The structural use of fibrous-cement in partially prestressed composite concrete construction

Saunders, J

Abstract

A new concept in composite construction has been developed
at the University of Salford, involving the use of
fibre-reinforced cement channels, combined structurally
with partially prestressed composite concrete T-beams.
The British Standards Institution Code of Practice,
CP110: 1972, "The Structural Use of Concrete", permits the
use of Class 2 and Class 3 (partially prestressed) concrete
members in structural design'. The limiting design criteria
for such members are usually the limit'states of deflection
and cracking and therefore, an improvement in their
flexural behaviour would be beneficial. This improvement
may be brought about by the addition of fibre-reinforcement,
in the form of two or three dimensionally randomly
distributed fibres. The Code of Practice, CP110: 1972, does
hot, however, give any guidance on the use of fibres in
structural members and it is also apl. arent that the methods
outlined in the code for the calculation of the limit
states are limited and can be improved.
The flexural behaviour of twenty-two partially prestressed
composite concrete T-beams was investigated.
Each beam consisted of a precast partially prestressed
X-joist web, combined with a cast-insitu lightweight
aggregate concrete flange. Alkali-resistant glass fibrereinforced
cement channels were placed at the soffits of
six beams and steel fibre-reinforced concrete was used in
the webs of two beams. The T-beams were subjected toshort-term, long-term and fatigue loading and their structural
performance was considered in terms of strength,
cracking and deformation.
Theoretical relationships are derived between the
applied moment and the depths of the neutral axes of stress
and bending, enabling a design equation relating applied
moment to the steel stress to be developed. Subsequently,
design equations for the calculation of the limit states of
deflection and cracking are developed, which are directly
applicable to both conventional and fibre-reinforced
structural members.
The use of a fibre-reinforced cement channel as an
integral structural part of a concrete member results in
many important advantages when compared with conventional
concrete members and the test results show that they considerably
improve the structural performance of the
partially prestressed composite concrete T-beams.

Citation

Saunders, J. The structural use of fibrous-cement in partially prestressed composite concrete construction. (Thesis). University of Salford, UK

• Thesis Type: Thesis
• Deposit Date: Jun 23, 2009
• Publicly Available Date: Jun 23, 2009
• Additional Information: Additional Information : PhD supervisor: Professor E. R. Bryan
• Award Date: Dec 1, 1976