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This research studies the performance of two- and four-story steel building models against progressive collapse in two cases: (1) skewed beam–column connections, and (2) straight cleated beam–beam connections. Nonlinear static and dynamic analyses were performed and then the time history analysis was performed under the simultaneous effect of the two horizontal components of three earthquake records and two column removal scenarios. The results showed that the 60-degree skewed connection had a weaker performance than the straight connection, and, according to the plastic hinge distribution, it was observed that the mentioned connection did not provide the life safety performance level. [ABSTRACT FROM AUTHOR]

Non-stationary characteristic in nature wind has a great effect on buffeting performance of long-span bridges. The influence of key parameters in non-stationary wind velocity models on nonlinear buffeting responses of a super long-span suspension bridge was investigated in this paper. Firstly, four non-stationary wind velocity models are established by combing the time-varying average wind velocity with an exponential function and the fluctuating wind velocity with four modulation functions, respectively. These non-stationary wind velocity models have obvious non-stationary characteristics and then are validated by the classical power spectrum densities. Finally, three displacement responses of the bridge deck under four different independent variables of β in the exponential function and four modulation functions were compared, respectively. Results show that the turbulence intensities using two non-uniform modulation functions (NMF) are larger than those using uniform modulation functions (uMF). Moreover, the root mean square (RMS) values of three displacement responses increase with the decrease of β. Besides, the RMS values of three displacement under two NMFs are larger than those under two uMFs, and their RMS values under the second uMF are the smallest. [ABSTRACT FROM AUTHOR]

The paper aims to determine the criteria and sub-criteria for evaluating the contractor's performance and finalize a master list of the criteria and sub-criteria to be used for evaluating contractor's performance with their respective weights. The method is incorporated in the framework proposed for the evaluation of the contractor's performance during the execution phase. An exploratory study has been opted, using a structured, close-ended multiple-choice questionnaire survey approach. The questionnaire survey was conducted in two phases, i.e. validation survey, and reliability survey. Fifteen experts responded to the validation survey, and thirty experts to the reliability survey. The experts were from Government and public sectors in India, working at various senior levels. The weights of criteria and sub-criteria were calculated from data collected in the survey, relative importance was calculated through the relative importance index and criteria were ranked. The paper provides criteria and subcriteria which were finalized through a questionnaire survey by classification of criteria identified in literature and tender review. The respective weights were finalized, which can be measured while evaluating contractors' performance. The weights assigned to criteria through the survey are; health and safety is 13.19%, followed by finance 11.93%, time 11.93%, quality 13.38%, client satisfaction 12.42%, environmental safety 12.32%, productivity 12.51% and regulation 12.32%. The paper provides the criteria and sub-criteria with their weights needed for evaluating the performance of contractors during the project execution phase. This research can lead to a culture of continuous measurement of performance for the satisfactory completion of projects. [ABSTRACT FROM AUTHOR]

An analysis of sandwich beams with truss core is an important issue in many fields of industry such as civil engineering, automotive, aerospace or maritime. The objective of the present study is a nonlinear static response of sandwich beams subjected to the three-point bending test configuration. The beams are composed of two parent components: upper and lower laminated face sheets (unidirectional tape) and a pyramidal truss core manufactured by means of 3D printing. A polyamide filament strengthened with chopped carbon fibres - CF-PA-12 is used for the core development. The both, experimental and numerical analyses are presented. A detailed numerical model of the sandwich beam was developed in Abaqus software. The numerical model considers modelling of the adhesive joint with an additional layer of material placed between the parent components of the beam. A continuum hybrid solid shell elements were used to model the adhesive layer. In addition, a special care was taken to use an appropriate material model for the CF-PA-12 filament. To do so, the uniaxial tensile tests were performed on 3D printed samples. Having acquired the test data, a hyperelastic material model was evaluated based on a curve fitting approach. [ABSTRACT FROM AUTHOR]

The concrete deck at the negative bending moment region of a continuous steel-concrete composite girder bridge is the weakest part of the structure. Introducing ultra-high performance concrete (UHPC) to the hogging region may overcome the shortage and break through the bottleneck. This paper explores the cracking performance of steel-concrete composite girders with concrete slabs topped by a thin layer of UHPC subjected to a negative bending moment. A real continuous composite girder bridge is briefly introduced as the engineering background, and the cracking characteristic of the concrete deck over the middle piers of the bridge is numerically modeled. Approaches to strengthen the cracking performance of the concrete deck at the hogging region through topping UHPC overlays are proposed. The effectiveness of the approaches is examined by conducting a series of numerical and experimental tests. Numerical results indicate that the normal concrete (NC) deck near the middle forums of the bridge would crack due to the large tensile stress from negative bending moments. Replacing the top concrete with an identical-thick UHPC overlay can increase the cracking resistance of the deck under the moment. As the thickness of the UHPC overlay increased from 6.0 cm to 12.0 cm, the maximum shear stress at the UHPC overlay-to-NC substrate interface under different load combinations was decreased by 56.3%-65.3%. Experimental results show that the first-cracking load of the composite beam using an NC-UHPC overlaid slab was 2.1 times that using an NC slab. The application of a UHPC overlaid deck can significantly improve the crack performance of the steel-concrete composite girder bridge. [ABSTRACT FROM AUTHOR]

In the paper, an indirect method for the identification of the final shape of the freshly executed jet-grouted column is developed. The method relies on the backward analysis of the temperatures measured inside the column, along the trace of the injecting pipe. Temperature changes in the column are caused by the hydration process of the cementitious grout. 2D axisymmetric unsteady heat conduction initial-boundary value problem is solved for finding the column shape which fits best the reference temperature measurements. The model of the column is solved using the finite element method. The search is performed using the global evolutionary optimization algorithm called differential evolution. It is shown that the proposed method can provide an accurate prediction of the column shape if only the model reflects the physical reality well. The advantage over previous results is that the cylindrical shape of the column does not have to be assumed anymore, and the full profile of the column along its length can be accurately identified. [ABSTRACT FROM AUTHOR]

