Analysis Of Horizontal Bearing Capacity Of PHC Pipe Piles Cap Connections With Different Construction Parameters

Prestressed high-strength concrete pipe piles(PHC pipe piles)have been widely used in various areas in recent years.The earthquake researches in many countries show that under the action of strong earthquakes,the location of the PHC pipe piles cap connections are extremely easy to damage.The horizontal bearing capacity of PHC pipe piles cap connections has attracted the attention of researchers.At present,many scholars have proposed a variety of structural forms to strengthen the connections between PHC pipe piles and caps.However,there are few comparative studies on the force characteristics of different connection forms.The proposed connection forms are rarely used in practical applications.In order to research the force characteristics of different PHC pipe piles cap connections under horizontal force,make the design better applied to the construction site,this paper establishes four types of PHC pipe piles cap connections based on ABAQUS.The model considers the soil action,studies its bearing capacity under the horizontal reciprocating load,seismic performance and the force characteristics of the detailed structure.In addition,this paper makes optimization design or parameter analysis for different connection forms.The conclusions are as follows:(1)The ordinary anchoring connection can strengthen the connection between the pile and the cap,but its ultimate bearing capacity and seismic performance are inferior to other joint forms.It is not recommended to be used in sites with high seismic fortification intensity.(2)The built-in type connection can better improve the ultimate bearing capacity and seismic performance.The round steel pipe is selected as the vertical limb,which can make the test piece have better seismic performance,but it is necessary to consider whether the construction is convenient;the space steel component as the built-in component does not significantly enhance the seismic performance of the structure,and is not recommended.(3)The effect of the additional type connection on the ultimate bearing capacity and seismic performance of the lifting node is also good.The square reinforcing ring and the circular reinforcing ring have similar force characteristics under cyclic reciprocating loading,while the square reinforcing ring is more convenient to construct.It is recommended in the engineering to use the square reinforcing ring as the form of the additional type node.(4)The prefabricated strengthening node makes the pile and the cap form a "hinged" connection,which protects the pile head part well.The disadvantage is that when the soil displacement or external load is large,the prefabricated reinforcement ring breaks faster.In general,it is a form of node that can be used.The height of the prefabricated reinforcing ring is recommended to be about 1000 mm.When the prefabricated reinforcing ring is placed on the single pile cap,the radius of the prefabricated reinforcing ring can be appropriately increased.