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Past bridge failures due to earthquakes have been found to be due to inadequate seismic design of the bridge piers. It is thus essential to investigate the effect of lateral confinement on the seismic behaviour of bridge piers. The aim of this study was to evaluate, experimentally and numerically, the seismic performance of reinforced concrete bridge piers with various types of transverse reinforcement. For this purpose, three scaled-down (1 : 4) circular bridge pier specimens were tested under constant axial and quasi-static cyclic loading (QSCL). A control specimen was made with spiral lateral reinforcement, while the other two specimens were made with stirrups with cross-ties and strips with cross-ties. The hysteresis loops, envelope curves, energy dissipation and stiffness degradation of all three specimens were determined in order to evaluate their seismic behaviour. Compared with the control specimen, the specimen with strips and cross-ties showed increased lateral load capacity, cumulative energy dissipation and higher initial stiffness due to the effect of increased confinement. The results of finite-element analysis showed good agreement with the experimental results. The findings of this study indicate that strips with cross-ties can be used in bridge piers when a high lateral load carrying capacity and energy dissipation are required.

The local scour around bridge piers is one of the main causes of bridge failures. In this study, scour hole dimensions around circular bridge piers were investigated under clear water scour conditions for various steady flow rates. The experiments were performed with four different bridge pier diameters and seven different flow rates by using uniform sediment with a median diameter of 1.63 mm and geometric standard deviation of 1.3. After each experiments the bathymetry of scour hole was determined. New empirical equations to estimate scour hole length, scour hole width and scour hole volume (V) are proposed by using experimental findings and experimental data available in the literature. The experimental results were also compared with those calculated using several empirical equations given by previous studies. Since there is a lack of data about scour hole dimensions, the experimental findings presented in this study are useful for the researchers investigating the local scour process, and have contributed to the few experimental data in the literature.

The seismic resilience of structures and infrastructures is affected by damage accumulation phenomena, mainly related to the type of hysteresis. Specifically, pinching drives the cyclic response of several building materials, such as reinforced concrete and masonry. Structural systems affected by pinching phenomena are prone to exhibit a dramatic increment of their displacement response after multiple cycles (e.g. repeated earthquakes). The authors estimate a reinforced concrete pier's response using truncated incremental dynamic analysis by concatenating three earthquake scenarios. The authors adopted a Bouc–Wen class hysteresis model to simulate the reinforced concrete pier's cyclic response, matching its experimental cyclic response. The current analysis proved that ductility and resistance primarily drive the seismic response after a single earthquake. However, the performance after multiple earthquakes strongly depends on the pinching, degradation and drift accumulation, which are generally neglected in standard design practices.

This study performed a bridge pier collar comparison for the purpose of reducing scour, while introducing a new collar design. The new collar, referred to as Collar Prototype Number 3, was designed based on an equilibrium scour hole and provides a method of controlling the horseshoe vortex. Numerical modelling was utilized to show the flow field and bed shear stress as a result of using Collar Prototype Number 3. A prototype model of Collar Prototype Number 3 and a flat plate collar were constructed for the purpose of comparing both experimentally under different flow conditions. Collar Prototype Number 3 proved to be an effective device as it reduced scour in terms of the maximum depth downstream of the pier and overall volume, in some instances, by up to 69.7% and 75.7%, respectively. Furthermore, Collar Prototype Number 3 outperformed the flat plate collar, especially because, unlike the flat plate collar, Collar Prototype Number 3 did not experience undermining.

In long-span fixed partial denture restoration, especially when pier abutment is present, a non-rigid connector as a stress breaker is indicated. The Non-rigid connector is classified into a dovetail, loop connector, split pontic, cross-pin, and wing. Split pontic is an attachment placed entirely inside the pontic, particularly indicated in the tilted abutment case, to prevent the box preparation of distal pier abutment. This case report presents A pier abutment case treated with long span porcelain fused to the metal fixed movable bridge using dovetail shaped attachment, assembling the split pontic as a non-rigid connector. Split pontic acts as the stress breaker to prevent the pier abutment acts as a fulcrum. Split pontic also transfers the shear stress to the alveolar bone, minimalizes the mesiodistal torquing of the abutment teeth, and enables individual tooth movement. The advantages of this design are preparation with minimal reduction and better esthetic outcome as the porcelain build up can be done. Thus, there is no metal exposure of the restoration. Longevity and success of fixed partial denture restoration depend on the size, shape, type, and connector position. In pier abutment cases, a non-rigid connector must be considered one of the treatment choices to restore the missing teeth and preserve the abutments.KEYWORDS: pier abutment, split pontic, non-rigid connector

Previous investigations have attributed some reinforced concrete (RC) bridge piers suffered significant damages during large earthquakes due to vertical ground motion effects. This has motivated this study to investigate the use of concrete-filled steel tube (CFST) columns as a more resilient and sustainable alternative to resist combined horizontal and vertical ground motions. The classic performance-based earthquake engineering (PBEE) framework is used to examine the seismic performance of a rigid-frame bridge with construction options of circular RC, circular CFST, and square CFST columns. The hysteretic response of each column is calibrated to the results of hybrid testing of columns under combined horizontal and vertical ground motions. The incremental dynamic analysis (IDA) is conducted using a suite of 50 near-fault records. The results are used to compare the observed damage states and quantify the repair sustainability metrics including repair cost (economic), repair downtime (social), and repair carbon emissions (environmental), as well as the loss of resilience. The losses are integrated with the hazard curves to compute the expected annual losses, all defined as a set of decision variables in the PBEE framework. The results confirm the outstanding seismic performance of CFST columns and highlight their benefits in improving the resilience and sustainability of critical and post-disaster bridges that are prone to strong multi-directional ground motions.

