Composite Bridge Research Articles

RBF-PSO-IS: An innovative metamodeling for reliability analysis of bridge's vortex-induced vibration

The complexity of vortex-induced vibration (VIV) instability analysis originates from the variability of the wind environment, the randomness of the analytical model, the ambiguity of the failure criterion, and the high-dimensional nonlinearity and non-explicitness nature of the instability function. This paper addresses the low sampling efficiency and challenges in approximating failure probability in prior research on reliability. By integrating an adaptive sampling strategy with particle swarm optimization (PSO), an initial VIV reliability metamodel is established, which is subsequently resampled to create a more refined metamodel. A combination of multiple reliability algorithms is then employed to calculate the maximum amplitude of VIV and the failure probability of the VIV interval. The validity and accuracy of the proposed method are demonstrated through two representative numerical examples. The results indicate that the proposed radial basis function (RBF)-PSO-importance sampling (IS) analysis method and its adaptive random sampling strategy can significantly reduce the computational cost associated with extensive finite element model operations and the complexity arising from the high-dimensional nonlinearity and non-significance of the limit state function (LSF). This method enables researchers to achieve more accurate and time-saving solutions for VIV in steel–concrete composite bridges.

Crashworthiness design of GFRP bar reinforced concrete bridge pier subjected to truck collision

This study investigates the failure behavior and post-impact damage of glass fiber reinforced polymer (GFRP) bar reinforced bridge pier under truck collision. The finite element model of a benchmark bridge with its pier reinforced with GFRP bars collided by a medium truck is established using LS-DYNA. The effectiveness of adopted material models and contact algorithm is verified by comparing the experimental and numerical observations of scaled GFRP reinforced concrete columns under horizontal impact loading. The failure analysis results show that the post-impact damage of the composite pier can be classified into four levels, and the shear force at pier bottom is a reasonable index that can represent the dynamic shear capacity of the composite pier. Besides, the influence of design variables on the dynamic shear capacity of the bridge pier is clarified, and a closed-form formula is proposed to predict the dynamic shear capacity based on response surface methodology. Furthermore, kinetic energy-based damage index and damage evaluation approach are developed to forecast the post-impact damage levels of the composite bridge pier. Finally, combining the post-impact performance objectives and damage evaluation approach, a performance-based crashworthiness design framework is developed and validated to provide a basic reference for design consideration of GFRP reinforced concrete bridge pier.

Experimental study on interfacial shear behavior of PBL shear connector deeply embedded in UHPC

To analyze the shear capacity and failure mechanism of perfobond strip (PBL) connectors in the junction of the steel-UHPC composite pedestrian truss bridge, this study conducted monotonic loading push-out tests on four specimens of PBL shear connector deeply embedded in UHPC and one specimen in normal concrete. The research primarily investigated the interfacial shear behavior of PBL connectors under static load, focusing on the effects of different concrete types, embedded depth of PBL connector, and diameter of transverse reinforcing bar, especially in the situation with a deep 240 mm embedded depth of PBL connectors. The results showed that the shear capacity of PBL connector in UHPC was 76% higher than that in normal concrete specimen. For UHPC specimens with 240 mm embedded depth, the failure mode of the specimens with 16 mm and 25 mm transverse reinforcing bar diameter was steel plate destroy while the specimens with 12 mm transverse reinforcing bar diameter showed transverse reinforcing bar fracture. Reducing the embedded depth of the PBL connector with 12 mm diameter transverse reinforcing bar increased the initial stiffness and shear capacity of PBL connector, but decreased the ductility. In this study, the experimental results were compared with several calculation equations, and a modified equation was proposed for PBL connectors deeply embedded in UHPC based on the force transferring mechanism and different failure modes. The predicted results were in good agreement with the experimental results. Furthermore, some design suggestions for PBL connectors deeply embedded in UHPC were concluded in this paper.

