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Prof. Hans De Backer
Ghent University, Department of Civil Engineering

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0 Buckling
0 Fatigue
0 Bridge Engineering
0 Tunnel engineering
0 road engineering

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Journal article
Published: 12 February 2021 in Applied Sciences
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The technological innovation of continuously reinforced concrete pavement (CRCP) that contains a significantly reduced amount of reinforcement and the same fundamental behavior as CRCP is called advanced reinforced concrete pavement (ARCP). This new concept of a rigid pavement structure is developed to eliminate unnecessary continuous longitudinal steel bars of CRCP by using partial length steel bars at predetermined crack locations. In Belgium, partial surface saw-cuts are used as the most effective crack induction method to eliminate the randomness in early-age crack patterns by inducing cracks at the predetermined locations of CRCP. The reinforcement layout of ARCP is designed based on the distribution of steel stress in continuous longitudinal steel bar in CRCP and the effectiveness of partial surface saw-cuts as a crack induction method. The 3D finite element (FE) model is developed to evaluate the behavior of ARCP with partial surface saw-cuts. The early-age crack characteristics in terms of crack initiation and crack propagation obtained from the FE simulation are validated with the field observations of cracking characteristics of the CRCP sections in Belgium. The finding indicates that there is fundamentally no difference in the steel stress distribution in the partial length steel bar of ARCP and continuous steel bar of CRCP. Moreover, ARCP exhibits the same cracking characteristics as CRCP even with a significantly reduced amount of continuous reinforcement.

ACS Style

Muhammad Kashif; Ahsan Naseem; Nouman Iqbal; Pieter Winne; Hans De Backer. Evaluating the Early-Age Crack Induction in Advanced Reinforced Concrete Pavement Using Partial Surface Saw-Cuts. Applied Sciences 2021, 11, 1659 .

AMA Style

Muhammad Kashif, Ahsan Naseem, Nouman Iqbal, Pieter Winne, Hans De Backer. Evaluating the Early-Age Crack Induction in Advanced Reinforced Concrete Pavement Using Partial Surface Saw-Cuts. Applied Sciences. 2021; 11 (4):1659.

Chicago/Turabian Style

Muhammad Kashif; Ahsan Naseem; Nouman Iqbal; Pieter Winne; Hans De Backer. 2021. "Evaluating the Early-Age Crack Induction in Advanced Reinforced Concrete Pavement Using Partial Surface Saw-Cuts." Applied Sciences 11, no. 4: 1659.

Journal article
Published: 06 January 2021 in Accident Analysis & Prevention
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Intersections are established dangerous entities of a highway system due to the challenging and unsafe roadway environment they are characterized for drivers and other road users. In efforts to improve safety, an enormous interest has been shown in developing statistical models for intersection crash prediction and explanation. The selection of an adequate form of the statistical model is of great importance for the accurate estimation of crash frequency and the correct identification of crash contributing factors. Using a six-year crash data, road infrastructure and geometric design data, and traffic flow data of urban intersections, we applied three different functional forms of negative binomial models (i.e., NB-1, NB-2, NB-P) and a generalized Poisson (GP) model to develop safety performance functions (SPF) by crash severity for signalized and unsignalized intersections. This paper presents the relationships found between the explanatory variables and the expected crash frequency. It reports the comparison of different models for total, injury & fatal, and property damage only crashes in order to obtain ones with the maximum estimation accuracy. The comparison of models was based on the goodness of fit and the prediction performance measures. The fitted models showed that the traffic flow and several variables related to road infrastructure and geometric design significantly influence the intersection crash frequency. Further, the goodness of fit and the prediction performance measures revealed that the NB-P model outperformed other models in most crash severity levels for signalized intersections. For the unsignalized intersections, the GP model was the best performing model. When only the NB models were compared, the functional form NB-P performed better than the traditional NB-1 and, more specifically, the NB-2 models. In conclusion, our findings suggest a potential improvement in the estimation accuracy of the SPFs for urban intersections by applying the NB-P and GP models.

ACS Style

Muhammad Wisal Khattak; Ali Pirdavani; Pieter De Winne; Tom Brijs; Hans De Backer. Estimation of safety performance functions for urban intersections using various functional forms of the negative binomial regression model and a generalized Poisson regression model. Accident Analysis & Prevention 2021, 151, 105964 .

AMA Style

Muhammad Wisal Khattak, Ali Pirdavani, Pieter De Winne, Tom Brijs, Hans De Backer. Estimation of safety performance functions for urban intersections using various functional forms of the negative binomial regression model and a generalized Poisson regression model. Accident Analysis & Prevention. 2021; 151 ():105964.

Chicago/Turabian Style

Muhammad Wisal Khattak; Ali Pirdavani; Pieter De Winne; Tom Brijs; Hans De Backer. 2021. "Estimation of safety performance functions for urban intersections using various functional forms of the negative binomial regression model and a generalized Poisson regression model." Accident Analysis & Prevention 151, no. : 105964.

