Numerical Simulation Study On Pit Seismic Performance Of Stainless-Carbon Steel Bar Reinforcement Concrete Hollow Piers

Corrosion of steel bars has become a key factor affecting the durability of concrete struc-tures.Replacing ordinary steel bars with stainless steel bars can fundamentally solve the prob?lem of rust expansion of concrete structures.At present,the research on stainless steel rein?forced concrete structure mainly focuses on the molecular composition of stainless steel mate-rials and corrosion resistance of stainless steel components.However,researches on seismic behavior of stainless steel reinforced concrete members are rare,which is obviously not condu-cive to the popularization and application of stainless steel reinforced concrete structures.And the initial cost of stainless steel reinforced concrete structure is high,so that most of the struc-tural design will not first consider the configuration of stainless steel reinforcement,which is also caused by the stainless steel reinforcement is difficult to promote a large area of another major factor.Therefore,it is necessary to conduct a detailed study of the internal structure of stainless steel bars and propose new structural forms.For this reason,this paper proposes to replace the original all stainless steel bars with carbon steel bars mixed with stainless steel bars.On the one hand,it can be widely used in the construction of hydraulic structures in the offshore areas of China;on the other hand,this type of reinforcement can fully reduce the project cost at the early stage of construction.In order to fully and carefully understand the mechanical properties of stainless steel stain?less steel stainless steel stainless steel bars S30408 is designed and carried out unidirectional tensile test at room temperature.The load-displacement curves of ordinary steel bars with the same strength level are compared.Based on the existing tensile constitutive model of stainless steel bars,the parameters of Quach model were modified to propose the constitutive model of steel bars suitable for austenitic stainless steel bars S30408.The main work of the thesis is as follows:(1)the diameter of the 12 groups of three kinds of austenitic stainless steel reinforcement S30408 unidirectional tensile test at room temperature,measured the austenitic stainless steel S30408 stress-strain full curves,on the basis of measuring the elongation,break elongation,the initial elastic modulus,elastic modulus,the secant modulus,yield strength,strain hardening index,and the basic mechanical properties such as ultimate tensile strength index.(2)analysis of the existing of stainless steel,mild steel and nickel chrome plate uniaxial tensile,compression stress-strain constitutive model,and finally on the basis of Quach consti?tutive model,in order to test measured stress-strain full curves of S30408 as data sources,to the constitutive parameters fitting correction,summed up the S30408 constitutive model for?mula of stainless steel reinforcement.(3)on the basis of the existing experimental study of hollow reinforced concrete pier,a numerical model of the mixed reinforcement of stainless steel-carbon steel was established,and the load-displacement curve of the pier under the seismic load was simulated to analyze the hysteretic performance of the composite energy dissipation characteristics of the stainless steel-carbon steel reinforced concrete pier.Based on the comparison of stainless steel,plain carbon steel bar concrete hollow pier,contrast analysis of three kinds of reinforcement in the form of hollow pier under the bearing capacity of energy dissipation,hysteresis property and character?istic,it is concluded that the stainless steel,carbon steel reinforced concrete hollow pier in the feasibility of internal reinforcement form,and analyze the seismic performance of stainless steel,carbon steel reinforced concrete hollow pier of the basic law.(4)By changing the axial compression ratio,reinforcement ratio and height-width ratio of stainless steel-carbon reinforced concrete hollow pier column,the influence law of various in?fluencing factors on the seismic performance of mixed reinforced hollow pier column was com-prehensively analyzed.