Bridge Expansion Joints Research Articles

A numerical analysis of inclination and rectification of ramp-bridge piers adjacent to surcharge load in soft clay area

The surrounding surcharge has an adverse impact on the service performance of buildings and bridges, and it can endanger their structural safety, especially in soft soil areas. As one case study, the inclination accident of an expressway ramp bridge and its rectification are investigated in this study. Through the three-dimensional (3D) finite element (FE) analysis of the overall structures composed of the bridge span, the pier, and the pile foundation, the whole process of the inclination by the adjacent dumped earth, partial recovery by the unloading, and the lateral pushing rectification of the bridge structure were simulated. The results show that the surcharge load leads to soil displacement near the bridge pile, and the pile-soil interaction leads to the pile deformation, which further causes the inclination of the pier, and the movement of the bridge span. The severity of the accident can be measured by the inclination of the piers and the opening widths of the bridge expansion joints. Due to the plastic deformation and drainage consolidation of the soft clay foundation under the surcharge load, the inclination of the piles and piers cannot be fully recovered after unloading. In order to capture these processes, the FE simulation was divided into three steps. First, the drainage consolidation of the soil foundation were identified by FE simulation and the field measurement of the recovery of the structure after unloading. Second, the effects of soil properties, the surcharge time and surcharge strength on the bridge inclination and the recovery capacity after unloading are discussed. Finally, the rectification of the bridge by lateral pushing was simulated, and the deformation and stress in the pier and pile were calculated to evaluate the safety of the structures. These analyses provided understanding towards the prevention of the bridge inclination under surcharge load, prediction of the recovery by the unloading, and the methods to reduce the residual deformation to meet the specifications.

Progressive Classifier Mechanism for Bridge Expansion Joint Health Status Monitoring System Based on Acoustic Sensors.

The application of IoT (Internet of Things) technology to the health monitoring of expansion joints is of great importance in enhancing the efficiency of bridge expansion joint maintenance. In this study, a low-power, high-efficiency, end-to-cloud coordinated monitoring system analyzes acoustic signals to identify faults in bridge expansion joints. To address the issue of scarce authentic data related to bridge expansion joint failures, an expansion joint damage simulation data collection platform is established for well-annotated datasets. Based on this, a progressive two-level classifier mechanism is proposed, combining template matching based on AMPD (Automatic Peak Detection) and deep learning algorithms based on VMD (Variational Mode Decomposition), denoising, and utilizing edge and cloud computing power efficiently. The simulation-based datasets were used to test the two-level algorithm, with the first-level edge-end template matching algorithm achieving fault detection rates of 93.3% and the second-level cloud-based deep learning algorithm achieving classification accuracy of 98.4%. The proposed system in this paper has demonstrated efficient performance in monitoring the health of expansion joints, according to the aforementioned results.

Sound Damage Detection of Bridge Expansion Joints Using a Support Vector Data Description.

A novel method is proposed for the damage identification of modal bridge expansion joints (MBEJs) based on sound signals. Two modal bridge expansion joint specimens were fabricated to simulate healthy and damaged states. A microphone was used to collect the impact signals from different specimens. The wavelet packet energy ratio of the sound signal was used to identify the difference in specimen state. Firstly, the wavelet packet energy ratio was used to establish the feature vectors, which were reduced dimensionality using principal component analysis. Subsequently, a support vector data description model was established to detect the difference in the signals. The identification effects of three parameter optimization methods (particle swarm optimization, genetic algorithm optimization, and Bayesian optimization) were compared. The results showed that the wavelet packet energy ratio of sound signals could effectively distinguish the state of the support bar. The support vector data description of Bayesian optimization worked best, and the proposed method could successfully detect damage to the support bar of MBEJs with an accuracy of 99%.

