既有厂房混凝土屋面板预应力损失及其对其承载性能的影响

Research on bearing capacity of structural members of existing buildings is a key issue in the durability evaluation and life prediction of reinforced concrete structures. In prestressed concrete structure，the value of effective prestress is an important parameter to evaluate the structure bearing capacity. However, practical detection method for the prestress loss is rare in engineering at present. Based on the bearing capacity experiment of some existing prestressed RC slabs, detailed finite element model of the testing slab was established. The effective prestress and the effect of prestress loss on bearing capacity, stiffness and cracks of the member were studied. The results show that the prestress loss has great influence on cracking load and stiffness after cracking of the member, but it has no influence on the initial elastic stiffness and ultimate bearing capacity. With the increase of the prestress loss, the roof slab is more prone to cracking, the stiffness decreases greatly after cracking, the fracture distribution range and the mid-span deflection are large when the member fails.