Seismic Analysis Of Reinforced Concrete Structures Considering Pile-Soil Interaction

Earthquake is one of the most serious natural disasters that endanger the safety of human life and property.Many large cities in our country are located near the fault or in the seismic belt.The previous earthquake damage indicates that the high-rise buildings located in the seismic activity area or the earthquake fault zone may be affected by near-fault earthquakes.China's current seismic design norms for near-field seismic considerations are not perfect.In this context,this paper focuses on the seismic performance of reinforced concrete structures under near-field earthquakes,and focuses on the experimental simulation and calculation of reinforced concrete structures under near-field seismic extreme disaster conditions,including consideration of pile-soil-structure system Interaction of sub-structure pseudo-dynamic test method,under different conditions of the structure of the reaction law and vulnerability analysis.In this paper,an eight-story reinforced concrete frame structure with pile foundation is designed,and the bottom two layers and the foundation are tested as sub-structures.The pseudo-dynamic test of the large-scale soil slab in the laboratory is carried out.Based on the Penzien pile-soil interaction model,a computational model considering the interaction of pile-soil-frame structure is established.The calculation model adopts free-field input.In the course of the experiment,the information of the lower structure is obtained by the sensor,and the test data is used as the basic data of the inversion analysis to determine the pile-soil working state and real-time correction of the pile-soil parameters in the model to complete the quasi-dynamic test.This test method is a new attempt to study the dynamic interaction of soil-pile-structure.The experimental results show that the proposed method can reflect the actual state of pile-soil and complete the quasi-dynamic test.The results show that:(1)the response of the structure is much larger than that of the ordinary mid-far field under the same peak,and the force and displacement curves show strong pulse characteristics.The high velocity velocity pulse causes the structure to produce(2)Considering the interaction between pile and soil,the deformation of the foundation significantly increases the top displacement of the structure,in which the viscoplasticity of the soil of the foundation soil makes it possible to reduce the displacement of the structure.The foundation of the irreversible corner,which greatly increased the structure of the top of the residual deformation,which for high-rise buildings,second-order effect will be very significant.For the structure under the action of near-field seismic,it is necessary to make a comprehensive analysis of the whole pile-soil-structure system in order to get closer to the actual situation.The finite element simulation of the frame structure and the shear wall structure of different layers is carried out.The influence of different site conditions and different seismic acceleration records on the structural response is investigated.(1)Under the same seismic record,the peak displacement response of the top layer is increased after the interaction of pile and soil,and the softer the site is,the higher the displacement response of the top layer is(2)the top-level acceleration response(3)the structure of the top of the earthquake(3)the higher the number of layers,the higher the number of layers,the higher the number of layers,the higher the number of layers,The peak value of the Fourier spectrum of the acceleration time curve is obviously shifted to the left,and the corresponding period becomes longer and the peak value of different frequencies increases and decreases.It can be seen that the magnification and filtering effect of the earth soil on the seismic record is obvious.(1)The softening the site of the same structure,the greater the coefficient of influence;(2)For the frame structure:the structure of the frame structure and the shear wall structure of the interlayer displacement and interlayer shear pile-soil interaction coefficient of influence found:When the number of floors is small,the influence of the inter-layer displacement and the influence coefficient of the interlayer shear force is small,and the influence coefficient of the interlayer displacement increases with the increase of the number of layers,and the influence coefficient of the middle layer increases;Shear wall structure:the influence of the displacement and shear force at the bottom layer is larger,and the influence coefficient of the upper floor is smaller.As the number of floors increases,the maximum influence coefficient increases.According to the site conditions and the epicentral distance,a large number of seismic records were collected and IDA analysis was carried out for different seismic loads with different layers of reinforced concrete frame structure and shear wall structure.IM index selection peak ground acceleration PGA,DM indicators select the maximum displacement angle between the layers ?max.The scores of 16%,50%and 84%were calculated,and the performance points of OP,IO,LS and CP with different structures were obtained.The vulnerability analysis was carried out according to the results of IDA analysis.The probability of failure of the same PGA under the near-field earthquake is larger than that of the far-field earthquake,and the more the structure layer is,the more soft the site and the greater the probability of failure.In the near-field earthquake,the structural failure probability is more sensitive to the field type than the far-field earthquake.