Study On Seismic Behavior Of RC Bridge Pier Column In Saline Soil Environment

The main feature of the saline soil environment is that it contains a variety of high concentrations of corrosive ions.Compared with the marine environment,the concentration of chloride ions contained in the saline soil environment is significantly higher.The presence of chloride ions will seriously affect the bearing capacity and deformation performance of the steel bars,thus affecting the seismic performance of the structures or components.The bridges as an important hub of transportation,bridges and pillars are the main supporting members of bridges,and their research on seismic performance is very important.Therefore,this paper mainly studies the seismic performance of reinforced concrete(RC)bridge pier columns in saline soil environment.In order to study the seismic performance of RC bridge pier columns in saline soil environment,10 RC bridge pier columns were designed and manufactured.The standard corrosion solution was prepared according to the characteristics of saline soil,and the solution was poured into a ring-shaped plastic bucket.The plastic corrosion zone of the specimen was subjected to a rapid corrosion test.After the specimen was rusted,the specimen was subjected to a low cycle repeated loading test.The corrosion rate and axial compression ratio are the main affecting factors,and the axial compression ratios include0.12 and 0.36.During the loading process,the load-displacement curves of the specimens were recorded in real time,and the seismic performance of the bridge pier columns with different corrosion rates and different axial compression ratios was compared and analyzed.Through the theoretical derivation,the calculation model of the restoring force of RC bridge piers in saline soil environment is established.Specifically,it includes the following aspects:(1)After the electrochemical rapid corrosion test of the tested specimens,the low-cycle repeated loading test was carried out,and the whole failure process of the specimen was observed and recorded in real time,and the displacement-load curve of the specimen was obtained.(2)After the specimen is loaded,the steel bars in the plastic hinge area of the test piece are sampled,derusted and weighed,and the actual corrosion rate of the steel barswere measured.(3)The failure modes of the specimens were compared and analyzed.The results show that the corrosion rate is higher when the axial compression ratio is constant,and the damage degree of the specimen is more serious.When the corrosion rate is constant and the axial compression ratio is within a certain range,the greater the axial compression ratio,the more serious the specimen damage.In addition,through comparative analysis of the skeleton curve and hysteretic curve of the specimens,it is found that corrosion will seriously affect the deformation capacity and bearing capacity of the specimens,and the axial compression ratio will seriously affect the ultimate displacement of the specimens.(4)The skeleton curve of the specimen is simplified into a three-fold line model,and the displacement and load of the key points(seismic yield point,seismic peak point,seismic failure point)are theoretically derived and calculated.On this basis,the regression analysis is carried out on the loading curve and the unloading curve under each control displacement,and the theoretical calculation results of the restoring force model are obtained.(5)By comparing the experimental results with the theoretical results,it is found that the degree of coincidence is high,which can provide reference for the seismic design of RC bridge pier columns in saline soil environment.