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  • 201.
    Collin, Peter
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Nakamura, Shunichi
    SEI Editorial Board.
    Steel Concrete Composite Structures: Introduction. Part I2009Inngår i: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 19, nr 4, s. 395-Artikkel i tidsskrift (Annet vitenskapelig)
  • 202.
    Collin, Peter
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Pétursson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Möller, Mikael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Composite bridges with prefabricated decks1998Inngår i: Proceedings / Nordic Steel Construction Conference 98: Bergen, Norway, September 14th - 16th, 1998 ; new materials, new codes, new applications, Oslo: Norwegian Steel Association , 1998Konferansepaper (Fagfellevurdert)
  • 203.
    Collin, Peter
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Pétursson, Hans
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Tornberg, Håkan
    Broar med integrerade landfästen2005Inngår i: V-byggaren : väg- och vattenbyggaren, ISSN 0283-5363, nr 3, s. 45-49Artikkel i tidsskrift (Annet vitenskapelig)
  • 204.
    Collin, Peter
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stoltz, Anders
    Luleå tekniska universitet.
    Möller, Mikael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Innovative prefabricated composite bridges2002Inngår i: IABSE symposium Melbourne 2002: towards a better built environment - innovation, sustainability, information technology; Melbourne, Australia 11 - 13 September, 2002, Zürich: International Association for Bridge and Structural Engineering, 2002Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The competitiveness of composite bridges depends on several circumstances such as site conditions, local costs of material and staff and the contractor's experience. One major advantage compared to concrete bridges is that the steel girders can carry the weight of the formwork and the wet concrete. Another advantage is the savings in construction time, which saves some money for the contractor but even more so for the road users, a fact that usually is neglected when evaluating alternative bridge designs. A further step to improve the competitiveness of composite bridges is to prefabricate not only the steel girders, but also the concrete deck. In this paper a new concept with dry joints between the elements is described.

  • 205.
    Coric, Ibrahim
    et al.
    Trafikverket.
    Täljsten, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Blanksvärd, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Skanska Sverige.
    Sas, Gabriel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Norut, Norge.
    Ohlsson, Ulf
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Railway Bridges on the Iron Ore Line in Northern Sweden– From Axle Loads of 14 to 32,5 ton2018Inngår i: IABSE Conference 2018 – Engineering the Past, to Meet the Needs of the FutureJune 25-27 2018, Copenhagen, Denmark: IABSE Reports, Vol 111, 2018, Vol. 111Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Iron Ore Railway Line was built around 1900 and has more than 100 bridges. It has a length of ca 500 km and runs from Kiruna and Malmberget in northern Sweden to the ice-free harbour in Narvik in Norway on the Atlantic and to Luleå in Sweden on the Baltic. The original axle load was 14 ton. The axle load has gradually been increased to 25 ton in 1955, to 30 ton in 1998 and to 32,5 ton in 2017.The increases in axle loads have been preceded by monitoring and assessment studies of the bridges. The capacity and need for strengthening or replacement of the bridges have been evaluated. Many of the bridges could carry a higher load than what it was designed for. Experiences from studies before the axle load was increased in 1998 and 2017 are presented and discussed.

  • 206.
    Cremona, Christian
    et al.
    Laboratoire Central des Ponts et Chaussées, Paris, France.
    Bien, Jan
    Wroclaw University of Technology, WUT, Poland.
    Feltrin, Glauco
    EMPA, Dúbendorf, Switzerland.
    Autissier, P-L
    SNCF, Paris, France.
    Instrumentation of the Avesnes Bridge: Sustainable Bridges Background document 7.22007Rapport (Fagfellevurdert)
    Abstract [en]

    This deliverable details the different instrumentations installed on the Avesnes/Helpe bridge between 2005 and 2007 in France for recording its structural response and its loading conditions during a two-days monitoring campaign (June 2005), for performing dynamic assessments (March 2006) and for detecting damages (June 2006-March 2007). The first series of tests were performed when the bridge was still operated by the French railways SNCF. In august 2005, the bridge was removed from operating conditions and conserved for research and demonstration purposes within the "Sustainable Bridges" project. This deliverable is dedicated to provide information and data for research actions regarding:

    - Condition Assessment

    - Structural assessment

    - Monitoring

  • 207.
    Cremona, Christian
    et al.
    Technical Department for Transport, Roads, Bridges and road Safety Bagneux Cedex.
    Eichler, Bjorn
    Johansson, Bernt
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Larsson, Tobias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Improved assessment methods for static and fatigue resistance of old metallic railway bridges2013Inngår i: Journal of Bridge Engineering, ISSN 1084-0702, E-ISSN 1943-5592, Vol. 18, nr 11, s. 1164-1173Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large number of the bridges in the European railway networks are metallic bridges. The increasing volume of traffic and axle weight of trains mean that for many structures the loads today are much higher than those envisaged when they were designed. This paper presents a summary of the different recommendations and advices proposed in "Guidelines for Load and Resistance Assessment of Existing European Railway Bridges" of the European Union founded project "Sustainable bridges" for assessing old metal railway bridges. The knowledge of the material properties of existing metal bridges is essential for the resistance assessment and the determination of the remaining lifetime of old metallic bridges. Furthermore, old bridges require more exact and efficient assessment methods that call for a precise description of the material. Among the problems met in metal bridges and material properties estimation, fatigue is the most common cause of failure. To be able to make accurate assessments of existing bridges, it is important to know the behaviour of bridges exposed to fatigue, and how the old materials behave due to cyclic exposure. The main question answered herein is how to make a safe estimation concerning the remaining life in service. The possible traffic load on steel rail bridges is usually limited by the fatigue resistance, but for certain situations the static resistance has also to be checked. Most design rules for steel structures, for instance those in Eurocode 3, are applicable also to riveted structures. However, some information is missing on how to deal with the special case that elements are intermittently connected in contrast welded structures that are connected continuously. As the traditional methods for assessing the resistance of steel bridges are based on elastic analysis, a method for utilizing a limited redistribution of bending moments based on beam theory is proposed.

