Double-column Pier Research Articles

Experimental Investigation on Failure Mechanism and Hysteresis Behavior of RC Single- and Double-Column Piers

Experimental Investigation on Failure Mechanism and Hysteresis Behavior of RC Single- and Double-Column Piers

Seismic Fragility Analysis of Reinforced Concrete Simply Supported Girder Bridges Resting on Double-Column Piers for High Speed Railway

Seismic Fragility Analysis of Reinforced Concrete Simply Supported Girder Bridges Resting on Double-Column Piers for High Speed Railway

Hydrodynamic analysis of sea-crossing bridge piers subjected to freak waves

Coastal areas are witnessing a surge in critical infrastructure development, such as sea-crossing bridges, to support growing populations and economic activities. However, these structures face ongoing challenges in harsh marine environments. Therefore, understanding the hydrodynamics of bridge structures under extreme freak wave conditions is imperative for designing effective countermeasures. This study investigates pier hydrodynamics using a three-dimensional numerical flume simulated by OpenFOAM, focusing on loading characteristics and wave climb differences under freak and linear waves. Results show that freak waves induce larger surges and forces compared to linear waves, with a notable “bell vibration” effect near the wave surface. Moreover, peak forces and bending moments increase nonlinearly with the wave height-to-significant wave height ratio. For double-column piers, transverse alignment concentrates wave climb on the rear side of the front pier, with forces increasing with spacing, while those on the rear pier decrease. Conversely, longitudinal arrangements show amplified loading effects. These findings provide valuable insights into the hydrodynamic behaviour of bridge piers under freak wave conditions, offering practical implications for the design and protection of sea-crossing bridges.

Seismic Performance and Damage Mechanism of RC Double-Column Pier Structure with Triple Coupling Beams

Seismic Performance and Damage Mechanism of RC Double-Column Pier Structure with Triple Coupling Beams

Research on the Factors Influencing the Seismic Performance of Grouting Sleeve Assembled Double-Column Piers

The present study investigated the influence of key design parameters on the seismic performance of prefabricated precast assembled piers’ connection parts to better adapt to the industrialized construction of prefabricated precast assembled pier connected using grouting sleeves. Relying on a prefabricated assembled bridge in the actual project, the ABAQUS software was used to establish a refined solid finite element model of prefabricated assembled piers connected with grouting sleeves. Numerical simulation analysis was conducted for the piers with low circumferential reciprocating loading. The seismic performance of the prefabricated assembled piers was evaluated in terms of hysteresis characteristics, dissipation characteristics, and damage development. The effects of the length of the grouting sleeve and the diameter of the longitudinal reinforcement on the seismic performance were also investigated. The maximum error between the numerical simulation results and the test results was 5.7%, and the plastic region of the precast assembled pier obtained from the numerical simulation was consistent with the test results, indicating that the numerical simulation method is accurate and reliable. When the length of the grouting sleeve increased from 0.6 to 1.2 m, the yield load, peak load, and dissipation of energy of prefabricated assembled piers increased by 11.6%, 10.9%, and 11.4%, respectively; no significant change in residual displacement; ductility coefficient decreased by a small amount. When the longitudinal reinforcement diameter increased from 20 to 50 mm, prefabricated assembled piers yield load, peak load, and dissipation increased by 99.6%, 89.3%, and 218.9%, respectively, whereas the residual displacement increased by 137.3%, and the ductility coefficient decreased more. Increasing the length of the grouting sleeve or increasing the diameter of longitudinal reinforcement improved the stiffness of the piers, causing the piers to displace less and damage less under the same force, but the residual displacement would increase.

Study on the Impact Law of V-Shaped Gully Debris Avalanches on Double-Column Piers

