Behaviour of fabric-formed concrete beams reinforced with FRP bars

Abstract

Casting non-prismatic optimised concrete beams in flexible fabric formwork can lead to a significant saving of concrete material and reduction of the embodied energy in concrete structures. It also offers the possibility to create interesting architectural features. However, the flexibility of this formwork may not allow an adequate control for ensuring the protective concrete cover, while the curvilinear profiles of such beams require a labour intensive pre-bending of the conventional steel reinforcement. Therefore, using Fibre Reinforced Polymer (FRP) materials as internal reinforcement in fabric-formed concrete beams might offer a number of advantages mainly in terms of avoiding the durability concern of steel corrosion. The light weight and flexibility of FRP bars, in addition, contribute to the overall low selfweight of the construction system and allow innovations such as supplying the FRP bars attached to the fabric and using the fresh concrete selfweight to pull down the bars into their design position without compromising the concrete cover. Nevertheless, reinforcing structurally optimised shallow beams with FRP bars is likely to result in large deflections and design governed by serviceability criteria. This paper presents the results of an experimental study on the structural behaviour of optimised fabric-formed beams reinforced with glass and carbon FRP bars. The use of self-compacting concrete is considered in order to aid the construction process. Other important aspects related to the structural design and predictability of deflections, such as the construction accuracy of fabric-formed beams, are also examined. © 2013, NetComposite Limited