  • 208.
    Cremona, Christian
    et al.
    Laboratoire Central des Ponts et Chaussées, Paris, France.
    Patron, A
    LCPC, Paris, France.
    Johansson, Bernt
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Luleå University of Technology, Sweden.
    Larsson, Tobias
    Luleå University of Technology, Sweden.
    Eichler, B
    RWTH, Aachen, Germany.
    Höhler, S
    RWTH, Aachen, Germany.
    Kühn, B
    PSP, Aachen, Germany.
    Improved Assessment Methods for Static and Fatigue Resistance of Old Steel Railway Bridges: Sustainable Bridges Background document D4.62007Rapport (Fagfellevurdert)
    Abstract [en]

    The report is divided into four parts related to the four research activities of the WP4 metal subgroup:

    – Analysis of material properties of existing metal railway bridges,

    – Fatigue of riveted structure,

    – Updated assessment methods for riveted structures,

    – Enhanced non destructive techniques for inspecting riveted structures.

  • 209.
    Cruz, Paulo J. S.
    et al.
    UMinho, Guimaraes, Potugal.
    de León, Abraham Diaz
    UMinho, Guimaraes, Potugal.
    Crack sensor with embedded optical fibre: Sustainable Bridges. Background document 5.32007Rapport (Fagfellevurdert)
    Abstract [en]

    This document reports the development of a distributed optical fibre crack sensor. This sensor can be employed for detection of cracks and measurement of crack widths in concrete structures. The basic principle of operation for the crack sensor is based on intensity variation of the optical power within the optical fibre due to the initiation and opening of cracks.

    The present report summarizes the improvements introduced in the sensor to make it appropriate for crack monitoring in bridges, performed by researchers of the University of Minho, in Portugal. The primary objectives of the work were:

    1) To select the proper polymeric material for making the plate;

    2) To optimize the manufacture process;

    3) To assure the bonding between the plate sensor and concrete members;

    4) To determine the corresponding calibration curves of intensity losses versus the crack aperture;

    5) The application of the plate sensor to the monitoring of single crack RC beams and masonry slabs and the monitoring of multiple cracks on RC beams;

    6) The field implementation of the plate sensor.

    The field implementation of the plate sensor in the destructive test carried out in the ÖvikBridge, in the north of Sweden, is also included. The main purpose of this test was to demonstratethe capability of the sensor plate to detect cracks and measure the crack opening in concrete railway bridges. This report provides the description of the bridge and gives an overview of the procedures for wiring and installing the sensor plate.

  • 210.
    Cwirzen, A.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    The effect of the heat-treatment regime on the properties of reactive powder concrete2007Inngår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 19, nr 1, s. 25-33Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of the curing regime on the mechanical properties and microstructure of ultra-high-strength mortar was studied. Nine different curing procedures were applied in which the start and duration of the heat treatment were varied. The studied mortars had a water-to-binder ratio of 0·17 and additions of amorphous silica fume and fine quartz filler. The microstructure and microchemistry were investigated by electron scanning microscopy and mercury intrusion porosimetry. The results revealed that longer heating times increased the degree of hydration, refined the microstructure and resulted in higher ultimate compressive strength, Very late and very early application of the heat treatment caused a lower degree of hydration and a smaller long-term increase of compressive strength. The scanning electron microscopy investigation revealed the formation of one hydration rim around anhydrous cement particles and the presence of a hollow shell in all investigated specimens. © 2007 Thomas Telford Ltd.

  • 211.
    Cwirzen, A.
    et al.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Habermehl-Cwirzen, K.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Nasibulin, A. G.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Kaupinen, E. I.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Mudimela, P. R.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Penttala, V.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    SEM/AFM studies of cementitious binder modified by MWCNT and nano-sized Fe needles2009Inngår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 60, nr 7, s. 735-740Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several compositions of cement paste samples containing multiwalled carbon nanotubes were produced using a small-size vacuum mixer. The mixes had water-to-binder ratios of 0.25 and 0.3. Sulfate resistant cement has been used. The multiwalled carbon nanotubes were introduced as a water suspension with added surfactant admixtures. The used surfactant acted as plasticizing agents for the cement paste and as dispersant for the multiwalled carbon nanotubes. A set of beams was produced to determine the compressive and flexural strengths. The scanning electron microscope and atomic force microscope studies of fractured and polished samples showed a good dispersion of multiwalled carbon nanotubes in the cement matrix. The studies revealed also sliding of multiwalled carbon nanotubes from the matrix in tension which indicates their weak bond with cement matrix. In addition to multiwalled carbon nanotubes also steel wires covered with ferrite needles were investigated to determine the bond strength between the matrix and the steel wire. These later samples consisted of 15-mm-high cylinders of cement paste with vertically cast-in steel wires. As reference, plain steel wires were cast, too. The bond strength between steel wires covered with nano-sized Fe needles appeared to be lower in comparison with the reference wires. The scanning electron microscope studies of fractured samples indicated on brittle nature of Fe needles resulting in shear-caused breakage of the bond to the matrix. © 2008 Elsevier Inc. All rights reserved.

  • 212.
    Cwirzen, A.
    et al.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Habermehl-Cwirzen, K.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Penttala, V.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Surface decoration of carbon nanotubes and mechanical properties of cement/carbon nanotube composites2008Inngår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 20, nr 2, s. 65-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present study investigated the effects of the method of surface decoration on the wetability of multi-walled carbon nanotubes (MWCNTs) and the mechanical properties of the cement paste incorporating these dispersions. The results showed that stable and homogenous dispersions of MWCNTs in water can be obtained by using surface functionalisation combined with decoration using polyacrylic acid polymers. The cement paste specimens incorporating these dispersions revealed good workability and an increase in the compressive strength of nearly 50% even with only a small addition of the MWCNTs, namely 0-045-0-15% of the cement weight. These results indicate the existence of chemical bonds between the OH groups of the functionalised MWCNTs and probably the C-S-H phase of the cement matrix, which enhanced the transfer of stresses. A second method that was studied included decoration of MWCNTs with polyacrylic acid polymers and gum Arabic. These dispersions appeared to be homogeneous only for approximately 2 h after which a progressive sedimentation occurred. Good workability was found for the cement pastes produced with all of the dispersions; the only significant difference being the slower hydration of the cement incorporating gum Arabic. The mechanical properties of the cement pastes incorporating MWCNTs treated with polyacrylic polymers were unchanged.

