Finite Element Analysis Of Seismic Behavior On Reinforced Concrete Columns With HRB500 Bundled Steel Bars

In practical engineering,reinforcement densely is hard to design and construction,the single reinforcements are combined in fasciculus,formed as bundled bars to solve this problem.The structural specifications of bundled bars is first put forward by Code for design of concrete structures(GB 50010-2010),bundled bar makes bond-anchorage properties decreases,and it is outstanding while using the high-strength reinforcement.This thesis is based on the experiment of HRB500 bundled bar concrete columns,adopting the finite element software of ANSYS combine with bond-anchorage pullout test of bundled bar,get some correlation conclusion about stress,strain,bearing capacity and ductility coefficient of bundled bars,provide reference for further application.The main work is given as follows:(1)Simulated the process of crack,yield and crush of bundled bars,get the conclusion that the member ultimate bearing capacity,deformation and ductility coefficient decreases while the number of bundled bars increase,this conclusion is basically identical with the experiment.The maximum descent range of ductility coefficient is 13.1%,it would get some influence of seismic behavior to members.(2)Compared the bearing capacity and displacement caused by different bond-slip model of reinforced concrete.Discussed 3 situations as below by using the finite element software of ANSYS:bond-slip model of pullout text,bond-slip model of Houde and none bond-slip model.The results showed that bearing capacity and displacement decreases while considering the bond-slip model,this result is coincidence with practical engineering.The bearing capacity that considering the bond-slip model of pullout text is smaller than considering the bond-slip model of Houde,but the difference of bearing capacity is less than 5%,HRB500 reinforcement can be analyzed by the bond-slip model of Houde.(3)Based on the bundled bar equivalent principle and considering the bond-slip model of Houde,we analyzed the mechanical behavior and seismic behavior by adjusting the axial compression ratio and concrete strength of members.The results showed that the bearing capacity and ductility coefficient of members decreases while the axial compression ratio increases,the descending rate of bundled bars' bearing capacity are similar to the single reinforcement columns,the descending rate of bundled bars' ductility coefficient are faster than single reinforcement columns.Incondition of high strength concrete,bundled bars' bearing capacity are similar to the single reinforcement columns,the ductility coefficient of members increased while the concrete strength increases,the increasing rate of bundled bars' ductility coefficient are lower than the single reinforcement columns.