The basic dynamic characteristics of façade scaffolding are natural frequencies of vibrations and corresponding mode shapes. These properties affect the scaffolding safety, as well as comfort and safety of its users. Many of the dynamic actions present at scaffolding are in the low frequency range, i.e. below 10-15 Hz. The first natural frequency of a structure is usually in the range of 0.7 to 4 Hz which corresponds to resonant frequencies of human body and it means that vibrations induced at scaffolding may strongly affect the human comfort. The easiest way of increasing the rigidity of the structure is by ensuring correct boundary conditions (support, anchorage) and bracing of the structure. The numerical analysis was performed for the real scaffolding structure of medium size. The analysis consisted of natural frequencies calculation for the original structure and for models with modified bracing and anchoring systems. The bracing modifications were introduced by reducing or increasing the number of vertical bracing shafts. The anchor system was modified by reduction of the 6 anchors in the top right corner of the scaffolding in three stages or by evenly removing nearly 1/3 of the total number of anchors. The modifications of bracing and anchor systems resulted in changing the natural frequencies. The increase of natural frequencies due to higher number of anchors and more bracing is not even for all mode shapes. Bracing is more effective in acting against longitudinal vibrations, while anchoring against vibrations perpendicular to the façade. [ABSTRACT FROM AUTHOR]

Investigation on the behaviour of hybrid beams is presented. Hybrid beam stands for an element with hybrid cross sections. This means sections that consist of steel and concrete parts, connected together with composite dowels, and both are considered for shear flow analysis. In practice, a more general solution may be used for bridges in the form of a beam in which the span sections are hybrid and the support sections are concrete. For the first time in the world, it was decided to introduce a girder in bridge construction, in which a concrete web with a thickness of only 20 cm was formed, directly connected to the steel web, so that a hybrid cross-section is created in accordance with the new European design regulations currently being developed (1994-1-102). The solution is new itself and requires also a new approach for internal forces determination. In this paper a parametric analysis of different hybrid beams with span range from 20 to 40 m and with different reinforcment ratio is performed to get knowledge on the influence of (1) concrete cracking and (2) rheology of concrete on the redistribution of internal forces. Results are analysed and conclusions are presented. As a final step, a general method for computer aided modelling of hybrid beams (hybrid beam concept) is proposed, which is based on the uncracked analysis. Such an analysis is designer-friendly and while appropriate benchmarked (as in this paper) can spare a lot of time needed for detailed iterative cracked analysis. [ABSTRACT FROM AUTHOR]

The application of used glazed waste in concrete production can improve the performance of the structure of the building. Flexural and shear behavior and action of reinforced HollowGlass Concrete Beams (HGCB) and Solid Glass Concrete Beams (SGCB) made with glass waste under a two-point load are studied in this paper. In this work, 6 reinforced concrete solid and hollow beams were tested under a four-point bending test to evaluate and calculate the flexural behavior of SGCB and HGCB. For that purpose, Beams were prepared with 1000 mm length, 230 mm height, and 120 mm. All beams were divided into groups and named according to the space stirrups steel bar. The experimental work investigates five main variables which are: first: the comparison between SGCB and HGCB with the concrete beams made with glass waste (Glass Concrete Beam GCB), second: comparison between Solid Concrete Beams for Normal Concrete Beams (NCB), and GCB, three: comparison between Hollow Concrete Beams for NCB and GCB, four: the comparison between HGCB and HCB, last: the comparison between SGCB and SCB. The test results indicated that GCB was offered higher strength than NCB, but the load-slip behavior of all specimens is similar for both types of concretes, and the bond strength is not influenced by steel specimens. Furthermore, the results of this study indicated that the contribution of GCB to the load is indicated to be considerable. The results indicate that the hollow opening affected the ultimate load capacity and deflection of HGCB. [ABSTRACT FROM AUTHOR]

Excessive settlement may induce structural damage and water leakage in immersed tunnels, seriously threatening the tunnels' safety. However, making accurate assessment of the settlement in immersed tunnels is difficult due to the incomplete knowledge of the geotechnical parameters and the inadequacy of the model itself. This paper proposes an effective method to accurately assess the settlement in immersed tunnels. An enhanced beam on elastic foundation model (E-BEFM) is developed for the settlement assessment, with the Bayesian adaptive direct search algorithm adopted to estimate unknown model parameters based on previous observations. The proposed method is applied to a field case of the Hong Kong-Zhuhai-Macao immersed tunnel. The original BEFM is used for comparison to highlight the better assessment performance of E-BEFM, particularly for joints' differential settlement. Results show that the proposed method can provide accurate predictions of the total settlement, angular distortion (a representation of tubes' relatively differential settlement), and joints' differential settlement, which consequently supports the associated maintenance decision-making and potential risk prevention for immersed tunnels in service. [ABSTRACT FROM AUTHOR]

The finite element method (FEM) using Ansys program (APDL) was used in this study to evaluate the idea of tuned vibration absorbers applied to a beam construction for the undamped system. The ideal location for the Dynamic Vibration Absorbers (DVAs) and their numbers to be installed on the fixed-fixed beam in order to lessen beam vibration was also investigated. The DVA was coupled to the fixed-fixed beam vibration node for three vibration modes. The natural frequency and frequency response of the beam were calculated in this study using modal and harmonic analysis, respectively. The vibrational characteristics of the F-F beam with and without DVAs were presented. The simulation results demonstrated that the vibration amplitude decreases in the presence of the DVAs and its reduction depends on the locations of the DVAs and its number. In addition, the attached DVAs affect the structural beam vibration. Depending on the modes of vibration, the vibrational peak is the optimal place to attach DVA. [ABSTRACT FROM AUTHOR]

Design of clamped crane rails with foot flange (type A) The interface between crane (mechanical engineering) and crane runway girder (civil engineering), which is not explicitly defined, has repeatedly led to misunderstandings in practice in the past. Only the contact pressure between the wheel of the crane and the rail surface is verified by the crane designer acc. to EN 13001‐3‐3. The design of the crane rail itself is not covered by the crane design standards. On the other hand, the design of clamped rails acc. to EN 1993‐6, that are subject of biaxial bending and torsion as a result of eccentric load introduction, has not been possible up to now because of missing design recommendations. This paper presents the current status of the design rules developed for the draft standard prEN 1993‐6 and presents comparisons with realistic numerical investigations. In addition, an improved calculation model for the longitudinal stresses from concentric wheel loading is presented that is able to describe the actual load‐bearing behaviour significantly more accurate in comparison to draft standard prEN 1993‐6. Furthermore, a recommendation for a fatigue verification is formulated. [ABSTRACT FROM AUTHOR]

