Ultimate load behaviour of composite T-beams having inelastic shear connections

• Main Author: Yam Chung Pong, Lloyd
• Published: Imperial College London 1967
• Subjects: 624
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.622996

This thesis is concerned with the theoretical study of the ultimate-load behaviour of composite T-beams as affected by the presence of slip between the concrete slab and the steel beam. Equations are derived on the assumption that there is no vertical separation between the slab and beam and are solved by computer. Correlation with existing test results of 17 simply supported beams and two continuous beams shows that the theory is rather satisfactory. Numerical investigation into a wide range of simply supported beams shows that the method recommended in CP 117, Part I, as regards ultimate moment calculation and shear connection design is adequate. Some interesting aspects of the ultimate-lead behaviour of simply supported beams are that (1) the loss of interaction is more significant with a point load at midspan than with u.d.1., (2) a higher ultimate moment can be attained with u.d.l. but the end slip at failure is much larger, (3) the presence of strain-hardening in the steel increases the ultimate load appreciably and may cause failure of the shear connection with u.d.l. On continuous beams, some limits on the application of the simple plastic theory are discussed and it is pointed out that the present analysis deals only with beams in which a collapse mechanism is formed as soon as the concrete crushes. Investigation on two-span continuous beams shows that the above condition is satisfied except under extreme circumstances, in which event the loads at which crushing occurs are rather near the ideal collapse loads. A simple method of shear connection design for continuous beams is studied and is found to be satisfactory. With u.d.1., the section of maximum moment must be located and the shear connection designed accordingly in order that connection failure may not occur.