Behavior of RC flat slabs with shear bolts under reversed horizontal cyclic loading

Abstract

An experimental work on reinforced concrete flat slab specimens to test the efficiency of postinstalled bolts, as punching shear reinforcement in resisting vertical and cyclic horizontal loads, was conducted and is presented in this paper. The test protocol consisted in increasing horizontal drifts combined with constant vertical load until failure. Two different detailing solutions for the shear reinforcement were considered, one using a radial distribution around the column and another using a cross distribution, being the results compared with a previously tested reference specimen. The dimensions of the specimens were 4.25 x 1.85 x 0.15 m 3 . The test setup used for these tests was developed by the research team and simulates the boundary conditions with already recognized good results. Postinstalled steel bolts were proven to be an efficient solution for strengthening of existing structures, improving the structural behavior, and the punching resistance. K E Y W O R D S bolts, cyclic horizontal action, flat slab, shear reinforcement, strengthening for punching

Slab–column connection punching and ductility improvement methods for seismic response of buildings with flat slabs

“…Almeida et al 28 , 17 tested four specimens reinforced with stirrups around the column. Two shear reinforcement ratios were tested: one was achieved by using 16 vertical legs of diameter 4.5 mm per perimeter and a higher ratio was achieved by using eight legs of diameter 6 mm plus eight legs of diameter 8 mm.…”

“…Almeida et al 17,28 tested two specimens strengthened with post‐installed bolts in two arrangements: radial and cruciform. Three perimeters of 12 M10 bolts were used, with a shear reinforcement area per layer similar to the specimens with studs.…”

“…Headed shear studs have been shown to be one of the most practical and effective solutions for lateral loading. [10][11][12] Properly detailed stirrups can significantly enhance the performance of slab-column connections under lateral loading [1][2][3]12 Other reinforcement systems such as lattice reinforcement, 13,14 thin-plate stirrups, 15 bent-up bars, 3,16 post-installed bolts [17][18][19] have also been investigated in slabcolumn connections under lateral loading.…”

“…The first tests were conducted on specimens without punching shear reinforcement, with varying gravity load. 26 Subsequently, tests on specimens reinforced with headed studs, 27 stirrups, 28 HSC, 29 FRC, 30 and strengthening with postinstalled bolts 17 were conducted. All these specimens had similar geometry, flexural reinforcement detailing, and quantity as well as a comparable ratio between the applied gravity load and the concentric punching shear resistance (gravity shear ratio [GSR]).…”

Eccentric punching strength of continuous flat slabs—Analysis of different experimental setups

“…19 The Lisbon setup represents an attempt to comply with the actual boundary conditions of a continuous flat slab. In the last years, several researchers used it: Isufi et al 24 investigated the use of rail studs, Almeida et al showed the influence of closed steel stirrups 25 and the use of postinstalled shear bolts, 26 while Gouveia et al 27 investigated the response of SFRC flat slabs. The numerical model of a theoretical continuous setup is also developed, using the same mechanical parameters of Almeida's specimens.…”