Journal article
Published: 23 December 2020 in Applied Sciences
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Since 1970, continuously reinforced concrete pavements have been used in Belgium. The standard design concept for CRCP has been modified through several changes made in the design parameters to eliminate the cluster of closely spaced crack patterns, since these crack patterns lead to the development of spalling and punch-out distresses in CRCPs. Despite adjusting the longitudinal reinforcement ratio, slab thickness, and addition of asphalt interlayer, the narrowly spaced cracks could not be effectively removed. The application of transverse partial surface saw-cuts significantly reduced the probability of randomly occurring cracks in the reconstruction project of the Motorway E313 in Herentals, Belgium. The field investigation has also indicated that the early-age crack induction in CRCP is quite susceptible to the saw-cut depth. Therefore, the present study aims to evaluate the effect of different depths and lengths of the partial surface saw-cut on the effectiveness of crack induction in CRCP under external varying temperature field. For this purpose, the FE software program DIANA 10.3 is used to develop the three dimensional finite element model of the active crack control CRCP segment. The characteristics of early-age crack induction in terms of crack initiation and crack propagation obtained from the FE model are compared and discussed concerning the field observations of the crack development on the active crack control E313 test sections. Findings indicate that the deeper saw-cut with longer cut-lengths could be a more effective attempt to induce the cracks in CRCP in desirable distributions to decrease the risk of spalling and punch-out distresses in the long-term performance of CRCP. These findings could be used as guidance to select the appropriate depth and length of saw-cut for active crack control sections of CRCP in Belgium.

ACS Style

Muhammad Kashif; Ahsan Naseem; Nouman Iqbal; Pieter De Winne; Hans De Backer. Numerical Evaluation of Early-Age Crack Induction in Continuously Reinforced Concrete Pavement with Different Saw-Cut Dimensions Subjected to External Varying Temperature Field. Applied Sciences 2020, 11, 42 .

AMA Style

Muhammad Kashif, Ahsan Naseem, Nouman Iqbal, Pieter De Winne, Hans De Backer. Numerical Evaluation of Early-Age Crack Induction in Continuously Reinforced Concrete Pavement with Different Saw-Cut Dimensions Subjected to External Varying Temperature Field. Applied Sciences. 2020; 11 (1):42.

Chicago/Turabian Style

Muhammad Kashif; Ahsan Naseem; Nouman Iqbal; Pieter De Winne; Hans De Backer. 2020. "Numerical Evaluation of Early-Age Crack Induction in Continuously Reinforced Concrete Pavement with Different Saw-Cut Dimensions Subjected to External Varying Temperature Field." Applied Sciences 11, no. 1: 42.

Journal article
Published: 01 December 2020 in Proceedings of the Institution of Civil Engineers - Transport
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An advanced design classification system for bicycle paths, based on geometric features and a force equilibrium, can pave the way for improved bicycle safety, accident prevention and design guidelines. Design and classification system exists for bicycle paths, but numerous accidents create ambivalence about its validity and effectiveness. Still, a universally accepted classification system has not yet been approved or adopted now. This manuscript presents a unique set of design parameters, analytically developed based on formulas which considers the physical characteristics and dimensions of individual bicycles. The proposed design system is based on theoretical trigonometric derivations. Later, the model is validated with the real-world geometry of the transportation infrastructure of the city of Antwerp, Belgium. The conclusions of this study are useful for evaluating the effectiveness of bicycle paths during design stage without the necessity for real-world experiments. This study will thus be valuable for stakeholders working on policy framework, bicycle safety, and riding comfort.

ACS Style

Zain Ul-Abdin; Sarmad Zaman Rajper; Ken Schotte; Pieter De Winne; Hans De Backer. Analytical geometric design of bicycle paths. Proceedings of the Institution of Civil Engineers - Transport 2020, 173, 361 -379.

AMA Style

Zain Ul-Abdin, Sarmad Zaman Rajper, Ken Schotte, Pieter De Winne, Hans De Backer. Analytical geometric design of bicycle paths. Proceedings of the Institution of Civil Engineers - Transport. 2020; 173 (6):361-379.

Chicago/Turabian Style

Zain Ul-Abdin; Sarmad Zaman Rajper; Ken Schotte; Pieter De Winne; Hans De Backer. 2020. "Analytical geometric design of bicycle paths." Proceedings of the Institution of Civil Engineers - Transport 173, no. 6: 361-379.

Journal article
Published: 02 October 2020 in Applied Sciences
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This study numerically investigates the limitations of structural hot-spot stress (SHSS) methods and proposes a guideline for the calculation of hot-spot stresses, which can be used for the better evaluation of fatigue-related problems. Four different SHSS evaluation methods have been applied to the rib-to-deck (RD) welded joint in orthotropic steel deck (OSD). These methods are used to calculate SHSS at this critical joint utilizing finite element analyses (FEA) based software Siemens NX.12. The limitations and the accuracy of these methods have been observed under different element types and meshing techniques. Moreover, the effect of the nodal-averaging feature is being studied. Two types of governing stresses are produced by the application of Eurocode fatigue load model-4. Essentially, the bending in deck-plate produces highly non-linear stress at the deck-toe, and the membrane effect in rib-plate generates linear stress at the rib-toe. Guidelines are proposed considering different parameters on these two stress states by applying SHSS evaluation methods. In comparison to other SHSS approaches, the International Institute of Welding (IIW) quadratic stress extrapolation (QSE) method shows better results for solid single-element, and the American Society of Mechanical Engineers (ASME) through thickness stress linearization (TTSL) method stands out in solid cubic-mesh technique. In general, shell elements have more consistent SHSS results as compared to solid elements for both stress states.

