Effects of fibre-reinforced cement composites' ductility on the seismic performance of short coupling beams

Abstract

The current study examines the effects of the deformation behaviour of cementitious material ductility on the seismic performance of shear-dominant coupling beams. Matrix ductility and reinforcement layouts comprise the main testing variables. Three short coupling beams with two different reinforcement arrangements and matrices are constructed and tested. They are subjected to cyclic loading under a suitable experimental set-up. All specimens are characterised by a shear span–depth ratio of 1·0. The reinforcement layouts consist of a classical scheme and diagonal scheme without confining ties. The effects of cement-based matrix ductility on crack patterns, failure modes, hysteretic characteristics and the ultimate shear load of the coupling beams are examined. The combination of a ductile cement-based matrix and steel reinforcement is found to result in improved energy dissipation capacity, simplification of reinforcement details, and damage-tolerant inelastic deformation behaviour. Test results show that high-performance hybrid fibre-reinforced cement-based composite (HPHFRCC) coupling beams behave better than normal reinforced concrete (RC) control beams. These results are evidenced by the tensile deformation capacity, damage tolerance and tensile strength of HPHFRCC material.

Shear performance of precast SHCC infill walls for seismic retrofitting of non-ductile frames

“…According to the results of research on direct tensile, flexural and compressive behaviour, a tensile strain of 2-4% was reported and behaviours were found to depend on the type and fibre volume fraction of the reinforcing fibres mixed in. Research studies on SHCCs have been performed on their use in repairing roads in the USA (Li et al, 2000); in seismic devices, especially dampers, in Japan (Fukuyama and Suwada, 2003); and in reinforcing materials for existing buildings (beams, walls and tunnels), seismic devices and structural members in the Republic of Korea (Yun et al, 2006;Yun et al, 2008). Yun et al (2006) performed one frame and four infill wall-frame tests with various matrix ductilities and reinforcement details of infill walls.…”

“…While a common infilled frame fails due to the shear failure of a column, the damage of a column can be transferred from the top to the mid-span of the column by making a notch in the infill wall. The other was the application of SHCCs, which represent improved matrix ductility and the dispersion of microcracks by hybrid fibre (polyethylene and polyvinyl alcohol) (Kawamata et al, 2003;Lawler, 2001;Li et al, 2001), to infill walls in order to absorb damage energy (Fukuyama and Suwada, 2003;Yun et al, 2008). The objectives of this study are:…”

Shear strength of pseudo strain hardening cementitious composite coupling beam

“…It shows that an adequate amount of longitudinal steel reinforcement for PSH2C beams efficiently controls shear crack opening. Park and Yun [15] Steel fiber + ECC …”

“…The shear strength (V plate ) of the embedded steel plate was computed from using Eq. (15) V nðplateÞ ¼ 0:6F y h w t w ðNÞ ð 15Þ…”

“…However, the available studies [15,16] on fiber reinforced composite beams with stirrups and embedded plates are very limited. Therefore, it is necessary to develop a model to predict shear strength because there are no specific current codes that address the shear strength of fiber reinforced composite beams, considering the contribution of the pseudo strain hardening material such as fibers, stirrups, and embedded steel plates.…”