Asphalt plug joint geometric analysis and improvement

Due to its unique advantages such as driving comfort, shock absorption, noise reduction, and convenient management and maintenance, Asphalt Plug Joint has been rapidly developed and applied. However, subject to the long-term coupling action of traffic loads and environmental factors, the Asphalt Plug Joint is prone to interface effects and stress concentration resulting in damage, especially the stress concentration at the contact part between the expansion joint and the steel cover plate is more prominent. The interface between the bridge expansion joint and the pavement, as well as the interface between the bridge expansion joint and the edge of the spanning slab, is prone to stress concentration. To solve the above problems, proposed an improved design scheme of the Asphalt Plug Joint: (1) The bonding performance of the interface has a great impact on the service life of the expansion joint. Therefore, through the pull-off and oblique shear tests, the binder with good bonding performance is selected, and the test data is introduced into the cohesion model to simulate the interface contact. (2) Through the finite element simulation analysis, the main parameters of the Asphalt Plug Joint, such as friction coefficient and the cross section form of the cross-seam plate, are analyzed. The results show that the reasonable use of binder can effectively improve the bonding performance of asphalt binder interface; The debonding of the steel cover plate and asphalt mixture and the easing of the cross section form of the joint slab edge can better adapt to the stress caused by the bridge vehicle and temperature load. The optimization of the geometric design of the steel cover plate has a significant effect on improving the mechanical performance of the Asphalt Plug Joint, and has an important reference value for improving its service performance and extending its service life.

Prediction of Life Expectancy in Bridge Expansion Joint considering Climate and Material Characteristics

Prediction of Life Expectancy in Bridge Expansion Joint considering Climate and Material Characteristics

Study on Preventive Maintenance Plan for Bridge Expansion Joint Rubber Seal using Superelastic Shape Memory Alloy

Study on Preventive Maintenance Plan for Bridge Expansion Joint Rubber Seal using Superelastic Shape Memory Alloy

Investigation of Interfacial Bonding Properties of Polyurethane Concrete and Cement Concrete/Steel Reinforcement

To solve the problem that the repair material of the bridge's expansion joint anchorage area is prone to debonding from the other bridge components, polyurethane concrete was designed and prepared, and the bonding performance of polyurethane concrete was tested by the bond splitting test, bond direct shear test, bond oblique shear test, and steel reinforcement pull-out test. The results show that the interfacial bond strength of polyurethane concrete and cement concrete can be improved by increasing the interfacial roughness. The bond splitting strength increases by up to 91.4%, the bond direct shear strength increases by up to 55.2%, and the bond oblique shear strength increases by up to 28.9%. The bond strength between polyurethane concrete and cement concrete are minimally influenced by temperature. An increase in the diameter of the reinforcement or the length of the bonded anchorage can increase the ultimate pull-out strength of the polyurethane concrete and the steel reinforcement. Polyurethane concrete is a novel composite material with excellent bonding performance with cement concrete and steel reinforcement, which can be widely used in practical projects, such as repairing bridge expansion joint anchorage areas in the future.

Experimental Research on Properties of UHPC Based on Composite Cementitious Materials System

As concrete damage occurs frequently in the transition zone of bridge expansion joints, this paper discussed ultra-high-performance concrete (UHPC) based on composite cementitious materials system for the repair of the bridge expansion joint transition zone. The performance of UHPC based on composite cementitious materials system was studied by combining the macroscopic properties and microstructure of the material with the hydration mechanism of the cementitious material. The influence of sulphate aluminum cement (SAC) on composite cementitious materials system was studied. The experimental results showed that the appropriate amount of SAC can effectively reduce the setting time in the composite cementitious materials system. While SAC caused the strength to decrease, it has little effect on the mechanical properties of the composite cementitious materials system. When the ratio of SAC is 0.1 in the composite cementitious materials system, the setting time is shortened with maintaining the dense micro-structure observed by the SEM images. It can achieve fast hardening and have good early mechanical performance while retaining excellent long-term properties. Therefore, the addition of SAC can effectively make it possible to apply the excellent performance of UHPC for the repair of highway and bridge.

