Numerical Modelling Analysis On Filled PHC Pipe Pile With Reinforcement Ring Under Horizontal Cyclic Loading

Compared with the conventional precast pile, prestressed concrete pipepiles have so many advantages that in high-rise buildings or bridges and otherprojects this kind of piles are widely used, such as high strength, high bearingcapacity, reliable quality, shorter construction period, cheaper cost, a wide rangeof design selection, etc. But under horizontal seismic force, because PHC pilebears greater bending moment in the head of pile, so bending failure is easilyobserved. It has been mentioned in existing pile atlas that by filling concrete intothe head position of pile, the carrying capacity of hollow pipe piles can beincreased, the ductility of pile can also be improved. And when the piles need towithstand greater force, in addition to the detailing requirements that fillingconcrete should be set into pile, the top of it is required to be strengthened aswell.ABAQUS finite element software can conveniently and quickly simulatestructural analysis among various working conditions, By using the software,this paper simulates the common PHC piles and the PHC pile with reinforcingring, and gains horizontal bearing capacity and ductility characteristics under cyclic loading. Moreover, by changing the parameters of the reinforcement ring,the optimal match with pile is explored so that a combination of both can havethe greatest effect.The results show that:(1) Under the larger horizontal loads, ordinary filled high prestressedconcrete pipe can not bear larger load, and its ductility is not rich enough either.(2) Reinforcing ring is set around the combination of pile and pile cap toincrease the force-sectional area indirectly and enhance the stiffness of joint,which can effectively improve the bearing capacity of prestressed pipe. Andbecause of the presence of concrete and steel skeleton within the reinforcementring, the ligation between pile and pile cap has been strengthened, and also itsductility and energy dissipation have been improved, thus, the horizontal bearingcapacity is improved greatly.(3) With the increase of the external diameter of the ring, the level of thebearing capacity has been increased substantially, and reached its maximum at1.5times external diameter of the pile, and then maintained stable with a slightdecline. If the distance between the steel skeleton and outer shell of the pile isreduced, increasing the external diameter can make the level of the bearingcapacity at or near the maximum. With the increase of height of the ring,although the level of carrying capacity has also been enhanced, the effect isrelatively small. Therefore, the external diameter of the ring and the steelskeleton inside the ring as well as its position should be regarded as the major parameters which influence the levels of bearing capacity of this kind ofenhanced filled PHC pipe pile.