The concrete piers in steep mountain areas are highly susceptible to damage disasters due to the impact of debris avalanches, which pose a serious threat to the safe operation of bridge structures. In order to investigate the impact load characteristics of debris avalanches on bridge pier structures in V-shaped valley mountain areas, Particle Flow Code 3D (PFC3D) models based on a discrete element method were applied in this study to establish a full-scale three-dimensional model of a debris avalanche in a V-shaped valley. By installing double-column piers in the influence zone of the debris avalanche, the impact force, accumulation morphology, motion characteristics of debris particles, internal force response of the double-column piers, and impact energy indicators were investigated. In addition, parameters such as the layout position of the piers and the impact angle of the debris were studied. The results showed that the particles at the front edge of the debris avalanche have a significant impact on the magnitude and distribution of the impact force on the piers. It is important to consider the layout position of the piers and the impact angle of the debris when designing bridge pier structures in high, steep mountain areas. There was a significant difference in the movement patterns between the particles at the front and rear edges of the landslide. The particles at the front edge had a higher velocity and stronger impact, while the particles at the rear edge had a slower velocity and were more likely to be obstructed by bridge piers, leading to accumulation. The obstruction effect of the piers on the debris particles was closely related to their positioning and the impact angle. Piers that were closer to the center of the valley and had a larger impact angle have a more significant obstruction effect, and the topography of the valley had a significant focusing effect on the debris avalanche, resulting in a greater impact force and energy on the piers located closer to the center of the valley. The impact force amplitude and duration of landslide debris on bridge piers showed a significant difference between the bottom and upper piers, as well as between the piers on the upstream and downstream sides. These research findings can provide valuable references for the design and disaster assessment of bridge piers for impact prevention in steep slopes and mountainous areas with deep ravines.

Effect of magnetic-spring bi-stable nonlinear energy sink on vibration and damage reduction of concrete double-column piers: Experimental and numerical analysis

Concrete structures suffer from crack damage under heavy vibrations, caused by seismic loads. Passive vibration control devices can be used to reduce the damage. The most common device is the tuned-mass-damper (TMD), which is tuned to match the natural frequency of the primary structure. However, under prolonged vibration load, the natural frequency of the concrete structure decreases, reducing the TMD's effectiveness in mitigating vibrations and damage, as it can only target a fixed natural frequency. Therefore, this study will propose and implement the nonlinear energy sink (NES), which is a vibration control device that can adapt to changing frequency, resulting in a larger effective bandwidth than the TMD. As a concrete structure, the cast-in-place double-column piers is seismically loaded with a shaking table with and without NES to observe the vibration and damage-mitigating properties of the NES. More specifically, a magnetic bi-stable NES (MBNES) with a viscous fluid damper (VFD) is designed and built. The bi-stable restoring force allows for a larger bandwidth than conventional NESs, and the magnets and VFD allow for easy manufacturability. An optimization method is proposed to obtain optimal parameters, and the restoring force and damping of the experimentally designed MBNES are verified using the restoring force surface method. The proposed design, optimization and identification procedure are generic and can be applied to any (concrete) civil structure. Shaking table tests are used to verify the robust performance of MBNES under continuous changes in the natural frequency of concrete double-column piers. The experimental results show that the MBNES can effectively mitigate vibrations of the pier and, consequently, reduce the damage of the pier, slow down the decrease of the stiffness of the pier, reduce the curvature and shear deformation of the pier. Numerical analysis results show that MBNES can absorb the energy of the primary structure in a wide frequency bandwidth and has excellent robust performance compared to conventional devices.

Damage mechanism and assessment of precast double-column bridge piers under blast impact

This paper aims to investigate the damage mechanism of precast double-column bridge piers under blast impact and propose a new damage evaluation method. The three-dimensional solid separation model of a pier column under explosion actions is established using ANSYS/LS-DYNA, and the accuracy of the numerical simulation method is verified by the existing experimental results. Subsequently, numerical experiments of the double-column bridge piers under explosions are carried out. The damage accumulation process and local failure mechanism are investigated with the analyses of the propagation of stress waves in concrete. In addition, the criteria containing residual bearing capacity and local damage are introduced in the damage assessment, aiming to evaluate the explosion damage degree of bridge piers comprehensively. The P-I (pressure-impulse) curves of precast double-column piers are established, based on the overpressure-impulse damage assessment method by Henrych’s empirical formula. The general evaluation process and method of double-column bridge piers under blast impacts are proposed and verified. The research results provide important insights and references for the anti-blast design of precast double-column piers and their bridge systems.

