55 year-old post-tensioned girder bridge in Kiruna, Sweden, in 2014, focusing on: (a) failure loading of the main girders, (b) failure loading of the slab, (c) the condition of post-tension cables, and (d) two strengthening systems using carbon fibre reinforced polymers (CFRP).The continuous reinforced concrete beams behaved in a nonlinear manner from an early stage in the loading. This is not usually considered in either the design or assessment of existing bridges, but should be for the verification to be accurate at the serviceability and ultimate limit states (SLS and ULS, respectively). The results also indicated that there was more redistribution of internal forces at the ULS than stated in standards. Thus, use of refined methods to assess bridges or other reinforced concrete structures can be beneficial for avoiding unnecessary repairs, strengthening or replacement measures. In addition, the tests demonstrated the importance of taking into account the interaction between flexural moments and shear forces. This is not considered in shear force resistance models included in, for example, the European standard.To date, too few reinforced concrete bridges have been tested to failure to parameterise assessment models robustly with low uncertainty levels. Thus, a programme aimed for verification and calibration of models for assessing existing bridges was designed. The comprehensive programme is described in the thesis, which also provides suggestions and a discussion for future research based on the tests and associated monitoring.During the full-scale tests of the Kiruna Bridge, data were acquired that are relevant to investigations in several fields related to bridge assessment. For instance the obtained data provide foundations for future research concerning: (a) the robustness, ductility and bridge behaviour, (b) the shear force and punching resistance of bridge girders and slabs, (c) assessment of post-tensioned steel cables’ condition, (d) strengthening methods using CFRP, (e) updating finite element models, and (f) reliability-based analysis.

  • 38.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bernspång, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Trafikverket.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Full-Scale Test to Failure of a Prestressed Concrete Bridge in Kiruna2014In: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, 83-86 p.Article in journal (Refereed)
    Abstract [en]

    To calibrate methods for condition assessment of prestressed concrete (PC) bridges, tests are planned for a 50 year old five-span bridge with a length of 121 m in Kiruna in northern Sweden. Both non-destructive and destructive full-scale tests will be performed. This paper summarises the test programme, which comprises evaluation of the structural behaviour of the bridge, the residual forces in the prestressed steel, methods for strengthening using carbon fibre reinforced polymers (CFRP) and the shear resistance of the bridge slab.

  • 39.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bernspång, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. Norut Northern Research Institute, Narvik.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. College of Civil Engineering, Southeast University, Nanjing.
    Carolin, Anders
    Trafikverket, Trafikverket, Luleå.
    Performance of a prestressed concrete bridge loaded to failure2015In: IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges, Geneva: International Association for Bridge and Structural Engineering, 2015, 1088-1095 p.Conference paper (Other academic)
  • 40.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Instrumentation and Full-Scale Test of a Post-Tensioned Concrete Bridge2014In: Nordic Concrete Research, ISSN 0800-6377, Vol. 51, 63-83 p.Article in journal (Refereed)
    Abstract [en]

    To meet new demands, existing bridges might be in need for repair, upgrading or replacement. To assist such efforts a 55-year-old post-tensioned concrete bridge has been comprehensively tested to calibrate methods for assessing bridges more robustly. The programme included strengthening, with two systems based on carbon fibre reinforced polymers (CFRPs), failure loading of the bridge’s girders and slab, and determination of post-tension cables’ condition and the material behaviour. The complete test programme and related instrumentation are summarised, and some general results are presented. The measurements address several current uncertainties, thereby providing foundations for both assessing existing bridges’ condition more accurately and future research.

  • 41.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Enochsson, Ola
    Sabourova, Natalia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Grip, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Emborg, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lundmark, Tore
    Ramböll Sverige AB, Luleå.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Protecting a five span prestressed bridge against ground deformations2015In: IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges, Geneva: International Association for Bridge and Structural Engineering, 2015, 255-262 p.Conference paper (Other academic)
    Abstract [en]