A superior seismic strengthening technology should be not only secure and reliable, but also economical and feasible for the widespread structures. In China, the gravity pier with low longitudinal steel ratio has been widely used in railway bridges, and most of them have insufficient seismic performance due to limited technological level in the early days. In this study, a novel preventive seismic strengthening technology with steel grid by planting and welding measures was presented for gravity railway bridge pier with flexural failure modes. Five 1/8-scale piers, including two different reference piers and three strengthening piers, were fabricated and tested through quasi-static test. It was shown that the piers exhibit uplifting and swaying behaviors due to highly-centralized crack at pier-footing region under lateral loading. The strengthening using steel gird led to a reduction up to 50% in residual displacement approximately, which was effective to prevent collapse of piers. The strengthening piers exhibited an enhanced the load-carrying capacity and cumulative dissipated energy by 120% to 150%, compared to the pier without strengthening. Moreover, the initial stiffness and cracking load of strengthening piers also were improved where the maximum increment was 1.5 times. The effect of strengthening thickness on strengthening efficiency was more significant than that of strengthening height. Therefore, it could be concluded that the seismic strengthening technology, by steel grid with reasonable arrangement at the pier bottom region, are suitable for gravity railway bridge pier with low longitudinal steel ratio in seismic zones.

According to recent data, many bridges tend to fail due to seismic inadequacy in design. Circular piers are more effective in reducing scour depth and increasing the durability of bridges than an elliptical bridge pier. The question is “whether circular pier performs better under seismic action than elliptical pier or not”. So a comparative study was conducted to analyze the behavior of circular and elliptical piers under earthquake forces, and complete nonlinear static pushover analysis was carried out for two different bridge models separately. Pushover curve data from Indian Standard Code was used to formulate the problem and performance outcomes of the bridges were analyzed. It was found that single circular pier showed no failure and better performance in both directions of the bridge, with more displacement capacity than double elliptical piers when subjected to incremental lateral loads. The design capacity (D/C) ratio in the longitudinal direction was 1.8 times more for single circular pier bridge and in the transverse direction, the ratio was 1.4 times more for double elliptical pier bridge for the considered earthquake situation. Results also showed 47% less drift value for single circular pier bridge compared to double elliptical pier bridge.

The catastrophic consequence of vehicle-pier collisions necessitates the research of vehicular impact forces on bridge piers. Since previous collision events that involve serious damage to bridge structures are mainly caused by heavy trucks, this study focuses on the impact force characteristic and mechanical behavior of trucks in collisions against piers. Using detailed finite element (FE) simulations, four typical trucks classified by Eurocode are selected to establish the truck-pier impact models. Then, more than two hundred impact cases are conducted to explore the influence of critical variables such as the truck type, impact velocity, and pier cross-section on the impact force and structural stiffness of the trucks. Based on the simulation results, the typical truck-pier impact process is identified, and empirical formulas for calculating the peak impact force (PIF) and equivalent static force (ESF) of piers imposed by the trucks are proposed. The importance of truck type on the truck-pier impact analysis is also highlighted. Besides, the impact force-crush depth relationships of the typical trucks are generated and simplified into a series of piecewise linear functions. For the anti-impact design of bridge piers, a simplified truck model is developed based on the mechanical behavior of the typical trucks and validated against simulation results obtained from detailed FE models.

From the field observations of bridge deck failures under extreme waves, it is shown many bridge decks were laterally displaced at varying displacements on the pier caps, and some decks with large lateral displacements even fell into the water. The repair cost varies with the lateral deck displacement, especially between different bridge states (Fixed state, Partially-displaced state, Falling-down state) after the disaster. To the author's knowledge, a comparative study of lateral displacements for T-deck and Box-deck under extreme waves has not been conducted. This paper discusses some fundamental questions related with the lateral deck displacement: (1) What are the influences of three essential parameters (relative clearance, wave height, deck weight) on the lateral displacements for two kinds of bridge decks? (2) Which kind of bridge deck is safer under the extreme solitary waves? In other words, is the lateral displacement of T-deck always larger or smaller than the Box-deck? (3) Does a larger horizontal or vertical wave force on two decks always induce a fiercer lateral motion response? (4) What is the most vulnerable condition for the failures of T-deck and Box-deck? Motivated by these questions, a comparative research on the wave-deck interactions for two movable decks under solitary waves is conducted by a numerical model solving the Navier-Stokes equations. A total of 330 numerical experiments based on this model have been designed to dynamically study the lateral responses of two bridge shapes under various conditions. This study provides researchers an insight into the dynamic properties for T-deck and Box-deck under solitary waves, and improves our understanding of the fragility of two decks under extreme waves.

In the present study, in view of the problem of nonlinear response caused by vehicle-RC pier collision, a new test system which can realize lateral impact is proposed, and two types of 1:3 scale RC components in five groups are subject to the lateral impact test at a velocity of 4.5 m/s. The system’s design characteristics represent the effect of stirrup spacing and axial compression ratio on the dynamic response of RC columns. In addition, the nonlinear response results of RC columns, such as impact force, acceleration, lateral displacement, failure mode and degree, are given in the test. Digital Image Correlation (DIC) technology is applied to the test. Next, the lateral strain response of RC columns during impact is measured, and the strain change process in every representative region is calculated. The data outlined in this study provide a reasonable basis for evaluating the shear capacity of RC columns and developing a finite element model (FEM). Finally, a typical FEM of vehicle-pier collision scenario is developed, while an improved equation for calculating the axial compression ratio-shear increment and a simplified calculation value of dynamic shear capacity of the RC pier are proposed.

