Research On Seismic Behavior Of Tubular Reinforced Concrete Columns Of Air Cooled Support Structure

Air-cooled condenser support system is the most important one to undertake theweight of air cooling equipments.Generally speaking，it usually has several structuralforms such as steel frame, spatial steel truss, spatial steel truss with steel bracings andect. Tubular reinforced concrete columns in spatial steel truss structure and spatial steeltruss with steel bracings structure have the characteristics of thin wall and great sizewhich are about4m in diameter,about0.3m to0.5m in thickness and40m high. Theysupport millions of tons of weight of the upper equipments. Once the columns collapsed,huge casualties and economic loss will be caused. Therefore, it has important practicalsignificance to study their seismic behaviors.In this paper, seismic performances of columns which are used in spatial steel trussstructure and spatial steel truss with steel bracings structure have been studied byexperimental and finite element methods.(1) Considering the economic and experimental conditions, four specimens1/8ofthe prototype columns of spatial steel truss structure are fabricated and tested bypseudo-static test. Mechanical and deformation properties are studied under cyclicloading.(2) Model test has been conducted for the spatial steel truss with steel bracingsstructure. The model which is1/4of the prototype and1/8scale was tested in two stages.Firstly, EL-Centro earthquake waves with different peak accelerations were inputduring the pseudo-dynamic test.Then, the pseudo-static test was conducted until thestructure damaged. Observe the development of cracks and failure conditions of tubularreinforced concrete columns during the experiment.(3)Build the finite element models of tubular reinforced concrete columns inspatial steel truss structure and spatial steel truss with steel bracings structure respectively by using earthquake engineering simulation software OpenSees.Comparethe hysteretic curves and skeleton curves through calculation with the experimental one.Verify the correctness of simplified methods and related parameters of the models.(4)Axial compression ratio and longitudinal reinforcement ratio are main factorswhich affect the seismic behavior of tubular reinforced concrete columns.Load-displacement curves are calculated by OpenSees with different axial compressionratio and longitudinal reinforcement ratio under cyclic loading to study the effects ofthese factors on the columns’ bearing capacity and energy dissipation properties.(5) Compare the calculation results of these two kinds of air cooled supportstructures columns; Study the influence of steel bracings on tubular columns’ seismicbehaviors.The experimental and calculation results in the paper can provide referencematerials for the design of tubular reinforced concrete columns in spatial steel trussstructure and spatial steel truss with steel bracings structure.