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Metallic dampers with plastic energy dissipation are often used in the seismic protection of civil structures. However, conventional metallic dampers cannot provide adequate energy dissipation capacity due to the small displacement vibrations. This paper proposed a torsional metallic damper to improve energy dissipation performance. The proposed damper utilized ball screw devices to amplify plastic deformation, which can excessively enhance its damping capacity. First, the axial tension and pure torsion experiments were conducted to evaluate the energy dissipation capacity of solid aluminum round rods under different loads. The torsional tests of three different sections of aluminum rods were carried out to explore the optimal section of torsional energy consumption. The results showed that aluminum 1060 exhibits good plastic properties under pure torsion and the solid aluminum rod had the best energy dissipation capacity among the three test specimens. Second, the dynamic theoretical model of the proposed damper was established and verified by experiment results. The influence of the diameter and length of the aluminum rod and the lead of the ball screw on the energy dissipation performance of the damper was also analyzed. Finally, a cable-stayed bridge was numerically modeled to verify the damping performance of the proposed damper for longitudinal seismic control, which indicates that the displacement of the bridge at the girder end and tower top is significantly reduced with the proposed damper compared to that without the damper. In general, the displacement amplification mechanism of the proposed damper can increase the damping capacity, and the optimal parameters of the damper designed from one certain earthquake wave are also effective for response reduction under other waves. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Prestressing plays a pivotal role in ensuring the tightness and integrity of prestressed concrete containment in nuclear power plants. The prestress loss reduces the compressive stress in concrete resulting from the prestressing strands and increases the risk of containment leakage under severe accident conditions. Therefore, the accurate prediction of prestress loss is essential for the design and in-service management of prestressed concrete containment. Unlike one-way beams or girders in building structures and bridges, two-way prestressing systems are used in prestressed concrete containment. In the current simplified method for evaluating time-dependent prestress loss, the interaction of concrete creep in two directions resulting from the two-way prestressing strands and the influence of the steel liner and mild steel rebars in two directions are neglected. In this study, based on the principle of creep superposition, the age-adjusted effective method for the creep estimation of concrete, and considering concrete shrinkage, concrete creep, and the relaxation of prestressing strands, as well as the influence of the steel liner and mild steel rebars in two directions, a sectional analysis is performed for prestressed concrete containment with bonded prestressing strands, and equations for calculating the two-way time-dependent prestress losses are derived. The results of the two-way time-dependent prestress losses predicted by the derived equations are compared with those of tests in the literature, and great agreement is achieved. Finally, a case study is given to show the application of the proposed method for the prediction of prestress loss in prestressed concrete containment in the nuclear power plant. [ABSTRACT FROM AUTHOR]

Corrugated steel flat plates have a number of benefits over conventional steel flat plates, including better buckling strength, a greater load capacity, a longer fatigue life, and cheaper construction costs. Corrugated plates have thus been used in a variety of civil engineering projects, including bridges, industrial structures, and steel coupling beams. To further enhance these properties, the web can be constructed as a core composed of two outside flat plates and a middle-corrugated panel. In this research, finite element software (ABAQUS 2017) was used to examine the effectiveness of steel plate girders containing various web types (flat plate, zigzagly corrugated plate, and core web with zigzagly corrugated panel). A large number of simply supported beam specimens were simulated and investigated under a three-point load in order to determine how the type of web affects the performance of girders under shear and flexural loadings. Three shear span-to-depth ratios (a/d) of 1.0, 1.83, and 2.5 were examined. Corrugation depth's impact on girder performance was also explored. The results of the study demonstrated that replacing flat plate web with corrugated plate having a zigzag shape improved the performance of the girders in regards to ultimate load and ductility. Additionally, when a core web was utilized, the performance of the girders was further improved. When compared to a steel girder with a flat web, the ultimate loads for girders with a core web and girders that only consisted of a corrugated plate web increased by 47% and 21%, respectively. [ABSTRACT FROM AUTHOR]

In this study, a spatial model of a steel truss arch bridge was established using the finite element software Midas/Civil to simulate and analyze the jacking construction process. The stress performance of the guide beam and main structure at each jacking stage was obtained. The results showed that in the first stage of jacking, the maximum stress and deflection values of the main girder were observed. The maximum stress on the upper edge of the main girder was 34.9 MPa, and on the lower edge, it was -60.4 MPa. The maximum deflection was -35.88 mm. The maximum stress in the guide beam occurred during the jacking process and was -53.2 MPa, corresponding to the crosssection at the root of the guide beam. The maximum deflection of the guide beam occurred in the maximum cantilever state and was -30.79 mm. During the arch rib jacking process, the maximum stress was -49.4 MPa. Both the maximum stress and deflection values were within the allowable range, indicating that the structure was in a safe state. This study provides a reference for similar bridge jacking construction projects. [ABSTRACT FROM AUTHOR]

Bridges generally exhibit complicated mechanical behaviors under external loads, such as flexural-shear coupling, compression-bending coupling, and flexural-shear-torsion coupling. In the context of deterministic design approaches such as design codes, these complicated coupled issues are generally simplified to the safety verification of bridge components under a single mechanical state (i.e. flexural, shear, torsion). Currently, it is available to collect external loads acted on bridges and understand bridge performance under these stochastic external loads. In this manner, the reliability-based full probabilistic approach could be applied to investigate the performance of bridges over their lifetime. However, the majority of existing bridge reliability assessments involving sitespecific traffic load measurements focuses on the analysis of bridge components under a single mechanical state. To address this shortcomings, a reliability-based probabilistic analytical framework is established to investigate the flexural-shear capacity of girder bridges subjected to random traffic loadings. The flexural-shear coupled failure path of bridge girders under random traffic loading is characterized for the first time, where the bivariate extreme value theory is incorporated to develop the extreme value distribution of combined flexural and shear load effects. The modified compression field theory recommended by AASHTO is employed to establish the coupled flexural-shear coupling resistances. Finally, the reliability of the flexural-shear performance of bridge girders is evaluated by solving the multivariate ultimate limit state equation. The proposed analytical framework is applied to a realistic bridge. The results show that the reliability index of the flexural-shear coupling evaluation is lower than that of the flexural or shear evaluation, which highlights the importance of the flexural-shear performance checking in the reliability assessment of bridges under random traffic loading. The proposed analytical framework could be further applied to the probabilistic assessment of bridge components subjected to combined loading mechanisms under random loadings. [ABSTRACT FROM AUTHOR]