Vehicle collision on reinforced concrete bridge pier (RCBP) frequently occurred all over the world in the past two decades, posing a potential threat to safety of the bridge. However, the impact-resistant design of RCBP in current regulations is only based on the equivalent static force of vehicle impact without considering the damage-performance correlation of the impacted RCBP. This study aims to establish the performance-based design procedure for the typical double-pier RC bridge against vehicle collision. By adopting the refined finite element models of light, medium and heavy trucks with the weight ranging from 3 to 50 t and impact velocity varying from 40 to 120 km/h, 54 numerical simulations of collision scenarios are carried out based on the validated numerical algorithm and material constitutive models. It derives that: (i) the dominated factor that evaluates whether RCBP fails or not under vehicle collision is the peak dynamic shear demand at the base of the RCBP, and related explicit expressions of the peak dynamic shear demand and capacity are further developed and verified; (ii) a new damage index, i.e., the ratio of peak dynamic shear demand to the dynamic shear capacity, is defined to evaluate different damage levels of the RCBP under vehicle collision; (iii) damage-performance correlation of the impacted RCBP is also established, e.g., the bridge is prone to collapse under vehicle collision once damage index exceeds 1.2. Finally, by proposing the impact-resistant performance objectives, the detailed performance-based design procedure is developed according to the importance level of roadway.

This paper aims to evaluate the seismic performance of isolated bridges under near-fault ground motions based on Energy Balance Method (EBM). This method invokes the concept of energy balance into the modal pushover analysis to assess the nonlinear behavior of lead rubber bearings on bridge piers. In EBM, the energy-based capacity curve is firstly obtained by the pushover analysis, while the demand curve is estimated based on the synthetic near-fault record. The target performance criterion can be derived by intersecting the capacity curve with the demand curve. The present paper also proposes the design method for seismic isolation based on the concept of EBM. The case study of an example isolated bridge at a near-fault site is used to illustrate the effectiveness and accuracy of the EBM. The results from this method are evaluated and compared with those from the nonlinear time-history analysis. Results show that the energy-based EBM is found to be able to evaluate the seismic performance of the pier isolated with lead rubber bearings under near-fault ground motions, which can be used as an effective alternative for rapid assess the seismic performance of isolated bridges The results also indicate that the EBM cannot only effectively evaluate the seismic responses of isolated bridges, but also can effectively estimation of the effect of isolation bearing in reducing the displacement and damage of piers.

Precast post-tensioned segmental (PPS) bridge piers mitigate global and local damages of bridge structures through natural hinges (joints between their segments) and rocking motion of their segments. The application of the PPS piers is currently growing in Accelerated Bridge Construction (ABC) where the segments are manufactured offsite with higher quality, and are assembled onsite in a short time. Structural vulnerability analysis of the PPS piers is very essential in extending their engineering implementation under seismic loading. Thus, this work particularly focuses on seismic vulnerability assessment of the PPS piers. To achieve this goal, a previously developed and experimentally validated robust Finite Element model of the PPS piers in OpenSees programme is used to analyse PPS piers of various aspect ratios. An equivalent reinforced concrete (RC) pier to one of the PPS piers is also analysed. Incremental Dynamic Analysis (IDA) is performed and fragility curves are generated to evaluate seismic performance of the PPS piers and an equivalent RC pier using a suite of 44 far-fault ground motions. The IDA results show that slenderising the PPS pier tends to change the failure criterion from the yielding of the post-tensioning tendon to the strength loss of the pier. For squat and slender piers, the yielding of the tendon governs the failure of the pier while the strength of very slender PPS piers drops due to second-order effects at small drift values prior to the yielding of the post-tensioning tendon. It is also found from fragility curves that squat piers are more prone to seismic collapse compared to slender piers. The equivalent RC pier reaches slight and medium damage states in lower intensity measures compared to the PPS pier.

Near-fault vertical ground motions (VGMs) caused great damage to bridge structures, but investigations of the effect on probabilistic seismic performance and structural vulnerability are insufficient. For this purpose, a novel model of bridge seismic fragility surface conditioned on the horizontal peak ground velocity (Vx) and the αVH (ratio of vertical to horizontal ground motion) is proposed. The quantitative formulation for probabilistic seismic demand model (PSDM) and probabilistic seismic capacity model (PSCM) of bridge piers considering the effect of VGM are established, and then the empirical model of fragility surface with the parameters of Vx and αVH is obtained by convolution. A simply supported bridge model is simulated in OpenSees as an illustrated example to establish the seismic fragility surface under the combined actions of horizontal ground motion and VGM. Furthermore, the damage probability (Fr) influenced by VGM is analyzed compared with the damage probability (Fr0) without VGM, and the sensitivity intervals of the difference between Fr and Fr0 for varying damage states are identified. The mechanism of fragility variation under VGM is explored, indicating that the variation of seismic demand caused by VGM is the main reason. Finally, the seismic fragility surface model considering VGM is applied to a set of variable piers, and the sensitivity interval associated with the fundamental period is investigated under different Vx.

Soil scour near a bridge pier foundation is one of the leading causes of bridge failures. Traditional vibration-based scour monitoring methods are nearly incapable of quantifying scour levels using a single acceleration response without knowledge of excitation information. In this paper, a new output-only scour level prediction method is introduced via the integration of an unscented Kalman filter (UKF), random decrement (RD), and newly derived continuous Euler–Bernoulli beam addressing river water, traffic loads, and the linear and nonlinear behavior of sediments around the pier as external effects. We conducted extensive simulation studies and applied the method to an existing medium-span bridge with a steel girder and concrete deck in service in the province of Manitoba, Canada. These studies show that our proposed method can accurately estimate scour levels using only one accelerometer, which was validated with an independent bathymetric survey of the soil level at the pier foundation. Furthermore, three different linear and nonlinear soil profiles representing the soil behavior around the pier were also investigated as case studies in the scour level estimation process. The results confirm that a cubic function exhibits the best performance in quantifying the scour level around bridge piers.

