Study of the behaviour of partially prestressed brickwork beams
Abstract
The thesis summarises the test results of 41 full-scale
partially prestressed brickwork beams. These beams were tested to
study the effect of:
(i) % area of steel
(ii) prestressing force
(iii) partial prestressing ratio
(iv) cover to non-tensioned steel
(v) brick strength
(vi) mortar strength or grade
upon the ultimate moment, deflection and cracking behaviour of
partially prestressed brickwork beams.
The properties of the materials to be used in the
theoretical analysis were obtained from experimental tests. The
stress/strain relationship and the ultimate compressive strength of
brickwork was obtained from a large number of tests carried out on
both axially and eccentrically loaded prisms.
An interactive programme for use on a micro-computer was
developed in conjunction with the experimental study. The programme
predicts the ultimate moment, moment-curvature, deflection and crack
widths of reinforced, fully and partially prestressed brickwork and
concrete beams utilising the non-linear material characteristics.
The programme also makes allowance for presence of a concrete cavity,
composite section, and the tension-stiffening effect of the brickwork
and concrete after cracking. The behaviour of the beams predicted by
the analysis was compared with the experimental results.
The ultimate moment and deflection of the test beams were
also compared with recommendations of the current limit state design
code of practice for reinforced and prestressed masonry, BS 5628,
Part 2.