ACS Style

Nouman Iqbal; Heng Fang; Ahsan Naseem; Muhammad Kashif; Hans De Backer. A Numerical Evaluation of Structural Hot-Spot Stress Methods in Rib-To-Deck Joint of Orthotropic Steel Deck. Applied Sciences 2020, 10, 6924 .

AMA Style

Nouman Iqbal, Heng Fang, Ahsan Naseem, Muhammad Kashif, Hans De Backer. A Numerical Evaluation of Structural Hot-Spot Stress Methods in Rib-To-Deck Joint of Orthotropic Steel Deck. Applied Sciences. 2020; 10 (19):6924.

Chicago/Turabian Style

Nouman Iqbal; Heng Fang; Ahsan Naseem; Muhammad Kashif; Hans De Backer. 2020. "A Numerical Evaluation of Structural Hot-Spot Stress Methods in Rib-To-Deck Joint of Orthotropic Steel Deck." Applied Sciences 10, no. 19: 6924.

Journal article
Published: 02 January 2020 in Applied Sciences
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Combining multiple tunnels into a single tunnel complex while keeping the surrounding area compact is a complicated procedure. The condition becomes more complex when soft soil is present and the area is prone to seismic activity. Seismic vibrations produce sudden ground shaking, which causes a sharp decrease in the shear strength and bearing capacity of the soil. This results in larger ground displacements and deformation of structures located at the surface and within the soil mass. The deformations are more pronounced at shallower depths and near the ground surface. Tunnels located in that area are also affected and can undergo excessive distortions and uplift. The condition becomes worse if the tunnel area is larger, and, thus, the respective tunnel complex needs to be properly evaluated. In this research, a novel triple tunnel complex formed by combining three closely spaced tunnels is numerically analyzed using Plaxis 2D software under variable dynamic loadings. The effect of variations in lining thickness, the inner supporting structure, embedment depth on the produced ground displacements, tunnel deformations, resisting bending moments, and the developed thrusts are studied in detail. The triple tunnel complex is also compared with the rectangular and equivalent horizontal twin tunnel complexes in terms of generated thrusts and resisted seismic-induced bending moments. From the results, it is concluded that increased thickness of the lining, inner structure, and greater embedment depth results in decreased ground displacements, tunnel deformations, and increased resistance to seismic-induced bending moments. The comparison of shapes revealed that the triple tunnel complex has better resistance against moments with the least amount of thrust and surface heave produced.

ACS Style

Ahsan Naseem; Muhammad Kashif; Nouman Iqbal; Ken Schotte; Hans De Backer. Seismic Behavior of Triple Tunnel Complex in Soft Soil Subjected to Transverse Shaking. Applied Sciences 2020, 10, 334 .

AMA Style

Ahsan Naseem, Muhammad Kashif, Nouman Iqbal, Ken Schotte, Hans De Backer. Seismic Behavior of Triple Tunnel Complex in Soft Soil Subjected to Transverse Shaking. Applied Sciences. 2020; 10 (1):334.

Chicago/Turabian Style

Ahsan Naseem; Muhammad Kashif; Nouman Iqbal; Ken Schotte; Hans De Backer. 2020. "Seismic Behavior of Triple Tunnel Complex in Soft Soil Subjected to Transverse Shaking." Applied Sciences 10, no. 1: 334.

Journal article
Published: 14 December 2019 in Frattura ed Integrità Strutturale
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Ageing infrastructure is of major concern for different industrial sectors across Europe. Fatigue cracking is one of the most important damage mechanisms that affect structural health of welded steel structures. Fatigue assessment of welded details in large, complex structures is a difficult and time consuming task. In this paper a numerical framework for fatigue assessment of welded details is presented. In view of industrial applications, automated hot spot stress algorithms for plate and tubular joints were developed and integrated in the framework. The framework provides practicing engineers with an effective tool for fatigue assessment of different components in conformity with leading design codes. Furthermore, apart from Miner’s rule the framework allows easy implementation of different non-linear damage accumulation models in order to account for load interaction and load sequence effects.

ACS Style

Kris Hectors; Wim De Waele; Mia Loccufier; Hans De Backer. A Numerical framework for fatigue lifetime prediction of complex welded structures. Frattura ed Integrità Strutturale 2019, 14, 552 -566.

AMA Style

Kris Hectors, Wim De Waele, Mia Loccufier, Hans De Backer. A Numerical framework for fatigue lifetime prediction of complex welded structures. Frattura ed Integrità Strutturale. 2019; 14 (51):552-566.

Chicago/Turabian Style

Kris Hectors; Wim De Waele; Mia Loccufier; Hans De Backer. 2019. "A Numerical framework for fatigue lifetime prediction of complex welded structures." Frattura ed Integrità Strutturale 14, no. 51: 552-566.

Journal article
Published: 18 November 2019 in Sustainability
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Risk perception influences cycling attributes toward its adoption. Researchers are investigating attributes associated with risk formation. In this study, various attributes were selected which influence the user’s formation of risk perception. For this purpose, an online questionnaire survey was conducted in Flanders, among all segments of the population (N = 774). Participants were asked questions for attributes relating to risk formation. Results suggested that risk formation among users evolves around tangible to non-tangible attributes. The spectrum of risk perception was developed which visualizes risk evolution, considering various attributes. Surprisingly, elements such as “comfort”, surface evenness, and policies were rated as being neutral. Infrastructure and the presence of opposite road users tend to be foreseen as critical factors for risk formation. Risk perception varies depending upon psychometric paradigm shifts, such as dread and unknown risk. This strange notion is considered to lie in a space between dread and unknown risk. This explains the difference in risk perception, knowingly or not knowingly (subconsciously), yet expressing cognitively and evolving inside. This is an interesting finding, but reasons behind such a motive need to be explained. A possible explanation behind such behavior is that people tend to change their responses due to knowledge acquisition during the survey.

