The strut and tie method presents a rational and consistent approach to
the design of all parts in a reinforced concrete structure. With this approach, the load
carrying mechanism of the structure is represented by approximating the compressive
stress fields as struts, and tensile stress fields as ties. The stress in the struts and ties
should not exceed the allowable compressive strength of the concrete or yield strength
of the steel respectively. In the design of structures by this method there are two
important issues to be addressed. The first issue is that of the visualization of an
appropriate strut-tie model for a given structural system. In many structures there may
be various load paths available and hence no unique strut-tie model exists. The second
issue is that of validity of chosen models in relation to the serviceability and ultimate
load characteristics of the resulting structure. It is important that the ductility of the
structure should be maintained by insuring that crushing of concrete prior to yielding
of steel is avoided at design loads. Since the strut and tie method involves a redistribution
of the stresses from the elastic pattern, it is necessary to determine the
extent to which that re-distribution can be allowed for, while preserving the required
performance from the structure. In this work, visualization of strut-tie models was
carried out using elastic finite element analysis. The resulting stress fields were used
to design structures which were analysed using an in-house non-linear finite element
program and also physically tested in the laboratory
