Research On Seismic Damage Of Reinforced Concrete Pier Column In Western Saline Soil Environment

In recent years,China has made great efforts to develop the infrastructure.With the further development of the western development strategy,the traffic in the underdeveloped areas of western of China,has been greatly improved.More and more bridge structures have been in the area of fortification intensity.As an important part of transportation,after an earthquake,whether is able to play a certain function to provide reliable help is to assess for bridge structures.At the same time,there are a great deal of saline soil in the western region of China.The pier column has been long serviced in the soil containing chloride and sulphates,concrete and steel are eroded,characteristic of the material will degenerate,therefore,in the actual environment,there must be some damage to the them under normal condition.It is necessary to evaluate the damage state of them,in different service periods.In this paper,a low cycle loading test of 13 pier columns is tested under different corrosion degrees,the seismic damage of pier columns under corrosive environment has been studied.? Focus on the damage of component level,the characteristics and nature of the research on damage of material,component and structure are introduced.The research progress of single parameter damage model and double parameter model is summarized in detail.The shortcomings of the damage models composed of various damage parameters are pointed out.At the same time,most of the two parameter damage models,improved,are based on Park-Ang model.? The effects of steel corrosion rate and axial compression ratio on the hysteresis curve,skeleton curve,stiffness degradation and energy dissipation capacity of pier columns with damage related indexes are studied.The results show that it is unfavorable to the stiffness and energy dissipation capacity of the specimen,which has an effect on the damage accumulation and development.? Based on the test results,a double parameter concrete bridge structure considering influence of corrosion damage model,model the normalized exponential relationship between displacement and the normalized energy is simplified as a linear relationship between parameter adjustment and the introduction of displacement and energy consumption proportion,so that the model has a good convergence? The damage factors of the specimen are analyzed,and the results show that the greater the corrosion rate and the axial compression ratio,the more serious the damage is.Compared with other damage models,it is found that the convergence and cumulative energy consumption of the model are all in line with theory and practice.? For a pier column,the normalized residual displacement has an exponential relationship with the damage index of the pier column,nonlinear fitting of all specimens is done,and the quantitative relationship between normalized residual displacement and damage index is given.Combined with the double parameter damage assessment relationship,a damage assessment method based on normalized residual displacement is established.At the same time,it provides a reference guide for the utilization of the damage criterion in practical engineering.