  • 213.
    Cwirzen, A.
    et al.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Habermehl-Cwirzen, K.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Shandakov, D.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Nasibulina, L. I.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Nasibulin, A. G.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Mudimela, P. R.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Kauppinen, E. I.
    Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Penttala, V.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Properties of high yield synthesised carbon nano fibres/portland cement composite2009Inngår i: Advances in Cement Research, ISSN 0951-7197, E-ISSN 1751-7605, Vol. 21, nr 4, s. 141-146Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The compressive strength and electrical resistivity of hardened pastes produced either from nanomodified Portland sulfate-resistant cement (CHH) or a mixture of nanomodified and pristine sulfate-resistant cements were determined. The nanomodification included grow carbon nanotubes (CNTs) and carbon nanofibres (CNFs) on the cement particles. Pastes having a water-to-binder ratio of 0-5 were produced. The test results revealed that partial replacement of sulfate-resistant cement by CHH cement decreased the electrical resistivity of the 28 day old specimens but worsened the mechanical properties. The lower compressive strength was attributed to a lower degree of hydration of the CHH cement. The addition of a mixture of surfactants enabled the production of specimens consisting entirely of CHH cement. The hardened material obtained was characterised by a nearly doubled compressive strength in comparison with the reference specimens made from pristine sulfate-resistant cement. This was attributed to a high degree of hydration as well as reinforcing action of the CNTs and CNFs. The electrical resistivity was lowered by one order of magnitude classifying this material as a semiconductor.

  • 214.
    Cwirzen, A.
    et al.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Penttala, V.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Vornanen, C.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Reactive powder based concretes: Mechanical properties, durability and hybrid use with OPC2008Inngår i: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 38, nr 10, s. 1217-1226Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The basic mechanical properties, frost durability and the bond strength with normal strength concretes of the ultra high strength (UHS) mortars and concretes were studied. The produced mixes had plastic or fluid-like consistency. The 28-day compressive strength varied between 170 and 202 MPa for the heat-treated specimens and between 130 and 150 MPa for the non-heat-treated specimens. The shrinkage values were two times higher for the UHS mortars in comparison with the UHS concretes. After the initial shrinkage, swelling was noticed in the UHS mortars. The lowest creep values were measured for the non-heat-treated UHS concretes. The frost-deicing salts durability of the UHS mortars and concretes appeared to be very good even despite the increased water uptake of the UHS concretes. The study of the hybrid concrete beams indicated the formation of low strength transition zone between the UHS mortar and normal strength concrete. © 2008 Elsevier Ltd. All rights reserved.

  • 215.
    Cwirzen, Andrzej
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Controlling physical properties of cementitious matrixes by nanomaterials p12010Inngår i: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 123-125, s. 639-642Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The majority of concrete used nowadays is based on matrixes formed by hydrating Portland cement. Latest developments in nanosciences introduced a new generation of nano-sized materials possessing often remarkable mechanical and physical properties. These materials can be also used to improve or alter the characteristics of the binder matrixes based on Portland cement. The results showed that mechanical properties such as compressive and flexural strength can be increased by up to 50% by addition of for example 0.23wt% of carbon nanotubes. Carbon nanotubes and carbon nanofibres and/or nanosilica appeared to improve also the frost resistance. Other properties, such as autogenous shrinkage decreased significantly after addition of carbon nanofibres. Nanosilica enabled an immense densification of the hydrated binder matrix, which in turn improved for instance the durability and mechanical properties. © (2010) Trans Tech Publications.

  • 216.
    Cwirzen, Andrzej
    et al.
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Engblom, Ronny
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Punkki, Jouni
    Consolis Technology Oy.
    Habermehl-Cwirzen, Karin
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Effects of curing: Comparison of optimised alkali-activated PC-FA-BFS and PC concretes2014Inngår i: Magazine of Concrete Research, ISSN 0024-9831, E-ISSN 1751-763X, Vol. 66, nr 6, s. 315-323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of curing on the mechanical properties, chemical composition, microstructure and shrinkage of optimised alkali-activated concretes (AACs) based on ternary mixtures of fly ash (FA), blast-furnace slag (BFS) and Portland cement (PC) were compared. Heat treatment was found to accelerate the early-age strength development of both the PC concrete and the AAC. The long-term strength of AAC was not adversely affected by the heat treatment after 90 d of dry curing. Water curing slightly enhanced the ultimate long-term strength of non-heat-treated AAC specimens but had barely any effect on the heat-treated specimens. Conversely, the dry-cured PC specimens showed a significant decrease in long-term compressive strength. The ultimate drying shrinkage of the PC concrete was lower compared with the AAC, independent of the type of applied curing. In the case of AAC, the drying shrinkage was significantly decreased by the application of heat treatment while water curing did not have any measurable effect. Conversely, the drying shrinkage of AAC cured at ambient temperatures was decreased with the application of water curing. Compared with the PC concrete, the microstructure of the AAC samples was denser and more homogeneous without visible microcracking of the binder matrix. The dominant phases were geopolymer and calcium silicate hydrate (C-S-H) gels intermixed with probably sodium and aluminium ions and crystalline inclusions of zeolitic hydroxysodalite. A large amount of unreacted FA and BFS was observed in the hardened binder matrix of the AAC specimens. At the same time, no anhydrous PC was observed, thus indicating its extensive dissolution and contribution to the formation of the modified C-S-H gel.