The behaviour of the Aluminium Bridge with comparison of composite steel bridge

The behaviour of the Aluminium Bridge with comparison of composite steel bridge

Investigations on influences of Engineered Cementitious Composites (ECC) on pull-out properties of studs in steel-concrete composite bridge

Stud plays an important role in the connection of steel-concrete composite bridge (SCCB). The stud is under pull-out load in the negative moment zone of SCCB. Engineered Cementitious Composites (ECC) are a new type of materials with tensile strain hardening and multiple cracking behavior to strengthen SCCBs. In this study, the cyclic pull-out effect on the ECC-stud connection was studied through pull-out tests. The stud diameter (d=13/16 mm) and the embedment depth (hef=40/60/80 mm) are included as design parameters, resulting in a total of 18 specimens of six scenarios. The failure mode, load-bearing capacity, and ductility factor of the specimens under cyclic loading are compared with those under monotonic loading, and the stiffness, energy dissipation capacity, and residual displacement of the specimens under cyclic loading are analyzed. Based on the experimental results, under cyclic loading, the concrete cone failure and splitting failure occur, and the threshold of hef/d between the two failure modes is 3.75–4.62, which is smaller than the threshold of the monotonic scenarios. Both concrete and splitting failure modes show ductile failure characteristics because of the bridging effect of fibers in ECC. The load-bearing capacity and ductility factor under cyclic loading are lower than those under monotonic load. This is because, under cyclic loading, the specimens show cumulative damage, which, however, is weakened due to the strengthening effect of ECC. As d and hef increase, the load-bearing capacity, ductility factor, stiffness, and energy dissipation capacity increase correspondingly, and the residual displacement decreases. The stud with a larger d shows a more obvious ductility holding stage.

Theoretical Method to Predict Internal Force of Crossbeam in Steel–Concrete Composite Twin I-Girder Bridge under Torsional Loading

During the operational phase of a bridge, the crossbeam, acting as a supporting member, plays an important role in keeping the cross-sectional shape constant in addition to resisting against various lateral and longitudinal loads and distributing the dead and the live loads to the adjacent main girders. The complex functional requirements lead to a complex internal force composition of the crossbeam. When subjected to torque, the two main beams of the twin I-girder bridge will have deformation in opposite longitudinal directions (known as warping deformation) to counteract the torque. The existing research has not considered the impact of main beam warping deformation on the internal force of the crossbeam. Based on the existing research, this article further considers the impact of main beam warping deformation on the internal force of the crossbeam, making the calculation of the internal force of the crossbeam more accurate. The results show that the torsional characteristics of the continuous twin I-girder bridge can be calculated using Vlasov’s theory of thin-walled structures combined with the displacement method. As for the effect of the crossbeam on the torsional stiffness of the structure, it can be managed by making the crossbeam stiffness continuous; however, in general, the equivalent stiffness is small compared to the stiffness of the main beam and it can be ignored. The crossbeam can be simplified to a bar with two solid ends for the internal force calculation whose formula is proposed in this paper, based on the existing frame model, and it can further consider the influence of warping deformation of the main beam on the internal force of the beam, and the calculation accuracy is high.

A Damage Detection Approach in the Era of Industry 4.0 Using the Relationship between Circular Economy, Data Mining, and Artificial Intelligence

Over the last decades, the emergence of new technologies has inspired a paradigm shift for the fourth industrial revolution. For example, circular economy, data mining, and artificial intelligence (AI), which are multidisciplinary topics, have recently attracted industrial and academic interests. Sustainable structural health monitoring (SHM) also concerns the continuous structural assessment of civil, mechanical, aerospace, and industrial structures to upgrade conventional SHM systems. A damage detection approach inspired by the principles of data mining with the adoption of circular-economic thinking is proposed in this study. In addition, vibration characteristics of a composite bridge deck structure are employed as inputs of AI algorithms. Likewise, an artificial neural network (ANN) integrated with a genetic algorithm (GA) was also developed for detecting the damage. GA was applied to define the initial weights of the neural network. To aid the aim, a range of damage scenarios was generated and the achieved outcomes confirm the feasibility of the developed method in the fault diagnosis procedure. Several data mining techniques were also employed to compare the performance of the developed model. It is concluded that the ANN integrated with GA presents a relatively fitting capacity in the detection of damage severity.