Seismic fragility and resilience improvement of conventional bridges supported by double-column piers utilizing shear links

A bridge structure is one of the most vulnerable parts of the transportation network system subjected to earthquakes. It is paramount to the seismic capacity improvement and the rapid recovery function of bridges during earthquakes. To address these challenges, shear links (SLs) are designed between the columns supporting the continuous girder bridges based on the structural fuse concept. The impacts of SLs on the life-cycle performance and seismic resilience of continuous girder bridges were studied by comparing the continuous girder bridges supported by double-column piers with and without SLs. The incremental dynamic analyses were performed to evaluate the seismic fragility of continuous girder bridges supported by double-column piers with and without SLs under the far- and near-field seismic waves. The economic losses were assessed to compare the financial superiority of continuous girder bridges supported by double-column piers with SLs in the life cycle. A resilience assessment methodology was employed to evaluate the post-earthquake resilience of continuous girder bridges supported by double-column piers with and without SLs. The results showed that the SLs preferentially dissipated a certain amount of earthquake energy so that the continuous girder bridge supported by new-type double-column piers with SLs exhibited lower seismic fragility and life-cycle losses compared to the continuous girder bridge supported by traditional double-column piers. Also, the proposed continuous girder bridge supported by new-type double-column piers with SLs behaved with higher post-earthquake resilience under the far- and near-field seismic waves.

Experimental and numerical investigation of seismic performance of prefabricated double-column piers used in accelerated bridge construction

The socket connection has been considered to be an effective connection for accelerated bridge construction (ABC) due to its promising advantages, i.e., higher construction tolerance rate, simpler connection method, easier quality control method, and better seismic performance when the socket depth is sufficient. To further facilitate the promotion of socket connections, a novel double-column piers system with socket connection was proposed, and the prefabricated piers and adjacent elements are connected using Ultra High-Performance Concrete (UHPC) grouting. Three 1:3 scale double-column pier specimens using novel type socket connection, ordinary grouted corrugated duct connection, and cast-in-place connection, respectively, were subjected to pseudo-static tests, aimed to compare the effects of connection methods on the damage development, failure mode, strain distribution, and seismic performance of the double-column pier. The test results indicate that all three double-column piers with three different connection forms exhibit good seismic performance, with the failure mode being the fracture of the longitudinal rebars of the piers. Compared with the piers fabricated with the other two connection forms, the piers with socket connection feature less residual displacement, and the damage is mainly concentrated at the bottom of the pier. Additionally, numerical analysis models were developed and validated for the socket-connected double-column piers to facilitate further research in this area.

Weathering steel damper and its application: A case study for double-column piers

Double-column piers can be damaged in an earthquake, seriously affecting the safety and use of bridges. The retrofitting of double-column piers using dampers is an important topic in bridge engineering. Using tests and finite element analysis (FEA), the mechanisms and damage states of new weathering steel dampers were studied. The results showed that weathering steel dampers have good resistance to fatigue under high-stress conditions in cyclic loading but also exhibit asymmetry under large deformation. Therefore, the damper connections were optimized based on FEA. In a case study, the installation of weathering steel dampers was performed, and the effects of weathering steel dampers on dynamic response and damage were examined. The results showed that retrofitted double-column piers have a significant damping effect, with a 15.1% reduction in structural damage and a 43.7% reduction in ultimate dynamic deformation response. This study provides a reference for the design and analysis of weathering steel dampers in engineering applications.

A novel machine learning-based framework for predicting impact force in ship-bridge pier collisions

The escalating occurrence of ship-pier collisions poses a substantial threat to coastal bridge infrastructures. To avert such accidents, various specifications have introduced several impact force models, yet engineers strive for accurate predictions. This study presents a framework for predicting impact forces by combining a precise finite element (FE) model, machine learning algorithms, and fast Fourier transform (FFT). Firstly, a reliable FE model is constructed to simulate barge collisions with a double-column pier, encompassing analyses of energy transformation, structural damage, time-frequency impact forces, and structural response. Subsequently, a machine learning approach combined with FFT is employed to predict the impact force, with a discussion on the impact force's sensitivity to barge weight and velocity. The study also presents two potential applications of the proposed framework. Numerical results demonstrate that the framework accurately predicts the duration and frequency series of impact forces. The sensitivity analysis reveals the importance of closely monitoring barge weight in comparison to velocity during the design and management stages. Additionally, the study reveals that increasing barge velocity and weight prolongs the impact duration and amplifies the response peak, with time-series responses primarily concentrated in a limited low-frequency band. In summary, this study not only proposes a novel and accurate framework for predicting the time-history of impact forces through time-frequency analysis but also offers valuable insights into preventing catastrophic ship-pier collisions and mitigating their impact on coastal bridge infrastructure.