  • 217.
    Cwirzen, Andrzej
    et al.
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Habermehl-Cwirzen, Karin
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Effects of reactive magnesia on microstructure and frost durability of portland cement-based binders2013Inngår i: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 25, nr 12, s. 1941-1950Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of portland cement (PC) replacement with magnesia (reactive magnesium-oxide) on properties of PC-based pastes, mortars, and concretes were investigated. The research included determination of mechanical properties and frost durability in addition to studies of the microstructure and microchemistry. The mortar and paste mixtures contained from 10-80 weight percent (wt%) replacement of PC by magnesia and had water to cementitious-binder ratios from 0.4-0.7, whereas concretes contained from 5-10 wt% magnesia and had a water to cementitious-binder ratio of 0.53. Replacement of PC by magnesia had adverse effects on the mechanical properties and frost durability. The magnesia reduced microcracking of the binder matrix in comparison with pastes containing only PC. The primary hydration product of magnesia was brucite in addition to regular hydration phases of PC. The amount of formed portlandite was increased. Magnesia caused densification of the microstructure but also increased the capillary porosity, resulting in lower frost-durability. © 2013 American Society of Civil Engineers.

  • 218.
    Cwirzen, Andrzej
    et al.
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Habermehl-Cwirzen, Karin
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Enhancement of Frost Durability by Application of Nanomaterials2010Inngår i: Additions improving properties of concrete: AdIPoC / [ed] Wolfgang Brameshuber, Bagneux: Rilem publications, 2010, s. 307-313Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The effect of carbon nanotubes (CNT), carbon nanofibers (CNF) and nano-sized silica (NS) on the frost durability of mortars was investigated. The test specimens were produced using Portland cement as binder and water to binder ratios of 0.5 and 0.33. CNT and CNF were added as water dispersion with superplasticizers. The NS was intermixed with micro silica and added as slurry. The frost durability was determined by a modified CIF method. The results showed that in the case of addition of nano-sized fibers a positive effect can be only found if the binder matrix is homogenous and dense. The combination of CNTs and NS resulted in the lack of any frost damage even after 180 freeze-thaw cycles.

  • 219.
    Cwirzen, Andrzej
    et al.
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Habermehl-Cwirzen, Karin
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    The effect of carbon nano- and microfibers on strength and residual cumulative strain of mortars subjected to freeze-thaw cycles2013Inngår i: Journal of Advanced Concrete Technology, ISSN 1346-8014, Vol. 11, nr 3, s. 80-88Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The strength and development of residual strain of normal strength mortars subjected to freeze-thaw cycles incorporating carbon nanotubes (CNTs) and carbon microfibers (CMF) were studied. The workability was influenced by the fiber type, the dispersion method, and the amount of fibers. The obtained results showed that the measured flexural strength increased only in the case of mortars incorporating CMFs. The compressive strength remained unchanged in the case of mortars containing CMFs and was slightly lower when CNTs were present. The residual strain due to freeze-thaw cycles was lowered in comparison with reference mortar only when incorporating CMFs. The obtained results confirmed that in order to utilize the outstanding mechanical properties of CNTs the binder matrix must be very homogenous to provide sufficient contact area for stress transfer. The used water to binder ratio was sufficiently low only for long CMFs, which were able to bridge numerous weak inclusions present on the binder matrix. © 2013 Japan Concrete Institute.

  • 220.
    Cwirzen, Andrzej
    et al.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Habermehl-Cwirzen, Karin
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Nasibulina, Larisa I.
    Department of Applied Physics, Aalto University, Department of Applied Physics and Center for New Materials, Laboratory of Physics, NanoMaterials Group, Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Shandakov, Sergey D.
    Department of Applied Physics and Center for New Materials, Aalto University, Laboratory of Carbon NanoMaterials, Kemerovo State University, Department of Applied Physics, NanoMaterials Group, Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Nasibulin, Albert G.
    Department of Applied Physics, Aalto University, Department of Applied Physics and Center for New Materials, Centre for New Materials, Laboratory of Physics, NanoMaterials Group, Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Kauppinen, Esko I.
    Department of Applied Physics, Aalto University, VTT Biotechnology, Laboratory of Physics, NanoMaterials Group, Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Mudimela, Prasantha R.
    Department of Applied Physics and Center for New Materials, Aalto University, Centre for New Materials, Department of Applied Physics, Laboratory of Physics, NanoMaterials Group, Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    Penttala, Vesa
    Department of Civil and Structural Engineering, Aalto University, Department of Structural Engineering, Laboratory of Building Materials Technology, Laboratory of Building Materials, NanoMaterials Group, Department of Applied Physics and Center for New Materials, Helsinki University of Technology, Espoo.
    CHH Cement Composite2009Inngår i: Nanotechnology in Construction 3: Proceedings of the NICOM3 / [ed] Zdeněk Bittnar ; Peter J.M. Bartos; Jiří Němeček; Vit Šmilauer; Jan Zeman, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2009, s. 181-185Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The compressive strength and electrical resistivity for hardened pastes produced from nanomodified Portland SR cement (CHH- Carbon Hedge Hog cement) were studied. The nanomodification included growing of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on the cement particles. Pastes having water to binder ratio of 0.5 were produced. The obtained hardened material was characterized by increased compressive strength in comparison with the reference specimens made from pristine SR cement, which was attributed to reinforcing action of the CNTs and CNFs. The electrical resistivity of CHH composite was lower by one order of magnitude in comparison with reference Portland cement paste

  • 221.
    Cwirzen, Andrzej
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Metsäpelto, Lari
    MSc, YIT Infra Oy, Helsinki, Finland.
    Habermehl-Cwirzen, Karin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Interaction of Magnesia with Limestone-Metakaolin-Calcium Hydroxide Ternary Alkali-Activated Systems2018Inngår i: Advances in Materials Science and Engineering, ISSN 1687-8434, E-ISSN 1687-8442, Vol. 2018, artikkel-id 1249615Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of magnesia on ternary systems composed of limestone, metakaolin and calcium hydroxide, alkali activated with sodium silicate, sodium hydroxide, and sodium sulphate was studied by determination of the compressive strength, X-ray powder diffraction (XRD), thermogravimetry (TG), and scanning electron microscope (SEM). Pastes activated with sodium silicate and sodium sulphate showed strength regression caused by a formation of an unstable prone to cracking geopolymer gel. The presence of magnesia in sodium hydroxide-activated system hindered this trend by promoting a formation of more stable crystalline phases intermixed with brucide. In general, magnesia densified the binder matrix by promoting a formation of amorphous phases while sodium hydroxide produced the most porous microstructure containing high amount of crystalline phases.

