The Seismic Study Of Property Of Prestressed Pipe Pile (PHC) Foundations In High Seismic Intensity Area

Aiming at high seismic intensity, the strength of soft soil influence the seismicbehavior of prestressed concrete pipe pile (PHC) technical problems, a structureperformance test, shaking table test, field test, theoretical analysis and simulation studywere developed, and got breakthrough in bending moment variation law of pile, pile soildeformation mechanism, seismic stability, deformation control method, the bendingfailure characteristics and quality detection. The study provides a scientific basis for theeconomic and reasonable design and construction of seismic behavior of prestressedconcrete pipe pile (PHC), and provides a powerful guarantee for the safe use ofprestressed concrete pipe pile (PHC) in high seismic intensity area (site category Ⅲ, Ⅳclass).The paper follows:1. It’s the first time proved that under the normal use state of the horizontal forceloading, the damage form of prestressed concrete pipe pile (PHC) is bending damage,rather than the shear damage, and shear damage of prestressed concrete pipe pile (PHC)behind in bending damage.2. It’s the first time identified that maximum bending moment position of theprestressed concrete pipe pile (PHC) in the working condition is about distance of5~6times the pile diameter. Through pile head backstepping prototype (PHC500-AB100), itcan be found that under the effect of El centro-seismic wave, there is no destruction ofthe most dangerous section occurs in0.2g, but maximum bending moment value is morethan the limit bending moment value in0.3g and0.4g. The section directly determine ifthe prestressed concrete pipe pile (PHC) in normal work condition, and if the section isthe dangerous section of seismic design.3. The numerical model of time history analysis of the prestressed concrete pipepile (PHC) was established and verified. The simulation calculation showed thatmaximum bending moment occur in five times the pile diameter, and has caused theprestressed concrete pipe pile (PHC) crack, whose value is close to or exceed the limit ofthe prestressed concrete pipe pile (PHC) bending moment value;4.In the soft soil foundation of high earthquake intensity, the existence of the weakinterlayer increases the surface displacement and the pile-soil relative displacement; Pipepile’s movement in soft soil showed the shear properties, and showed that the softer thesoil is, the greater the relative displacement is.5.In order to ensure the security and stability of prestressed concrete pipe pile (PHC)in high seismic intensity(site category Ⅲ Ⅳclass), It’s the first time put forward that thedesign principles of bending strength checking of vertical bearing capacity design, which showed that through Bending strength checking of pipe pile foundation seismic design,the seismic risk hidden danger can be ruled out. If this principle applied, it will greatlyimproves the safety of the building.