Hysteretic behavior of post-tensioned precast segmental CFT double-column piers

Hysteretic behavior of post-tensioned precast segmental CFT double-column piers

Seismic performance of precast double-column pier with UHPC-filled socket connections

Precast piers have been extensively investigated and applied in low seismic intensity areas, owing to the faster construction speed, limited traffic interruption, and environmental friendliness. However, few studies and engineering practices of the precast double-column piers (PDPs) located in high-intensity seismic areas have been reported. Therefore, in this study, a novel socket connection filled with ultra-high-performance concrete (UHPC) was proposed for the PDPs. The socket connections with concrete filled steel tube (CFST) are used to enhance the strength of the column-cap beam joints, at the same time the socket connections with the tooth-shaped shear keys are adopted at the column-footing joints to reduce the required anchorage length. The PDP with a scale ratio of 1:3 was constructed and then tested under the quasi-static load to investigate its seismic performance. Finally, a simplified analytical model of the socket connections was proposed based on the concept of the elastic foundation beam. The test results demonstrate that the damage of the specimen PDP was mainly concentrated at the bottom of the columns, and the damage at the damage ends of the PDP specimen was severer than that of the cast-in-place (CIP) specimen. The load-bearing capacity of the PDP is slightly higher than that of the corresponding CIP specimen, while the energy dissipation and displacement ductility of PDP are slightly smaller than those of the CIP specimen. The proposed model could accurately and efficiently capture the hysteretic behavior of the proposed PDP with socket connections.

On dynamic response and damage evaluation of bridge piers under far-field explosion loads

This paper aims to investigate of the dynamic response and damage mechanism of typical bridge piers under far-field explosions numerically and develop a feasible scheme for rapid damage evaluation of bridge piers. An ANSYS-AUTODYN-based explicit finite element formulation is introduced in which the dynamic input method of blast waves is developed using subroutines. The tests of drop hammer impact and far-field explosion are referenced to verify the reliability of the formulation and the mesh scale applicable to beam-column members is determined. Based on the validated formulation, the refined fluid–solid coupling models of typical single-column and double-column piers are established to explore their far-field blast responses. The effects of input parameters (i.e., the strength and angle of the blast wave,) on the pier response are analyzed. It is demonstrated that bending damage occurs in bridge piers is similar to that of cantilever beam under different strength loads, while the damage of double-column pier members under the constant displacement increases with the increase of the blast wave angle. By incorporating the crack distribution, quantitative assessing criterion and P-I diagram, a damage evaluating scheme is proposed and the damage regularities of piers under far-field blast loads are acquired. The present work can serve as a valuable reference for blast-resistant design and damage assessment of bridge piers under far-field blast loads.

Dynamic behaviors and equivalent static force of double-column pier under horizontal impact

The booms in transportation and bridge engineering are accompanied by the increasing threat of vehicular collisions with bridge piers. This study experimentally and numerically examines the dynamic behaviors of double-column reinforced concrete (RC) pier subjected to horizontal impact. Firstly, a series of reduced-scale horizontal impact test on five double-column RC pier specimens (containing the impacted pier, adjacent pier, and bent cap) is conducted considering different impact velocities and mass. Then, based on the previously-validated material models and finite element (FE) analysis algorithms, the five present and twelve additional impact cases are numerically simulated. The test and simulated results indicate that, (i) the whole impact process can be divided into cracking, resiling, and oscillating stages, and the impact force–time history and impact force-lateral displacement curve can be simply characterized by six critical points; (ii) the impact velocity dominates the development of impact force–time history, while the effect of impact mass becomes more significant with impact process progressing; (iii), the damage levels of impacted and adjacent piers as well as bent cap, and the maximal lateral displacement of impacted pier are positively related to the impact kinetic energy rather than the impact momentum. Finally, based on the pier shear resistance and the energy conversion, the novel equivalent static force (ESF) and corresponding ESF-based performance design are proposed for double-column RC pier against horizontal impact. The present work can provide the benchmark test data for validating the FE models, and the determination approach for the ESF-based performance design of bridge piers under vehicular collisions.

