Progressive Collapse Analysis Of Reinforced Concrete Frame Structure And Fortification Criterion

In order to improve the ability of progressive collapse, from2008, our country successively put forward the design principle of progressive collapse in the revision of the engineering structure design specification and compile progressive collapse resistance design code. Based on the reference, the paper study the progressive collapse of a six-story reinforced concrete frame structure under different seismic fortification and column grid layout. The results show that the most of horizontal component are unable to meet the requirements of progressive collapse design, meet the collapse preventing design level component steel quantity should be increased by12%～480%, but the most column can meet the local strengthening method. The paper compiled the design table on the beam mechanism and suspension mechanism, as well as the local strengthening method to provide a reference.Based on the above analysis, the design to prevent progressive collapse first of all should improve the ability of the vertical component and increase the incidental force from200kN/m2to800kN/m2. Greatly improving the ability of vertical component is the key to prevent collapse. Combined with concepts of the DoD different fortification criterion, this paper puts forward lines of resistance, improving ability of vertical component as the first line, the beam mechanism of horizontal component as the second line, the suspension mechanism or standby power transmission path as the third line. Fortification criterion of building progressive collapse can be divided into four levels, the low-level:vertical component resists the accidental200kN/m2; the middle-level:vertical component resists the accidental400kN/m2; the high-level: vertical component resists the accidental400kN/m2+beam mechanism or suspension mechanism; the further high-level:vertical component resists the accidental400kN/m2+beam mechanism+suspension mechanism or standby power transmission path(corner post) and vertical component resists the accidental800kN/m2+beam mechanism(corner post).