变预应力度混合配筋混凝土管桩受弯性能OA北大核心CSTPCD

In order to improve the ductility of prestressed concrete pipe piles with hybrid reinforcement(PRC pipe pile),a variable prestress concrete pipe piles were formed through reduced the tensile stress of the prestressed steel bars and exerted a certain tensile stress to the hot rolled high strength reinforcement.The effects of different control stresses of prestressed steel bar and high strength steel bar in flexural behavior of PRC pipe piles were investigated through flexural performance experiments and numerical simulation of four variable prestress concrete pipe piles and one PRC pipe pile.It was revealed that the failure mode was similarity of traditional PRC pipe pile,which still belonged typical flexural failure.With the decrease of the stress of the prestressed steel bar(0.6fptk to 0.4fptk,fptk is the standard value of tensile strength of prestressed steel bars),the ductility coefficient of the specimen increases gradually(about 32％),and the corresponding cracking moment reduces gradually,but it has little effect on the bearing capacity.The ductility coefficient of variable prestress concrete pipe piles increases(about 60％)with the increase of stress of high strength reinforcement(0.4fyk to 0.8fyk,fyk is the standard value of yield strength of high strength reinforcement).Considering the influence of the tensile force value of the prestressed steel bar,the formula for calculating the flexural capacity of the variable prestress concrete pipe piles is derived.The ratio between the calculated value and the test result is about 0.85.