Seismic behavior of a novel prefabricated thin-walled CFST double-column pier system for simple on-site assembly

To expedite the development of concrete-filled steel tubular (CFST) piers for simple on-site assembly (SOA), a novel prefabricated thin-walled CFST double-column pier system is proposed with the advantages of accelerated on-site construction, facilitated transportation, reasonable constructional cost, and good seismic performance. Two prefabricated thin-walled CFST double-column pier specimens were tested under quasi-static loading, and their failure modes, deformation characteristics, hysterical responses, energy dissipation capacity, stiffness degradation, and residual drift ratio are discussed in detail. The test results indicate that the proposed prefabricated thin-walled CFST double-column pier system shows a fairly good seismic performance with reasonable failure mode, sufficient energy dissipation, and relatively small residual deformation, and the SOA connections can effectively guarantee the overall deformation of the system under a maximum drift ratio of 4.8%. The specimen with double RC tie beams is superior in lateral resistance and initial stiffness to the one with a single RC tie beam, while they show similar performance in ductility and energy dissipation efficiency.

Seismic fragility and resilience assessment of bridge columns with dual-replaceable composite link beam under near-fault GMs

The beam-column joints of piers with reinforced concrete link beams (RCLB) are easy to be damaged during earthquakes. Post-earthquake maintenance is very inconvenient since the beam-column joints are integrally cast. Therefore, a novel dual-replaceable composite link beam (DRCLB) is proposed to replace the traditional RCLB, which is composed of angle steels, concrete-filled steel tubes (CFST), connection steel plates, and an RC beam. The dual-replaceable mechanism of DRCLB is that the angle steel and CFST of DRCLB are damaged in sequence, and can be quickly replaced separately after the earthquake. The multi-stage damage model of DRCLB is quantified by pushover analysis, which can be applied to seismic fragility and resilience assessment. The seismic fragility and resilience analysis are carried out under near-fault ground motions for double-column piers with DRCLB and RCLB respectively. The results indicate that DRCLB can effectively reduce the peak response of the beam-column joint. Meanwhile, the columns of double-column piers with DRCLB and RCLB respectively present approximately identical performance. Based on seismic resilience analysis, the recovery capacity of the pier is effectively improved due to the well dual-replaceable performance of DRCLB.

Seismic fragility curves development for double-column piers of highway bridges applying Cox hazard models of survival analyses

Fragility analyses have undoubtedly been critical steps in the seismic risk assessment of highway bridges, and even in transportation networks. In view of the shortcomings of the previous fragility analysis methods, this paper discusses the application of survival analysis based on the Cox hazard model in the establishment of bridge pier seismic fragility. In the IDA framework, the ground motion intensity and censored value (damage state) are taken as dependent variables, and the pier attributes are used as covariates to generate fragility curves. Next, the uniform design experiment is used to generate the attribute data set training model of the pier samples. It can be observed that compared with the traditional strip analysis method, the proposed procedure can provide accurate estimation of the fragility curves, and the fragility curves established by the traditional method are in fact the fragility curve corresponding to the pier average sample. In addition, the primary survival analysis of the pier samples with average value and the hazard ratio provided by the Cox model can be used to quickly analyze the impact of significant factors on the fragility curves and estimate the seismic loss. The pier height, reinforcement ratio and reinforcement strength may be the dominant factors affecting the pier seismic loss in highway bridges.

Seismic fragility and loss assessment on earthquake-resilient double-column tall piers with shear links subjected to far-field and near-fault ground motions

This paper aims to study the benefits of the shear links (SLs) to improve the seismic resilience of the traditional double-column tall pier after earthquakes. Therefore, a double-column tall pier with SLs was designed and compared with a conventional double-column tall pier with reinforced concrete beams (RCBs). The seismic fragility of the double-column tall piers with SLs and RCBs was evaluated using incremental dynamic analyses when subjected to far-field and near-fault ground motions. The economic losses in the life cycle between the double-column tall piers with SLs and RCBs were compared using the proposed loss assessment methodology. The results revealed that the SLs between the columns could provide additional energy dissipation to reduce the seismic damage and vulnerability of the double-column tall pier. Therefore, the double-column tall pier with SLs exhibited lower damage probability for the various damage states and fewer economic losses than the traditional double-column tall pier due to the SLs dissipating enough energy. The proposed double-column tall pier with SLs manifested more reliable seismic resilience than the conventional double-column pier with RCBs. The double-column tall pier with SLs showed a better economy in the long-term time interval. Moreover, the life cycle losses of the double-column tall pier with SLs and RCBs under the far-field ground motions are lower than those of the double-column tall pier with SLs and RCBs under the near-field ground motions.