Experimental Study On Seismic Performance Improvement Of Prestressed Solid Square Pile With Buckle Type Mechanical Connection

Compared with cast-in-place piles and ordinary reinforced concrete precast piles,prestressed concrete piles have mature technology and have the advantages of high bearing capacity and corrosion resistance.As the country actively promotes the industrialization,informatization,and greenization of buildings,the application of prefabricated concrete components has become more and more widespread.However,domestic and foreign studies on the use of mechanically connected pre-stressed square piles in earthquake-resistant fortified areas are still lacking.In particular,the joints between pre-stressed square piles and caps under earthquake action are subject to complex forces and are prone to damage.Research on the seismic performance of prestressed concrete precast piles and the performance of connection nodes has become a hot spot in the industry.In this paper,ten mechanically connected prestressed square pile-cap joint specimens were designed and produced,and reciprocating load tests were carried out to study the effect of different prestress degrees,steel anchoring methods,and ordinary steel diameters on mechanically connected prestressed square piles.A numerical analysis model of the mechanically connected prestressed square pile-cap joint specimens was established by combining the ABAQUS finite element software with the influence of the seismic performance of the test piece of the cap joint.The strain cloud diagram under the reciprocating load was studied,and the damage model of mechanically connected prestressed square pile-cap joint specimens was established,and the influencing factors were analyzed,the main work and results are as follows:（1）Through the reciprocating load test on the specimens of mechanically connected prestressed square pile-cap joints,the test results show that the horizontal bearing capacity of the specimens of mechanically connected prestressed square piles-cap joints increases with the degree of prestress of the specimens.Increase and increase,the ultimate displacement will decrease accordingly;the anchoring effect of the 135° hook at the end of the anchoring steel bar of the cap is better,and the hysteresis curve of the corresponding test piece is also fuller;the configuration of ordinary steel can significantly improve the prestress of the mechanical connection The seismic performance of the square pile-cap joint test piece,the hysteresis curve is more full,and the ultimate bearing capacity is also improved.The larger the diameter of the steel bar,the more obvious the effect.（2）The numerical analysis model established based on ABAQUS finite element software can better simulate the hysteretic characteristics of mechanically connected prestressed square pile-cap joint specimens under reciprocating loads.The numerical analysis results show that: under reciprocating load conditions Below,the increase of the effective prestress value will slow down the development of cracks in the specimens of mechanically connected prestressed square pile-cap joints and restrain the deformation of concrete.（3）The energy consumption index and damage index calculated by the damage model based on the law of conservation of energy are in good agreement with the test results.The model can provide a basis for the engineering application of mechanically connected prestressed square pile-cap node specimens.