Shaking table test is an important means for the seismic research of structures, and many scholars have conducted shaking table tests on bridge structures. However, relatively few studies have focused on a curved bridge with a longitudinal slope. In this research, a 1/10-scale test model of a curved bridge with the different pier hights was designed by the principle of structural test similarity. The seismic records in the hanging-wall (HW), footwall (FW), and neutral zones were selected to conducted shaking table tests. Results showed that the seismic spectrum and peak value are remarkably affected by HW ground motions and have strong destructive power. The dynamic response of the curved bridge is remarkable under HW seismic records. The motion form of main girder is spatial and produces obvious rotation under HW seismic records. The displacement response of the curved bridge is closely related to the height of piers and the angle between pier displacement and seismic input directions. The displacement responses at the beam end and the bearing displacement are related to the motion state of the main girder.

PurposePrefabricated pier technology has the advantages of quick construction time, relatively little traffic interference and relatively small environmental impact. However, its applicability under earthquake conditions is not yet fully understood. The seismic performance and influence parameters of a prefabricated concrete pier connected by embedded grouting sleeve (GS) in a pile cap are investigated in this study.Design/methodology/approachTwo prefabricated pier scale model specimens with different reinforcement anchorage lengths and two comparative cast-in-place (CIP) pier model specimens are designed and manufactured for a seismic simulation shaking table. With the continuous increase of input ground motion strength, the changes in basic dynamic characteristics, damage development, acceleration and displacement variation laws, and pier bottom strain responses are compared among the specimen. The finite element software ABAQUS is used to simulate the test pier.FindingsThe crack location of the two prefabricated pier specimens is almost the same as that of the CIP pier specimens; CIP pier specimens show more penetrated cracks than prefabricated pier specimens, as well as an earlier crack penetration time. The acceleration, displacement and strain response of the CIP pier specimens are more affected by earthquake activity than those of the prefabricated pier specimens. The acceleration, displacement and strain responses of the two prefabricated piers are nearly identical. The finite element results are in close agreement with the acceleration and displacement response data collected from the test, which verifies the feasibility of the finite element model established in ABAQUS.Originality/valueA GS connection method is adopted for the prefabricated pier, and on the premise of meeting the minimum reinforcement anchorage length required by the code, this study explores the influences of different reinforcement anchorage lengths on the seismic performance of prefabricated piers in high-intensity areas. A shaking table loading test is used to simulate the real changes of the structure under the earthquake. This work may provide a valuable reference for the design and seismic performance analysis of prefabricated pier, particularly in terms of seismic stability.

PurposeConcrete-filled steel tube structures are widely used for their high bearing capacity, good plasticity, good fire resistance and optimal seismic performance. In order to give full play to the advantages of concrete-filled steel tube, this paper proposes a prefabricated concrete-filled steel tube frame joint.Design/methodology/approachThe concrete-filled steel tube column and beam are connected by high-strength bolted end-plate, and the steel bars in the concrete beam are welded vertically with the end-plates through the enlarged pier head. In addition, the finite element software ABAQUS is used numerically to study the seismic performance of the structure.FindingsThe ductility coefficient of the joint is in 1.72–6.82, and greater than 2.26 as a whole. The equivalent viscous damping coefficient of the joint is 0.13–3.03, indicating that the structure has good energy dissipation capacity.Originality/valueThe structure is convenient for construction and overcomes the shortcomings of the previous on-site welding and on-site concrete pouring. The high-strength bolted end-plate connection can effectively transfer the load, and each component can give play to its material characteristics.

Design codes in the United States and Canada limit the use of high-strength steel (HSS) and high-strength concrete (HSC) to bridge components that are expected to remain elastic during a seismic event. Although HSS and HSC have higher tensile and compressive strengths, respectively, their lower inelastic strain capacities impose for such restrictions. To assess the seismic performance of HSS and HSC, the pier of an existing bridge is redesigned using concrete compressive strength of 50 and 80 MPa, and reinforcement yield strength of 420, 690, and 830 MPa. Static pushover and nonlinear dynamic time-history analyses were performed to generate force–deformation and seismic fragility curves. Bridge piers incorporating HSS and HSC attained the maximum load capacity yet were the least ductile. They were less seismically vulnerable than those incorporating conventional materials at minimal and repairable damage states, but not at extensive and probable replacement damage states.

Current design codes and guidelines do not permit reinforcing the plastic hinge region of bridge piers using high strength steel (HSS) rebars. This is due to the lack of adequate research on the seismic response of HSS reinforced bridge piers. The objective of this study is to develop analytical expressions for predicting the drift at the onset of different performance limit states for high strength concrete (HSC) bridge pier reinforced with HSS reinforcement. Utilizing damage data obtained from incremental dynamic analysis of HSC circular bridge piers reinforced with HSS, this study developed drift ratio relationship accounting for the aspect ratio, concrete and steel material properties, axial load ratio, and reinforcement ratio, using validated finite element models. Analytical equations are developed for estimating the drift at the inception of rebar yielding, concrete spalling, and bar buckling using multivariate regression analysis. The proposed equations showed reasonable precision when corroborated against experimental results.

