SMALL-COLUMN COMPRESSION TESTS ON CONCRETE CONFINED BY WWF

Tests on 127 X 127 X 381 mm concrete columns were carried out to study the efficacy of welded-wire fabric (WWF) as confining transverse rein forcement in columns. Three different wire spacings and a total of fiv e wire sizes were used. The WWF was placed transversely in columns at close longitudinal spacing. The longitudinal spacing to column width r atio (S/D) varied from 0.1 to 0.3. For each of the five wire sizes, fo ur different S/D ratios were used. This resulted in 20 reinforced colu mn specimen designs. Each design was tested under displacement-control led uniaxial compression with three identical specimens. The axial str ess-strain curves were recorded. For the range of parameters tested, t he WWF reinforcement provided varied degree of confinement to the conc rete, as reflected in the varied level of enhancement of concrete stre ngth and ductility. The S/D ratio seems to have a more dominant effect on confinement than the volumetric ratio of WWF. From the test result s, a relationship between the S/D ratio and the volumetric ratio of WW F was deduced to serve as a boundary separating ductile behavior of th e confined concrete from brittle behavior. It is concluded that, with proper design, WWF can be effective In providing lateral confinement t o concrete in column construction. Further study using large columns i s suggested.