Experimental Research On Fire Resistance Of B-type Joints In The Reinforced Concrete Structure With Bearing Column Girder Transfer Floor

With the development of the multi function construction,conversion layer is more and more widely used,many scholars on the structure conversion layer and the stress characteristics of research work carried out widely,and achieved fruitful results,but there are few reports about the study on fire resistance of structural transformation.The transition structure plays a key role in the building structure.In the fire,the deterioration of its bearing capacity will have a serious impact on the safety of the structure.Therefore,it is of important theoretical and practical significance to carry out research on fire resistance of transfer structures.transfer structure is one of the familiar transfer structures in the transfer story.This paper mainly tests the fire resistance of B type joints in reinforced concrete column transition structures.Considering the influence of load ratio,under fire conditions change,the node of B type heating resistance under the coupling effect of the whole process and load test in the standard test,observed phenomenon,analyzed and summarized the node specimen temperature field distribution,deformation characteristics,failure form and fire resistance,analyzed and summarized influences of load ratio,under fire conditions on the fire resistance of joints.The performance of the joint specimens under thermal mechanical coupling is simulated and compared by ABAQUS large finite element software.The test results showed that under high temperature and loading,specimens of the applied load ratio is larger,the relative refractory time is shorter,the fire resistance limit is smaller;when the load ratio under the same conditions,the specimen surrounded by fire fire resistance limit of less than three face under fire,surrounded by deflection ratio under fire three face under fire,fire resistance of girder transfer floor structure of B type joints under fire surface decreased the specimen;in the node to reach the fire resistance limit the natural cooling of the specimen was observed on the deflection of column asymmetry,the maximum deflection in the top side(side of the eccentric loading columns).The beam crack is at the bottom of the tension zone vertical bending cracks,vertical cracks start to the column direction extendsobliquely near the central joist section height,the failure of specimens are due to several main bending Caused by the development of cracks.