3. Evaluation of axial and lateral stress–strain curves
The above lateral-to-axial strain model, axial stress–strain
model and confining stress–lateral strain model are integrated
together for the evaluation of the lateral strain, confining stress
and axial stress–strain behavior of FRP-confined concrete. To
obtain the complete lateral strain–axial strain and axial stress–
strain curves, the axial strain is applied as prescribed axial strain
to the concrete and the lateral strain, confining stress and axial
stress are evaluated by the following procedures:
(1) Apply a prescribed axial strain ez to the concrete incrementally
in small axial strain increments starting from zero.
From numerical experience, each small axial strain increment
may be taken as 0.0001.
(2) Evaluate the lateral strain eTx
and confining stress rr using
the lateral-to-axial strain model and confining stress–lateral
strain model by try and error. This can be done either manually
using a spreadsheet program or automatically using a
computerized iterative procedure of alternately estimating
the lateral strain from the estimated confining stress and
estimating the confining stress from the estimated lateral
strain until convergent results are obtained.