Experimental research on curved continuous steel-concrete composite twin I-girder bridge

Due to the excellent economy and convenient erection, curved continuous steel–concrete composite twin I-girder (CTIG) bridges have been applied in mountainous bridges and unban overpasses. Rigorous investigation of the bending-torsion interaction is important for the curved continuous CTIG bridge design. A CTIG model bridge with a span arrangement of 17.46 m + 17.46 m and a curved radius of 200 m, was fabricated and tested under a symmetric static load. The mechanical behavior and failure modes of the model bridge were investigated. Results show that the non-uniform torsion and the web distortion effect are the characteristic mechanical behaviours of the curved CTIG bridge. The crossbeams resist the web distortion to ensure the transmission of the torsional moment. The constraint of the web distortion by the crossbeams results in the bottom flanges of the CTIG bridge being subjected to additional lateral bending moments. The ultimate strength of the CTIG bridge studied in this research is reached by a shear failure involving web buckling, formation of diagonal web yielding, and concrete deck crushing. This study contributes to a deeper understanding of the mechanical behavior of the curved continuous CTIG bridge and provides a valuable experimental basis for research regarding the design of bridges of this type.

Fatigue test study of weathering steel-concrete composite beam under corrosive environment

In this paper, two sets of comparative fatigue tests on weathering steel-concrete composite girders were carried out in the context of steel-concrete composite girder bridges. The load-deflection relationship of the weathering steel-concrete composite girders under fatigue loading in different environments was investigated contrastively. The experimental results show that under the coupled effect of corrosive environment and fatigue load, the weathering steel still shows obvious corrosion; the simple fatigue load has no significant effect on the stiffness and fatigue modulus of the weathering steel-concrete composite beam, while the coupled effect of corrosive environment and fatigue has a significant weakening effect on the stiffness of the beam, and the weakening of concrete is apparently greater than that of steel beam.

Composite Bridge Girders Structure Health Monitoring Based on the Distributed Fiber Sensing Textile

Distributed structure health monitoring has been a hot research topic in recent years, and optic fiber sensors are largely developed for the advantages of high sensitivity, better spatial resolution, and small sensor size. However, the limitation of fibers in installation and reliability has become one of the major drawbacks of this technology. This paper presents a fiber optic sensing textile and a new installation method inside bridge girders to address those shortcomings in fiber sensing systems. The sensing textile was utilized to monitor strain distribution in the Grist Mill Bridge located in Maine based on Brillouin Optical Time Domain Analysis (BOTDA). A modified slider was developed to increase the efficiency of installation in the confined bridge girders. The bridge girder’s strain response was successfully recorded by the sensing textile during the loading tests that involved four trucks on the bridge. The sensing textile demonstrated the capability to differentiate separated loading locations. These results demonstrate a new way of installing fiber optic sensors and the potential applications of fiber optic sensing textiles in structural health monitoring.

Numerical Investigation on Novel Shear Connectors in Prefabricated Composite Beams

An innovative horizontal-arranged shear stud was proposed for prefabricated composite beams, in response to the engineering demand for accelerated precast decks construction on steel–concrete composite bridges. In order to verify the shear behavior of the studs, a push-out test was performed in which two groups of specimens were designed, and each group included three specimens. In addition, a finite element method based on the ABAQUS2020 software was adopted to analyze the influence factors of the prefabricated studs, which reveals the most influential factor, to provide a guide for optimum design. Therefore, 10 models were established, including one finite element model with the same parameters as the push-out test, and 9 models based on an orthogonal testing design. The results showed that, firstly, the prefabricated shear studs had longitudinal shear resistance, the same as conventional shear studs. Secondly, the ultimate load capacity, as well as the ductility of the prefabricated studs, was better than conventional studs. Thirdly, the modeling results were in good agreement with the push-out test results, which indicated the validity of the modeling method. Lastly, by analyzing the calculated results of the nine orthogonal models, it was found that the stud diameter was the most influential factor for the shear capacity, and the shear capacity was directly proportional to the stud diameter, while it was not proportional to the other factors. This study is evidence that the orthogonal testing design has a high efficiency in finite element modeling, which will provide a guide for the optimum design of prefabricated shear studs.

