Research On Static Behavior Of Grouted Sleeve And Prefabricated Pier

Prefabricated piers have the advantages of high prefabricated pier columns,short construction time,less interference with traffic,and can reduce the life cost of the bridge.Prefabricated piers are widely used in bridge construction.The connection between the sections of fabricated piers is the weak point of the structural bearing capacity,which is directly related to the safety of the structure.The research on the static and dynamic performance of fabricated piers has important theoretical value and practical significance.The static behavior of the grouted sleeve and the connected pier is focused on.The main contents and conclusions are as follows:(1)Nine defect-free whole grout sleeve specimens were designed and manufactured,and unidirectional tensile and repeated tensile and compression tests were carried out to study the bearing capacity,residual deformation and total elongation of the specimen.The test indicated that the specimens were all fractured and damaged outside the sleeve,and the bearing capacity was high;the residual deformation was less than 0.3mm,the total elongation was slightly less than 6%,and had certain ductility and repeated tensile and compression properties.(2)Nine preset defect whole grout sleeve specimens were produced and subjected to unidirectional tensile test,which was compared with non-defective specimens.The analysis results showed that the defective specimens had two failure modes: steel bar fracture and bond slip;the ultimate bearing capacity of the offset steel specimen was 1.9% lower than that of the non-defective specimen;as the length of the middle defect increased,the ultimate bearing capacity of the specimen showed a downward trend.(3)Sleeve tube wall strains,steel bar strains,and steel bar relative sleeve slip were measured.The distribution and change laws of the sleeve tube wall axial and hoop strains,steel bar strains changes,and the steel bar slippage and its variation law in each stage were obtained.(4)The ultimate load-bearing capacity of the middle-defect specimen with bond-slip failure was calculated.The results showed that the theoretical calculation overestimated the ultimate bearing capacity of the central defect specimen.The central defect caused the interruption of stress transmission,and the bonding stress on the two steel bar anchoring sections did not reach the peak at the same time,which greatly increased the unevenness of the stress distribution and greatly reduced the bearing capacity of the specimen.(5)Taking the actual project as the background,a full-scale finite element model of the sleeve-connected assembled double-column pier was established.The whole process of the longitudinal thrust of the pier was simulated,and the load-pier top displacement curve,ductility and damage evolution of the pier were analyzed.(6)The stress distribution of the connecting section between the pier column and the socket sleeve was extracted and analyzed.