Flexural performance of a prefabricated steel–UHPC composite deck under transverse hogging moment

Abstract

This paper aims to investigate the flexural performance of a prefabricated steel–ultra-high-performance concrete (UHPC) composite deck (PSUCD) consisting of an orthotropic steel deck (OSD) and a reinforced UHPC layer under transverse hogging moment. Ten full-scale steel–UHPC composite slab specimens were subjected to four-point flexural tests, which varied shear connectors, steel reinforcement, and wet joint interfaces. The results showed that all specimens exhibited typical flexural failure with excessive opening of critical cracks in the UHPC layer. The specimens utilizing notched perfobond strip connectors (NPBLs) with perforating rebars had higher nominal cracking strength (maximum crack width of 0.05 mm) and ultimate capacity by 15% and 27%, respectively, compared to those using studs. The perforating rebars in NPBLs improved post-cracking performance, increasing nominal cracking strength and ultimate capacity by 14% and 16%, respectively. The lateral interfaces of rectangular-tooth-shaped wet joints resulted in a local weak link in PSUCDs, leading to a 17% decrease in nominal cracking strength, and as much as 26% if interfacial roughening was omitted. Increasing the diameter of surficial reinforcement from 10 mm to 12 mm improved nominal cracking strength and ultimate capacity by 20% and 17%, respectively. Considering the influence of wet joint interfaces, prediction models for maximum crack width, nominal cracking strength, and ultimate capacity were developed and validated for the performance design of PSUCDs under transverse hogging moment.