Estrutura pré-fabricada de concreto de alto desempenho reforçado com fibras de aço para pontilhões rodoviários

Abstract

In general, short-span reinforced concrete highway bridges in Brazil have been neglected regarding inspection and maintenance. In this scenario, the adoption of cementitious materials is found attractive due to their resistance to different weather conditions, therefore resulting in an increased structural durability. Thus, this work aims to develop a High-Performance Fibre-Reinforced Concrete (HPFRC) short span highway bridge comprising prefabricated cellular modules, with external prestress cables inside the cross-section core, and to demonstrate it fulfil the design project requirements dismissing passive reinforcement bars, and thereby favouring durability. Given that, the constitutive laws for compression and tension behaviours were obtained from specimens moulded with HPFRC and from specimens extracted from a box girder mock-up. Two methods to determine fibre orientation factor and then predict fibre dispersion were applied, followed by results analysis aided by computer tomography images of scanned specimens. Finally, a prestressed short-span box girder mock-up was tested under shear force and the evolution of shear cracks were observed; this behaviour was also analysed via finite element numerical models. The results indicate that it is possible to dismiss both passive transverse (webs) and longitudinal (bottom flange) reinforcements and highlight the importance of the orientation factor when designing a structure with a fibre-reinforced material.