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Jonasson, Jan-Erik
Publikasjoner (10 av 108) Visa alla publikasjoner
Al-Gburi, M., Jonasson, J.-E. & Nilsson, M. (2018). Prediction of Restraint in Second Cast Sections of Concrete Culverts using Artificial Neural Networks (ed.). European Journal of Environmental and Civil Engineering, 22(2), 226-245
Åpne denne publikasjonen i ny fane eller vindu >>Prediction of Restraint in Second Cast Sections of Concrete Culverts using Artificial Neural Networks
2018 (engelsk)Inngår i: European Journal of Environmental and Civil Engineering, ISSN 1964-8189, E-ISSN 2116-7214, Vol. 22, nr 2, s. 226-245Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Estimation of restraint is very important for accurately predicting the risk of early thermal and shrinkage cracking in concrete structures. The stress in young concrete is affected by changes in its dimensions during hydration and the restraint imposed by adjoining structures. In concrete culverts, the restraints from existing structures acting upon the first and second casting sections to be cast are different, causing them to exhibit different early cracking behaviour. This work presents a new method for predicting restraint in complex concrete structures using artificial neural networks (ANNs). Finite element calculations were performed to predict restraint in 108 slabs, 324 walls and 972 roofs from second sections of concrete culverts, and the results obtained were used to train and validate ANN models. The ANN models were then used to study the effects of varying selected parameters (the thickness and width of the roof and slab, the thickness and height of the walls, and the length of the culvert section) on the predicted restraint. Mathematical expressions for predicting restraint values in slabs, walls and roofs were derived based on the ANN models’ output and implemented in an Excel spreadsheet that provides a simple way of predicting restraint in practical applications. Restraint values predicted in this way agree well with the results of finite-element calculations

sted, utgiver, år, opplag, sider
Taylor & Francis, 2018
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-13947 (URN)10.1080/19648189.2016.1186116 (DOI)000427321300006 ()d43d84f0-c1d2-4a54-9629-77677abf0d2c (Lokal ID)d43d84f0-c1d2-4a54-9629-77677abf0d2c (Arkivnummer)d43d84f0-c1d2-4a54-9629-77677abf0d2c (OAI)
Merknad

Validerad;2017;Nivå 2;2017-12-04 (svasva)

Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-04-06bibliografisk kontrollert
Hösthagen, A., Jonasson, J.-E., Emborg, M. & Nilsson, M. (2017). Thermal Crack Risk Estimations of Concrete Walls: Temperature and Strain Measurements Correlated to the Equivalent Restraint Method. In: Proceedings of the 23rd Nordic Concrete Research Symposium: . Paper presented at 23th Symposium on Nordic Concrete Research & Developement, Aalborg, Denmark, 21 - 23 August 2017. Oslo, Norway: Nordic Concrete Federation
Åpne denne publikasjonen i ny fane eller vindu >>Thermal Crack Risk Estimations of Concrete Walls: Temperature and Strain Measurements Correlated to the Equivalent Restraint Method
2017 (engelsk)Inngår i: Proceedings of the 23rd Nordic Concrete Research Symposium, Oslo, Norway: Nordic Concrete Federation , 2017Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

 Self-induced non-elastic deformations in hardening concrete, caused by restrained volume changes due to thermal dilatation and moisture deformations, often leads to cracking. In crack risk analyses, determination of the degree of restraint is vital. One model to estimate the restraint and calculate the thermal crack risk is the Equivalent Restraint Method, ERM. The method has previously been analyzed but needs to be further examined and validated. Recordings of tunnel sections were performed and compared to calculated values by ERM. Satisfying correlation between theoretically estimated and observed temperatures, strains and time of through cracking was achieve which is promising for future implementation and testing of the method.

sted, utgiver, år, opplag, sider
Oslo, Norway: Nordic Concrete Federation, 2017
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-65990 (URN)978-82-8208-056-9 (ISBN)
Konferanse
23th Symposium on Nordic Concrete Research & Developement, Aalborg, Denmark, 21 - 23 August 2017
Tilgjengelig fra: 2017-10-06 Laget: 2017-10-06 Sist oppdatert: 2018-06-20bibliografisk kontrollert
Al-Gburi, M., Jonasson, J.-E. & Nilsson, M. (2016). Reduction of Early Age Crack Risks in Concrete Walls by Using a New Casting Technique (ed.). Structural Engineering International, 26(3), 216-224
Åpne denne publikasjonen i ny fane eller vindu >>Reduction of Early Age Crack Risks in Concrete Walls by Using a New Casting Technique
2016 (engelsk)Inngår i: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 26, nr 3, s. 216-224Artikkel i tidsskrift (Fagfellevurdert) Published
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.

