Effect of Aspect Ratio on Fire Resistance of Hollow Core Concrete Floors

Abstract

Previous studies have shown that the fire performance of hollowcore units is significantly affected by the end support conditions, but it has not been clear how the fire resistance of the overall floor system can be improved by providing side supports. The previous studies used beam grillage and shell elements to separately model the hollowcore units and the topping concrete slab using the platform of the non-linear finite element program SAFIR. The modelling method required a lot of computational resources and is not ideal to model a large floor area. This paper describes the effect of the side supports and the aspect ratio of the floor on the predicted fire resistance. It also compares the efficiencies of shell elements and short beam elements for finite element modelling of the topping concrete in fire conditions. The results show that integrating the topping concrete slab into the beam grillages reduces the complexity of the model and also provides satisfactory results. Side supports can increase the fire performance of hollowcore floor slabs provided that the spacing of the side supports does not greatly exceed the span length.

Investigation on performance of prestressed hollow core slabs exposed to elevated temperatures

“…The structural behavior of the hollow core slab under fire was also influenced by axial restraints provided at supports and the fire resistance was enhanced with the provision of axial restraints (Shakya and Kodur, 2015;Thienpont et al, 2023). The load-bearing performance of prestressed hollow-core slab is influenced by various factors such as slab depth (Pothisiri and Kositsornwanee, 2015;Kodur and Shakya, 2017;Heo et al, 2021), length of slab (Chang et al, 2010;Heo et al, 2021), load ratio (Ehab Ellobody, 2014;Kodur and Shakya, 2017;Heo et al, 2021), axial restraints (Shakya and Kodur, 2015;Thienpont et al, 2023), boundary condition (Kodur and Shakya, 2017) and aggregate type (Aguado et al, 2016). Based on an extensive review of the literature, it is observed that factors governing the performance of hollow-core slabs were predicted for standard fire curve exposure and there is limited research considering the worst-case fire scenario.…”

“…The load-bearing performance of prestressed hollow-core slab is influenced by various factors such as slab depth (Pothisiri and Kositsornwanee, 2015; Kodur and Shakya, 2017; Heo et al. , 2021), length of slab (Chang et al. , 2010; Heo et al.…”

Shear behavior of deep precast/prestressed concrete hollow-core slabs with and without fibers at ambient and under fire conditions

“…Previous studies have shown that PCHC slabs exposed to fire can fail in bending, anchorage, shear-compression, and web-shear modes (Borgogno and Fontana 2000, Fellinger 2005, Chang, Moss et al 2010, Aguado, Espinos et al 2012, Torić, Divić et al 2012, Jansze, Klein-Holte et al 2014, Shakya and Kodur 2015. Among the four, fire tests conducted over the past 40 years showed that shear and anchorage failures dominate the fire behavior of PCHC slabs rather than bending failure (Fellinger 2004).…”