Concrete bridge piers are vulnerable to strong ground motions because of inducing significant residual drifts, which reduce the seismic resilience of bridges. A broad range of mitigation techniques is presented in the literature to reduce the vulnerability of bridge piers located in high seismic zones. Hybrid reinforced concrete piers are the most popular techniques to improve the seismic resilience of highway bridges. In addition, posttensioned segmental bridge piers are proposed as an alternative to expedite the construction procedure and also meliorate the performance of bridges in terms of residual deformations. However, very limited studies investigated the seismic performance of a whole bridge, especially for the purpose of comparing seismic resilience of the bridge columns. In this paper, a comparative study is implemented to explore the seismic vulnerability of a bridge reinforced with a hybrid configuration (i.e. combination of shape memory alloys (SMA) and normal-strength bars, and combination of high-strength and normal-strength bars) as compared to a reference conventional pier, which fully reinforced by normal-strength rebars. Moreover, a posttensioned segmental pier is considered to evaluate the strength and self-centering ability of this pier as compared to the monolithic ones. To do so, a 2D bridge model is developed in OpenSees simulation platform. Fragility curves are developed to assess the seismic vulnerability of the bridge model constructed with different piers. In this regard, a suite of 20 near-fault earthquake motions are applied to the bridge through Incremental Dynamic Analysis (IDA). Each of these records is scaled to 15 Peak Ground Accelerations (PGAs) ranging from 0.1 g to 1.5 g . The fragility curves reveal the chance of failure for each bridge model and aid in determining the impact of each pier on the seismic vulnerability of the bridge.

This article presents a study to evaluate the structural response of a cable-stayed bridge under a novel system, partially earth-anchored system with crossing cables at the main span. Six side-to-main span ratios, ranging from 0.24 to 0.39 in increments of 0.03, are tested for different bridge response parameters for both the superstructure and substructure. The loads considered in the analysis are the dead load and traffic load. Three-dimensional finite element models of the bridge are developed using structural analysis software SAP2000 and are validated based on the data available in the literature. From this study, it is found that the side-to-main span ratios have a significant effect on girder axial force and anchorage forces while having a very minor effect on cable axial forces. The results also show that the ratio does not affect the bending moment of the main span, but that when a small ratio is considered particular attention needs to be paid to the pier farther from the pylon to avoid uplifting. Deck vibration and longitudinal movement, as well as pylon longitudinal displacement, are not to be an issue for this super-long bridge.

The seismic performance and design method of fabricated concrete bridge piers limit their applications in complex and harsh environments. In this study, a continuous bridge pier in an 8-degree seismic fortification intensity area was considered as a prototype. Two 1/3-scale models were designed and manufactured. The specimens were connected via a grouted sleeve connections (SFP) and a grouted sleeve prestressing tendon composite connections (SSFP), respectively. Moreover, a cast-in-place 1/3-scale model (reinforcement concrete pier, RCP) was designed as a comparison specimen. Quasi-static experiments were performed on these three specimens. The seismic performance of the specimens was analysed according to the failure phenomena, bearing capacity, displacement ductility, stiffness, energy-dissipation capacity, and residual deformation. On these basis, a bearing-capacity estimation method for SFP (including SSFP) was developed and validated. The results indicated that the damage to the SFP and SSFP mainly accumulated along the top and bottom of the sleeves. The plastic hinge area of the SFP and SSFP moved up or down. Thus, the damage to the SFP and SSFP was concentrated at the joints. Cracks first occurred at the seam of the two fabricated specimens when the loading drift was relatively small. Then, the concrete at the loading edge of the joints was crushed. Furthermore, the longitudinal bars yielded and broke. Finally, the specimens failed. Compared with the RCP, the SFP and the SSFP had larger yield and ultimate displacements. The bearing capacities of the RCP and the SFP were similar. However, the bearing capacity of the SSFP was significantly higher. The bearing capacities of the SFP and SSFP did not decrease significantly before the specimens failed. Compared with the RCP, the SFP had a lower initial stiffness, a lower stiffness degradation rate, similar displacement ductility, smaller residual displacement, and less cumulative energy dissipation. The SSFP was better than the SFP with regard to the displacement ductility, initial stiffness, and cumulative energy dissipation. Thus, the SFP and SSFP can satisfy the seismic requirements of high-intensity areas. The proposed bearing-capacity estimation method can be used for the seismic design and evaluation of SFPs and SSFPs.

Resilience in bridges is of paramount importance as bridges are important transport assets that maintain mobility after disasters. The most common cause of extreme stress development on structures and especially bridges is dynamic loads due to floods, earthquakes, strong winds, truck and ship collisions. In the international literature, there an ongoing research in support of adaptable and low-damage bridge connections for bridges and structures exposed to dynamic loads. This paper focuses on the design and assessment of a novel connection based on extensive numerical modelling of a 3D Finite Element (FE) model of the connections developed in Abaqus. The connection, which is essentially a resilient hinge, connects the foundation with the bridge pier and the latter with the deck, which are the positions where typically RC hinges are formed during extreme dynamic loads, e.g. earthquakes. A similar connection was designed before, however, this paper offers a design methodology and advances the connection by providing improvements to its mechanical characteristics, i.e. the geometry, resolving issues with regard to stress concentration by improving the contact surface geometry, the consideration of the friction and the optimization of its components. The paper concludes with a discussion on the connection constructability, therefore enabling further applications of the proposed design. The results also demonstrate that even though the rebars of the hinge undergo excessive elongation, the connection maintains a significant bending moment capacity, therefore not hindering the integrity of the bridge. Moreover, it is observed that the compressive zone of the hinge remains intact, thanks to the high strength of the steel, therefore no shortening of the RC column is expected.