Study on the Vertical Stiffness of Bridge Expansion Joints Based on the Vehicle-Track-Bridge Coupled Model

Bridge expansion joints (BEJs) are equipped at the girder end of long-span railway bridges to ensure the reliable transition of the track. BEJs should have suitable dynamic stiffness to ensure the running safety and stability of the vehicle. To explore the influence of dynamic vertical stiffness of BEJs on the dynamic response of vehicle, track, and bridge, a three-dimensional vehicle-track-bridge coupled model is established, and the influence of sleeper spacing and vehicle speed are taken into consideration. Taking a high-speed railway line in China as a case study, the dynamic response of the whole system is calculated. The results show that (1) the dynamic response of BEJs and the vehicle is affected by the vehicle speed and sleeper spacing. With the increase of vehicle speed and sleeper spacing, the dynamic response of the system increases; (2) the vertical stiffness of BEJs will affect the dynamic response of BEJs and the interaction between the wheel and rail: the vertical dynamic displacement of movable sleeper will exceed the limit if the vertical stiffness of pressure-bearing is insufficient, and the wheel unloading rate may exceed the limit if the vertical stiffness of the cushion plate is insufficient. Based on the results, the larger vertical stiffness of the cushion plate and pressure-bearing is recommended. These results have been applied to the design of BEJs on the studied railway line, which are in good service condition at present.

Moving Force Identification Based on Group Lasso and Compressed Sensing

Moving force identification (MFI) is one of the challenging tasks in bridge structural health monitoring (SHM). Especially when the vehicles get on and off the bridge, or cross bridge expansion joints and speed humps, the impact of vehicle loads on bridge structures is commonly focused and the accuracy of MFI results still needs further enhancements. To address this issue, a new MFI framework is proposed by using both group sparsity theory and compressed sensing (CS) in this study. Specifically, with the help of the relationship between moving vehicle loads and bridge responses induced by the traffic, a redundant dictionary based on CS is used to establish the motion equation of the vehicle–bridge system in conjunction with classical theory of MFI. A group structure on the sparse coefficient vector of each moving force tends to be divided into different groups (no overlapping), where sparse coefficient vectors and measurement matrices are divided in different groupings and eventually reconstructed for unknown vectors of moving forces. Additionally, the effect of different ratios of number of groups to sparsity (g/k) on the MFI results is considered. Finally, numerical simulations and experimental verifications are carried out to assess the performance and capability of the proposed framework. The illustrated results show that the group lasso could precisely reconstruct the moving forces more accurately after proper grouping. The proposed new MFI framework outperforms the traditional L2regularization or CS methods with a higher identification accuracy and a good robustness to measurement noises, which can be effectively used for the MFI problem in practice.

Construction Quality Control of Bridge Expansion Joints in Highway Bridge Construction

Construction Quality Control of Bridge Expansion Joints in Highway Bridge Construction

Investigation on the properties of epoxy asphalt mixture containing crumb rubber for bridge expansion joint

The purpose of this research is to propose epoxy asphalt materials for bridge expansion joints. Epoxy asphalt was modified by adding 0%, 20%, 30% and, 40% crumb rubber (CR). The viscosity, tensile properties, adhesion, high-temperature stability, moisture resistance, low-temperature, and stress relaxation properties of rubber-modified epoxy asphalt (REA) were investigated comparing with the commercial BJ200-red. Thermal stress of epoxy asphalt expansion joint was also simulated by the finite element analysis platform. The results indicated that with the increase of CR content, the viscosity and deformation of REA binder increase, while operation time, the tensile strength, and adhesive decreases. CR has a slight negative effect on the high-temperature performance of epoxy asphalt mixture, and has a positive effect on low temperature deformation. When the rubber powder content is 30%, epoxy asphalt mixture has excellent mechanical properties and its high-temperature stability is higher than BJ200 mixture, but the low-temperature performance of the two is equivalent. Thermal stress analysis shows that epoxy asphalt containing 30% CR cannot fracture above −15 ℃, so it can be recommended for bridge expansion joints.