  • 222.
    Cwirzen, Andrzej
    et al.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Penttala, Vesa
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Aggregate-cement paste transition zone properties affecting the salt-frost damage of high-performance concretes2005Inngår i: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 35, nr 4, s. 671-679Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of the cement paste-aggregate interfacial transition zone (ITZ) on the frost durability of high-performance silica fume concrete (HPSFC) has been studied. Investigation was carried out on eight non-air-entrained concretes having water-to-binder (W/B) ratios of 0.3, 0.35 and 0.42 and different additions of condensed silica fume. Studies on the microstructure and composition of the cement paste have been made by means of environmental scanning electron microscope (ESEM)-BSE, ESEM-EDX and mercury intrusion porosimetry (MIP) analysis. The results showed that the transition zone initiates and accelerates damaging mechanisms by enhancing movement of the pore solution within the concrete during freezing and thawing cycles. Cracks filled with ettringite were primarily formed in the ITZ. The test concretes having good frost-deicing salt durability featured a narrow transition zone and a decreased Ca/Si atomic ratio in the transition zone compared to the bulk cement paste. Moderate additions of silica fume seemed to densify the microstructure of the ITZ. © 2004 Elsevier Ltd. All rights reserved.

  • 223.
    Cwirzen, Andrzej
    et al.
    Laboratory of Building Materials Technology, Faculty of Engineering and Architecture, Helsinki University of Technology, Espoo.
    Penttala, Vesa
    Department of Civil and Structural Engineering, Aalto University, Department of Structural Engineering, Laboratory of Building Materials Technology, Laboratory of Building Materials.
    Vornanen, C.
    Aalto University.
    RPC mix optimization by determination of the minimum water requirement of binary and polydisperse mixtures2005Inngår i: ISISS 2005: Innovation & Sustainability of Structures / [ed] Z. Lu; A. Li; Z. Wu; S. Meng, 2005, Vol. 1-3, s. 2191-2201Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Reactive powder concrete (RPC) is an ultra high performance material which development was strongly associated with the maximization of the packing density. This paper presents an alternative approach for the optimization of the mix design of RPC by using the determination of the water demand of binary, ternary and polydisperse mixes. Measurements of the water demand of quartz/sand and quartz/sand/cement/silica fume mixes were performed. The control mixes-having water to binder ratio of 0.187, 25% of silica fume and 5% of superplasticizer measured from cement content-were produced for the assessment of fresh concrete properties and compressive strength. The concretes were heat-treated at 90 degrees C. The results showed that maximum compressive strength was obtained in concretes having binary quartz/sand mixes characterized by the highest packing density. The best rheorogical properties were obtained in mixes, which had the highest packing density when measured on polydisperse mixes containing all RPC components.

  • 224.
    Cwirzen, Andrzej
    et al.
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Provis, John L.
    Department of Chemical & Biomolecular Engineering, University of Melbourne.
    Penttala, Vesa
    Department of Civil and Structural Engineering, Aalto University.
    Habermehl-Cwirzen, Karin
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    The effect of limestone on sodium hydroxide-activated metakaolin-based geopolymers2014Inngår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 66, s. 53-62Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Blends of metakaolin and limestone can be alkali-activated with NaOH to form solid binders, which show relatively low strength but offer potential as a model system by which the reaction processes of more complex systems can be better understood. The effects of curing procedure, limestone content and alkalinity of the activator are able to be related to the mineralogy, mechanical properties and microstructure of hardened pastes. The presence of limestone enhances the release of Al and Si ions from metakaolin, with the Al released in the early stages of the reaction being bound into AFm-type phases. Dissolution of LS is slightly higher when a lower alkalinity sodium hydroxide activator is used. The heat treatment of pastes activated with 3 M NaOH solution resulted in a lower extent of reaction of limestone, while with 5 M solution, heat-curing at early age resulted in more reaction. The main alkali-activation product in metakaolin-limestone-NaOH pastes is a geopolymer gel with inclusions of unreacted metakaolin, limestone particles, zeolite A, and AFm phases, with different zeolites such as faujasite-like and hydrosodalite phases also identified at higher reaction temperatures. © 2014 Elsevier Ltd. All rights reserved.

  • 225.
    Cwirzen, Andrzej
    et al.
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Sztermen, P.
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Habermehl-Cwirzen, Karin
    Department of Civil and Structural Engineering, Aalto University, School of Engineering, Espoo.
    Effect of baltic seawater and binder type on frost durability of concrete2014Inngår i: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 26, nr 2, s. 275-282Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of Baltic seawater on frost durability of PC concretes using sulfate resistant portland cement and combination of rapid hardening portland cement with silica fume were studied. The freeze-thaw cycles were performed on specimens exposed to the Baltic seawater, 3% sodium chloride solution and deionized water. The freeze-thaw cycles appeared to cause the most extensive internal damage in specimens based on sulfate resistant cement (SR) and exposed to seawater. The most extensive surface scaling was observed in the case of concretes containing silica fume and exposed to deicing salts. Based on the thermo gravimetric and X-ray diffraction analyses it was concluded that extensive internal damage of concrete based on SR was caused by changes of the microstructure due to secondary formation of ettringite, carbonation, and formation of calcite. The results showed also that low C3A content of the SR did not fully mitigate formation of secondary ettringite during freeze-thaw cycles. A combination of rapid hardening portland cement and silica fume appeared to form more frost resistant concrete when exposed to seawater. © 2014 American Society of Civil Engineers.

