دانلود رایگان مقاله تاثیر گذاری عامل قدم زنی بر تیرهای عمیق بتن تقویت شده

Abstract

In a current study, a new strut effectiveness factor based on Strut-and-Tie Model (STM) is proposed to assess the ultimate shear strength of reinforced concrete (RC) deep beam subjected to dynamic loads. The derivation of the new effectiveness factor of concrete struts is based on Mohr–Coulomb criterion failure. Two types of concrete failure, diagonal splitting and concrete crushing failure modes, are proposed and examined. The modification of the proposed model is simulated in a MATLABSIMULINK environment. The proposed model exhibits efficiency in assessing dynamic shear resistance for deep beams. Moreover, a parametric study is then conducted to examine the effect of flexural reinforcement ratio, transverse reinforcement and shear-span to depth ratio on shear behavior of RC deep beams with consideration of the changes in strain rate. The proposed effectiveness factor is validated by utilizing the experimental results obtained from the literature and shows good accuracy for prediction the shear strength of reinforced concrete deep beams under different loading conditions.

6. Summary and conclusions

A simple STM approach is extended to account for the effect of strain rates, main reinforcement, and web reinforcement on the behavior of RC deep beams. Linear interactive failure is used to imply the softening effect. Moreover, the MATLAB SIMULINK software is used in simulating the proposed model. The experimental results [4] were compared with the predictions of proposed model A new effectiveness factor for concrete struts was proposed based on the failure principles of Mohr–Coulomb. The proposed STM exhibits efficiency in assessing dynamic shear resistance for RC deep beams under varying loading rates, which could be implemented quite satisfactorily. The main conclusions of the current study are presented below. • The dynamic shear resistance of RC deep beams increases with loading rates increase. • The analysis results indicated that the web reinforcement does not have significant effect on DIF of ultimate strength. Whereas, the results exhibit increasing in DIF with the increase of shear span-to-depth ratio for all strain rates.