    A 55 year-old, 121.5 m long, five span prestressed bridge was situated in the deformation zone close to a mine in Kiruna in northern Sweden. There was a risk for uneven ground deformations so the bridge was analyzed and monitored. Results and measures taken to ascertain the robustness of the bridge are presented.The analysis resulted in an estimate that the bridge could sustain 24 mm in uneven horizontal and 83 mm in uneven vertical displacement of the two supports of a span. To be able to sustain larger deformations, the columns of the bridge were provided with joints, where shims could be inserted to counteract the settlements. To accomplish this, each one of the 18 columns of the bridge was unloaded by help of provisional steel supports. The column was then cut and a new foot was mounted to it. This made it possible to lift each individual column with two jacks, when needed, and to adjust its height by inserting or taking away shim plates.The deformations of the bridge and the surrounding ground were monitored. The eigenmodes of the bridge were studied with accelerometers and by analysis with finite elements (FE) models. Comparison indicated good agreement between the model and the actual bridge, with calculated eigenfrequencies of 2.17, 4.15 and 4.67 Hz, for the first transversal, vertical and torsional modes, respectively. Measurements during winter resulted in higher values due to increased stiffness caused by frozen materials.

  • 42.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Tu, Yongming
    College of Civil Engineering, Southeast University, Nanjing.
    Carolin, Anders
    Trafikverket.
    Loading to failure of a 55 year old prestressed concrete bridge2015In: IABSE Workshop Helsinki 2015: Safety, Robustness and Condition Assessments of Structures, Zurich: International Association for Bridge and Structural Engineering, 2015, 130-137 p.Conference paper (Refereed)
    Abstract [en]

    In order to provide relevant data for calibration and development of methods for assessment ofexisting bridges, a 55 year old posttensioned concrete bridge has been subjected to non-destructiveand destructive tests. The bridge, located in Kiruna, Sweden, was a 121 m long girder bridgecontinuous in five spans. The test programme included failure loading of the girders and slab,respectively, condition assessment of the post-tensioned cables and material tests. Moreover, twostrengthening systems, using carbon fibre reinforcing polymer (CFRP), were evaluated. In this paperthe experimental programme and some preliminary results are presented to give an insight to researchproject.

  • 43.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    O'Connor, Alan
    Department of Civil, Structural and Environmental Engineering, Trinity College Dublin.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Pedersen, Claus
    Department of Bridges, Rambøll Danmark A/S.
    Moment redistribution in RC beams: A study of the influence of longitudinal and transverse reinforcement ratios and concrete strength2014In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 80, 11-23 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, the results from an experimental programme, aimed at investigating moment redistribution in statically indeterminate reinforced concrete structures, are presented and compared with theoretical analysis of the structural behaviour. Due to the nonlinear structural behaviour of reinforced concrete structures, linear elastic analysis can lead to an inaccurate assessment of the behaviour and, therefore, it can become necessary to use more advanced methodologies to achieve sufficiently accurate analysis. Furthermore, more advanced methods can enable a higher degree of performance optimisation of structures than those resulting from the simplified approaches adopted by existing design codes based on linear elastic analysis with redistribution of internal forces. In order to assess the load-carrying capacity at the ultimate limit state (ULS), a model combining plastic and nonlinear analysis is presented. The evolution of moment redistribution to structural collapse was studied experimentally for continuous two-span beams. The focus of the experiments was on the influence of the longitudinal tensile reinforcement ratio at the intermediate support, the transverse reinforcement ratio and the concrete strength. The experimental response at the ULS was further compared with the predicted distribution of internal forces according to the theoretical model. Evaluation of the experimental study indicated a highly nonlinear structural behaviour of the tested beams with the distribution of moment differing from linear elastic analysis, even for low load levels. The evolution of moment redistribution and the moment redistribution at the ULS were appreciably dependent on the arrangement of longitudinal reinforcement, whilst the transverse reinforcement ratio had a marginal impact up to yielding of the longitudinal reinforcing steel, with the concrete strength slightly reducing the degree of moment redistribution. For those beams which failed in flexure, predictions from the theoretical model presented were in good agreement with the experimental results. However, several beams collapsed in shear-related failure modes.

  • 44.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Shu, Jiangpeng
    Chalmers University of Technology.
    Plos, Mario
    Chalmers University of Technology.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Punching Capacity of a Reinforced Concrete Bridge Deck Slab Loaded to Failure2015Conference paper (Other academic)
    Abstract [en]

    Full-scale failure tests of a 55 year old prestressed concrete girder bridge have been carried out to calibrate models for assessment of existing bridges. This paper summarises the outcome from the punching test and analytical analysis according to the model stated in the Eurocode. The experimental load was approximately 2.4 times the code value using measured material properties.