Application And Improvement of Composite Materials in Truss Bridge Structure

Composite materials are new materials with the features of light weight, high strength, high specific modulus, strong corrosion resistance, and aging resistance. The truss structure is subject to unidirectional force, which gives full play to the advantages of high strength of composite materials along the fiber direction. Therefore, composite truss structure is gradually attracted attention in engineering fields, i.e., aerospace, bridges, and construction. By analyzing the application status of composite truss bridge at home and abroad, it can be concluded that compared with traditional steel truss, composite truss bridge has advantages in flexural performance, tensile performance, stability and other mechanical properties. However, due to the stiffness control design, the strength of composite material is not fully utilized, and the structural reliability of composite truss bridge is low due to the low efficiency of structural joints. The improvement methods of these two problems are reducing the allowable deflection-span ratio of composite truss bridge design and using composite materials with greater stiffness and changing the laying Angle and laying proportion of composite materials, respectively.

Load Distribution Factors For Horizontally Curved Composite Concrete-Steel Girder Bridges

This paper focuses on Load distribution factors for horizontally curved composite concrete-steel girder bridges. The finite-element analysis software“SAP2000” is used to examine the key parameters that can influence the distribution factors for horizontally curved composite steelgirders. A parametric study is conducted to study the load distribution characteristics of such bridge system due to dead loading and AASHTO truck loading using finite elements method. The key parameters considered in this study are: span-to-radius of curvature ratio, span length, number of girders, girders spacing, number of lanes, and truck loading conditions. The results have shown that the curvature is the most critical factor which plays an important role in the design of curved girders in horizontally curved composite bridges. Span length, number of girders and girder spacing generally affect the values of the moment distribution factors. Moreover, present study reveals that AASHTO Guide criterion to treat curved bridges with limited curvature as straight one is conservative. Based on the data generated from the parametric study, sets of empirical equations are developed for the moment distribution factors for straight and curved steel I-girder bridges when subjected to the AASHTO truck loading and due to dead loading.

Experimental investigation on mechanical behavior of T-type perfobond rid shear connectors under combined shear and tension

The stress of shear connectors becomes more complicated as the span length of steel-concrete composite bridges increases. To bear the great shear and uplift forces, a T-type perfobond rib (T-type PBL) shear connector with sufficient stiffness and ductility is proposed. While the shear behavior of T-type PBL connectors has been evaluated in previous studies, its mechanical performance under combined shear and tension is not well understood due to the particular shape and numerous impact factors. Therefore, one pull-out test considering pure tension and seven modified push-out tests considering combined shear and tension were carried out to investigate the failure mode, bearing capacity, and load-slip behavior of T-type PBL connectors under combined actions. The pull-out test was performed to determine the tensile resistance, followed by a series of modified push-out tests with constant horizontal tension to investigate the structural behaviors. Additionally, the effects of the rib height, flange width, and hole numbers were evaluated. Based on the test results, conical failure surfaces formed from the flange of the T-type PBL to the concrete surface for all specimens, and the concrete failure angle was approximately 32°. The bearing capacity of the specimen improved by 26% when the perfobond rib height increased from 100 mm to 120 mm, but the flange width barely had any effect. The capacity of 1-hole specimen dropped by 20% while 2-hole specimen increased by 8% compared to the standard specimen, which may relate to the distance between adjacent holes. Increasing the rib height by 25% and 50% reduced the initial relative slip (S90) by 30% and 32%, respectively, indicating the improvement in initial stiffness. Generally, the pull-out resistance of the T-type PBL shear connector was enhanced by increasing the flange width, rib height, and number of holes. An evaluation equation considering the hole number and hole spacing was suggested for the bearing capacity of T-type PBL shear connectors under the combined actions. The validity was verified by test results, with a calculated-to-test-result ratio of 1.12 and standard deviation of 0.15. This study could enhance the understanding of the behavior of T-type PBL connectors under the combined actions, and promote the potential application in long-span composite bridge decks.

Full-Scale Fatigue Test and Finite Element Analysis on External Inclined Strut Welded Joints of a Wide-Flanged Composite Box Girder Bridge.

