Experimental Study On Different Span-depth Ratio Steel Fiber Reinforced Concrete Coupling Beams

In recent years, the high-rise building continue to increase with the development of the city.As one of the most important structure,reinforced concrete coupled shear walls is used in practical engineering more extensive. In the structure of coupled shear walls, coupling beams which has the characteristic of small span and stiffness is an important part and the transmission link between the shear wall power. Coupled shear walls structure with a suitable bearing capacity, stiffness and good deformation properties in the event of a strong earthquake, the first line of defense as a structural coupling beams yield before the wall limb first yield and play its plastic deformation, dissipation of earthquake energy to effectively alleviate the damage to the main structure, which requires the coupling beam at the same time with good bearing capacity, ductility and deformation capacity. Therefore, how to improve the performance of coupling beams received the extensive attention of scholars around the world. However, most existing research is to change the reinforcement section or the section type to improve the bearing capacity of the coupling beam which often brings connect complex, construction difficulties, or the expense of the bearing capacity and stiffness of the structure. Steel fiber reinforced concrete can significantly increase the concrete tensile, bending, shear and impact performance, so that it has good ductility and toughness, and excellent energy dissipation capacity, which can increase the deformation of the reinforced concrete structure capacity and seismic performance. So reinforced concrete added with the steel fiber in the structure of coupled shear walls can improve the problem above.In this dissertation according to test code with a realistic method of reinforced concrete coupling beams,6different span-depth ratio steel fiber reinforced concrete coupling beams are designed to study its main force performance under the horizontal cyclic loading test. Complete the following work:(1)Design the experimental which can let the coupling beams be tested as actual situation and design test scheme according to test code. (2)Detailed record the of the trial’s carried out situation and the development of the six different span-depth ratio of steel fiber reinforced concrete coupling beams in the horizontal cyclic loading test. Draw the skeleton curve and the load displacement hysteresis curve according to experimental data in-depth,and then deeply study the performance of their ductility, energy dissipation and stiffness. We were able to significantly draw that span-depth ratio serious affect the performance of steel fiber reinforced concrete coupling beams. With the improvement of span-depth ratio, the bearing capacity of the coupling beams significantly reduce and the ductility, energy dissipation improved, just as stiffness degradation decreases significantly. Compare the ductility and energy dissipation of different span-depth ratio of coupling beams, we can obtain that when span-depth ratio of coupling beams is3.0, its ductility and energy dissipation is best.(3)Analysis the ultimate bearing capacity of strength of steel fiber reinforced concrete coupling beam, give a formula of shear capacity of steel fiber reinforced concrete coupling beam abort the span-depth ratio under horizontal cyclic loading test.