Vehicular collision with bridge pier can cause significant structural damage, and even partial or full collapse of the bridge, while the existing work mainly focuses on the vehicular-impact resistance of bridge pier. This study aims to study the collapse process and damage levels of the bridge collided by medium and heavy trucks. Firstly, the refined finite element (FE) model of the typical simply supported two-span double-pier RC bridge is established via the commercial software LS-DYNA, and the adopted material constitutive models and numerical algorithms are validated by comparing with the prototype truck-pier collision test and full-scale drop-weight test on RC beam. Then, the validated FE model is employed to numerically reproduce the actual heavy truck collision accident involving the collapse of bridge, and the dynamic behaviors and collapse process of the collided bridge are analyzed. It shows that, for the present bridge type: (i) truck-bridge collision is not a single impact but a successive impact with bumper, engine and cargo, in which the shear failure on the reinforced concrete bridge pier (RCBP) induced by the engine impact is the dominant factor resulting in the bridge collapse; (ii) during the collision process, the impacted RCBP firstly suffers shear failure at the bottom, and followed by the inclination of the bent cap and superstructure, and then the neighboring RCBP sustains flexible-shear failure at the top, which eventually results in the instability of substructure and collapse of superstructure. Furthermore, a total of 35 truck-bridge collision cases are numerically simulated and assessed, and a new quantitative damage evaluation approach, including the modified damage index, damage level and evaluation criterion, is proposed for the bridge under vehicular collision. In addition, the relationship between the damage level of the collided bridge and superstructure inclination is clarified, which is beneficial for bridge engineers to feasibly assess the vehicular-impact resistance of bridge.

In this study, a resilience-based multi-objective optimal seismic design method is proposed to maximize the seismic performance and minimize the material cost of highway reinforced concrete (RC) bridges. The size of the elastomeric bearings and cross-sectional arrangement of the RC pier are selected as the design parameters. To improve the accuracy and efficiency, the nonlinear time history analysis based on cloud analysis approach and response surface method are applied to obtain the seismic resilience during the seismic optimization process. The optimization problem is solved through an improved non-dominated sorting genetic algorithm (NSGA-II). Following, the proposed method is applied to a highway RC bridge, and the optimal design schemes are determined from the Pareto optimal solutions. The numerical results show that the resilience response surface model can be used to predict the seismic resilience of bridges. Moreover, the proposed method can minimize the material cost and maximize the seismic resilience by adjusting the damage grades of various bridge components.

The seismic resistance of reinforced concrete (RC) bridge piers reduces over time due to gradual deterioration processes, such as reinforcement corrosion. Using a ductile fiber reinforced concrete ...

The results of linear static analysis explained that the increasing of pier heights was leaded to rise the values of positive bending moment, tensile stresses, and downward vertical deflection. Whereas the compressive stresses and negative bending moment were decreased, indicating that the structural performance of bridge structure representing by stiffness, bearing capacity of structural members, and elasticity will decrease and the bridges structures will be damaged. Therefore, the bridges structures need safe design when using tall piers by adopting high quality materials such as high strength concrete, more steel reinforcement, more prestressed tendons, and increasing of cross section dimensions of girders and piers. The results of modal analysis show that the un-loaded dynamic frequency for three types of bridges models were decreased when the pier heights were increased, indicating that the stiffness of bridges structure was became low with higher pier height. According to response spectra and time history analysis results, the loaded dynamic frequency (vibration state) and dynamic displacement were increased when the pier heights were increased, showing that the bridge of structure will suffer from high vibration when the pier height was high. It can be concluded that from this study, the piers heights have significant effects on the static and dynamic structural performance of bridges structures under traffic loads.

The pounding effect at the expansion joints on the seismic response of a long-span deep-water high pier bridge with multiple approach spans under earthquake is studied considering the fluid–structure interaction effect. The nonlinear fibre element is used to simulate the main piers and transition piers. The contact element is employed to consider the seismic pounding effect at the expansion joints. The hydrodynamic pressure is applied to the main piers and transition piers in the form of added mass of graded accumulation. Forty seismic records of different earthquakes are used as input to conduct the longitudinal time history analysis of the whole bridge. The seismic responses of bridge structure with and without pounding effect are compared to analyse the impact of pounding on the structure. The results show that considering the pounding effect at the expansion joints, the seismic response of the main pier under the fluid–structure interaction effect is reduced, which indicates that the pounding is beneficial to the main pier. Due to the out-of-phase vibration between the main bridge and the approach spans, the pounding force at the expansion joints on the left and right transition piers is the largest, and the pounding transmission effect is obvious. The transmission effect makes the positive displacement amplitude of the right bearings on the top of each pier of the right approach spans increase evidently. The increased amplitude of each pier is not synchronous, which will increase the possibility of unseating.

A collaborative investigation between the University of Virginia (UVA) and the Virginia Transportation Research Council was performed on the Mecklenburg Bridge (I-85 over Route 1 in Mecklenburg County). The research team aided the Virginia Department of Transportation—Richmond District in the characterization of the bridge behavior of one of the bridge beams that had been repaired due to a previous web buckling and crippling failure. The investigation focused on collecting full-field three-dimensional digital image correlation (3D-DIC) deformation measurements during the dropping sequence (removal of jacking to support beam on bearing/pier). Additionally, measurements were taken of the section prior to and after dropping using a handheld laser scanner to assess the potential of lateral deformation or out-of-plane buckling. Results from the study demonstrated that buckling of the tested beam did not occur, but did provide a series of approaches that can be used to evaluate the effectiveness of repaired steel beam ends. Specifically, the results provided an approach that could estimate the dead load distribution through back-calculation.