Development of an assessment and prediction framework for bridge expansion joints

Expansion joints (EJ)s are considered one of the weakest elements in bridges as their lifetime is considerably shorter than that of other elements. The objective of this research was to select an appropriate system for assessment and maintenance of bridges’ EJs. The system seeks to predict the conditions of EJs, with the aim of offering appropriate maintenance and repair strategies that extend their life spans. An EJ management system (EJMS) was developed that optimizes cost over time, targeting the optimum maintenance strategy for EJs, through visual inspections and a genetic algorithm to construct a unique Markov chain transition matrix capable of predicting EJ deterioration. The model was tested using case studies of existing bridges in Egypt and the results were compared against visual inspection, with the comparison showing deviations between 3.2% and 8.1%. The EJMS can help decision makers in selecting the optimum maintenance strategy that maximizes the overall conditions of EJs while meeting budgetary constraints.

Experimental research on mechanical properties of Fiber-Reinforced Polyurethane Elastic Concrete (FRPEC)

Given the shortcomings of conventional repair materials for bridge expansion joints, such as ease of damage and lengthy maintenance cycles, this research developed a new type of Fiber-Reinforced Polyurethane Elastic Concrete (FRPEC) that can be used for rapid repair of bridge expansion joints. FRPEC has the advantages of short setting time, high initial strength, excellent bonding performance and satisfactory deformation and toughness. The objective of this research was to explore and experimentally investigate the basic mechanical properties of the new material (FRPEC) such as failure mechanism, compressive strength and flexural strength, workability and toughness. The orthogonal test range analysis and analysis of variance (ANOVA) were used to optimize FRPEC mixtures based on the compressive and flexural strengths under varying P:CS ratio, cement proportion, and fiber content. Results show that a decrease in the P:CS ratio from 1:1.5 to 1:3 led to an improvement in the mechanical properties of FRPEC, whereas an increase in cement proportion from 40% to 70% adversely affected the mechanical properties. The incorporation of steel fiber improved the strength and toughness of FRPEC.

Study on the Construction Quality Control of Highway and Bridge Expansion Joint

Study on the Construction Quality Control of Highway and Bridge Expansion Joint

Dynamic Response of a Vehicle-Bridge Expansion Joint Coupled System

The paper investigates the dynamic vibration property of the vehicle-bridge expansion joint coupled system with the proposed model. The dynamic response of the expansion joint under the action of the vehicle is the key factor affecting the life of the expansion joint. The changes of contact state and tire geometric characteristics were frequently left aside in the past to simplify the tire model. This is because the contact between tire and expansion joint is a very complex process. But this will seriously underestimate the impact effect of the vehicle on the expansion joint. In this paper, a dynamic mathematical model of the 2-axle vehicle-modular bridge expansion joint (MBEJ) coupled system is established by introducing a flexible roller tire model. The influence of tread rigid displacement and change in the tire contact patch length are considered in the dynamic model. Based on this model, the characteristics of the dynamic tire load and the center beam vibration displacement in the coupled system are obtained by simulation. The results show that the maximum dynamic tire load of the vehicle occurs at the end of the bridge deck behind the MBEJ, so local structure reinforcement needs to be considered. The interaction between the front and rear wheels of the 2-axle vehicle can be ignored. The vehicle position, vehicle velocity, gap width, and spring stiffness of the center beam bearing have significant effects on the impact factors of tire load and center beam vibration displacement. The impact factor of tire load may exceed the recommended values of Chinese and European bridge codes. These should be taken seriously.