ACS Style

Zain Ul-Abdin; Pieter De Winne; Hans De Backer. Risk-Perception Formation Considering Tangible and Non-Tangible Aspects of Cycling: A Flemish Case Study. Sustainability 2019, 11, 6474 .

AMA Style

Zain Ul-Abdin, Pieter De Winne, Hans De Backer. Risk-Perception Formation Considering Tangible and Non-Tangible Aspects of Cycling: A Flemish Case Study. Sustainability. 2019; 11 (22):6474.

Chicago/Turabian Style

Zain Ul-Abdin; Pieter De Winne; Hans De Backer. 2019. "Risk-Perception Formation Considering Tangible and Non-Tangible Aspects of Cycling: A Flemish Case Study." Sustainability 11, no. 22: 6474.

Journal article
Published: 09 July 2019 in Sustainability
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The majority of bicycle crash studies aim at determining risk factors and estimating crash risks by employing statistics. Accordingly, the goal of this paper is to evaluate bicycle–motor vehicle crashes by using spatial and temporal approaches to statistical data. The spatial approach (a weighted kernel density estimation approach) preliminarily estimates crash risks at the macro level, thereby avoiding the expensive work of collecting traffic counts; meanwhile, the temporal approach (negative binomial regression approach) focuses on crash data that occurred on urban arterials and includes traffic exposure at the micro level. The crash risk and risk factors of arterial roads associated with bicycle facilities and road environments were assessed using a database built from field surveys and five government agencies. This study analysed 4120 geocoded bicycle crashes in the city of Antwerp (CA, Belgium). The data sets covered five years (2014 to 2018), including all bicycle–motorized vehicle (BMV) crashes from police reports. Urban arterials were highlighted as high-risk areas through the spatial approach. This was as expected given that, due to heavy traffic and limited road space, bicycle facilities on arterial roads face many design problems. Through spatial and temporal approaches, the environmental characteristics of bicycle crashes on arterial roads were analysed at the micro level. Finally, this paper provides an insight that can be used by both the geography and transport fields to improve cycling safety on urban arterial roads.

ACS Style

Hwachyi Wang; S. K. Jason Chang; Hans De Backer; Dirk Lauwers; Philippe De Maeyer. Integrating Spatial and Temporal Approaches for Explaining Bicycle Crashes in High-Risk Areas in Antwerp (Belgium). Sustainability 2019, 11, 3746 .

AMA Style

Hwachyi Wang, S. K. Jason Chang, Hans De Backer, Dirk Lauwers, Philippe De Maeyer. Integrating Spatial and Temporal Approaches for Explaining Bicycle Crashes in High-Risk Areas in Antwerp (Belgium). Sustainability. 2019; 11 (13):3746.

Chicago/Turabian Style

Hwachyi Wang; S. K. Jason Chang; Hans De Backer; Dirk Lauwers; Philippe De Maeyer. 2019. "Integrating Spatial and Temporal Approaches for Explaining Bicycle Crashes in High-Risk Areas in Antwerp (Belgium)." Sustainability 11, no. 13: 3746.

Journal article
Published: 22 May 2019 in Journal of Constructional Steel Research
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A three-dimensional finite element welding simulation procedure is developed with the software Siemens NX and solver type SAMCEF in order to determine the residual stresses of a welded component of an orthotropic bridge deck. The welding process of a deck plate which is welded to a closed trapezoidal stiffener is simulated. A decoupled thermal-mechanical analysis is performed. During the thermal analysis, the temperatures introduced by the passage of the welding torch are calculated for different time steps. This temperature field is used during the thermal analysis to determine the residual welding stresses for the same time steps. The decoupled thermal-mechanical analysis gives the distribution of the residual stresses. For the transverse direction, there are tensile yield residual stresses on the deck plate near the weld region. In between the welded webs of the stiffener, there are compressive residual stresses. For the longitudinal stiffener, there are again tensile yield residual stresses near the weld which decrease at a greater distance and turn into compressive residual yield stresses. For the longitudinal direction, there are tensile yield stresses present near the weld and a compressive residual stress in the middle of the deck plate. The stiffener only shows a small tensile stress peak near the weld root and along the stiffener there are small tensile residual stresses. The results from the finite element analysis are validated by experimental measurements with the incremental hole-drilling method. A residual stress distribution for the top and bottom side of the deck plate and the longitudinal stiffener is determined for both the longitudinal and transverse direction.

ACS Style

Evy Van Puymbroeck; Gilles Van Staen; Nouman Iqbal; Hans De Backer. Residual weld stresses in stiffener-to-deck plate weld of an orthotropic steel deck. Journal of Constructional Steel Research 2019, 159, 534 -547.

AMA Style

Evy Van Puymbroeck, Gilles Van Staen, Nouman Iqbal, Hans De Backer. Residual weld stresses in stiffener-to-deck plate weld of an orthotropic steel deck. Journal of Constructional Steel Research. 2019; 159 ():534-547.