For a wide-flanged composite box girder bridge, the risk of fatigue cracking in the external inclined strut welded joint under the fatigue vehicle load is a problem. The main purposes of this research are to verify the safety of the main bridge of the Linyi Yellow River Bridge, a continuous composite box girder bridge, and to propose suggestions for optimization. In this research, a finite element model of one segment of the bridge was established to investigate the influence surface of the external inclined strut, and, using the nominal stress method, it was confirmed that the fatigue cracking of the welded details of the external inclined strut was risky. Subsequently, a full-scale fatigue test of the external inclined strut welded joint was carried out, and the crack propagation law and S-N curve of the welded details were obtained. Finally, a parametric analysis was conducted with the three-dimensional refined finite element models. The results showed that the welded joint in the real bridge has a fatigue life larger than that of the design life, and methods such as increasing the flange thickness of the external inclined strut and the diameter of the welding hole are beneficial to improve its fatigue performance.

Optimization of Construction Process and Determination of Intermediate Cable Forces for Composite Beam Cable-Stayed Bridge

This paper presents a comprehensive study of the Xiangsizhou Bridge, a double-tower double-cable steel–concrete composite girder cable-stayed bridge located in Pingnan, Guangxi, China. A finite element model of the full-bridge spatial truss system was established using a dual main beam simulation of the steel–concrete composite girder. To obtain the initial reasonable bridge state, the minimum bending energy method was employed, followed by optimization of the state using the unknown load coefficient method to attain the final reasonable completion state. This paper proposes an innovative construction scheme for the erection of the main girders, which is designed to address the issue of excessive tensile stresses in the bridge deck slabs that can arise in conventional construction schemes. This scheme can save about 4 months of construction time and shorten the construction cycle of main beam erection by 60%. Furthermore, the study derived and verified a formula for the intermediate cable force during the construction process, which demonstrated its effectiveness. This study provides practical value for the design and construction of similar bridges.

A Review of Fibre Reinforced Polymer Bridges

Fibre-reinforced polymer composites (FRPs) offer various benefits for bridge construction. Lightweight, durability, design flexibility and fast erection in inaccessible areas are their unique selling points for bridge engineering. FRPs are used in four bridge applications: (1) FRP rebars/tendons in concrete; (2) repair and strengthening of existing bridges; (3) new hybrid–FRP bridges with conventional materials and (4) all–FRP composite new bridges made entirely of FRP materials. This paper reviews FRP bridges, including all–FRP and hybrid–FRP bridges. FRP bridges’ history, materials, processes and bridge components—deck, girder, truss, moulded parts and cables/rebars are considered. This paper does not discuss the use of FRP as an architectural element and a strengthening system. While lack of design codes, material specifications and recycling are the major challenges, the high cost of FRPs still remains the most critical barrier to the progress of FRPs in bridges.

Current Evidence on the Fiber-reinforced Composite Bridges

Current Evidence on the Fiber-reinforced Composite Bridges

Vibration Serviceability Evaluation of a Single Span Steel–Concrete Composite Foot Bridge under Dynamic Pedestrian Loadings Considering Moving Mass Effect

In this paper, we present the analysis results on the vibration serviceability of a pedestrian bridge considering the effect of pedestrian moving mass inertia. Using dynamic finite element analysis, we considered different walking scenarios, including pedestrian density, walking speed, random walking, and synchronized walking, to analyze the acceleration response of a 40m long single-span bridge with a steel composite box cross section. We showed that the equivalent fixed mass analysis method did not significantly differ from the moving mass analysis in the random walk scenario and a wider frequency excitation band may be useful to consider when evaluating vibration serviceability in a random walk scenario.

Vibration Influence on Structural Perspectives According to Pedestrian Traffic Type of Pedestrian Bridge

The vibration acceleration response and excellent frequency generated by pedestrian’s walking type of the steel composite wooden bridge were measured and analyzed. Based on the modified Reiher-Meister vibration curve, vibration influence evaluation on the structural perspectives of the pedestrian bridge was performed. The pedestrian’s walking types were divided into walking, running, rolling, and shaking, and eight experimental cases were set up by combining them with the number of users and moving direction. A total of 37 measurements were made. To evaluate the vibration serviceability of pedestrian bridges, the pedestrian’s walking type must be considered, and a standardized study on the pedestrian’s walking type will be necessary in the future.