  • 226.
    Czmoch, Ireneusz
    Luleå tekniska universitet.
    Influence of structural timber variability on reliability and damage tolerance of timber beams1998Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The thesis addresses two main problems: 1) Probablistic modelling of lengthwise variability in structural timber, 2) Reliability and damage tolerance analysis of beams made of structural timber. Timber is considered as an elastic-brittle material. Dependence of timber properties on time and environment conditions is neglected. The presented statistical analysis of MOE is based on experimental data. An original method for determination of the MOE function on the basis of a measured deflection curve has been developed. The Log-normal, Gumbel or Normal distributions can be recommended as the probability distribution model of the homogeneous random field of MOE with the scale of fluctuation equal to 1.5-2.5 m. The variability of bending strength of timber beams has been studied with help of a weak-zone model. Assuming a marked Poisson random field as a probabilistic model of bending strength, analytical solutions have been derived for a number of particular problems. The influence of the correlation between strengths of weak zones has been studied with help of the Monte Carlo simulation. Time invariant reliability indices and damage tolerance indices have been computed for the weak-zone model and the corresponding homogeneous modelof a timber beam. The difference in reliability indices between the homogeneous and weak-zone models depends more on the probability model of the weak-zone strength than on the mean distance between the weak zones. There is no significant difference in the damage tolerance indices computed for the two considered models of a timber beam.

  • 227.
    Daerga, Per-Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Low cyclic fatigue tests on concrete in tension1993Inngår i: Proceedings: Nordic Concrete Research Meeting : Göteborg 1993, Oslo: Norsk Betongforening , 1993, s. 177-Konferansepaper (Fagfellevurdert)
  • 228.
    Daerga, Per-Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Properties of hardened concrete at low temperatures: a literature reveiw1988Rapport (Annet vitenskapelig)
  • 229.
    Daerga, Per-Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Some experimental fracture mechanics studies in mode I of concrete and wood1992Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 230.
    Daerga, Per-Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Tensile properties of a high performande concrete1992Inngår i: Proceedings of the First International Conference on Fracture Mechnics of Concrete Structures / [ed] Z P Bazant, Amsterdam: Elsevier, 1992, s. 465-469Konferansepaper (Fagfellevurdert)
  • 231.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Bernander, Stig
    Emborg, Mats
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Egenspänningar i undervattensgjutna bottenplattor: inverkan av temperaturförlopp under hydratationen1986Rapport (Annet vitenskapelig)
  • 232.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Draghållfasthet hos högpresterande betong1991Inngår i: Bygg & Teknik, ISSN 0281-658X, nr 7, s. 25-26, 28Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 233.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Ohlsson, Ulf
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Behaviour of concrete at low temperatures1989Inngår i: POAC '89: 10th International conference on port and ocean engineering under arctic conditions / [ed] Kenneth B.E. Axelsson; Lennart Å. Fransson, Luleå: Luleå tekniska universitet, 1989, Vol. 2, s. 808-819Konferansepaper (Annet vitenskapelig)
  • 234.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Pettersson, Maria
    Luleå tekniska universitet.
    Pöntinen, David
    Fracture properties in tension of a high-performance concrete1993Inngår i: Utilization of High Strength Concrete : Proceedings: Symposium in Lillehammer, Norway / [ed] Ivar Holand, Oslo: Norsk Betongforening , 1993, s. 1193-1200Konferansepaper (Fagfellevurdert)
  • 235.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Pöntinen, David
    A fatigue criterion for concrete based on deformation1993Rapport (Annet vitenskapelig)
    Abstract [en]

    A hypothesis is presented for fatigue failure of concrete structures. It is based on a deformation formulation, and utilizes the monotonic F - delta curve and the fatigue creep curve. The hypothesis is applied to flexural fatigue tests on notched beams of a plain high performance concrete. The experimental part comprises monotonic loading in deformation control and constant amplitude loading at three different load levels in flexural tension. The hypothesis is in all essentials consistent with the experimental findings. Furthermore, it provides a deformation formulation for accumulated damage estimation and remaining service life prediction, which takes account for the nonlinear nature of damage development in contrast to the linear Palmgren-Miner hypothesis

  • 236.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stephansson, Ove
    Luleå tekniska universitet.
    Sagefors, I.
    Boliden Wp.
    Funnel Store: new concept for large rock caverns1987Inngår i: Large rock caverns: proceedings of the International Symposium, Helsinki, Finland, 25-28 August 1986. / [ed] K.H.O. Saari, Oxford: Pergamon Press, 1987, Vol. 1, s. 479-488Konferansepaper (Fagfellevurdert)
  • 237.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sundquist, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Material testing with Regula: demonstration and verification1991Rapport (Annet vitenskapelig)
  • 238. Danielsson, Georg
    et al.
    Johansson, Håkan
    Thun, Håkan
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Töjningsmätning på järnvägsbro över Luossajokk i Kiruna2002Rapport (Annet vitenskapelig)
  • 239.
    Demeter, Istvan
    et al.
    Politechnica University of Timisoara.
    Nagy-György, Tamas
    Politechnica University of Timisoara.
    Stoian, Valeriu
    Politechnica University of Timisoara.
    Daescu, Cosmin
    Politechnica University of Timisoara.
    Sas, Gabriel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Carolin, Anders
    Seismic retrofit of precast RC wall panels with cut-out openings using FRP composites2009Inngår i: The 9th International Symposium on Fiber-Reinforced Polymer Reinforcement for Concrete Structures (FRPRCS-9) / [ed] D. J. Oehlers; M.C. Griffith; R. Seracino, Adeleide: University of Adelaide , 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The present study was conceived in order to investigate the shear behaviour of the Precast Reinforced Concrete Wall Panels (PRCWP) with cut-out openings subjected to in-plane seismic loading conditions and to assess the shear capacity gain obtained using Fiber Reinforced Polymer (FRP) composites as retrofit solution. The structural system of Precast Reinforced Concrete Large Panels (PRCLP) was extensively used in Romania, from 1950 to 1990, for housing buildings with 5 and 9 stories. Cut-out openings are often required to facilitate direct access from outside or between adjacent apartments, predominantly at the ground floor, where both gravity and seismic capacity demand is maximum. However, cut-out openings performed in structural walls results in the modification of the internal force flow paths, loss of load bearing capacity and reduced structural safety. Similar experimental researches are scarce in the literature. The earthquake resisting behaviour of Reinforced Concrete (RC) structural walls with openings, strengthened by Carbon FRP (CFRP) sheets and grids, was investigated in the post-damage repair and strengthening case. The shear and flexural strengthening effect of differently oriented CFRP sheets was examined on cantilever type RC shear walls in both prior-to-damage and post-damage situations. Experimental research was performed on high slenderness RC walls with door openings distributed on four height levels, strengthened with CFRP sheets.

