Experimental Study And Analysis Of I-shaped Concrete Beams With Web Opening

With the increasing improvement in the degree of intelligent housing and the expansion of the building auxiliary facilities, it forces a large number of pipeline through the beam of interior building construction; and on the premise of guaranteeing clear height of building to meet the needs of the function, which is bound to increase the height of the building, and increase the engineering cost, especially in the high-rise structure;Let the equipment pipeline through the opening of structure beam, which can be an effective way to solve the problem. It will cause the abdominal hole with concrete beams the problem of resistance to opening and cutting.This paper in view of the cast-in-situ hollow slab with flat beam floor and concrete box girder, its calculation is equivalent to I beam, it is about to study the shear performance of web opening, to expand the scope of the web plate hole, and to explore the shear performance of different hole location of the shear bending section of the web, and to design the three roots of single-hole I-beam in the different position of shear bending section of the web. The opening position, separately, is located in the middle web of span 1/4, 1/5, 1/6, with the form of round hole and hole size of about a third the height of cross section, moreover, the paper designs the circular stirrup to do the reinforcement around the hole. Through the testing of the three beam’s shear performance, it helps to test its deflection, crack, shear bending section of the concrete, stirrup or circular stirrup strain and the shear failure mode. On the basis of experimental study, it can get the following main conclusions after analysis:(1)Through the web openings concrete I beam shear performance test research and analysis, it is confirmed that the circular hole’s opening diameter is about a third the beam height of beam in the central web of the 1/6 span, and through feasibility of the hoop reinforcement, so as to expand the scope of opening web of concrete I beam. At the same time, it should be avoided the open hole from the loading point and support position that less than the 1 times the high beam.(2)Through the existing shear cracking load calculation theory of concrete beam, and compared with the test results, it can be analyzed that with the reasonable opening and under the action of circular stirrup, the web cracking load of the beams of web opening concrete I beam and plain girder is close to each other.(3)On the basis of theoretical analysis of concrete beam shear bearing capacity, combined with shear failure mode of the concrete web openings I beam, it puts forward calculation formula of hoop reinforcement shear bearing capacity of the concrete web openings h beam, which can provide a theoretical basis for the beam shear bearing capacity.