sted, utgiver, år, opplag, sider
International Association for Bridge and Structural Engineering, 2016
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-9105 (URN)10.2749/101686616X14555429843960 (DOI)000386695500004 ()2-s2.0-85021095055 (Scopus ID)7ac04418-9d63-4c95-b719-af26f19330d0 (Lokal ID)7ac04418-9d63-4c95-b719-af26f19330d0 (Arkivnummer)7ac04418-9d63-4c95-b719-af26f19330d0 (OAI)
Merknad

Validerad; 2016; Nivå 2; 2016-11-25 (andbra)

Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Edrees, T., Nikolakopoulos, G., Jonasson, J.-E. & Hedlund, H. (2015). A state-of-the-art review of Structural Control Systems (ed.). Paper presented at . Journal of Vibration and Control, 21(5), 919-937
Åpne denne publikasjonen i ny fane eller vindu >>A state-of-the-art review of Structural Control Systems
2015 (engelsk)Inngår i: Journal of Vibration and Control, ISSN 1077-5463, E-ISSN 1741-2986, Vol. 21, nr 5, s. 919-937Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Nowadays the utilization of structural control systems for alleviating the responses of civil engineering structures, under the effects of different kinds of dynamics loadings, has become a standard technology, while still there are numerous of current research approaches for advancing the effectiveness of these methodologies. The aim of this article is to review the state of the art technologies in structural control systems by introducing a general literature review for all the types of vibrations control systems that have been appeared till now. These systems can be classified into four main groups: a) passive, b) semi active, c) active, and d) hybrid based on their operational mechanism. A brief description of each of these main groups and their subgroups, with their corresponding advantages and disadvantages will be also extendedly reported in this review. This article will conclude by providing an overview of some innovative practical implementations of devices, which are able to demonstrate their potentials and future directions of structural control systems in civil engineering.

HSV kategori
Forskningsprogram
Konstruktionsteknik; Reglerteknik
Identifikatorer
urn:nbn:se:ltu:diva-15436 (URN)10.1177/1077546313478294 (DOI)000350494700008 ()2-s2.0-84924735330 (Scopus ID)ef121d13-c5ba-4b17-9422-3b09bb900d8e (Lokal ID)ef121d13-c5ba-4b17-9422-3b09bb900d8e (Arkivnummer)ef121d13-c5ba-4b17-9422-3b09bb900d8e (OAI)
Merknad
Validerad; 2015; Nivå 2; 20130109 (geonik)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Edrees, T., Nikolakopoulos, G. & Jonasson, J.-E. (2015). Comfort Level Identification for Irregular Multi-storey Building Subjected to Vibrations (ed.). Paper presented at . Automation in Construction, 50, 40-49
Åpne denne publikasjonen i ny fane eller vindu >>Comfort Level Identification for Irregular Multi-storey Building Subjected to Vibrations
2015 (engelsk)Inngår i: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 50, s. 40-49Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

In this article, the System Identification approach is being used to identify the vertical frequencies of the top storey in a multi-storey building prefabricated from reinforced concrete in Stockholm. Before building construction, detailed investigation indicated that the building will not be affected by train vibrations from the nearby railway yard. After building completion, disturbing vibrations were observed in the building. Three measurement types namely: ambient vibration test, forced vibration test on the rails, and forced vibration test have been performed in order to specify the probable reasons for these vibrations. Five methods of structural identification approach, specifically: ARX, ARMAX, BJ, OEand State Space Models have been implemented for the identification process in this study usingthe tests' results. All the test types and model structures utilized have identified a concentration inthe floor only, which is close to the frequencies of human body parts. Furthermore, the article concludes that the ARMAX model and the Output Error model have indicated an excellent performance to predict the mathematical models of vibration's propagation in the building, when compared with other models used from the three types of tests. In addition, the results of the aforementioned system identification methods, implemented for this study, have indicated that there are no other reasons for the disturbing vibrations still observed in the building. Furthermore, the results confirmed the correctness of the previous theoretical and experimental results obtained by different specialists, who stated that the values of floor acceleration are within the acceptable limits, and the probable reason for any disturbance is the resonance between the generated low frequencies and the human body parts’ frequencies.

