EFFECT OF TRANSVERSE REINFORCEMENT ON EFFICIENCY FACTORS OF BOTTLE SHAPED STRUTS

Abstract

The effect of amount and orientation of transverse reinforcement on strength of steeply inclined concrete bottle-shaped struts measured in terms of efficiency factors has been experimentally investigated for three transverse reinforcement ratios - 0.0031, 0.0050 and 0.0071, with the control bottle-shaped strut being transversely unreinforced. Efficiency factor increase of 10.5% was observed when the transverse reinforcement ratio was increased from nil to 0.0030 for the vertically oriented transverse reinforcement whereas for the horizontal transverse reinforcement the increase in efficiency factor was relatively very small. Service load crack widths in all the transversely reinforced struts were less than an upper bound value of 0.3 mm. 1-lorizontal transverse reinforcement proved to be more adequate for restraining the crack width. Unlike some of the current design codes, the results of this investigation emphasize the role of amount and orientation of transverse reinforcement in the strength of bottle-shaped struts and show that the 0.003 critical transverse reinforcement ratio recommended in the AC! Building Code is the optimum amount of such reinforcement in concrete reinforced bottle-shaped struts.