Chicago/Turabian Style

Evy Van Puymbroeck; Gilles Van Staen; Nouman Iqbal; Hans De Backer. 2019. "Residual weld stresses in stiffener-to-deck plate weld of an orthotropic steel deck." Journal of Constructional Steel Research 159, no. : 534-547.

Journal article
Published: 20 February 2019 in Theoretical and Applied Fracture Mechanics
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The numerous welded joints in orthotropic steel decks (OSDs) lead to a high probability of fatigue damage. One of the most detrimental problems is the severe reduction of the serviceability due to cracks in rib-to-deck welded joints, which require in-depth studies on the entire fatigue process. The linear elastic fracture mechanics has been proven to be effective in this aspect. When put into practice on actual projects, however, its accuracy and feasibility are largely dependent on features in various scales. This paper presents an investigation on the fatigue behavior of orthotropic steel decks with respect to multiscale concerns. By performing fatigue tests on OSD specimens welded by 15-mm-thick deck plates and 6-mm-thick stiffeners of S355 steel, the rib-to-deck weld toe crack that penetrates the deck plate is produced and the crack growth path is addressed using beach mark method. Afterwards, a two-dimensional local model of the rib-to-deck weld toe crack is built using the extended finite element method by which the stress intensity factors for early-stage cracks can be obtained. Based on the similar concept of nominal stresses, it can easily be linked to the macroscopic model and forms a non-concurrent method that enables to simulate the crack growth at rib-to-deck weld toe. As a result, a crack growth rate curve for the test specimen is given and different stages are analyzed with respect to the Paris law, indicating a clear influence of the early-stage fatigue cracks. The material constants of crack growth are obtained and validated, which may further be introduced to the fatigue assessment and life estimation for the maintenance work of OSDs.

ACS Style

Benjin Wang; Wim Nagy; Hans De Backer; Airong Chen. Fatigue process of rib-to-deck welded joints of orthotropic steel decks. Theoretical and Applied Fracture Mechanics 2019, 101, 113 -126.

AMA Style

Benjin Wang, Wim Nagy, Hans De Backer, Airong Chen. Fatigue process of rib-to-deck welded joints of orthotropic steel decks. Theoretical and Applied Fracture Mechanics. 2019; 101 ():113-126.

Chicago/Turabian Style

Benjin Wang; Wim Nagy; Hans De Backer; Airong Chen. 2019. "Fatigue process of rib-to-deck welded joints of orthotropic steel decks." Theoretical and Applied Fracture Mechanics 101, no. : 113-126.

Journal article
Published: 05 February 2019 in Applied Sciences
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For welded bridge components, the knowledge of residual stresses induced by welding is essential to determine their effect on the fatigue life behavior resulting in optimal fatigue design and a better knowledge about the fatigue strength of these welded connections. The residual stresses of a welded component in an orthotropic steel bridge deck are determined with the incremental hole-drilling method. This method is specified by the American Society for Testing and Materials ASTM E837-13a and it can be used only when the material behavior is linear-elastic. However in the region of the bored hole, there are relaxed plastic strains present that can lead to significant error of the measured stresses. The hole-drilling procedure is simulated with three-dimensional finite element modeling including a simplistic model of plasticity. The effect of plasticity on uniform in-depth residual stresses is determined and it is concluded that residual stresses obtained under the assumption of linear-elastic material behavior are an overestimation. Including plasticity for non-uniform in-depth residual stress fields results in larger tensile and smaller compressive residual stresses. Larger tensile residual stresses cause premature fatigue failure. Therefore, it is important to take these larger tensile residual stresses into account for the fatigue design of a welded component.

ACS Style

Evy Van Puymbroeck; Wim Nagy; Ken Schotte; Zain Ul-Abdin; Hans De Backer. Determination of Residual Welding Stresses in a Steel Bridge Component by Finite Element Modeling of the Incremental Hole-Drilling Method. Applied Sciences 2019, 9, 536 .

AMA Style

Evy Van Puymbroeck, Wim Nagy, Ken Schotte, Zain Ul-Abdin, Hans De Backer. Determination of Residual Welding Stresses in a Steel Bridge Component by Finite Element Modeling of the Incremental Hole-Drilling Method. Applied Sciences. 2019; 9 (3):536.

Chicago/Turabian Style

Evy Van Puymbroeck; Wim Nagy; Ken Schotte; Zain Ul-Abdin; Hans De Backer. 2019. "Determination of Residual Welding Stresses in a Steel Bridge Component by Finite Element Modeling of the Incremental Hole-Drilling Method." Applied Sciences 9, no. 3: 536.