Emneord
Information technology - Automatic control, Informationsteknik - Reglerteknik
HSV kategori
Forskningsprogram
Konstruktionsteknik; Reglerteknik
Identifikatorer
urn:nbn:se:ltu:diva-10315 (URN)10.1016/j.autcon.2014.10.009 (DOI)000349580400004 ()2-s2.0-84926169980 (Scopus ID)91b57f6b-44c5-4dbf-8a94-3dad5190c871 (Lokal ID)91b57f6b-44c5-4dbf-8a94-3dad5190c871 (Arkivnummer)91b57f6b-44c5-4dbf-8a94-3dad5190c871 (OAI)
Merknad
Validerad; 2014; Nivå 2; 20141022 (geonik)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Edrees, T., Nikolakopoulos, G., Grip, N. & Jonasson, J.-E. (2015). Investigation of changes in modal characteristics before and after damage of a railway bridge: A case study (ed.). Paper presented at . The IES Journal Part A: Civil & Structural Engineering, 8(2), 131-144
Åpne denne publikasjonen i ny fane eller vindu >>Investigation of changes in modal characteristics before and after damage of a railway bridge: A case study
2015 (engelsk)Inngår i: The IES Journal Part A: Civil & Structural Engineering, ISSN 1937-3260, E-ISSN 1937-3279, Vol. 8, nr 2, s. 131-144Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The linear, time-invariant transfer function Txy has been utilized for the construction of FRF, based on the ambient vibration measurements. The results presented here indicated the possibility to identify and localize damages in steel railway bridges from the variations in the modal characteristics of the structure. The comparison between the modal characteristics for the healthy and collapsed bridge confirmed that damage had been existed. The abnormal percentage of change in modal damping, between the healthy and any other condition for a structure, can be regarded as a serious indicator for early stages of damage, while the high percentage of change in modal damping can clearly indicate the existence of damage in that structure. The average ratio of change in the damping ratio from the healthy to the collapsed bridge was about 206 % and this ration could be regarded as an index for the existence of a serious damage in steel bridges, which needs further evaluation in other test cases.

Emneord
Structural Identification, Damage Detection, Non-Destructive Evaluation, Health Monitoring., Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
HSV kategori
Forskningsprogram
Konstruktionsteknik; Reglerteknik; Matematik
Identifikatorer
urn:nbn:se:ltu:diva-3067 (URN)10.1080/19373260.2015.1020889 (DOI)2-s2.0-84928928602 (Scopus ID)0d4f141e-c90a-46ec-8522-13749de68d77 (Lokal ID)0d4f141e-c90a-46ec-8522-13749de68d77 (Arkivnummer)0d4f141e-c90a-46ec-8522-13749de68d77 (OAI)
Merknad
Validerad; 2015; Nivå 1; 20150217 (taredr)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Al-Gburi, M., Jonasson, J.-E. & Nilsson, M. (2015). Using Artificial Neural Network to Predict the Restraint in Concrete Culvert at Early Age (ed.). Paper presented at . Structural Engineering International, 25(3), 258-265
Åpne denne publikasjonen i ny fane eller vindu >>Using Artificial Neural Network to Predict the Restraint in Concrete Culvert at Early Age
2015 (engelsk)Inngår i: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 25, nr 3, s. 258-265Artikkel i tidsskrift (Fagfellevurdert) Published
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

HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-13425 (URN)10.2749/101686614X14043795570570 (DOI)000370775600003 ()2-s2.0-84941962665 (Scopus ID)ca62ce25-6bf8-45cf-8228-03e331ee8dfe (Lokal ID)ca62ce25-6bf8-45cf-8228-03e331ee8dfe (Arkivnummer)ca62ce25-6bf8-45cf-8228-03e331ee8dfe (OAI)
Merknad
Validerad; 2015; Nivå 2; 20150316 (majali)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Edrees, T., Nikolakopoulos, G. & Jonasson, J.-E. (2014). A comparative study on the identification of building natural frequencies based on parametric models (ed.). In: (Ed.), (Ed.), Proceedings of the 33rd IASTED International Conference on Modelling, Identification and Control: February 17 – 19, 2014, Innsbruck, Austria. Paper presented at IASTED International Conference on Modelling, Identification and Control : 17/02/2014 - 19/02/2014.
Åpne denne publikasjonen i ny fane eller vindu >>A comparative study on the identification of building natural frequencies based on parametric models
2014 (engelsk)Inngår i: Proceedings of the 33rd IASTED International Conference on Modelling, Identification and Control: February 17 – 19, 2014, Innsbruck, Austria, 2014Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

