Experiment And Theory Research On Progressive Collapse Resistance Of RC Special-shaped Columns Space Frame Structures

Reinforced concrete structure is one of the most widely used structural systems in China.Progressive collapse of the structure has begun to attract the attention of the world,since the collapse of Ronan point in London in 1968.The developed countries al so began to put forward their own research and design ideas for this area of research.In this aspect our country starts late.At present,there are no relevant regulations proposed for the progressive collapse design of structures in this area.In recent years,the special shaped column frame structure is favored by people in the construction market because of its advantages in the use of space and furniture layout.While the research of the anti continuity collapse of the special-shaped column frame structure is basically in the blank stage.In the contradiction of the market needs and the theoretical research less,research on the collapse resistance of the frame structures with special-shaped columns is an urgent need for domestic scholars to solve.In view of the demand situation,this paper has done the relevant research.Through laboratory site design construction,we made a 1/3 scale two storey 3 * 2 span special-shaped column frame structure model.The mechanical behavior,load transfer path and the final failure mode of the structure are simulated through the static loading.The experiment is divided into two parts,simulating the sudden failure of corner column and side column.Evaluation of anti collapse performance of structure through comparison and analysis of the simulation and test structure of post failure at different positions.Load displacement curve displays that after the failure of the column,the failure of the structure has experienced four stages: elastic stage,elastic-plastic stage,plastic stage and failure stage.The structure appears plastic hinge connected with column failure,occurrence of redistribution of internal force,finally entered the stage of catenary.The test structure shows that the load of the column is transmitted to the surrounding member through the frame beam and the floor slab;corner column failure is more likely to cause the collapse of the structure continuity;Load transfer path of failure column is connected to stiffness of frame beam and the distance between surrounding columns and failure column.After a large deformation,frame beams connected with failure column pull together,the frame beam into the catenary effect stage.The occurrence of catenary action can improve the ability of resisting progressive collapse of structures.The effect of catenary side column failure is obviously better than that of failure at the corner.