Experimental Research And Analysis Of Seismic Performance Of Frame Joints Poured With Beams' Concrete

In the reinforced concrete high-rise frame structures,it is not proper if the sectionalarea of the columns is too big, and the axial force ratio of columns should not surpassthe limitation. So the columns are often using the high-strength concrete. But thehigh-strength concrete is not proper and require to the beams and slabs which aremainly used as bending resistance component. So the strength of the concrete in thecolumns is usually higher than that of the beams. In construction, the column-beamjoints is usually poured with the same strength concrete as columns, it requires highconstruction technology and some problems are difficult to solve such as formworkplanning, construction joint and quality of construction. So it is screaming for thecolumn-beam joints poured with the same strength concrete as beams and slabs inconstruction. But because of the absence of the research about this construction method,it is seldom used in construction in China. In this paper, the bearing capacity of the column-beam joints poured with thesame strength concrete as beams and slabs of a construction in Chongqing is checked,so the feasibility of column-beam joints poured with the same strength as beams andslabs is discussed. And six column-beam joint specimens are tested which is subjectedto cyclic loading. Based on measurement of strains of both horizontal stirrups in thejoint core and longitudinal reinforcement passing through the joint, and the research ofthe specimens' ductility, energy-dissipation capacity and bond deterioration ofreinforcement passing through the joint, the influence of the column-beam joints pouredwith the same strength concrete as beams and slabs on the seismic performance of thespecimens was investigated. Some conclusions have been got as following: ① It is feasible that the column-beam joints poured with the same strengthconcrete as beams and slabs. ② The checking of bearing capacity of column-beam joints poured with the samestrength concrete as beams and slabs. ③ Proper measurement for improving bearing capacity of column-beam joints isnecessary when the bearing capacity of column-beam joints is not enough. ④ The seismic performance of the specimens which the column-beam jointspoured with the same strength as beams and slabs is not good as the specimens whichthe column-beam joints poured with the same strength as columns, but the descentdegree is very small. 1黄淮海摘 要 ⑤ When the column-beam joints are under relatively big shear compression ration,the relatively big pressure on the column is disadvantageous to the bearing capacity ofcolumn-beam joints, especially to the interlayer edge joints and interlayer corner joints. ⑥ The joints restriction by beams and slabs can reduce the stress of the horizontalstirrups in the joints, so the shearing capacity of the column-beam joints can beimproved. At the end of the paper, the lack of present research and the following work isdiscussed..