Study On Behaviour Coupling Beams Of Shear Wall Under Circle Load

It'swell known that RC coupled shear walls structure has superior earthquake resistant behavior,which comes from not only its strong wall legs but also its coupling beams.Coipling beams are the link of wall legs.Under earthquake loading the most important part of coupled shear walls structure,load-bearing walls,will be protected if coupling beams from plastic hinge which dissipate earthquake energy. When coupling beams have little depth-to-span ratio,routine coupling beams have less energy dissipaton. In China Code for Design of Concrete Structures(GB50010-2002), there are no design methods for coupling beams when the depth-to-span ratio is less than 2.5, which is one of the critical problems of the code for design of concrete structures unsolved. In this study, ANSYS software of the finite element is used to investigate seismic response of the different coupling beams under circle loads.In this study include the following:the finite element analysis was processed to routine coupling beams with different depth-to-span ratio;the element annlysis was processed to diagonal and diamond-patterned reinforced bar coupling beam with depth-to-span ratio of 1.0;coupling beams'stresses and strains were analyzed with the development of cracking;the ductility and seismic response of the coupling beams with different reinforced bars.coupling beams'stresses.Conclusion through calculation analysis was abtained, include the following: when depth-to-span ratio is 2.0, routine coupling beams'destroyed type is bend and slipping destruction, it have better ductility and energy dissipation; When depth-to-span ratio is 1.0, coupling beams'destruction type is inclined press shear destruction. The loading capability of reinforcing steel bar can not be valid exertived on destroyed and concrete was cracked and less ductility. It is belong to brittleness destruction. So it have less energy dissipation. In smallly depth-to-span coupling beam, pass to install the diagaonal and diamond- patterned reinforcing bar, at connect 45 degrees of the coupling beam should form effectively organization of transfer force stress inconcentrated area. It make that the loading ability of longitudinal reinforcing steel bar can be get valid exertive and pass lately install reinforcing bar can effecttively restrict the crack of concrete opening, it make inclined press destruction of concrete lead to inclined press shear destruction to postpone appear, then make the coupling beam have to better ability of energy dissipation, ductility and retention performance.The suitable radio of longitudinal reinforcement in coupling beam is about 2%, the suitable radio of hooop reinforcement in coupling beam is about 1.5%,and the diameter of hoop reinforcement is better to less than 12mm,and the radio of lumbar reinforcement is better to less than 1%. The infinite element modeling has demonstrated that the newly designed coupling beam with diagonal and diamond-patterned reinforcing bars has better ductility, with about 30% increase compared to the routine beams. With the force well balanced, the newly designed coupling beam is much ductile under earthquake attack. In comparison with the hidden columnar diagonally bar reinforced small depth-to-span ratio beams, the newly designed coupling beam has the advantages of achieving smaller span. Also, it is easily engineered.