Research On Performance Of The Corroded Reinforced Concrete Column Under Lateral Impact

With the rapid growth of the public transportation, mounts of cross-river and cross-sea bridges are constructed. The frequency of bridge impact accidents by cars, ships and floaters rises. Bridge piers under sea environment are faced with the corrosion problems of reinforcement. So it’s important to study the performance of corroded reinforced concrete column under lateral impact. In this paper, 8 corroded concrete column of different corrosion rate were built through accelerated electric corrosion experiment. The drop hammer experiment was carried to finish the impact experiment. An ultimate state calculation method was established considering rate effect of the material, the mechanical degradation of corroded reinforcement, bonding performance degradation between the concrete and the steel and the penetration of concrete. A numerical model was established using finite element software ANSYS/LS-DYNA. Analyze the performance of columns under lateral impact with different corrosion rate. Expand based on the model, considering the influence of support type and concrete strength to the performance of concrete under impact load. Conclusions as below:(1) Initial crack width and length of the columns rose with the increase of the corrosion rate.(2) Columns’ failure pattern of different corrosion rate differed. Failure pattern of low corrosion rate columns were crush on the impact location and bending shear fail with the development of bending shear cracks. Failure pattern of high corrosion rate columns were crush on the impact location and the no warning shear brittle fail. The ductility decreased with the rise of the corrosion rate.(3) Average impact force and the peak impact force of the columns with high corrosion rate were larger than those with low corrosion rate under low load condition. During the fail load condition, average impact force and the peak impact force of the columns with high corrosion rate were lower than those with low corrosion rate. Corrosion rate affect the impact bearing capacity at the same time with fail pattern.(4) Average and peak strain of the high corrosion rate reinforcements under pull side were lower than those with lower corrosion rate. The main reason was that bonding capacity’s degradation resulted to the strain lag. Using strain lag coefficient ? to consider the strain lag of reinforcement. The calculation result was close to the experiment result. The deviation was 6.8%.(5) The ultimate state calculation method was established considering rate-effect of the material, the mechanical degradation of corroded reinforcement, bonding performance degradation between the concrete and the steel and the penetration of concrete. The deviation was 5.27%(6) During the finite element analysis, observe the maximum stress distribution of the column and find that the location of 1/3 length of the column’s both side under simple support is the weaken part. Location of 1/3 length of the column’s fixed support side is the weaken part when the column is supported by fixed support one side and simple the other. Column cap’s corner parts are the compression weak part.(7) Peak impact force of column with high compression strength was larger than those with lower strength. For concrete’s rate sensitivity, Rose of concrete’s peak impact force was low under lower impact velocity and high under high velocity.