In order to consider the effect of near-field vertical earthquake, a model of a two-span continuous beam bridge is established. On the basis of superposition of longitudinal and vertical seismic actions, the possible separation of vertical earthquake is considered, and the influence of separation on structural failure is calculated. The transient wave characteristic function method and the indirect mode superposition method are used to solve the response theory of the bridge structure during the earthquake. When the vertical seismic excitation period is close to the vertical natural vibration period of the bridge, structure may separate. For the high-pier-type bridge, the separation enlarges the deformation of the pier and even causes the pier failure. The external conditions such as the time difference of arrival of seismic wave and the stiffness of support will affect the deformation of bridge piers. In addition, the number of separations will also change the seismic response of the pier.

Precast segmental piers are attracting the bridge community due to the merits of faster construction speed, smaller site disruption and higher construction quality. Compared to numerous experimenta...

During earthquakes, large relative displacements can be generated between different structural parts of a bridge. This can lead to collisions between the girder ends and the abutments and can even result in the girder unseating. A widely used prevention method adopts unseating prevention systems. The commonly cable-type unseating prevention device (C-CUPD) has low energy dissipation capacity and its cable fractures easily during strong earthquakes. In order to address these shortcomings, an energy dissipation cable-type unseating prevention device (E-CUPD) with an energy absorption tube is proposed in this study. The paper describes the basic structure and working mechanism of the device, and then investigates its energy absorption characteristics and limit performance, drawing upon theoretical analysis, numerical simulations, and testing of a scaled model. The influence of structural parameters and loading velocity on the energy absorption characteristics of the device are discussed, and the seismic responses of the bridge equipped with the device under different seismic input intensities are studied. The results show that the longer the device, the thicker the tube, and the larger the diameter, the better the energy absorption performance, while the larger the outer diameter, the lower the energy absorption performance. The axial expansion load of the energy absorption tube increases with an increase in the impact velocity. Before and after the characteristic velocity of 1 m/s, the sensitivity of load to velocity is weakened and the variation range decreases gradually. The integrity of the bridge structure equipped with the E-CUPD is improved and the seismic force is evenly distributed among piers with an acceptable value of spring displacement. The device can effectively reduce the relative displacement of the piers and beam subjected to different earthquakes and can absorb a large amount of seismic energy. With the increase in the seismic input intensity, the limiting effect of the E-CUPD becomes more prominent. At the higher seismic input intensities, the relative displacement of the pier and the beam can be reduced by nearly 30% compared to bridge without device. Compared to the C-CUPD, the E-CUPD can improve the limiting performance by about 15%.

This study investigated flow characteristics around a cylindrical pier under a partially submerged bridge deck. The tests were carried out in clear water conditions for both free-surface and pressure-flow conditions. Three-dimensional velocity measurements were taken at different positions along the centreline of the flume using an acoustic Doppler velocimeter. The results showed that the longitudinal and vertical velocity components of the pressure-flow increased in the vicinity of the pier as compared with those of the free-surface flow. Large values of the turbulence intensities, turbulent kinetic energy and Reynolds shear stress were observed at the upstream edge of the bridge deck within the shear layer and downstream of the pier under the deck due to the generation of wake vortices. Flow contraction and acceleration around the pier's sides resulted in a local increase of the bed shear stress.

In the past decades, more and more precast piers have been used in actual engineering, which brings convenience in construction and standardization of production. However, precast piers still have some shortcomings, such as shear slip between segments and poor energy dissipation. Thus, a self-centering mortise-tenon segmental bridge pier was proposed in this paper. To research the seismic performance of the self-centering mortise-tenon segment piers, three scaled model piers with their scale ratio as 1:3 were designed and prefabricated, namely as a cast-in-place model pier (CP) and 2 self-centering mortise-tenon segment model piers (designated as MTSP1 and MTSP2) with the initial pretension of 1302 MPa and 1488 MPa, respectively. The cyclic pseudo-static tests of the three piers were carried out. The comparison analysis was made respecting to the test results including the damage form, hysteretic characteristics, skeleton curve, energy dissipation capacity, residual displacement and equivalent stiffness of the three specimens. It was shown that MTSP specimens had higher horizontal bearing capacity. While the yield load, ultimate load, displacement ductility coefficient and initial stiffness of MTSP1 and MTSP2 were higher than those of CP. The MTSP had better performance considering the above aspects. The mean value of the residual displacement of MTSP2 was lower than that of CP 21.14 % and 29. 72 % respectively, as the drift ratio reaching 5 %. The MTSP specimens had better self-centering capacity due to the increased pretension stress which reducing the residual displacement greatly. The energy dissipation reinforcements improved the energy dissipation capacity of the segmental assembled piers. Based on the ABAQUS model, the numerical simulation was carried out and compared with the experimental data. MTSP had great energy dissipation capacity and self-centering capacity. It was suggested that MTSP should be used to make up for the deficiency of segmental assembled pier and improve the seismic performance of segmental assembled pier.

The main purpose of this study was to analyze and predict scour depth and hydraulic performance of piers using soft computing methods and to estimate scour depths using artificial neural networks and ANFIS methods. In the present study, three situations were studied: a rectangular pier without a cable (type I), a rectangular pier with a cable that has a diameter equal to 10% of the pier diameter, and a cable twist angle of 15 degrees (type II), and a rectangular pier with a cable 15% of the pier diameter and an angle of twist of 12 degrees (type III). Tests were carried out with different flow-approach angles: zero, 5, 10, and 15 degrees. Dimensional analysis based on the π Buckingham method was performed. Then, the effect of different parameters, and their importance for estimating scour depth was investigated. Piers with an angle of 15 degrees with respect to the direction of flow had the greatest depth of scouring. Cables can reduce scour depths at this angle; for the second and third classes of piers, the scouring is 10 and 22% compared to the first pier classification. For the second type of pier, angles of 5, 10, and 15 degrees led to increases in scouring depths of 3, 21, and 37% compared to the zero-angle situation.