  • 240.
    Dempsey, John P.
    et al.
    Clarkson University, Potsdam, NY.
    Jochmann, Peter
    Hamburg Ship Model Basin.
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Mu, Z.
    MMI Engineering, Houston, TX..
    Weiss, Jerome
    CNRS, LGGE, Saint-Martin d'Hères.
    Palmer, A.C.
    National University of Singapore.
    Cleavage fracture of warm brackish ice2013Inngår i: Proceedings of the International Conference on Port and Ocean Engineering under Arctic Conditions: June 9-13, 2013 Espoo, Finland, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Two sets of cleavage (cracking parallel to the ice surface) fracture toughness tests were conducted at the Hamburg Ship Model Basin (HSVA) on brackish ice harvested from two separate locations in the Gulf of Bothnia. The ice was split using a pin-loaded compact tension geometry. The fracture tests were accompanied by tensile and compressive tests. This paper discusses the experiments and the results.

  • 241.
    Ditrani, Marco
    et al.
    Politecnico di Milano.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Eriksen, Jörgen
    Enochsson, Ola
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Andersson, P.
    Vägverket.
    Eriksson, Per
    Vägverket.
    Improving transportation investment decision through life-cycle cost analysis: case study on some bridges in the north of Sweden2009Inngår i: Sustainability of Constructions - Integrated Approach to Life-time Structural Engineering: Proceedings of the Workshop Timişoara, 23-24 October 2009. COST Action C25, 2009, s. 266-275Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The scope of this project is to perform Life Cycle Cost Analysis (LCCA) on different types of bridges, in order to learn which is most cost-efficient in a particular situation. A second scope is to study the impact of different cost items on the whole Life Cycle Cost. The work is performed to enable optimal strategic decisions regarding future investments.Beam and Slab Bridges, Slab Bridges and Slab Frame Bridges are analyzed. The bridges are located in the north of Sweden, in the regions of Norrbotten and Västerbotten. All bridges have a total length of around 20 m, which is the most common length in Sweden and in Europe. Furthermore, the analysis includes Timber and Soil-Steel bridges in order to understand the prospects for this types of bridges in Sweden. The analysis does not focus on a particular bridge but, based on information from some Swedish producers, it studies different scenarios.The data collection covers initial investments, maintenance, repair and rehabilitation (MR&R) costs, user and demolition costs.

  • 242.
    Domaschuk, L.
    et al.
    University of Manitoba, Winnipeg.
    Shields, D.H.
    University of Manitoba, Winnipeg.
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Reactive soil pressures along pile in frozen sand1991Inngår i: Journal of cold regions engineering, ISSN 0887-381X, E-ISSN 1943-5495, Vol. 5, nr 4, s. 174-194Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multistage, lateral, pile-load creep test is carried out in a frozen sand maintained at -3° C. The pile is a tubular pipe, 150 mm square and 1,800 mm long. A series of plate load cells is mounted along the primary bearing face of the pile. Application of lateral loads of 35, 65, and 115 kN result in attenuating creep, whereas a lateral load of 145 kN leads to accelerating creep. The immediate components of pile displacement increase approximately linearly with applied load, while the creep components increase exponentially. Generally, the soil reaction forces near the ground surface decrease as the result of pile creep, and those further down the pile increase. Moduli of horizontal subgrade reaction computed on the basis of the measured soil reaction forces and the pile displacement are found to vary with applied pressure and creep. Magnitudes based on immediate displacements range from 1 to 7.5 GN/m3, while those based on total displacements range from 0.3 to 2 GN/m3.

  • 243.
    Domaschuk, Len
    et al.
    University of Manitoba, Winnipeg.
    Fransson, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Shields, Don H.
    University of Manitoba, Winnipeg.
    Interaction between a laterally loaded pile and frozen soil1988Inngår i: Permafrost: Fifth International Conference : proceedings : August 2-5, 1988 / [ed] Kaare Senneset, Trondheim: Tapir Academic Press , 1988, Vol. 2, s. 1060-1065Konferansepaper (Fagfellevurdert)
  • 244. Dury, Robin
    et al.
    Bernander, Stig
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Kullingsjö, Anders
    Skanska Teknik AB.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Pusch, Roland
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Progressive Landslide Analysis with Bernander Finite Difference Method2017Inngår i: / [ed] Vikas Thakur, Jean-Sébastien L’Heureux, Ariane Locat, 2017, s. 1-Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The poster presents a new Spreadsheet developed by Robin Dury (2017) to simplify the use of the Finite Difference Method developed by Stig Bernander et al (2011, 2016).

    It includes:

    - Material Properties

    - Finite Difference Method

    - Progressive failure process with five phses

    - Discussion

    - References

  • 245.
    Duvnjak, Ivan
    et al.
    University of Zagreb, Croatia.
    Bartolak, Marko
    University of Croatia.
    Nilimaa, Jonny
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Sas, Gabriel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Blanksvärd, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Täljsten, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Lessons Learnt from Full-Scale Tests of Bridges in Croatia and Sweden2018Inngår i: IABSE Symposium, Nantes 2018: Tomorrow's Megastructures, International Association for Bridge and Structural Engineering , 2018, artikkel-id S23-127Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Load testing is a way to control the capacity and function of a bridge. Methods and recommendations for load testing are described and examples are given form tests carried out in Croatia and Sweden. In order not to damage the bridge being tested, the load must be limited, often to be within the serviceability limit state (SLS). Numerical models can be calibrated by load tests and then be used to check the carrying capacity for higher loads than what has been tested. Need for further work and recommendations are discussed. By effective planning, costs can be saved and a more sustainable use of bridges can be obtained.