Recently, temporary bridges have been developed to facilitate rescue operations and minimize damage to affected areas. High‐strength bolts are preferred for end‐plate connections to expedite construction, reducing the bolt count. Regarding parts reusability, we propose an I‐girder designed with an L‐shaped notch and a novel support block as a structural member. Finite Element Method (FEM) analysis was conducted to investigate the girder end's buckling behavior and failure mode and to verify the effect of the support block's geometry and bolt arrangement on load‐bearing capacity. The findings indicate that the load‐bearing capacity of the girder end with the support block is equivalent to that of a standard I‐girder end, despite reducing the area of the support block's effective compression area by 40% under shear force and bending moment. [ABSTRACT FROM AUTHOR]

The buckling "General Method" of EN 1993‐1‐1 and EN 1993‐1‐5 can be applied to solve problems characterized by non‐uniform geometries and complex stress fields. A typical example occurs during the incremental launching of bridge girders with slender web panel subjected to patch loading. However, this method does not explicitly provide the most critical verification point of a structural element and does not allow to consider the mechanical interaction between instability modes. The objective of the study is the development of a novel methodology that can solve these important special design issues, using a completely automatic process by linear static and linear buckling analyses only. The procedure provides the definition of a slenderness parameter for each point of the structure, in order to avoid the nonlinear analyses with imperfections permutation (as described in Annex C of EN 1993‐1‐5) that require a high computational effort. This pointwise slenderness parameter indicates not only where the slenderness is maximum in each buckling mode, but also the slenderness in other points of the structural elements. This would allow to consider the interaction between global and local buckling, with the definition of an equivalent slenderness parameter for buckling modes coupling. [ABSTRACT FROM AUTHOR]

Over the last century, the definition of the design traffic loads for Italian road bridges has undergone a continuous evolution, starting from the first code in 1933 up to the current code. The changes in the arrangement and in the intensity of the design loads that have occurred over the years resulted in significant variations, both decreasing and increasing the overall static demand required to the bridges compared to previous codes. As part of a broader study on the structural risk of existing bridges with respect to traffic loads, it is certainly of interest to investigate the influence of the adopted design code on the risk itself. The paper presents some of the results of a study conducted with this purpose, regarding Prestressed Concrete beam‐and slab bridges with simply supported spans, one of the most common typology among bridges with medium‐small span. The comparison between historical codes and current one is carried out in terms of internal forces of the most stressed girder, taking into account the transverse distribution of loads. The study can provide useful elements for the definition of a fast procedure for the preliminary assessment of typical existing Italian bridges based on the geometric characteristics of the decks and their design age. [ABSTRACT FROM AUTHOR]

The relatively new fibre optic measurement technique: distributed fibre optic sensing (DFOS) is provided to control strains and displacements, used in the structural health monitoring of a decommissioned wind turbine blade (WTB) bridge girder. The DFOS system is characterized by the following features: accurate, reliable and continuous strain measurements, possibility of assessing shape and displacements, detection of local damages, high durability. Exemplary results of DFOS measurements performed under laboratory conditions on the full‐scale WTB bridge girder are presented. The paper describes the concept of the WTB bridge girder with integrated DFOS monitoring system to control the girder's behavior under loading. Exemplary data of DFOS efficiency were presented and the overall accuracy and reliability of the DFOS measurement system were revealed. [ABSTRACT FROM AUTHOR]

The article describes a specific method of using innovative transverse systems of flat bar frames as structures forcing elastic shape transformations of nominally flat folded sheets into the forms of ruled shell roof coverings. An innovative method for parametric shaping these forms and arrangement of frames constituting structural systems of sheds with folded thin-walled roof coverings, taking account of the specificity of designing elastically transformed roof sheeting, was proposed. The proposed method for defining the loads of the considered frames supporting lower shelves of the folds of transformed roof sheeting, as loads distributed uniformly along the length of the upper chord of a roof frame girder, is also an innovative approach. The above unconventional premises result in the innovative topic of the research presented in terms of checking the impact of changing the shape of subsequent flat frames (intended for the construction of sheds roofed with the transformed sheeting) on the geometric and mechanical properties of the members of these frames. For the defined loads and the proposed parameterization of the frame forms, an innovative set of conditions was developed to optimize their performance, and then a theoretical analysis of the observed dependencies was carried out. This analysis was performed in an unconventional, novel way using section modules of the cross-sections of all members. The performed computer simulations confirmed the significance of changes in the inclination of girders and columns on the geometric and mechanical properties of the members. The obtained results are the basis and justification for simulations and tests in the scope of further modification of the form, loads, work, and methods of using various configurations of flat frames in constructions. [ABSTRACT FROM AUTHOR]

The present paper intends to illustrate the seismic behaviour of different configurations for a ten storeyed "inverted Y" eccentrically braced frame provided with rigid and/or pined beam/column and diagonal/column connections. Four configurations were analysed for the "inverted Y" braced frame, sized for the forces produced by the same code seismic base shear force. In the first configuration, rigid connections were used for all kind of structural elements. The second configuration had hinged beam/column and diagonal/column connections. In case of the third configuration, rigid connections were used among all kind of structural elements and additional potentially plastic zones with reduced cross‐sections (resembling the "dog‐bone" detail) were considered along the girders and braces, near the member ends connected to the columns. The fourth configuration had hinged diagonal/column connections and additional potentially plastic zones were considered only along the frame girders, near the girder ends connected to the columns. The behaviour of each frame configuration during static and dynamic nonlinear analyses was observed. The extreme values for deformations and member forces were compared. The steel consumption was estimated for each of the four considered configurations. [ABSTRACT FROM AUTHOR]