The analysis and design of civil engineering structures is a complex problem, which is based on many assumptions to simplify these operations. This in turn, leads to a difference in the structural behaviour between calculations based models and real structures. Structural identification was proposed by many researchers as a tool to reduce this difference between models and actual structures. Moreover, Parametric models and non-parametric models were used intensively for system identification by many researchers. In this research effort, the system identification concept is utilized to identify the natural frequencies for a steel building’s frames. Different black box linear parametric models such as Transfer Function model (TF), Auto-Regressive model with eXternal input model (ARX), Auto-Regressive Moving Average with eXternal input (ARMAX) model, Output Error model structure (OE), and Box-Jenkins model (BJ) were examined for identifying the first 10th natural frequencies for the building’s frames, based on simulation results. Abaqus 6.12 finite-element software was utilized to perform the time history analysis for the examples and the obtained responses at one point of the roofs (assumed as a sensor) were further processed by the parametric models to obtain the building’s natural frequencies based on the Abaqus time history analysis results (assumed as a measurements). After that, Abaqus 6.12 was utlized again to perform another analysis, which is called frequency analysis to obtain the building’s natural frequencies and mode shapes based on the stiffness and mass (not the measurements) of the buildings. The results showed that the linear parametric models TF, ARX, ARMAX, OE, and BJ are robust to identify the natural frequencies of building and they are recommend for future work.

Serie
Modelling, Identification, and Control, ISSN 1025-8973
Emneord
Information technology - Automatic control, Informationsteknik - Reglerteknik
HSV kategori
Forskningsprogram
Konstruktionsteknik; Reglerteknik
Identifikatorer
urn:nbn:se:ltu:diva-38346 (URN)10.2316/P.2014.809-008 (DOI)2-s2.0-84898460092 (Scopus ID)cb4a5a5f-2332-4302-a086-907ef2807a75 (Lokal ID)cb4a5a5f-2332-4302-a086-907ef2807a75 (Arkivnummer)cb4a5a5f-2332-4302-a086-907ef2807a75 (OAI)
Konferanse
IASTED International Conference on Modelling, Identification and Control : 17/02/2014 - 19/02/2014
Merknad
Godkänd; 2014; 20131113 (geonik)Tilgjengelig fra: 2016-10-03 Laget: 2016-10-03 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Al-Gburi, M., Jonasson, J.-E. & Nilsson, M. (2014). Effect of casting sequences on the restraint in slab-on-ground (ed.). Paper presented at Concrete Innovation Conference : 11/06/2014 - 13/06/2014. Paper presented at Concrete Innovation Conference : 11/06/2014 - 13/06/2014.
Åpne denne publikasjonen i ny fane eller vindu >>Effect of casting sequences on the restraint in slab-on-ground
2014 (engelsk)Konferansepaper, Oral presentation only (Fagfellevurdert)
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

Emneord
Restraint cracks, through cracking, early age concrete, casting sequence, slab-on-ground., Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-27959 (URN)1952cb57-ba4e-470c-99d8-1bc91a56dafa (Lokal ID)1952cb57-ba4e-470c-99d8-1bc91a56dafa (Arkivnummer)1952cb57-ba4e-470c-99d8-1bc91a56dafa (OAI)
Konferanse
Concrete Innovation Conference : 11/06/2014 - 13/06/2014
Merknad
Godkänd; 2014; 20140618 (majali)Tilgjengelig fra: 2016-09-30 Laget: 2016-09-30 Sist oppdatert: 2018-03-26bibliografisk kontrollert
Al-Gburi, M., Jonasson, J.-E. & Nilsson, M. (2014). Effect of the boundary conditions on the crack distribution in early age concrete (ed.). Paper presented at Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014. Nordic Concrete Research, 50, 347-351
Åpne denne publikasjonen i ny fane eller vindu >>Effect of the boundary conditions on the crack distribution in early age concrete
2014 (engelsk)Inngår i: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, s. 347-351Artikkel i tidsskrift (Fagfellevurdert) Published
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.

HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-35902 (URN)aa1a1048-666a-411e-8f71-de9393198743 (Lokal ID)aa1a1048-666a-411e-8f71-de9393198743 (Arkivnummer)aa1a1048-666a-411e-8f71-de9393198743 (OAI)
Konferanse
Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014
Merknad
Godkänd; 2014; 20140812 (majali); Konferensartikel i tidskriftTilgjengelig fra: 2016-09-30 Laget: 2016-09-30 Sist oppdatert: 2018-03-26bibliografisk kontrollert
Organisasjoner