  • 45.
    Bennitz, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Externally unbonded post-tensioned CFRP tendons: a system solution2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The introduction of Fibre Reinforced Polymers (FRP) to the civil engineering market in the late 1980s resulted in the emergence of a range of new tools for rehabilitating and strengthening concrete structures. Strengthening using FRPs is typically accomplished using non-prestressed externally bonded FRPs. The technical and economic benefits of such strengthening could be further increased by prestressing the FRPs, especially when dealing with concrete structures. Prestressing concrete structures suppresses the appearance and growth of cracks in the serviceability limit state. This in turn increases the structure’s stiffness and resistance to degradation. Prestressing also increases the structure’s yield load but does not change its failure load relative to that of an analogous non-prestressed structure, provided that all other parameters are kept constant. In 2004, a pilot study was carried out at the Luleå University of Technology (LTU) to investigate the scope for using unbonded Carbon Fibre Reinforced Polymer (CFRP) strengthening systems, particularly those involving prestressing. In the early stages of this project, a number of difficulties were encountered in anchoring the CFRP rods to concrete structures: the conical wedge anchorages that were used tended to either cause premature failure of the rods or allowed the rod to slip out of the anchorage. It was therefore decided to study the mechanisms at work within these anchorages in more detail. The goal of the project was to develop a small, practical, reliable, and userfriendly anchorage for use in unbonded external CFRP strengthening systems. On the basis of a thorough literature review, which is described in Paper 1, it was concluded that despite the difficulties encountered, the conical wedge anchorages used with steel reinforcing rods were the most promising starting point for the design of a new anchorage for use with CFRPs. Importantly, the conical wedge anchorage can be made small in size and easy to mount while retaining a high degree of versatility; this is not true of bonded, sleeve, and clamping anchorages. Analytical and numerical models were used to investigate the distribution of radial stress within these highly pressurized anchorages. Paper 2 describes an evaluation of the capability of three types of models - an analytical axisymmetric model based on the thick-walled-cylinder-theory and two Finite Element (FE) models, one axisymmetric and one three-dimensional - to predict the behaviour of a conical wedge anchorage. It was concluded that the axisymmetric models were incapable of modelling the stress distribution within the anchorage with sufficient accuracy, and so 3D FE models were used exclusively in subsequent studies. Paper 3 describes the development of a new anchorage for CFRP rods. The design process involved conducting pull-out studies on a series of prototypes, in conjunction with computational studies using a basic FE model, to identify and understand the prototypes’ failure modes. Between the computational data and experimental results, a good understanding of the factors affecting the interaction between the CFRP rod and the anchorage was obtained. The new anchorage design employs a one-piece wedge which effectively incorporates the three wedges and the inner sleeve from more conventional wedge anchorages into a single unit. This increases the reliability and user-friendliness of the anchorage because it eliminates the need to check the alignment of individual wedges. The new design has been patented; the published Swedish patent is included in the thesis as Paper 6. The newly-developed anchorage was then incorporated into a prestressing system and its performance was evaluated using a series of test beams. In parallel with the planning of these tests, a series of pull-out tests was conducted using the new anchorage. The strain measurements obtained in these experiments were compared to predictions made using a new, more advanced FE model, and used to refine the design of the new anchorage. Paper 4 describes this new FE model, the most important parameters affecting anchorage behaviour, and the final anchorage design. Paper 5 focuses on the possibilities provided by the new anchorage. Tests were performed using seven three meter long concrete beams prestressed with external unbonded CFRP tendons. One beam was unstrengthened; the other six were strengthened in different ways, with different prestressing forces, initial tendon depths, and with or without the use of a midspan deviator for the tendons. The results of these tests were compared to those obtained using otherwise identical beams prestressed with steel tendons and to the predictions of an analytical beam model developed for use with steel tendons. These tests showed that the prestressing works as intended and that the behaviour of beams prestressed with external unbonded CFRP tendons is fully comparable to that of beams prestressed with steel tendons. It was also found that the predictions of the analytical model were in good agreement with experimental observations, although there were some differences between the measured and predicted tendon stresses. The development of a functional anchorage represents a fulfilment of the objectives laid out at the start of this project, and represents an important step towards the practical use of prestressed unbonded external CFRP tendons in strengthening concrete structures. However, a number of outstanding questions remain to be addressed. Little is known about the safety of this kind of system, and the benefits of using CFRP tendons should be quantified. Furthermore, there are a number of potential technical issues that must be addressed. These include the risk of creep-rupture in the CFRP, the effects of thermal contraction and expansion on the anchorage, and the scalability of the anchorage as the tendon diameter is increased. Finally, the long-term behaviour of the anchorage and prestressing system should be investigated.