The ways of designing and building steel girder bridges with a composite concrete deck vary much between different parts of the world. A bridge system with twin steel I‐girders or a concept with multiple (more than two) girders can be used. The design and use of details and secondary systems also vary a lot. In order to give horizontal stabilization and distribute horizontal loads, bracing between the I‐girders bracings are often used. Although not so common, the bracing can also be used to distribute vertical loads between the main girders. To describe and to analyze the possible impact from using a lateral bracing, this paper describes the design of a curved bridge in Guatemala City and its challenges. The new Bridge over the Pinula River is designed as a steel‐concrete composite bridge with multiple steel girders with a concrete deck on top and has lateral bracing between the girders. The bridge is used as a case study to analyze the impact from a lateral bracing system on the vertical load distribution between the longitudinal girders. The bridge was designed with lateral bracing between the top flanges along the whole bridge and with bracing between the lower flanges near the supports. The case study shows that the distribution of eccentric vertical loads between the longitudinal girders can be improved by using lateral bracing between the lower flanges for multiple girders. In some cases, it may not be beneficial to use lateral bracings along the whole bridge length, like for example this bridge. In this case due to the governing design cases in the construction stages where these bracings influenced the torsional stiffness of the bridge in such way that an unfavorable distribution of the support reactions between the six girders at some supports was achieved. [ABSTRACT FROM AUTHOR]

The present paper analyses some possibilities to improve the provisions concerning the seismic design of diagonal braced frames according to the in charge European and Romanian seismic design code (EN 1998‐1:2004 [1], respectively P100‐1/2013 [2]). Three design variants were used for the dimensioning under seismic actions of two ten story concentrically braced frames, taking into consideration different contributions of the tensioned and compressed braces in carrying horizontal seismic forces. The considered braced frames had two spans of 6.0m and ten storey of 3.5m. One of the frames had ascendant diagonal braces (from the lateral columns to the central column) and the other had descendant diagonal bracings (from the lateral columns to the central column). Static nonlinear analyses were performed with all the designed variants of the frames. The loading and deformation states at different steps during the analyses were compared. The distribution of plastic hinges in the structure was analysed. A more favourable behaviour of the frame during static nonlinear analysis was ensured by providing reduced cross‐sections along all frame girders ends (resembling the dog‐bone detail). [ABSTRACT FROM AUTHOR]

The retrofitting method using CFRP (Carbon Fiber Reinforced Plastic) plates was applied to a steel highway bridge in 2002 for the first time in Japan, where some of CFRP plates have been detected to be peeled from their ends, recently. CFRP plates are light‐weight and anti‐corrosive comparing with steel plates, while they have problems in the durability of adhesives bonding CFRP plates to steel plates. Currently, recycled CFRP plates have been developed for the environmental load reducing. Additionally, long sized CFRP plates are required to retrofit bridge members. In this study, the effectiveness of TRS (Thread Rolling Screw) used to connect the long‐size recycled CFRP plate end to the steel girder bottom flange with adhesives is investigated through static and fatigue loading tests using large size steel girder specimens. As a result, TRS can prevent long‐size recycled CFRP plates from peeling off under allowable stress static loadings, while the long‐size recycled CFRP plates connected by only adhesives without TRS peeled off from their ends. In fatigue loading tests, TRS can also prevent long‐size recycled CFRP plates from peeling, though fatigue cracks were developed from TRS holes under higher stress range. [ABSTRACT FROM AUTHOR]

High‐strength steel materials (steel grades of S500 ‐ S960) gaining prominence in civil engineering, especially for large‐span bridges. In the case of bridges, the application of hybrid girders combining low‐ and high‐strength steel materials is an effective and economical solution. The hybrid girders generally consist of webs comprised of low‐strength steel and flanges made of high‐strength steel. In Europe, apart from some minor practical applications and research results in Sweden, these structure types are completely new solutions in bridges, and the theoretical background of their stability design is missing from the current European standardized design provisions. To determine the theoretical background of this girder type and to develop the design theories for application purposes it is essential to execute experimental laboratory test programs. Analyzing the local buckling and plastic behavior of hybrid steel plate girders through experiments is essential to have an approopriate knowledge on the geometrical and structural imperfections of the hybrid girders. Therefore, in the present paper the measurement of geometric imperfection on 14 welded hybrid steel box‐section girders with varying geometry is presented and their results are evaluated and discussed. The flanges of the examined hybrid girders are made of S700 or S500, the web of the specimens consists of S355 steel grade. The measured imperfection values are evaluated based on the steel grade and geometric parameters such as plate width or thickness. Using the measured imperfection, a numerical model will be developed to predict the bending and shear resistance of the specimens. [ABSTRACT FROM AUTHOR]

Crane runway girders are installed in industrial buildings to carry heavy loads from crane operation. The wheels of the bridge crane introduce concentrated forces in the crane runway girder via the rails. This leads to local vertical stresses in the web plates of the crane runway girders in addition to the global bending stresses. The local stresses at the top of the web usually become crucial for the fatigue design of the girder. The potential eccentricity of vertical wheel loads as well as additional horizontal forces from operation of the crane can lead to torsional rotations of the rail and the top flange and subsequently to transverse bending of the web plate of the crane runway girder. In the current design model of EN 1993‐6, the rotation at the top of the web plate is described by assuming the rail and the top flange of the girder acting as a bar under torsion, supported continuously by the bending stiffness of the web. Within this paper the existing model for the rotations is improved and it is shown that these modifications lead to more accuracy in comparison with numerical finite element calculations. It is also shown that the current simplified procedure for calculating the resulting stresses in the web is not able to adequately describe the real stresses for all practical cases. It is found that the quality of the stress predictions can significantly be improved by considering the web as a simply supported plate with the previously identified rotations on its top edge. [ABSTRACT FROM AUTHOR]