Journal article
Published: 01 February 2019 in Journal of Transport Geography
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Most bicycle collision studies aim to identify contributing factors and calculate risks based on statistical data (Loidl et al., 2016). The aim of this paper is to follow this approach, focusing on bicycle-motorized vehicle (BMV) collisions through a spatio-temporal workflow. For the spatial dimension (Kernel Density Estimation (KDE) method), a general estimation of the collision risks was obtained and the labour-intensive work of collecting counting data was avoided on the macro-scale level. The temporal dimension (negative binomial modeling method) focused on data from collisions occurring on bridges, enabling the inclusion of traffic exposure (counting data on the micro-scale level). Bridge collision risks and contributing factors related to road environment and cycling facilities were estimated using databases from eight government authorities and field investigation. For the presented case study, 2044 geo-coded bicycle collisions in the Taipei-Capital Region (Taiwan) were analysed. The data set covers three years (2015–2017) and includes all BMV collisions reported by the police. Through the spatial workflow, urban bridges were identified as areas with the highest density of collisions. This is unsurprising given that bicycle facilities on urban bridges face design difficulties due to limited space, discrepancy in elevation and traffic volume. Through this approach the characteristics of BMV collisions on bridges, traffic engineering, road environment, traffic control system, and driving behaviour were then analysed in the temporal dimension. This paper concludes by providing information relevant to traffic engineers concerning the enhancement of bicycle safety on high-risk areas in the city. In this paper, we aim to (1) understand the risk patterns of bicycle collisions spatially (where?) and temporally (when?), from a region-scale (macro) level to a location-scale (micro) level. To this end, a spatio-temporal (two-stage) workflow was developed for the exploration of the collision data. Through the spatial stage, urban bridges were identified as having the highest density of BMV collisions. Building on results from the spatial stage, we sought to (2) further explain “how” bridge infrastructure influences bicycle collisions in Taipei-Capital Region (Taiwan) by studying contributing risk factors. Countermeasures can thus be made to enhance bicycle safety. This paper is organized as follows. Section 2 provides an overview of the literature related to bicycle collision studies. Section 3 describes the study concept of the spatio-temporal workflow and its methodologies. Section 4 presents the study area and provides the descriptive statistics of BMV collisions. Section 5 describes the data used in spatio-temporal modeling. Section 6 discusses the main results and Section 7 finally concludes with the contribution and recommendation of this research.

ACS Style

Hwachyi Wang; Hans De Backer; Dirk Lauwers; S.K.Jason Chang. A spatio-temporal mapping to assess bicycle collision risks on high-risk areas (Bridges) - A case study from Taipei (Taiwan). Journal of Transport Geography 2019, 75, 94 -109.

AMA Style

Hwachyi Wang, Hans De Backer, Dirk Lauwers, S.K.Jason Chang. A spatio-temporal mapping to assess bicycle collision risks on high-risk areas (Bridges) - A case study from Taipei (Taiwan). Journal of Transport Geography. 2019; 75 ():94-109.

Chicago/Turabian Style

Hwachyi Wang; Hans De Backer; Dirk Lauwers; S.K.Jason Chang. 2019. "A spatio-temporal mapping to assess bicycle collision risks on high-risk areas (Bridges) - A case study from Taipei (Taiwan)." Journal of Transport Geography 75, no. : 94-109.

Conference paper
Published: 01 January 2019 in IABSE Congress, New York, New York 2019: The Evolving Metropolis
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Longitudinal ribs with the trapezoidal section are broadly adopted in orthotropic steel decks especially for long span bridges. When the tire load is eccentric from the axis of the rib, the torsional rigidity of ribs is critically reduced by distortion which impedes the horizontal dispersal of load. Because of the existence of cutouts in crossbeam, the high stress concentration at the rib-to-crossbeam joint caused by the rib distortion makes the joint easily prone to fatigue damage. In this paper, based on the parametric analysis of several classical design parameters, static load experiments of an orthotropic steel deck specimen are performed. Measurement results support the positive correlations between the weld length of rib-to-crossbeam joint and the distortional stress. The most unfavorable load position of stress concentration induced by rib distortion is also verified, which is about 1600 mm away from the investigated crossbeam. Experimental results indicate that ribs are deformed toward different directions at the midspan section and the crossbeam section separately when the load is eccentric from the axis of rib.

ACS Style

Heng Fang; Nouman Iqbal; Amelie Outtier; Muhammad Kashif; Hans De Backer. Experimental study of rib distortion in orthotropic steel decks. IABSE Congress, New York, New York 2019: The Evolving Metropolis 2019, 704 -710.

AMA Style

Heng Fang, Nouman Iqbal, Amelie Outtier, Muhammad Kashif, Hans De Backer. Experimental study of rib distortion in orthotropic steel decks. IABSE Congress, New York, New York 2019: The Evolving Metropolis. 2019; ():704-710.

Chicago/Turabian Style

Heng Fang; Nouman Iqbal; Amelie Outtier; Muhammad Kashif; Hans De Backer. 2019. "Experimental study of rib distortion in orthotropic steel decks." IABSE Congress, New York, New York 2019: The Evolving Metropolis , no. : 704-710.

Conference paper
Published: 01 January 2019 in IABSE Congress, New York, New York 2019: The Evolving Metropolis
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Orthotropic Steel Decks (OSDs) are widely used in long span bridges because of their extremely light weight when compared to their load carrying capacity. These deck types typically consist of a grillage of closed trapezoidal longitudinal stiffeners and transverse web stiffeners, welded to a deck plate. As a result, fatigue problems occur due to the extensive use of complex welded connections. Unfortunately, fatigue effects have often been overlooked during design, which was also the case for an important multiple span box girder viaduct in Belgium (1978).Due to a renovation program of the ring road around Brussels, the number of traffic lanes on the viaduct should be extended from three to four. As a result, questions have been raised about the current structural health of the OSD due to fatigue and future fatigue damage accumulation. Therefore, extensive FEM analyses have been performed, taking into account various parameters such as increased traffic volume and accompanying axle loads, historical positions of the heavy lanes, historical road pavements and their temperature-dependent load spreading effects. In conclusion, accurate fatigue damages have been determined for all fatigue details. Therefore, focused inspections and design solutions can be provided, resulting in a durable bridge management for the next 60 years.

