Simplified Interactive Flexure-Shear Design Method for Concrete Beams Based on Plastic Stress Field

Rational design approach for reinforced concrete beam under combined bending and shear needs to be developed, since they always occur simultaneously. Based on the Thurlimann’s fully-plastic stress field model, a parabolic envelope and an additional limitation for intensive shear capacity is derived. Then, a simplified flexural-shear design method for concrete beams is proposed suitable for different reinforcement layout, which is illustrated by a working example. It has to be admitted that the parallel cracked model is more applicable to shallow beam, for cracking pattern in small shear-to-span ratio regions is quite different. In addition, the ductility of reinforcement must be ensured to prevent possible brittle premature failure.