Transverse stiffeners are used in steel plate girders with slender webs to provide lateral support to the web along the span and thus increase the plate girder shear resistance. Furthermore, transverse stiffeners anchor the tension field, resulting in axial compression in the stiffener. Despite this, it is widely assumed that the design axial force provided by the FprEN 1993‐1‐5 [1] for the transverse stiffeners is significantly greater than that observed in experimental testing and numerical simulations. The results of 550 nonlinear numerical simulations of plate girders loaded in shear up to failure are presented. Shear resistance and axial stiffener forces are evaluated while the effects of a wide parameter range as web aspect ratio and thickness, flange‐to‐web area ratio, and steel grade are investigated. The numerical results are compared to the European standard design values. Finally, a statistical analysis of the set of results is presented. The numerical analyses show that the axial forces installed in the intermediate transverse stiffeners are significantly lower than those specified by FprEN 1993‐1‐5 [1]. [ABSTRACT FROM AUTHOR]

The fatigue behavior of steel girders with flange thickness transition and cope hole has been experimentally analyzed with two large‐scale cyclic tests. Special attention is paid to the arising and interacting local effects. The fatigue tests have been conducted in a four‐point bending setup. Both girders have shown fatigue‐induced failure at the flange butt welds at the thickness transition. The experimental results are presented in terms of fatigue life, differentiating the initiation and propagation life, as well as observed crack position and shape. Moreover, an advanced fatigue life prediction using the Two‐Stage‐Model is applied to the tested girders. The Two‐Stage‐Model applies the Strain‐Life and the Crack Propagation Approach to assess the total fatigue life. Thereby, the number of cycles as well as the crack shape show a good agreement with the experimental results and proves the applicability of the Two‐Stage Model for an advanced fatigue assessment. [ABSTRACT FROM AUTHOR]

With the increasing need to replace ageing bridge infrastructure, new concepts for sustainable constructions are needed. Ways to achieve this include material choice, concept design and the consideration of life‐cycle‐costs. Within the scope of FOSTA research project P1521, a concept will be derived for a modular frame corner for bridge spans up to 45 m. The load transfer of horizontal and vertical forces, as well as the bending moment of the frame corner, are analyzed in experimental tests and subsequent numerical studies. To determine the bending resistance, load paths and critical details of the connection, the node is split into an upper and lower part, connecting the main girder and the sheet‐piles respectively to the abutment. Composite dowels with high fatigue resistance are used to transfer both forces and moments through a newly designed shear connection. This article looks at the results of 4 static tests from the upper‐part series as well as numerical studies. The results of both experimental as well as numerical models shows a high load bearing capacity of the connection with the composite dowels contributing positively to the constraining of the main girder. The concept shows promising results for future application. [ABSTRACT FROM AUTHOR]

Flange thickness transitions are common constructional details in welded girders, such as crane runway girders or main girders of highway and railway bridges, to adapt the bending moment capacity of the girder to variable bending moment distributions. At these details the transverse butt weld is often decisive for the fatigue verification of the member. Based on comprehensive studies at Graz University of Technology, including also two fatigue tests, stress concentration factors for the fatigue verification of the butt welds at the girder flange were developed. However, due to the complex local stress fields at the flange thickness transition, cope holes were not included in these studies. Within a research cooperation of Graz University of Technology and Ruhr University Bochum, flange thickness transitions with cope holes are studied recently. Based on comprehensive numerical FE‐ calculations within the practically relevant geometric parameter range, the complex local stress fields near the cope hole are analyzed both, within the web and the flange plate. For validation of the FE‐model also strain measurements were carried out at large‐scale test girders. Applying the hot spot stress method, the decisive hot spots are determined, and a simplified design model is developed for an accurate prediction of these hot spot stresses. The paper presents this design model in detail and shows its accuracy ‐ compared to the FE‐results ‐ for a wide range of different geometrical conditions, as used in practice (e.g. variation of girder dimensions, flange thickness ratio, tapering to the outside and to the inside). Finally, also the results of full‐scale fatigue tests on two different welded girders with flange thickness transitions and cope holes are presented. This provides an accurate fatigue resistance for the proposed design model, based on the hot spot stress method. [ABSTRACT FROM AUTHOR]

At the main girders of a three span continuous girder railway bridge, built in the 1960s, through‐thickness cracks were detected in the web, at the location of the transverse stiffener to main girder connections. The transverse stiffeners are not welded to the girder flange, in order to increase their fatigue resistance. Instead, fitting strips between the stiffeners and the bottom flanges were used. First of all, the paper presents the results of local strain measurements at the original detail, without any reinforcement, for individual train passages. These results confirm a distortion‐induced fatigue failure, due to an unexpected high‐frequency oscillation of the web plate. Based on that, three different types of reinforcement were developed and installed at the bridge. For each type of reinforcement further strain measurements were done during regular train service. Also, a weigh‐in‐motion‐system was installed, to specify a representative passenger and freight train each. From the local strain measurements, during the passage of these two trains, the stress‐spectra were evaluated for all three types of reinforcement. Furthermore, existing fatigue test data of a similar connection detail from the literature were reassessed in order to provide an accurate fatigue resistance for the damage accumulation. The comparison of the evaluated fatigue damage of these individual stress spectra indicates the efficiency of each type of reinforcement. Finally, also representative reduction factors of the initial stress ranges without reinforcement, were developed for each type of reinforcement. This allows a more generalized assessment, regarding the efficiency of the different types of reinforcement, not just valid for individual trains but also for the whole train traffic. [ABSTRACT FROM AUTHOR]

Thin‐walled cold‐formed sections are extensively used as primary structural elements in storage system structures or steel houses, or as secondary elements like roof and wall systems, floor girders, etc. Despite their many advantages, such as transportability and lightweight, these members are usually susceptible to lateral‐torsional buckling as they are not always laterally restrained. This paper deals with the elastic stability of such beams and, in particular, is focusing on cross‐sections that are symmetrical about their major axis only, like channel or sigma profiles, and loaded perpendicular to their axis of symmetry. Their stability has been studied analytically, in accordance to available provisions in the concerned codes, and numerically with two different finite element tools. [ABSTRACT FROM AUTHOR]

