Papers by Keyword: Bridge Pier

Abstract: The dynamic testing of large-scale structures continues to play a significant role in earthquake engineering research. The pseudo- dynamic test (PDT) is an experimental technique for simulating the earthquake response of structures and structural components in time domain. A CFST-RC pier is a modified form of CFST laced column in which CFST members are connected with RC web in longitudinal direction and with steel tube in transverse direction. For this study, a CFST -RC pier is tested under three different earthquake time histories having scaled PGA of 0.05g. From the experiment acceleration, velocity, displacement and load time histories are observed. The dynamic magnification factors for acceleration due to Chamoli, Gorkha and Wenchuan ground motions are observed as 12, 10 and 10 respectively. The frequency of the pier is found to be 1.42 Hz. The result shows that this type of pier has excellent static and earthquake resistant properties.

Abstract: After more than fifty years from the opening of the largely discussed “Autostrada del Sole” Highway in 1964, the infrastructure system in Italy appears marked by the passing of time, similarly to what observed in several other countries worldwide. The great heterogeneity of the Italian landscape has determined a great variety of construction types, such as large span concrete bridges over the northern rivers and large arch concrete bridges over the valleys of the central region. Increment of vehicle traffic and new seismic regulations are setting new requirements to adapt the existing infrastructure, which should be otherwise replaced. Moreover, reinforced concrete (RC) aging and deterioration have led to structural and material degradation, including severe cracking and corrosion. Specialized materials such as High Performance Concrete (HPC) could represent a viable convenient solution for repairing, strengthening and retrofitting of RC structures as both structural capacity and durability can be refurbished. However, alongside high mechanical performance, HPC is characterized by a high cracking sensitivity at very early age, due to its high stiffness and shrinkage. Restrained shrinkage cracking, particularly significant in repaired structures where the existing concrete generates a considerable restraint against the free movement of the repair material, may represent a limit to the effective application of these materials. For this reason, shrinkage compatibility of HPC with the existing concrete substrate needs to be experimentally and numerically assessed. A study is herein presented where, based on experimental tests, different numerical models are developed and compared to assess and eventually minimize the risk of shrinkage cracking in bridge piers strengthened with HPC.

Abstract: This paper addresses the usage of new construction materials made of natural fibre reinforced polymer and concrete composite for future earthquake-resistant structures. The structure considered is a simple circular bridge pier. To evaluate the seismic performance of the structure shake table experiments were performed. To reveal the consequence of the magnitude of the ground excitation for the structure the effect of a gradual increase of the peak ground displacement is investigated. The results show that although external damage to the structure cannot be observed the bond between polymer and concrete is a significant factor that determines the performance of the structure.

Abstract: Objective. To analysis of steel concrete piers load - displacement curve of the whole process, to explore steel concrete piers ultimate bearing capacity and deformation effects at different temperatures. Method. Using ABAQUS finite element software for concrete piers steel axial compression nonlinear analysis, analyze the effects of different temperatures on the piers ultimate bearing capacity and deformation capacity utilization of the whole curve obtained. Results. As the temperature increases, the ultimate bearing capacity of concrete steel piers greatly reduced, the yield strength of the material is also decreased, reached the ultimate bearing capacity of the pier when the corresponding displacement is also significantly reduced. Conclusion. The temperature has a significant impact on ultimate bearing capacity and yield strength.

Abstract: In the study of bridge pier’s dynamic characteristics, the modal analysis is the foundation of other dynamic analysis and is of great significance for studying other dynamic performance. Based on the dynamic theory of fluid-solid interface coupling, a 3D water-structure coupling finite element modal is established and computed by ANSYS. To verify the validity of the calculation results, the results of finite element software is compared with the analytical solutions in reference books. The analysis indicated that the results of finite element software are reasonable when the radius of bridge pier is five times the radius of water body. The ratio of water depth and the bridge pier’s height has a great influence on the change scale of bridge pier’s frequency. With the increase of bridge pier’s height-diameter ratio, the first three order natural vibration frequency is reduced.

Abstract: The drifting ice sheets impact with the bridge pier and other hydraulic structures in the rivers, which may damage even cause collapse of the structures. In this paper, the FEM software package LS-DYNA was used to performed the numerical simulations of the collision process of the ice sheets and the bridge piers to make clear the interaction between them and to understand the failure mechanism of the ice sheet. The elastic strain-stress model with von mises failure criterion was used to describe the ice material. The brittle damage material model was used to describe the concrete pier. Three types thickness of ice sheets were performed at various velocity of the ice sheet respectively. The impact process of every case were displayed and the time history curve of the collision force were given out. The simulations results show that the peak value of the collision force time history curve increases with the velocity of the sheet firstly and then decreases with the velocity of the ice sheet. There is one critical velocity which relate to the compressive strength of the ice sheet. The simulation result were also compared with the different bridge design code, which show that the code result is more conservative in bridge design.

Abstract: The seismic performance of the bridge piers is a basic study in seismic analysis of bridges. Hollow section piers have high bending strength and stiffness, as well as reduced amount of reinforced concrete needed and thus good economic returns, which have been widely applied in the high-pier, large-span bridges in high-intensity area of western China. Current study status and future development trends about the seismic behavior of hollow section reinforced concrete piers were presented. The necessity of carrying out seismic performance studies of hollow section reinforced concrete bridge piers was also pointed out.

Abstract: The ultimate limit state of the curvature for circular section reinforced concrete bridge pier was studied from the uncertainty of the deformation capacity. This article firstly uses the bridge pier with the diameter of 1.0m as the benchmark pier to study the relations between the ultimate limit state of the dimensionless yield, service and damage control curvature and the axial compression ratio, longitudinal reinforcement ratio and stirrup ratio. Results have shown that axial compression ratio is the main factor influencing the average value at the ultimate limit state of dimensionless yield and service horizontal curvature, while the axial compression ratio and stirrup ratio are main factors influencing the average value at the ultimate limit state of dimensionless damage control horizontal curvature. Then this article built the approximate formula for the calculation of diameter adjustment coefficient for the piers with other sections and diameters corresponding to the ductility at different ultimate limit states by means of regression analysis.

Abstract: The original concept of self-centering system was first proposed under the PRESSS research project in 1991 in UC San Diego. The particularly promising and effective structural solution was initially defined as hybrid system in literature and then self-centering system recently. In the ductile connection of self-centering system, inelastic demand is accommodated through the opening and closing (control rocking) of a pre-existing gap at the critical interface, with no consequent damage such as the plastic hinges in traditional structural elements. This paper provides an overview of the recent advances of self-centering system, especially for bridge piers, to summarize several analytical models and experimental tests that were widely recognized. Besides, a brief introduction of the study conducted by Tsinghua University is presented, including a stiffness degrading analytical model and a series of experimental tests.

Abstract: To investigate the seismic performance of FRP strengthened RC hollow section bridge piers under multi-dimensional earthquake excitation, the pseudo-static test was carried out to RC rectangular hollow section as-built and CFRP confined bridge piers under constant axial compression force and bidirectional horizontal repeated load. The failure characteristics, lateral force-deformation curves and ductility of specimens were analyzed. The experimental result shows that CFRP constraining may change the failure mode of hollow section bridge piers, and significantly improve the deformation ductility, plastic deformation, however, it is less contribution to horizontal force of specimens with less wall-thickness.