Research On Seismic Performance Of Special-shaped Column Frame Joints Connected By Top And Bottom Angle Steel

With the upgrading of the construction industry and the implementation of the industrialization strategy,the prefabricated construction method is more and more widely used.Prefabricated buildings have the advantages of high construction efficiency,industrialization and more energy saving and environmental protection.The spliced way of prefabricated components is an important factor affecting the seismic performance of prefabricated structures.For multi-storey and high-rise prefabricated concrete structures,the spliced way of components is mostly used in situ,while rural buildings are mostly single-storey and two or three-storey multi-storey structures,which have relatively small seismic response.In the construction of prefabricated concrete frame structure,prefabricated beam and column components by the way of on-site assembly construction,can minimize the site wet operation,more environmental protection,and construction efficiency is higher.In order to meet the functional requirements,the special-shaped column frame structure should be used in rural residential buildings.Using Angle steel and bolts as connecting pieces,the precast special-shaped columns and beams are spliced on site,giving full play to the efficiency advantage of prefabricated structure.In this paper,the seismic behavior of concrete special-shaped column frame joints connected with Angle steel and bolts is studied by the method of combining test and numerical analysis.The main work is as follows:1.Read relevant literature at home and abroad to understand the research status of prefabricated buildings,especially prefabricated frame nodes,and summarize the advantages and disadvantages of various connection modes and research methods of nodes.2.The bearing capacity of the assembled joints connected with Angle steel can be improved by adding stiffeners with ordinary Angle steel.3.Based on the test,the finite element model of Angle steel with bolt was established,and the finite element modeling method of Angle steel with bolt was determined by comparing the test results.4.According to three common spans of 4 meters,4 to 5 meters and 5 to 6 meters,the material selection table of top and bottom Angle steel of prefabricated special-shaped column frame is given for seismic design of prefabricated joints of 2 to 3 stories residential buildings.The results show that:1.The finite element simulation method based on Angle steel mechanical properties test can better simulate the stress and deformation state of special-shaped column frame joints connected with Angle steel at the top and bottom,and then analyze the seismic performance of joints.2.The bearing capacity of the assembled joints connected with Angle steel can be improved by adding stiffeners with ordinary Angle steel.3.The Angle steel adopts Q235 steel and the stiffening rib adopts Q345 steel,which can realize the seismic design requirements of strong joints and weak members under the condition of changing the size of Angle steel and the thickness of stiffening rib.4.According to three common spans of 4 meters,4 to 5 meters and 5 to 6 meters,the material selection table of top and bottom Angle steel of prefabricated special-shaped column frame is given for seismic design of prefabricated joints of 2 or 3 stories residential buildings.5.The ratio of the stiffness between the assembled special-shaped column frame joint and the cast-in-place joint in the elastic stage is 1-0.7,and 0.8 and 0.7 are taken as the stiffness reduction coefficient to analyze the force on the joint and determine the design of the beam reinforcement.6.The finite element simulation results show that the seismic performance of the prefabricated joint is basically the same as that of the cast-in-place joint.However,with the increase of beam height,the constraint ability of Angle steel bolts to joints decreases,and the seismic performance of assembled joints and cast-in-place joints is different.