In this article, the seismic performance of box-shaped steel piers embedded with energy-dissipating shells under a multi-directional seismic load is investigated. A finite element (FE) model was accurately established and verified by the quasi-static test results. A parametric analysis of the hysteretic behaviour of a novel box-shaped steel pier under eccentric pressure was carried out on this basis. We discussed the influence of the eccentricity, axial compression ratio, thickness of embedded shell, ratio of slenderness, spacing of transverse stiffening ribs on the embedded shell, and width-to-thickness ratio of wallboard on the anti-seismic performance of a novel box-shaped steel bridge pier. The results revealed that the load carrying capacity and ductility coefficient of the specimen are substantially influenced by the eccentricity, variation in the axial compression ratio, and slenderness ratio. The specimen’s plastic energy dissipation capacity can be effectively improved by increasing the thickness of the embedded shell. The spacing of the transverse stiffening ribs only marginally affects seismic performance. In addition, the width-to-thickness ratio of the wallboard exerts a more considerable influence on the deformability of the square-section specimen. Finally, a formula for calculating the bearing capacity of the novel box-shaped steel piers under cyclic loading is proposed.

The Dynamic characteristics such as damping ratio and natural frequency are an important indicator for predicting the dynamic behavior of bridges, but it is customary during the design that the designer assess the dynamic properties of the dynamic analysis because it is very difficult to determine the damping of the origin before construction and damping is taken as a predetermined constant value independent of the response amplitude and frequency of the structure. In the dynamic analysis of constructions design some experimental research has been concerned with the determination of dynamic structural properties and their relationship with the response amplitude experimentally, but the changes in dynamic properties with vibration amplitude has never been taken During dynamic analysis, further analytical treatments and computer modeling were required to study different cases based on the experimental results available by simulating them with a computer model. Dynamic characteristics are very essential to accurately determine the dynamic response, and it is necessary to study the effect of changes of the actual dynamic characteristics of bridges, which were determined by measuring their vibration in the results of dynamic analysis and comparing them with results that do not take into account the changes of dynamic properties and with laboratory results in order to assess the role of. Dynamic analysis inputs in simulating vibrations by monitoring their responses. As a result, it was found that the dynamic properties are independent of the shape of the external exactions. Also, it was concluded that relationships express the change of dynamic properties in terms of vibration amplitudes. And Similar reliance of the dynamic characteristics to the vibration amplitude is confirmed for the pier model, where the increase of the amplitude of the acceleration is accompanied by a decrease in the natural frequency, and an increase in the damping ratio is obvious. Before choosing design values when considering the dynamic characteristics of a structure, we need to give unique concentration to the predictable vibration amplitudes. Dynamic characteristics changes during dynamic analysis should be considered to produce analytical results that simulate experimental results and are closer to reality.

Hollow steel tubular members are extensively used in multi storey car parks, bridge piers, building columns, offshore structures and subway columns. An earthquake of moderate intensity can result in extensive damage and potential collapse of bridges. During a large earthquake, traditional seismic lateral resisting system can experience significant damage and it cause residual drifts. Thus, a suitable strengthening or retrofitting technique needs to be developed for minimising structural damage and human casualty due to imposed lateral impact loading. The steel shell acts as longitudinal and transverse reinforcement. The primary role of stiffeners is to prevent local buckling prior to overall buckling and to increase overall buckling strength. In seismic applications, an additional, yet equally important role of stiffeners is to increase ductility of the cross section under cyclic loading. Stiffeners are the secondary plate or sections which are attached to web or flanges to stiffen them against out of plane deformation. This paper presents the research work on analytical prediction and finite element simulation of steel tubular pier with stiffeners. A non-liner 3D model was developed using ANSYS programme.

The re-centring ability and durability of important bridges have been the main objectives in recent provisions of seismic design codes. To achieve better recoverability and durability for piers, th...

An improved cyclic softened membrane model (ICSMM) based smeared reinforced concrete (RC) plane stress element has been developed in the present study. The newly developed two-dimensional (2D) element has been implemented in the OpenSEES nonlinear finite element analysis (NLFEA) framework. The effectiveness of the developed element has been thoroughly validated using experimental results of three RC panels tested under cyclic pure shear loading and three hollow rectangular RC (HRRC) bridge piers tested under static axial and reversed cyclic in-plane bending loads. The accuracy of the NLFEA model based on ICSMM based plane stress elements has been further verified with the results obtained from the simulation of the considered test specimens using the NLFEA model based on existing CSMM based plane stress elements. After thorough validation ICSMM based NLFEA model has been used to perform incremental dynamic analysis (IDA) and develop seismic fragility curves for the three considered HRRC bridge piers using maximum likelihood estimation (MLE) method. The robustness of the fragility curves, thus obtained have also been verified by comparing with the fragility curves of the same bridge piers developed using two commonly used one dimensional (1D) NLFEA models based on fiber-beam-column elements that can capture axial-flexure and axial-shear-flexure interactions. The advantages and disadvantages of using ICSMM based NLFEA model over 1D fiber based NLFEA models for seismic fragility assessments have also been presented. It has been concluded from the results obtained that the ICSMM based NLFEA model is very effective to assess the complete nonlinear response of HRRC bridge piers under both in-plane reversed cyclic and seismic loads compared to the existing CSMM based 2D model and two other widely used 1D simulation models.