| Reinforced concrete coupled shear walls in tall buildings are known as efficient structural systems to provide lateral resistance to wind and earthquake. The coupling beams connecting two shear walls are normally subjected to very high bending and shear stresses.; The work in this thesis covers experimental studies and the development of theoretical modelling for composite reinforced concrete coupling beams embedded steel plates as shear reinforcement. Experimental studies are first conducted to investigate the behaviour and shear strength of the steel-plate reinforced concrete coupling beams under monotonic loading. In the test programme, sixteen large-scale coupling beam specimens are constructed and tested. The important variables studied include the percentage of steel plate, the span-to-depth ratio, and the longitudinal reinforcement ratio. From the experiment, two major failure modes, namely diagonal-shear failure and shear-bond failure, are observed. The test results are very encouraging, showing that the shear capacity of the coupling beams can significantly be enhanced after employing steel plates as web reinforcement. It has also been shown that the ultimate shear stress of the cross-sections can be much higher than that designed to current codes of practice, including BS 8110 and ACI 318. The proposed structural system appears promising.; A theoretical model in the name of Variable Crack-Angle Softened-Truss Model is then developed for predicting the load-deformation characteristics and ultimate shear strength of reinforce concrete membrane elements, ordinary reinforced concrete beams and reinforced concrete-encased steel plate composite beams subjected to combined in-plane shear and normal stresses. The proposed model is derived based mainly on the two state-of-the-art shear theories for reinforced concrete: Modified Compression Field Theory and Fixed Angle Softened-Truss Model.; A series of analyses has been carried out for comparing the results of the proposed theory with those obtained from a wide range of experiment work on reinforced concrete membrane elements, ordinary reinforced concrete beams and steel-plate reinforced concrete coupling beams. The results show very good agreement. It has been shown that the proposed Variable Crack-Angle Softened-Truss Model can provide an accurate means for predicting the load-deformation behaviour and shear capacity of ordinary reinforced concrete and reinforced concrete-encased steel plate composite beams. (Abstract shortened by UMI.)... |