  • 46.
    Bennitz, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Mechanical anchorage of prestressed CFRP tendons: theory and tests2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fibre Reinforced Polymers (FRPs) are slowly becoming important materials to consider also for a structural engineer. They are light-weight, insensitive to corrosion and have highly modifiable mechanical properties. Strengths five times higher than that of ordinary reinforcing steel are common and that combined with the possibility to vary the modulus of elasticity makes them suitable to use in combination with concrete. Carbon fibre based polymers (CFRPs) especially serve as an excellent substitute for steel in the rehabilitation of structures. A case study on that subject is presented in this thesis while the focus lies on the use of CFRP as a material for use in prestressing tendons, and to be more precise, on the anchorage of prestressed CFRP tendons. FRPs orthotropic properties highly influence their behaviour in different directions. The best properties are reached through tension in the fibre direction, and as such CFRP is as good for prestressing tendons as any prestressing steel. It is also not sensitive to corrosion and easy to work with due to its light weight. Mechanical properties in the transverse direction are however not that advantageous and early attempts to anchor CFRP bars by traditional mechanical prestressing anchorages have consistently failed. A thorough program for the development of a successful anchorage has therefore been undertaken. In a first step a literature review was conducted to investigate CFRPs possibilities to replace steel in prestressing applications, internally and externally, as well as traditional anchorage techniques for steel tendons. From the literature study it was concluded that CFRP may very well serve as tendons but some doubts also arose concerning the environmental effect on the CFRPs long term behaviour and the materials ability to work under bent conditions in multispan applications. The traditional anchorages will however not work properly, all of them use mechanical grip to keep the steel stressed. This is possible through the steels capacity to yield but not suitable to anchor the brittle CFRP. A state-of-the-art survey on attempts made globally during the last 15 years to come up with a suitable frictional anchorage has also been performed. It can be seen that several ideas are discussed, often in one or two publications. One Canadian research team, Al-Mayah et al. (2001-2008), has taken the development further and focused on variations of the traditional wedge anchorage. Based on the knowledge gained from the literature it was decided to further concentrate on a conical anchorage with a barrel of steel and three smooth wedges in aluminium. Simple analytical approaches to the conical wedge anchorage with smooth interior surfaces prove the importance of the angle in the wedge-barrel interface. Also frictional behaviour in the rod-wedge and wedge-barrel interfaces proves to be important factors. Numerical studies of these and other geometrical and mechanical properties give further input into the development of a pilot anchorage to be tested in the laboratory. The optimum angle of the wedge towards the barrel seems to be between 2-3°. The thickness of the wedge should be kept as small as possible and it is favourable with high strength steel in the barrel. A small displacement of the wedges towards the unloaded end of the tendon in the design of the anchorage does also reduce the overall slip of the rod during tension. After overcoming initial problems not discovered in the analytical or numerical models the developed anchorage performed well during laboratory tests. In short term tests performed on an 8 mm thick circular rod 100 % of the rods ultimate capacity was reached. During the tests measurements of displacements and strains were performed. Fibre Optical Sensors (FOS - Bragg gratings) were for the first time included in the interior of the anchorage to give a complete picture of the load phase. These measurements were compared to a refined finite element model and show reasonable agreement. The largest source of error is assumed to be the complicated frictional behaviour in the material interfaces and the transverse material properties of the CFRP. Lastly a case study on the strengthening of a 50 year old trough bridge in Frövi is included. The bridge was successfully strengthened for bending in the transverse direction with 23 Near Surface Mounted Reinforcement (NSMR) bars in the lower part of the slab while 11 holes are drilled underneath the upper steel reinforcement to facilitate CFRP tubes with an outer diameter of 32 mm and a thickness of 4 mm. The lack of bending capacity was discovered by a consultant in 2005 and calculations with a new approach in this thesis show that the strengthening was necessary although on a minor scale. New calculations of the capacity show that the bridge's capacity after strengthening is well above the design load and measurements on site secure that the CFRP is utilized correctly as a load carrier.

