ABSTRACT
Conventional steel reinforcing bars in concrete bridge approach slabs (BAS) are subject to high corrosion levels, and hence, fibre reinforced polymers (FRP) bars are their potential substitutes in aggressive environments, since they have higher resistance to aggressive exposures and corrosion. BAS seldom receive appropriate design considerations and are common sources of problems. Their behaviour is governed by soil-slab interaction, leading to varying relative stiffnesses which affect the straining actions especially under heavy loads, and where the moments are reduced with the reduction in rigidity. If neglected, this may lead to irrational designs. BAS are applications where the mechanical properties of FRP bars, i.e. high strength and low stiffness (rigidity), are suitable and advantageous. The BAS is designed as structurally reinforced with FRP bars adapting the principles of reinforced concrete strength design. FRP bars not only enhance strength but also durability. However, serviceability rather than strength requirements control the design. The inherent differences between FRP reinforced BAS and steel reinforced BAS are highlighted and some special considerations of BAS addressed.
