Research On Lateral Impact Resistance Of Assembled PHC Pipe Pile Columns

The assembled PHC pipe pile column is a new type of assembled prefabricated column formed by prestressed high-strength concrete pipe pile（PHC pipe pile）which is lifted on site and then configured with steel reinforcement and poured with core concrete.The assembled PHC pipe pile column has the advantages of low cost,formwork-free construction,convenient procurement and high strength,but the PHC pipe pile in its component has the characteristic of brittleness,and if the assembled PHC pipe pile column is used as a load-bearing member in the parking lot,it will play a crucial role in the safety performance of the building structure.Therefore,the study of lateral impact resistance of assembled PHC pile columns is of practical significance and has reference value for engineering construction.This thesis investigates the lateral impact resistance and damage morphology of PHC pipe piles and assembled PHC pipe pile columns through drop hammer impact test and numerical simulation and measures the residual bearing capacity of the specimens after impact damage,in which the main work is carried out and conclusions are as follows.（1）To investigate the dynamic response and damage morphology of PHC pipe piles under lateral impact loading.The impact test was carried out on four full-scale PHC pipe pile specimens using an ultra-high drop hammer impact test device,and the vertical displacement time course curve,impact force time course curve and concrete strain time course curve of the specimens were measured,and the experimental results showed that:（a）PHC pipe pile has better elastic recovery capacity under the action of low-velocity impact;（b）when PHC pipe pile was subjected to 2 cumulative impact loads,the 2nd impact was weaker than the first impact resistance is weakened.（2）ABAQUS finite element program was used to simulate the impact of four PHC pipe pile specimens in the test,and the model parameters were used to predict the structural dynamic response of the assembled PHC pipe pile column after core reinforcement,and the model data were compared and analyzed with the test results,which showed that（a）the finite element model data were in good agreement with the PHC pipe pile test results;（b）the impact mechanical properties of the assembled PHC pipe pile column specimens after core reinforcement could be better predicted by using the relevant parameters of the PHC pipe pile model.（3）Two full-scale assembled PHC pipe pile column specimens were used for impact tests to investigate their structural response,and the results of impact tests of this assembled PHC pipe pile column and PHC pipe pile were compared and analyzed,which showed that（a）the PHC pipe pile mainly suffered bending shear damage,and the assembled PHC pipe pile column after core filling with reinforcement suffered bending damage;（b）the assembled PHC pipe pile column after core filling had a reduced peak impact force and increased energy dissipation compared with the PHC pipe pile,and the impact resistance was enhanced.（4）In order to investigate the residual vertical bearing capacity of PHC pipe pile and assembled PHC pipe pile column specimens after impact damage,one impact damaged PHC pipe pile and two impact damaged assembled PHC pipe pile column specimens were used for vertical axial compression test,the results show that the residual bearing capacity of PHC pipe pile and assembled PHC pipe pile column after impact damage can still meet the design requirements of the code.