Finite Element Analysis On Behavior Of Double-limb Built-up Beam And Column Joints

The prefabricated building is composed of prefabricated parts assembled in the construction site,which has the advantages of good quality of components,short construction period and low environmental pollution.In order to adapt to the development of the times,the construction industry of our country carries on the transformation and upgrading,takes the sustainable development,the green development,the industrialization development road.Under the guidance of national policy,prefabricated architecture has gained rapid development.With the development of research,more and more new prefabricated structure systems have been proposed.In this paper,the double-limb built-up beams and column joints are introduced as a kind of joint connection form in the assembled beam-slab composite floor.The channel steel beams are arranged around the prefabricated monolithic floor to form a skeleton,subsequently binding steel bar and pouring concrete on the top of the skeleton.A single beam-plate composite floor is made in a factory.In order to realize the splicing between the floors,two channel steel beams are placed against each other and spliced together by high-strength bolts to form a double-limb built-up beam,which is then connected to the column.The double-limb built-up beams and column joints are connected by welding.In this paper,the nonlinear numerical analysis of joints specimens are made by software ABAQUS.First,analyzes the effect of panel zone strength on seismic performance of double-limb built-up beams and column joints.And the optimum panel zone strength for the new joints is obtained;Then,the influence of bolts end distance,beam stiffeners,gap of double-limb built-up beams on performance of the joints are analyzed;Finally,the flange of the beam is weakened,and the optimum dent size of the double-limb built-up beams and column joints is studied when the bolts end distance is different.The finite element analysis shows that: the bolts are installed on the web of the double-limb built-up beams can effectively prevent the instability of the channel steeland increase the integrity of the double-limb built-up beams.When the bolts spacing is less than 1.25 times the height of the beam section,the mechanical behavior of double beam joints are close to that of common I-section beam joints;The panel zone strength is not the same with different spacing of bolts,and the thickness of panel zone can be calculated according to the difference of bolts spacing;The end distance of bolts has a great influence on the joints failure pattern,but has little effect on the hysteretic curve,skeleton curve and energy dissipation curve of the joints;The stiffeners can strengthen the high stress section of the beam,and the local buckling position of beam web and flange can be changed effectively,the bearing capacity and energy dissipation ability of joints can be enhanced,and makeing the plastic hinge away from the connection;The bearing capacity of joints can be improved by setting gap between double-limb built-up beams,but the energy dissipation capacity of joints will decrease,so the gap between the double-limb built-up beams should be avoided in construction;The weakening of the flange of the beam can make the joints appear different degrees of plastic hinge moving outside,and increase the ductility of the joints,protect the weld of the joints,prevent the joints occurs brittle fracture;When the beam flange is weakened,the joints with different of bolts end distance produce different mechanical behavior,so the optimum dent size of the double-limb built-up beams and column joints should be determined according to the different of bolts end distance.