In this research, the effect of fire exposure time and the concrete co
ver thickness on the behaviour of R.C. beams subjected to fire in shea
r zone and cooled by water is investigated. Eight reinforced concrete
beams (180 x 20 x 12 cm) were investigated. The beams were divided int
o two groups. Group (1) consists of four beams with a cover thickness
of 2 cm and group (2) consists of four beams with a cover thickness of
4 cm. Each group was subjected to a fire of 650 degrees C for differe
nt periods of time, i.e. 0, 30, 60, 120 min. The concrete compressive
strength of the beams was determined nondestructively by using a Schmi
dt hammer the next day after exposure to fire. The beams were tested b
y applying two transverse loads incrementally. Strains and deformation
s were measured at each load increment. Cracking loads, crack propagat
ion and ultimate loads were recorded for each beam. The behaviour of t
he beams exposed to fire in the shear zone is highly affected by the f
ire exposure time and the change of the cover thickness. (C) 1997 Else
vier Science Ltd.