Typically, longitudinal stiffeners of plated structures pass through the entire girder (continuously) or span from one transverse stiffener to another (discontinuously). The present research deals with a design method predominantly executed in crane manufacturing – non‐continuous longitudinal stiffening. Non‐continuous longitudinal stiffeners end within the buckling field, i.e., leaving a gap ahead of the transverse stiffener or the end of the girder. To date, the standardization in EN1993‐1‐5 is limited to conventional longitudinal stiffening (continuous and discontinuous), as defined above. This paper deals with a numerical study aiming to obtain initial insights into the load‐bearing behavior of non‐continuously stiffened plates. Geometrically and materially nonlinear buckling analyses with imperfections (GMNIA) are performed to provide the foundation for a series of experimental tests. Alongside the realization of realistic boundary conditions, estimating the most realistic ultimate load‐bearing capacity is of particular importance to comply with the constraints in the laboratory. The simulations reveal a significant load‐bearing behavior and capacity modification compared with conventional longitudinal stiffening. [ABSTRACT FROM AUTHOR]

Vertically acting wheel loads from overhead bridge cranes and potential additional horizontal crane loads induce two types of stresses in crane runway girders: i) global stresses due to bi‐axial bending and torsion and ii) local stresses which mainly affect the girder's web. The latter typically represent one of the most decisive criteria for the fatigue design check of welded girders and are the focus of this paper. Crane rails with foot flange are typically connected to the top flange with rail clips. These clips maintain the position of the rail in vertical and horizontal transverse direction, but they generally allow for longitudinal movement of the rail. Rails with foot flange are used with and without elastomeric bearing pads between the rail and the top flange of the girder. The local stresses in the webs of crane runway girders are strongly affected by discontinuities of the crane rails. Such discontinuities can originate from unplanned rail cracks as well as planned rail expansion joints. The current mechanical models for concentric as well as eccentric wheel loading in relevant design standards assume continuous crane rails. However, rail joints are expected to significantly increase the local stresses in the region beneath rail joints. The present paper focuses on the impact of rail joints on the local stresses in crane runway girders. The research activities comprise experimental tests as well as finite element calculations. The aim of the investigations is to develop a better understanding of the mechanical behaviour in order to avoid future fatigue damage due to an unexpected increase of local stresses at a rail joint. [ABSTRACT FROM AUTHOR]

Aluminium provides many advantages as a construction material in civil engineering, such as for example light weight, functionality by extruded profiles and corrosion resistance. It is obvious to use these advantages also for trusses. However, most aluminium alloys develop zones of weakening due to welding. The so called heat affected zones (HAZ) reduce the load‐bearing capacity of welded aluminium joints by up to 50%. Consequently, the design and execution of welded X‐joints within lattice girders are challenging. Indeed, the design of welded aluminium X‐joints is not specifically treated in EN 1999. Until now, the calculation of aluminium welded X‐joints relies on the steel standard EN 1993‐1‐8, which does not take into account the characteristic of aluminium. This results in errors and inefficient design. Thus, in this experimental research project the behavior of welded X‐joints in real‐scale models is explored. To this purpose, tests have been carried out on lattice girders made from aluminium alloy EN AW 6082 T6. In total, six girders with varying coefficient β and shape of the hollow section of brace members have been investigated. Thereby, the girders were loaded vertically until the failure of the X‐joints. Strains at the brace and chord members were measured by strain gauges and respective stresses were derived. In addition, a comparative analysis between experimentally and theoretically ‐ based on Eurocodes (EN 1993 part 1‐8 and EN 1999 part 1‐1) ‐ obtained results has been made. The analysis shows that the reduction of the load‐bearing capacity of welded aluminium X‐joints due to the HAZ is not constant but varies with the value of coefficient β and the shape of the cross‐section of the brace member. Obviously, the design of welded aluminium X‐joints based on EN 1993‐1‐8 applying a constant value for the HAZ does not reflect the true behavior of these joints as it leads to a quite conservative design approach. [ABSTRACT FROM AUTHOR]

For the area developments on IJburg in Amsterdam, there was a need to connect the various islands with the mainland. The connection between the 'Centrumeiland' and the 'Strandeiland' is the Gerda Taro Bridge; with 'Bridge 2125' as project name. The Gerda Taro Bridge is part of the bridge family 'Buitenwater'. The bridge is suitable for all types of road traffic and has a total length of approximately 115m. Royal HaskoningDHV did the complete engineering of the road bridge for both the tender phase and all design phases up to and including implementation in collaboration with contractor Ballast Nedam. The Gerda Taro Bridge consists of a steel‐concrete supporting structure. Both the main girders and cross girders consist of welded I‐sections. The concrete deck is connected by means of studs, ensuring composite action between the steel and the concrete. The deck structure is supported by spatially oriented steel hollow sections on five intermediate supports. [ABSTRACT FROM AUTHOR]

Assessment of the structural behaviour of steel and steel‐concrete composite plate girders exposed to web shear buckling is essential when it comes to their implementation involving heavy loads and/or long spans. In this paper, numerical model of a benchmark steel‐concrete composite girder capable of capturing this phenomenon has been developed using the ABAQUS software. The developed finite element model, based on a series of large‐scale girders planned to be tested in the future, has been evaluated and elaborated on. That includes the implementation of appropriate analysis procedures, element types and contact behaviour in the study of the post‐critical buckling behaviour of steel and steel‐concrete composite plate girders. The advantages and disadvantages as well as recommendations for the future use of the investigated modelling strategies have been scrutinized. In the end, this study demonstrates the parameters with the most significant influence on the structural behaviour of composite girders exposed to shear loading. [ABSTRACT FROM AUTHOR]

Sinusoidal corrugated web girders, which are in the focus of the current paper, have been increasingly used in the past years in civil engineering applications due to economical design. Recently, a number of experiments dealing with the particular behaviour of this girder type have been carried out at room temperature, while the structural behaviour at elevated temperature has not been widely analysed and requires further investigation and clarification. The current paper deals with the improved geometrically and materially nonlinear analysis with imperfections (GMNIA) of sinusoidal corrugated web girders under fire conditions. The developed finite element model, which is validated based on previous measurements during fire tests found in the international literature, is capable of modelling the specialties, e.g., the so‐called 'accordion effect', of corrugated web girders. The applicability of design formulae is also illustrated in the paper while an extensive numerical parametric study is also carried out to demonstrate the impact of different parameters on the stability behaviour and failure mode of corrugated web girders at elevated temperature. [ABSTRACT FROM AUTHOR]

