Assessing the effectiveness of a NSM-CFRP flexural strengthening arrangements for continuous RC slabs by experimental and numerical research

Abstract

A program formed by continuous slab strips strengthened in flexure with near surface mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) laminates was carried out, and the obtained results showed the possibility of increasing significantly the load carrying capacity of these elements, maintaining high levels of ductility. The experimental program is formed by slab strips of two equal span lengths, and has the main purpose of exploring the potentialities of distinct NSM flexural strengthening configurations for the increase of the load carrying capacity of this type of structures. In the present work two types of strengthening arrangements were investigated, one with CFRP laminates exclusively applied at the intermediate support, H series (hogging region), and the other with laminates applied at both hogging and sagging regions (HS series). For assessing the predictive performance of a FEM-based computer program (FEMIX V4.0), the experimental results are compared with values predicted by this software. Then, a parametric study with 144 numerical models is carried out to investigate the influence of the strengthening arrangement and CFRP percentage in terms of moment redistribution and rotational capacities of continuous RC slab strips flexurally strengthened by the NSM technique. The obtained results are presented and analyzed in this paper.