9th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE 2018), PARIS 17-19 JULY 2018 July 17-19, 2018 Paris EXPERIMENTAL STUDY OF BLAST RESPONSE OF RC SLABS WITH EXTERNALLY BONDED REINFORCEMENT A. Maazoun 1 2 , B. Belkassem 2 , S. Matthys 3 , D. Lecompte 2 , J. Vantomme 2 , R. Mourão 2 , B. Reymen 2 1 Ghent University, Magnel Laboratory for Concrete Research, Belgium, (azer.maazoun@ugent.be) 2 Royal Military Academy, Civil and Materials Engineering Dept, Belgium 3 Ghent University, Magnel Laboratory for Concrete Research, Belgium ABSTRACT The present paper discusses experimental work on the efficiency of externally bonded reinforcement (EBR) on reinforced concrete (RC) slabs under blast loads using an explosive driven shock tube (EDST). This study focuses on four tests which have been performed on simply supported RC slabs retrofitted with carbon fiber reinforced polymer (CFRP) strips and subjected to explosions for the same pressure and impulse. Pressure transducers are fixed at the end of the tube to measure the pressure of each experiment. Maximum deflection and strain distribution in the concrete and CFRP strips are recorded using digital image correlation (DIC) measurements. Due the explosion, the RC slabs are submitted to a dynamic vibration in both directions and during the first inbound displacement phase, the kinetic energy of the retrofitted specimen is stored as elastic strain energy in CFRP strips. All this elastic strain energy stored in FRP strips is violently released as kinetic energy during the rebound phase of the slab. The results indicate that EBR increases significantly the flexural capacity and the stiffness of RC slabs under blast loads. KEYWORDS Blast loading; Externally bonded reinforcement; Explosive Driven Shock Tube; Dynamic response; RC slab. INTRODUCTION Many types of exiting RC structures are not designed to resist an explosion and upgrading of structural robustness is becoming necessary because of the industrial accidents and terrorist attacks that happened all over the world and cause severe damage and loss of life. Recently, a number of studies have been conducted on the use of CFRP EBR to strengthen RC structures against blast loading (Maazoun, Matthys, and Vantomme 2016). Crawford and John (2013) conducted tests on six reinforced concrete columns strengthened with CFRP for resisting to blast loads. They stated that the main benefit of wrapping a reinforced concrete column with CFRP resides in the increase of strength and ductility of the concrete. Muszynski et al. (2003) tested two reinforced concrete walls which were retrofitted with carbon fibres and with aramid (Kevlar) fibres. The walls were subjected to the blast wave resulting from the detonation of 830 kg TNT at a standoff distance of 14.5 m. They reported that the reinforced elements retrofitted with carbon and aramid FRP respectively showed a reduction of 25% and 40% of the maximum deflection at mid span of the wall, compared to unstrengthened reference specimens. Silva et al. (2007) used CFRP for strengthening RC slabs on either one side only or on both sides. They concluded that slabs retrofitted with CFRP on both sides exhibited better blast resistance than those retrofitted on only one side. They explain this behaviour by the better resistance against negative bending moments due to rebounding of the slab. The present study focuses on four tests which have been performed on simply supported RC slabs retrofitted with CFRP strips, subjected to explosions for a constant charge weight. Maximum deflection and strain distribution in the concrete and in CFRP strips are recorded using DIC measurement. EXPERIMENTAL ASSESSMENT Four RC slabs are casted in laboratory conditions with the following dimensions (Maazoun et al.): length 2.3 m, width 0.3 m and thickness 0.06 m. The average compressive strength (cubes with side length 150 mm) and the Young's modulus of the concrete are f cm = 53 N/mm 2 and E C = 36400 N/mm 2 . The main reinforcement is composed of 6 bars of 6 mm diameter. The steel has a characteristic yield strength of f y =500 N/mm 2 and Young's modulus of E s =210,000 N/mm 2 . Fig. 1 shows the slab reinforcement details. brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Ghent University Academic Bibliography