  • 246.
    Dăescu, Cosmin
    et al.
    Politechnica University of Timisoara.
    Nagy-György, Tamas
    Politechnica University of Timisoara.
    Sas, Gabriel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Barros, Joaquim
    University of Minho.
    Popescu, Cosmin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Numerical Assessment of Dapped Beam Ends Retrofitted with FRP Composites2013Inngår i: FRPRCS-11: 11th International Symposium on Fiber Reinforced Polymer for Reinforced Concrete Structures / [ed] Joaquim Barros; José Sena-Cruz, Universidade do Minho , 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This document presents the work related to the assessment of the effectiveness of strengthening reinforced concrete (RC) dapped-end beams using carbon fiber reinforced polymers (CFRP). Several non-linear finite element analyses were performed using different strengthening configurations, from the simplest solutions to the more complex ones in which different application schemes were overlapped. The work is focused on evaluating the strengthening systems, considering the ultimate capacities they can lead to and the failure modes involved. There were modeled 17 different strengthening configurations. While some of them provided a marginal in the ultimate load that can be applied, several of them provided important load bearing capacity increase. The observed failure modes ranged from a sudden failure of the whole strengthening system up to the desired progressive failure of the individual components of each strengthening system.

  • 247.
    Edeskär, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Vägytemätning för utvärdering av vägar vintertid2017Rapport (Annet vitenskapelig)
  • 248.
    Edrees, Tarek
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Structural Control and Identification of Civil Engineering Structures2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In general, the main purpose of a structural control system is to apply powerful control techniques that improve the behaviour of civil structures under various kinds of dynamic loading. The first part of this thesis presents novel applications of posicast and input shaping control schemes that have never previously been applied in the field of structural control. Numerical simulations of a benchmark three-story building with an MR damper are used to verify the efficiency of the proposed control theories. The superiority and effectiveness of the suggested schemes at reducing the structure’s responses were demonstrated using six evaluation criteria and by comparison to results achieved with well-established classical control schemes. Moreover, a comprehensive procedure for generating scaled real ground motion records appropriate for a seismic analysis and design of structures using the linear spectrum matching technique is presented based on a seismic hazard study.To efficiently control a structure, it is necessary to estimate its real-life dynamical behaviour. This is usually done using the Structural Identification approach, which is also addressed in this thesis. Structural Identification is commonly utilized to bridge the gap between the real structure and its modeled behaviour. It can also be used to evaluate the structure’s health, detect damage, and assess efficiency. Despite the extensive development of parametric time domain identification methods, their relative merits and the accuracy with which they predict the behaviour of vibrating structures are largely unknown because there have been few comparative studies on their performance under diverse test conditions, and they have not been verified against real-life data gathered over extended periods of time.Thus, the second part of this thesis focuses on applications of parametric and non-parametric models based on the Structural Identification approach in order to clarify their potential and applicability. In addition, a new strategy is proposed that combines this approach with techniques based on Singular Value Decomposition (SVD) and Complex Mode Indicator Function (CMIF) curves to detect structural damage.The methods developed in this work are used to predict the vertical frequencies of the top storey in a multi-storey building prefabricated from reinforced concrete in Stockholm, and to detect and locate damage in a benchmark steel frame. In addition, the non-parametric structural identification approach is used to investigate variation in the modal characteristics (frequency, damping, and mode shapes) of a steel railway bridge.

  • 249.
    Edrees, Tarek
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Structural Identification of Civil Engineering Structures2014Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The assumptions encountered during the analysis and design of civil engineering structures lead to a difference in the structural behavior between calculations based models and real structures. Moreover, the recent approach in civil engineering nowadays is to rely on the performance-based design approaches, which give more importance for durability, serviceability limit states, and maintenance.Structural identification (St-Id) approach was utilized to bridge the gap between the real structure and the model. The St-Id procedure can be utilized to evaluate the structures health, damage detection, and efficiency. Despite the enormous developments in parametric time-domain identification methods, their relative merits and performance as correlated to the vibrating structures are still incomplete due to the lack of comparative studies under various test conditions and the lack of extended applications and verification of these methods with real-life data.This licentiate thesis focuses on the applications of the parametric models and non-parametric models of the System Identification approach to assist in a better understanding of their potentials, while proposing a novel strategy by combining this approach with the utilization of the Singular Value Decomposition (SVD) and the Complex Mode Indicator Function (CMIF) curves based techniques in the damage detection of structures.In this work, the problems of identification of the vertical frequencies of the top storey in a multi-storey¸ building prefabricated from reinforced concrete in Stockholm, and the existence of damage and damage locations for a bench mark steel frame are investigated. Moreover, the non-parametric structural identification approach to investigate the amount of variations in the modal characteristics (frequency, damping, and modes shapes) for a railway steel bridge will be presented.

  • 250.
    Edrees, Tarek
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Identification of building damage using armax model: A parametric study2016Inngår i: Diagnostyka, ISSN 1641-6414, Vol. 17, nr 3, s. 3-14Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Structural Identification approach is used to identify and localize the existence of damage for a steel frame. The black box linear parametric model called Auto-Regressive Moving Average with eXternal input (ARMAX) was utilized for the construction of the Frequency Response Functions, based on simulation results. The Singular Value Decomposition method was adopted to identify how many significant eigenvalues exist and plot the Complex Mode Indicator Function for the complete frame. Three damage indices were adopted to evaluate the state of damage in the frame. The results indicated that the ARMAX is a robust scheme for structural damage detection.

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