Analysis On Seismic Performance Of Hollow Thin-walled Rectangular Piers

Piers damage always causes the whole bridge collapsed under seism action. Research of the earthquake response of the bridge pier plays a key role in the seismic research. Due to difficult terrain in the west area, high pier often need to be built to across the mountains. The higher the bridge piers, the greater section size are needed. Given that, it is usually designed to be a hollow section, in order to save cost, reduce weight and enhance the flexible. Most of the bridge pier entered the stage of elastic-plastic deformation under the large earthquake. Using completely elastic theory for structural analysis and design is difficult to meet practical requirement. So, elastoplastic seismic analysis was carried out on the pier structure becomes more and more important. In this thesis, large-scale finite element software ABAQUS was performed to study the seismic response of hollow thin-walled pier, which has important implications to perfect our bridge seismic design code. In this paper, by using the method of combining the theoretical analysis and numerical simulation, the seismic performance of typical hollow thin-walled pier has been studied, the major research contains:(1) In this paper, six big proportions of the hollow thin-walled piers under low reversed cyclic horizontal load simulation have been analyzed on basis of simulation. It has discussed hysteretic characteristic, skeleton curves, displacement ductility and energy dissipation of bridge piers under compound stress. It found that: 1) displacement ductility coefficient was between 1.99 and 4.42;The main factors influencing the seismic performance of hollow thin-walled pier were volumetric percentages of stirrups, With the increase of its value, bearing capacity improved slightly, while the ductility increases significantly; 2)With the increase of axial compression ratio, the bearing capacity has been increased, the ductility decreased, which has greater influence on high reinforcement ratio; 3) Reinforcement ratio could enhance the loading capability of the structure, deformation ability reduced at the same time; The influence of reinforcement ratio of hollow thin-walled pier is more obvious under a large axial pressure; 4) Hollow thin-walled pier seismic has the same performance with the general reinforced concrete member, not only save materials but also lower cost.(2) Large scale finite element model have been established to study the ductility and strength under the same stirrup reinforcement ratio but different stirrup way. It found that: with a certain number of stirrups in reinforced concrete helped enhance the strength and ductility of concrete, increased the energy dissipation; It produced larger plastic deformation and had the best ductility when configurate composite stirrups. At the time, concrete ultimate strain reached 0.00871, increased 5.29 times compared to that not being reinforced, and increased 0.482 times compared to that configurate straight stirrups connection; When added diagonal connect stirrups, the ductility improved slightly but was not convenient to construction; Hollow thin-walled pier has a lager force on the angle, when the construction conditions permit, the angle should be made into some form of chamfer.(3) Using the principle and implementation method of Push-over, capacity spectra and seismic demand spectrum curve have been built, and thin-wall rectangular hollow pier under the effect of different seismic response has been assessed.