Experimental study on long spanning composite cellular beam under flexure and shear. (January 2016)

• Record Type: Journal Article
• Authors: Sheehan, Therese; Dai, Xianghe; Lam, Dennis; Aggelopoulos, Eleftherios; Lawson, Mark; Obiala, Renata
• Is Part Of: Journal of constructional steel research. Volume 116(2016:Jan.)
• Page Start: 40
• Page End: 54
• Publication Date: 2016-01
• Subjects: Composite beams -- Shear connection -- Cellular beams -- Experiments -- Unpropped construction -- Eurocode 4; Steel, Structural -- Periodicals; Building, Iron and steel -- Periodicals; Acier de construction -- Périodiques; Construction métallique -- Périodiques; 624.1821
• DOI: 10.1016/j.jcsr.2015.08.047
• Languages: English
• ISSNs: 0143-974X

Abstract

Abstract: This paper describes a sequence of experiments on a long-span asymmetric composite cellular beam. This type of beam has become very popular, combining the composite action between the steel and concrete with the increased section depth, compared with more commonly used solid-web I sections. Openings in the steel web also reduce the self-weight and can accommodate the passage of service ducts. Eurocode 4 recommends a high degree of shear connection for asymmetric composite beams despite the practical difficulties in achieving this. Recent research suggests that the required degree of shear connection could be reduced, particularly for beams that are unpropped during construction. However, little test data exists to verify the behaviour of unpropped composite cellular beams. Therefore two series of tests were conducted on a 15.26 m long asymmetric composite cellular beam with regular circular openings and an elongated opening at the mid-span. The degree of shear connection was 36%, less than half of that recommended in Eurocode 4, and the beam was unpropped during construction. The beam was subjected to uniformly distributed loading and shear load during the tests. The end-slip, mid-span vertical deflection, shear connector capacity and strain distribution were examined. The beam failed at an applied uniform load of 17.2 kN/m 2 (3.4 × design working load 5.0 kN/m 2 ). The member withstood an applied shear load that was 45% higher than predicted, and exhibited a Vierendeel mechanism at the elongated opening. Overall, these tests demonstrated the potential of unpropped composite cellular beams with low degrees of shear connection. Highlights: A long composite cellular beam was tested under bending and shear. Unpropped construction was used and the beam had a low degree of shear connection. The maximum bending moment was 3.4 times greater than that predicted by Eurocode 4. The maximum shear force was 45% greater than predicted. A Vierendeel mechanism was observed but no shear connectors failed.