Experimental study on lateral overstrength capacity of RC structures designed with DBJ/T 15-92-2021'Technical specification for concrete structures of tall building'
In order to study the lateral overstrength capacity and safety reserve of reinforced concrete(RC)structure,the low-cyclic reversed loading tests of the scaled plane structural specimens were conducted,as well as the pushover analysis of the prototype building structure.Taking seismic structural level as the parameter,the allowable stress method was adopted to design three twelve-storey RC frame structures and three twelve-storey RC frame-shear wall structures.One-bay plane structure at bottom three-stories was selected to conduct the seismic test of twelve(1/4 scaled)specimens,which included two batches of specimens constructed by two groups at various periods.Taking the building height,slab flange and infill wall as the parameters into consideration,the structural models were established with using the Perform-3D to conduct the pushover analysis,the change mechanism of different parameters was researched,such as the overstrength coefficient of lateral-force resisting system and the lateral ductility.The low-cyclic reversed loading experimental results indicate that the main damage mechanism of the twelve scaled plane specimens is compression and bending damage.The hysteresis curves are full,the ductility is relatively large.The average of yielding overstrength coefficient is 2.21 for frame structure specimens and 2.26 for frame-shear structure specimens.The tendency indicates that the overstrength capacity is higher and the ductility is better for specimens designed with higher seismic structural level.Pushover analysis results indicate that the lateral force-resisting capacity at performance-point of RC structures after encountering an earthquake of rare intensity exceeds the yielding load,rather than the peak load,which illustrates that the overstrength capacity satisfies the seismic design requirements of not damaged after a fortification intensity earthquake,and reparable or not collapsed after a rare earthquake.The recommended value of yielding overstrength coefficient is 2.0 for the RC seismic structures designed with DBJ/T 15-92-2021'Technical specification for concrete structures of tall building'.
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