ACS Style

Wim Nagy; Glenn Thierens; Hendrik Blontrock; Hans De Backer; Philippe Van Bogaert; Kristel Reynaert; Johan Maljaars. Fatigue assessment of an existing orthotropic steel deck to comply with future traffic intensity. IABSE Congress, New York, New York 2019: The Evolving Metropolis 2019, 711 -717.

AMA Style

Wim Nagy, Glenn Thierens, Hendrik Blontrock, Hans De Backer, Philippe Van Bogaert, Kristel Reynaert, Johan Maljaars. Fatigue assessment of an existing orthotropic steel deck to comply with future traffic intensity. IABSE Congress, New York, New York 2019: The Evolving Metropolis. 2019; ():711-717.

Chicago/Turabian Style

Wim Nagy; Glenn Thierens; Hendrik Blontrock; Hans De Backer; Philippe Van Bogaert; Kristel Reynaert; Johan Maljaars. 2019. "Fatigue assessment of an existing orthotropic steel deck to comply with future traffic intensity." IABSE Congress, New York, New York 2019: The Evolving Metropolis , no. : 711-717.

Conference paper
Published: 01 January 2019 in IABSE Congress, New York, New York 2019: The Evolving Metropolis
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In this paper, standardization and optimization of Orthotropic Steel Deck (OSD) is carried out to increase its usage as an essential bridge component. OSD’s are more often used in the long span bridges because they considered expensive and more complex structure. There are fatigue crack complications associated with these type of steel decks due to their direct contact with the heavy cyclic loading. The idea of standardizing the OSD’s is floating in the research industry for last two decades. To facilitate this concept numerical simulation study is carried out with and without additional cutouts with different deck thicknesses and span lengths. The Cross beams without stress relieving cutouts have been introduced which will reduce the labor cost for special cutouts preparation and increase the fatigue endurance of critical welded joints. Based on these numerical results; recommendations have been made. Standardization and optimization of OSD’s will definitely increase their usage in bridges.

ACS Style

Nouman Iqbal; Heng Fang; Gilles Van Staen; Ahsan Naseem; Hans De Backer. Standardization and Optimization of Orthotropic steel deck with Numerical modelling. IABSE Congress, New York, New York 2019: The Evolving Metropolis 2019, 1351 -1358.

AMA Style

Nouman Iqbal, Heng Fang, Gilles Van Staen, Ahsan Naseem, Hans De Backer. Standardization and Optimization of Orthotropic steel deck with Numerical modelling. IABSE Congress, New York, New York 2019: The Evolving Metropolis. 2019; ():1351-1358.

Chicago/Turabian Style

Nouman Iqbal; Heng Fang; Gilles Van Staen; Ahsan Naseem; Hans De Backer. 2019. "Standardization and Optimization of Orthotropic steel deck with Numerical modelling." IABSE Congress, New York, New York 2019: The Evolving Metropolis , no. : 1351-1358.

Journal article
Published: 31 December 2018 in Procedia Structural Integrity
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An orthotropic steel bridge deck consists out of a number of longitudinal and transverse stiffeners. These stiffeners are welded to the deck plate which cause residual stresses to be present near the vicinity of this connection. In addition, the welding operation causes multiple fatigue problems across the bridge deck which lead to the formation of fatigue cracks. For an accurate fatigue design of an orthotropic bridge deck, the residual stresses should also be taken into account to determine the effect of these stresses with respect to the load-induced stresses. Tensile residual stresses should be avoided since they tend to open fatigue cracks which results in a shorter fatigue life. The welding of the longitudinal stiffener to the bridge deck plate is simulated with finite element modelling. The effect of the size of the tack welds, the welding current and the welding speed on the residual stresses is determined. These different welding sequences are modelled in order to minimize tensile residual stresses near the weld connection. The welding configuration which leads to smaller tensile residual stresses will result in an orthotropic steel bridge deck with a longer fatigue lifetime.

ACS Style

Evy Van Puymbroeck; Wim Nagy; Hans De Backer. Influence of the welding process on the residual welding stresses in an orthotropic steel bridge deck. Procedia Structural Integrity 2018, 13, 920 -925.

AMA Style

Evy Van Puymbroeck, Wim Nagy, Hans De Backer. Influence of the welding process on the residual welding stresses in an orthotropic steel bridge deck. Procedia Structural Integrity. 2018; 13 ():920-925.

Chicago/Turabian Style

Evy Van Puymbroeck; Wim Nagy; Hans De Backer. 2018. "Influence of the welding process on the residual welding stresses in an orthotropic steel bridge deck." Procedia Structural Integrity 13, no. : 920-925.

Conference paper
Published: 31 December 2018 in Plant-Microbes-Engineered Nano-particles (PM-ENPs) Nexus in Agro-Ecosystems
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Non-destructive tests (NDTs) are the most economical and easy to use techniques to determine different soil properties. They expedite the process of determining sub-surface characteristics. These include Ground Penetrating Radars (GPRs), Seismographs, Shear Wave Velocity (SWV) and Electrical Resistivity Test (ERT) etc. ERT is nowadays getting worldwide popularity for determining the sub-surface geology in geotechnical engineering, as it does not require extensive testing. This research aimed at developing empirical correlations of ERT with different soil parameters by performing extensive conventional laboratory tests in order to get all the required soil parameters by just performing ERT in the future, which otherwise require great time and effort to be determined by the conventional laboratory tests. The developed correlations include relationship of resistivity value obtained in the field with the internal friction angle (r2 = 0.964), cohesion (r2 = 0.946) and the bearing capacity of shallow foundation (r2 = 0.90) for depth to width ratios of 0.5 and 1.0 respectively. The regression coefficients obtained ensured the development of quite good correlation for the sandy-clayey soil.

