Research On Efficiency Of Slot-cutting Around Frame Joint For "Strong Column And Weak Beam" Under Earthquake Action

In Wenchuan earthquake, most frames were shown the form of column-hingingfailure mechanism, and it could not achieve the design target of "strong column andweak beam". The main reason of appearing this seismic damage phenomena is that theseismic design code(GB50011-2001) did not consider the fact that slab bar near theframe beam can enhance the bearing capacity of beam. The paper mainly analysesframe beam-column joints with slot-cutting on the slab, compares its result with theordinary beam-column joint and the joint with carbon fiber, and evaluates thatslot-cutting on the slab improve "strong column and weak beam" of RC frame.Based on the related theories and methods at home and abroad, in this paper, theframe joints with slot-cutting on the slab is analyzed from the following aspects.Firstly, the related research status and latest achievements of strong columnand weak beam of the frame structure at home and abroad are briefly described. Thespecific definition and the relevant seismic design codes of "strong column and weakbeam" in different countries are introduced. And then various methods to achieve thetarget of strong column and weak beam are discussed and compared.Secondly, a six-storeys RC frame structure of2×3is analyzed withelastic-plastic dynamic analysis method. The yielding mechanisms of joint with slot,ordinary joint and joint with carbon fiber under both unidirectional and bi-directionalseismic action are discussed. The analysis results demonstrate that the structure ofjoint with slot can better achieve the yielding mechanism of strong column-weakbeam than the other two structures.Finally, an engineering example of the A teaching building of Xuankou middleschool is analyzed with elastic-plastic dynamic analysis method. The yieldingmechanisms of slot-cutting joints and traditional joints of the structure are discussedunder both unidirectional and bi-directional seismic action. The analysis results showthat the slot-cutting joints on the slab can well achieve the yielding mechanism of"strong column and weak beam" under earthquake action.It can be proved that the slot-cutting partly eliminate the enhancement effect of slabreinforcement to the beam rigidity, which can well achieve the yielding mechanism of"strong column and weak beam".