考虑空心楼板效应的预应力压接装配框架结构边柱失效极限承载能力试验研究OA

The connection forms of beams,slabs,and columns in prestressed compression-connected precast concrete frame(also known as precast prestressed efficiently fabricated frame,PPEFF)structures differ significantly from those of cast-in-situ reinforced concrete(RC)structures.Consequently,the synergistic effect between components and the interaction mechanism between precast prestressed hollow-core slabs are complicated.To this end,based on an existing five-story full-scale test building,this paper carried out an ultimate bearing capacity experiment for floors incorporating precast prestressed hollow-core slabs(including partial openings)under the column removal scenario.Whole-process data of the remaining structure,including yield load,peak load,residual bearing capacity under large deformation corresponding to a beam chord rotation of 1/6.5,component deformation and rebar strains,were obtained.The corresponding damage and failure modes were also recorded.Experimental results indicate that when the vertical displacement at the loading point(VDLP)reaches 1/25 of the adjacent short beam span,the static peak load is achieved,and it is measured to be approximately 3.1 times the characteristic gravity load borne by the removed column.When the VDLP reaches 1/21 of the adjacent short beam span,the dynamic peak load is achieved,and it is approximately 2.7 times the characteristic gravity load borne by the removed column.When the VDLP increases to 1/6.5 of the adjacent short beam span,the total vertical load remains 1.8 times the characteristic gravity load borne by the removed column.After complete unloading of the applied vertical load,the recovery of the VDLP reaches 9％of the maximum displacement.This structure exhibits favorable progressive collapse resistance and ductility.Notably,even at the high VDLP of 924 mm,the precast prestressed hollow-core slab floor system with a 50 mm thick composite layer sustains local damage and fracture,yet no detachment takes place,indicating that its progressive collapse resistance meets practical engineering requirements.The experiment also reveals that openings in precast hollow-core slabs induce new plastic hinges at the corresponding positions of frame beams,which substantially affects the structural stiffness,bearing capacity,and failure modes of the entire structure throughout the collapse process.Furthermore,this paper proposed a simplified method for estimating the structure's yield load and peak load,which can provide a reasonably accurate prediction of the lower bound of the progressive collapse resistance for slab-integrated structures under the column removal scenario.