ACS Style

Ahsan Naseem; Fazal-E Jalal; Hans De Backer; Ken Schotte; Muhammad Kashif. Correlation of Electrical Resistivity Test with the Geotechnical Parameters of Sandy Soil. Plant-Microbes-Engineered Nano-particles (PM-ENPs) Nexus in Agro-Ecosystems 2018, 191 -193.

AMA Style

Ahsan Naseem, Fazal-E Jalal, Hans De Backer, Ken Schotte, Muhammad Kashif. Correlation of Electrical Resistivity Test with the Geotechnical Parameters of Sandy Soil. Plant-Microbes-Engineered Nano-particles (PM-ENPs) Nexus in Agro-Ecosystems. 2018; ():191-193.

Chicago/Turabian Style

Ahsan Naseem; Fazal-E Jalal; Hans De Backer; Ken Schotte; Muhammad Kashif. 2018. "Correlation of Electrical Resistivity Test with the Geotechnical Parameters of Sandy Soil." Plant-Microbes-Engineered Nano-particles (PM-ENPs) Nexus in Agro-Ecosystems , no. : 191-193.

Conference paper
Published: 20 September 2018 in IOP Conference Series: Materials Science and Engineering
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When adopting the trapezoidal section of ribs in orthotropic steel decks, the torsional rigidity of ribs losses radically because of rib distortion especially when the load is eccentric from the axis of the rib. Hence, the rib distortion causes high stress concentrations at the rib-to-crossbeam joint which makes this joint easily prone to fatigue. In this paper, the influence of 4 conventional design parameters on distortional behaviour is investigated by numerical simulation adopting the hot spot stress approach and the sub-model analysis technique. A refined finite element model of an orthotropic steel deck specimen with the dimension of 8.2 m × 4.1 m is built. Research results indicate that the distortional stress rises with the increment of the spacing of crossbeam or the weld length of rib-to-crossbeam joint. The thickness of rib is negatively correlated with the distortional stress. The influence of the spacing of rib on distortional stress depends on the relative size between the width of load area and the spacing of rib. The most unfavourable load position is determined by rib geometries, i.e. the thickness of ribs, whereas rest three parameters do not have obvious influence.

ACS Style

Heng Fang; Evy Van Puymbroeck; Nouman Iqbal; Zain Ul-Abdin; Hans De Backer. Numerical simulation of rib distortion in orthotropic steel decks. IOP Conference Series: Materials Science and Engineering 2018, 419, 012012 .

AMA Style

Heng Fang, Evy Van Puymbroeck, Nouman Iqbal, Zain Ul-Abdin, Hans De Backer. Numerical simulation of rib distortion in orthotropic steel decks. IOP Conference Series: Materials Science and Engineering. 2018; 419 (1):012012.

Chicago/Turabian Style

Heng Fang; Evy Van Puymbroeck; Nouman Iqbal; Zain Ul-Abdin; Hans De Backer. 2018. "Numerical simulation of rib distortion in orthotropic steel decks." IOP Conference Series: Materials Science and Engineering 419, no. 1: 012012.

Conference paper
Published: 11 July 2018 in International Conference on Transportation and Development 2018
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Ride quality under different pavement conditions is considered critical for adoption and modal shift for bicycle users. Vertical vibration and road roughness values have severe impact on user perception and ride quality. Ride quality depends upon subjective ratings of pavement conditions and quantitative values for surface conditions. Bicycle use in Flanders, Belgium, is considered prominent. In order to stimulate bicycle adoption, governments consider different policy measures. But those policy measures remain insignificant if the user comfort levels are not determined for the current infrastructure. Subjective ratings were collected from 40 different bicycling sections of Flemish cycling infrastructure. The survey reveals critical information regarding bicyclists and surface conditions. Regression models were developed, predicting the comfort level for riding on Flemish bicycle paths. The results reveal good correlation between the evenness coefficient, the roughness, and the subjective ratings for bicycle users under different pavement conditions, i.e., asphalt, concrete, and block pavements. This comfort rating system can be used by transportation planners and government officials. Based on the developed rating system, transportation professionals can determine the comfort levels of different pavement conditions for bicycle paths.

ACS Style

Zain Ul-Abdin; Hans De Backer; Pieter De Winne; Sarmad Zaman Rajper. Ride Quality for Bicycle Paths under Different Pavement Conditions. International Conference on Transportation and Development 2018 2018, 1 .

AMA Style

Zain Ul-Abdin, Hans De Backer, Pieter De Winne, Sarmad Zaman Rajper. Ride Quality for Bicycle Paths under Different Pavement Conditions. International Conference on Transportation and Development 2018. 2018; ():1.

Chicago/Turabian Style

Zain Ul-Abdin; Hans De Backer; Pieter De Winne; Sarmad Zaman Rajper. 2018. "Ride Quality for Bicycle Paths under Different Pavement Conditions." International Conference on Transportation and Development 2018 , no. : 1.