Reserve of strength in prefabricated reinforced concrete slab of bridge decks and RC culverts

Abstract

This study intends to develop a deconstructable steel-concrete composite deck with external restraining system to mobilise the arch action and accordingly increase the cracking load, ultimate load carrying capacity and fatigue life and durability of the bridge decks. The possibility for partial replacement of reinforcing steel bars with dispersed fibres is considered and application of bolted shear connectors for connecting the precast concrete slabs to steel beams and developing composite action in the longitudinal and arching action in the transverse direction is studied. It is shown that the bolt connectors can facilitate the dismantling, repairing and upgrading of the bridge deck in future. The structural efficiency and feasibility of this novel bridge deck subject to static and cyclic fatigue loads is investigated experimentally. Moreover, the reserve of strength provided by arch action in the deconstructable concrete decks and buried RC culverts are investigated numerically. In the first two series of experiments, structural behaviour of the transversely restrained deck slabs subjected to static load is evaluated and in the third series of specimens, fatigue behaviour of reinforced concrete slabs (with or without fibres) subjected to high range cyclic loading is studied. In addition to proof of feasibility of proposed construction method, the experimental results indicate that, development of arching action not only increases the ultimate load capacity of deconstructable precast deck slabs but also enhances the fatigue life of specimens significantly. Furthermore, it is shown that adding certain amount of steel fibres can improve the behaviour of the deck slabs under service and ultimate loading conditions. The numerical study of this thesis comprises of two parts. In the first part, 3D continuum based finite element models of the deconstructable deck slabs with transverse restraining systems are developed, analysed and validated against the experimental data. In the second part, 2D nonlinear continuum-based FE models of RC culverts in conjunction with surrounding soils are developed and analysed to assess the enhancing effect of arching action on the strength and fatigue life of slabs in buried RC culvert. A parametric study is also conducted using validated finite element models.