Synergistic effect of corrosion and residual stress on fatigue cracks of finger-type bridge expansion joints

Finger-type expansion joints (FJs) have been extensively used in highway bridges and are exposed to the repeated impacts of traffic loading and corrosive environments. In this study, the corrosion and cracking behaviors of FJs serving in bridges for more than 25 years were investigated. The microstructure, electrochemical properties, and dynamic response of the FJs were investigated to analyze the fracture mechanism. The results showed that the crack-induced mechanisms of the two main failure modes were different because the synergistic effect of corrosion with residual stress changed depending on the degree of corrosion. First, considerable residual tensile stress, which enhanced the effective stress range, was the critical cause of fatigue crack initiation in the less corroded heat-affected zone (HAZ). Second, the dominant mechanism for cracking was the applied stress to the severely eroded FJ bottom, which was accelerated by galvanic corrosion. Crack-inducing factors included a combination of stress concentration and dynamic springback behavior.

Flexural Performance of Emulsified-Asphalt-Modified ECC for Expansion Joint Use

The concrete transition zone plays an important role in bridge expansion joint structure, which provides a good connection between the expansion joint installation and bridge decks. However, the premature deteriorations of concrete transition zone are found to be the major diseases of expansion joint during service life. Therefore, a material with high ductility, superior durability, and low modulus/stiffness is highly desired for transition zone. Engineering cementitious composites (ECC), a kind of high-performance concrete featuring the prominent ductility and durability, are a promising material for transition zone of expansion joint. This paper introduces a specific ECC material for transition zone, which is modified by emulsified asphalt (EA-ECC), and has the high deformation ability and low modulus/stiffness. The flexural mechanical properties including flexural stress-load displacement relation, flexural secant stiffness, and elastic modulus of the EA-ECC’s matrix were investigated experimentally. The microstructures of EA-ECC were observed via scanning electron microscope (SEM) imaging. Additionally, the influence of test temperature on flexural mechanical properties of EA-ECC was also investigated. It is found that the ultimate flexural stress of EA-ECC reduces gradually with increasing EA content. Conversely, the flexural deformation capacity shows an increasing trend with EA content. Additionally, incorporating EA significantly reduces the flexural secant stiffness and elastic modulus of EA-ECCs. The research results concluded that incorporating EA in ECC can significantly improve the flexural deformation ability accompanied by relatively lower modulus, which is likely to reduce the impact load on transition zone caused by vehicle bumping and prolong the service life of the whole bridge expansion joint structure.

Research on the impact coefficient of vehicle wheel load on bridge expansion joint by scale model experiment

The wheel load of the vehicle acting on the bridge expansion joint is a kind of dynamic load, and its impact coefficient needs to be determined, so as to provide basic design parameters for the bridge expansion joint. In this paper, the scale model of the bridge and the vehicle is designed and constructed, and the experimental study of vehicle model passing through bridge model is carried out. In the experiment, the wheel impact load of the vehicle on the bridge expansion joint is measured, and the impact coefficient of the wheel load is calculated. The measured results show that the greater the vehicle speed, the greater the impact load of the wheel on the expansion joint, that is, the greater the impact coefficient. The larger the width of the gap in the expansion joint, the greater the impact load and impact coefficient of the wheel on the expansion joint. The greater the mass of the vehicle, the longer the contact length between the wheel and the road surface, which reduces the impact effect and the impact coefficient of the wheel load on the expansion joint. The maximum impact coefficient of wheel load is greater than the design value in the Chinese bridge code, i.e. 0.45, even greater than that in the American bridge code, i.e. 0.75.

Research on mechanical performances of composite cementitious material system in new bridge expansion joint UHPC material

In the bridge expansion joint repair project, in order to ensure the efficiency of the project, the repair material needs to have better flow properties and higher early strength. The introduction of sulphoaluminate cement will significantly change the properties of UHPC. Compared with ordinary Portland cement, the composition of its cement clinker mineral belongs to another physical and chemical system, which has excellent properties such as early strength, high strength, impermeability and corrosion resistance. Therefore, different groups of UHPC were prepared by changing the content of sulphoaluminate cement, and the fluidity test of each group of slurry and the compressive strength and flexural strength test of 1d, 3d, 7d, 28d were carried out to study the sulfur. The influence of aluminate cement content on slurry fluidity and early mechanical properties in order to obtain the optimal mix ratio of UHPC materials for new bridge expansion joints.