3D nonlinear FE analyses of existing plate‐girder bridges were carried out to investigate system redundancy. A comparison of the ultimate live load factors between a whole bridge system (WBS) model and a single girder (SG) model shows that WBS's ultimate live load factor is larger than SG's factor. This difference in the ultimate load factors is interpreted as the system redundancy effect. A system factor to quantify the system redundancy has been proposed based on the nonlinear FE analysis results. The proposed system factor is defined as a factor to convert the ultimate live load factor and rating factor for load rating based on linear analysis into those based on nonlinear analysis. A case study to calculate the system factor for three existing bridges shows dependency of the system factor on the number of girders, composite/non‐composite girders, simple span/continuous span. [ABSTRACT FROM AUTHOR]

In traditional structural crane design, the fatigue strength of the structure is qualitatively evaluated, only depending on the steel type, working level and joint form, which leads to the excessive service life of some parts of the existing main girder structure, resulting in a waste of industrial resources and manufacturing costs. Based on the concept of equal life design, this paper obtained the service information of the crane in the scheduled inspection period through the rapid prediction method of "field collection+machine learning." Combined with the bearing capacity evaluation method and the fatigue life assessment method of "S-N curve+fracture mechanics," a nonlinear mixed integer equal life optimization model of crane girder structure was established, and the multi-specular reflection optimization algorithm was used to optimize the life distribution at different positions and overall weight of the main girder. The structural design parameters of the crane main girder which meet the bearing capacity and have the characteristics of "equal life+lightweight" were obtained. The performance of the optimized main girder structure was verified by finite element simulation. The results show that this method can realize the quantitative control of the life distribution of each position of the crane main girder structure and the lightweight design of the whole structure, and provides a scientific reference for the equal life and lightweight design of large construction machinery products. [ABSTRACT FROM AUTHOR]

An analytical exploration of the effects of shear span-to-depth ratio on the shear strength of reinforced concrete beams was carried out using a meso-scale finite-element method. Prior to the numerical analysis, a method of defining concrete as meso-scale composites of multi-phases was described. The concrete was assumed to be a composite with three phases (aggregates, cement matrix and interfacial transition zone), and the material properties of each phase were applied for the numerical analysis. The shear failure behaviour of reinforced concrete beams was examined by the numerical model that was constructed, and the effect of span-to-depth ratio on shear strength was confirmed through these analyses. An investigation of cases where span-to-depth was less than 1.0 was also carried out. Moreover, the performance of the numerical model was evaluated by comparing the numerical results with the experimental results obtained from the model code and other researchers. It was confirmed that the application of a meso-scale finite-element method was appropriate for the study on the effect of span-to-depth ratio on shear strength and the occurrence and progress of bending and shear cracks. [ABSTRACT FROM AUTHOR]

This paper presents the experimental testing and numerical simulations of four full-scale I-shaped welded steel girders to examine their lateral–torsional buckling (LTB) and lateral–distortional buckling (LDB) behaviors and evaluate the adequacy of the associated provisions in North American steel design standards. The test specimens and setup are first presented, followed by the experimental test results used to assess the inelastic LTB and LDB behaviors. A corroborated finite-element model is then used to further evaluate the influences of web distortion on the flexural response of the girders and to assess the adequacy of the design provisions when applied to girders with web depth-to-thickness ratios close to the Class 2/3, or compact/noncompact boundary (i.e., h/w≈90). The results show that LDB, in combination with inelastic LTB, influences the flexural response and resistance of welded steel girders with webs of this slenderness. Furthermore, the North American steel design provisions may overestimate the flexural moment resistance of such girders. [ABSTRACT FROM AUTHOR]

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The development of infrastructure is progressing rapidly, particularly for National Strategic Projects, such as the construction of the Jakarta-Cikampek Toll Road (Japek) South II Package 3, which is currently in progress. This toll road project also includes the construction of several interchanges that utilize girders in the process. The purpose of this study is to identify the dominant risk and risk control in erection girder work in the Japek Selatan II Package 3 toll road project. The project commenced during a challenging time when Indonesia was facing the adverse effects of the Covid-19 pandemic, adding an additional obstacle to infrastructure work. Girder Erection Work, in particular, has recorded various types of accidents over the past few years. In response, the Ministry of Public Works and Public Housing has issued Ministerial Regulation No. 10 of 2021, which provides guidelines for Construction Safety Management Systems (SMKK). By employing the Hazard Identification, Risk Assessment, and Risk Control (HIRARC) method, it is anticipated that construction practitioners can effectively manage risks and reduce workplace accidents in this project. Additionally, the Probability Impact Matrix (PIM) will be utilized to identify the most likely hazards and risks that could significantly impact the project's implementation in the event of an accident. In this study, out of the 57 variables validated by experts, the respondents identified 17 risks classified as high-risk and determined 8 main/dominant risks in the girder erection work of the Jakarta-Cikampek Toll Road Japek South II Package 3 Project. Subsequently, control measures and mitigations are planned for these 8 main risks. [ABSTRACT FROM AUTHOR]

This paper carried out wind tunnel tests and numerical analysis to study the effect of the spatial position of deflector plates on the vortex-induced vibration (VIV) of a double-deck truss girder. The wind tunnel tests found that setting the web deflector plate and the lower chord deflector plate significantly suppressed the VIV. In order to study the suppression mechanism of the deflector plate on VIV, numerical simulations were conducted using the computational fluid dynamics (CFD) method. We analyzed the suppression mechanism of the deflector plate on VIV by combining the vertical amplitude obtained by numerical simulation with the change in the vorticity magnitude and direction. The results showed that the flow velocity around the lower surface of the airflow was reduced, resulting in significantly lower vorticity at the exact position of the lower chord deflector plate and web deflector plate section compared to the original section. The web deflector plate and the lower chord deflector plate broke the vortex shedding mode in the wake flow region, and the vortex shedding frequency was far away from the self-oscillation frequency of the double-deck truss girder, thus suppressing the VIV. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)