Design of composite haunch beams and connections for long span applications

Abstract

This thesis is concerned with the behaviour of steel-concrete composite haunch beams and connections. Experiments were carried out to investigate the ultimate load behaviour of composite haunch beams and connections. Three continuous composite haunch beams and ten composite haunch connections were tested to failure. It is found that through proper design and detailing, optimum design of composite haunch beam can be achieved when plastic hinge occurred at haunch toes followed by at the mid-span to form a plastic collapse mechanism. Haunch toe could be designed as the weakest section to form a plastic hinge with suitable amount of reinforcement in the slab and range of haunch length. Experimental results show that composite haunch beam exhibit a ductile moment-rotation behaviour and is able to redistribute moment to the mid-span by loss of stiffness due to cracking of concrete slab and yielding of either steel reinforcement or cross section.