  • 47.
    Bennitz, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Polymerbaserade kompositspännstag: litteratursammanställning2009Report (Other academic)
  • 48. Bennitz, Anders
    et al.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, Thomas
    Kronborg, A.
    Wahlberg, A.
    Dynamic behaviour of the Vindel River railway bridge2006In: Condition Monitoring and Diagnostic Engineering Management: COMADEM 2006: proceedings / [ed] Uday Kumar; Aditya Parida; Raj B. K. N. Rao, Luleå: Luleå tekniska universitet, 2006, 721-729 p.Conference paper (Refereed)
    Abstract [en]

    The Swedish Railway administration has launched several projects aimed at increasing the accessibility of the railway lines in northern Sweden to meet future demands. One of these lines connects the southern and northern parts of Sweden and constitutes one of the major arteries for the transportation of heavy goods. Major investment are planned to upgrade the load bearing capacity of this railway line. The work is mainly focused on the larger structures and their dynamical properties. These properties can be used to assess existing infrastructure and to evaluate the performance. Advantages are obvious since the existing structural integrity form the base for investments in structural repair and upgrade of bridges. The Vindel River Railway Bridge situated 55 kilometers northwest of Umeå came into focus when large motion was discovered during train passages. The behaviour of the bridge crossing the river of Vindeln has been measured two times. Measurements of displacements and acceleration of the bridge during train passages has been conducted, the first measurements was done to give more experience on the motion of the bridge and to try out new sensors. The second measurement gave more information about the bridge's motion, results that could be used to calibrate a 3D FE-Model of the bridge used in the study. Based on the measurements, eigenfrequencies in the range of 0 to 8 Hz could be detected, modal shapes up to the ninth order could be extracted, deflections and transverse displacements for different sets of train and different train speeds were also found. However, new measurements are planned for this summer and will hopefully reinforce the already attained result and give answers to some of the unresolved questions.

  • 49.
    Bennitz, Anders
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Grip, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Schmidt, Jacob W.
    Technical University of Denmark.
    Thick-walled cylinder theory applied on a conical wedge anchorage2011In: Meccanica (Milano. Print), ISSN 0025-6455, E-ISSN 1572-9648, Vol. 46, no 5, 959-977 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, we derive and examine an analytical model for the internal stresses and strains within the anchorage for a prescribed presetting distance. This model is derived from the theory of thick walled cylinders under the assumptions regarding plane stress and axial symmetry. We simplify the resulting system of ten nonlinear equations and derive a method for solving them numerically. A comparison of plotted results for three different angles on the wedge's outer surface and six different presetting distances follows. These results are also compared to both axi-symmetric and 3D FE (Finite Element) models. Analytical and FE axi-symmetric models show good correspondence, though compared to the 3D FE model, they show a clear difference in the predicted radial stress distribution on the FRP. Thus, the derived analytical model can be a useful and faster alternative to FE modeling of axi-symmetric anchorages. However, the model is of more restricted value and should be complemented by, for example, 3D FE models for other designs.

  • 50.
    Bennitz, Anders
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Grip, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Schmidt, Jacob W.
    Department of Civil Engineering, Technical University of Denmark.
    Thick-walled cylinder theory applied on a conical wedge anchorage: Research report with Matlab implementation documentation2010Report (Other academic)
    Abstract [en]

    Conical wedge anchorages are frequently used to anchor steel tendons in prestressing applications within the construction industry. To replace the steel tendons with non-corrosive and low weight FRPs (Fiber Reinforced Polymers), the different mechanical interactions between the steel and FRPs call for further development of the anchorage.In this paper, we derive and examine an analytical model for the internal stresses and strains within the anchorage for a prescribed presetting distance. This model is derived from the theory of thick walled cylinders under the assumptions regarding plane stress and axial symmetry. We simplify the resulting system of ten nonlinear equations and derive a method for solving them numerically. A comparison of plotted results for three different angles on the wedge's outer surface and six different presetting distances follows.These results are also compared to both axi-symmetric and 3D FE (Finite Element) models. Analytical and FE axi-symmetric models show good correspondence, though compared to the 3D FE model, they show a clear difference in the predicted radial stress distribution on the FRP. Thus, the derived analytical model can be a useful and fasteralternative to FE modeling of axi-symmetric anchorages. However, the model is of more restricted value and should be complemented by, for example, 3D FE models for other designs.

1234567 1 - 50 of 1597
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf