Study on Load Bearing Capacity of Compressive Arch Action for Prestressed Concrete Frames under Column-Removal Scenarios

Abstract

In order to investigate the progressive collapse capacity of prestressed concrete frame structures, we established a nonlinear finite element model of a bonded-prestressed concrete frame. The experimental data were used to verify the model. On this basis, the differences of mechanical mechanism between bonded prestressed frame and reinforced concrete frame in the process of progressive collapse were studied, and the influencing factors of the first peak bearing capacity of prestressed frame were analyzed. The studies show that the application of prestress enhances the arch compression effect and weakens the failure of the side column, but it aggravates the failure of the middle column. The ratio of reinforcement, depth of beam and span have great influence on the bearing capacity of arch compression (Fa.u). When the top reinforcement ratio increased from 0.66% to 1.32%，Fa.u increased by 19.6%. When the bottom reinforcement ratio increased from 0.66% to 1.32%, Fa.u increased by 31.5%. When the depth of beam increased from 700 mm to 900 mm，Fa.u increaseds by 220.7%. When the span increased from 9 m to 15 m，Fa.u decreaseds by 64.0%. When the size of column section is small，increasing the size of column section has a great influence on Fa.u. However，when the column section size is large，increasing the column section size has little influence on Fa.u. The initial tensile control stress and tendon area have little effect on Fa.u.

Keywords:  prestressed concrete,  bonded,  finite element analysis,  collapse analysis,  compressive arch mechanism,  bearing capacity