1. Linear strain variation across the depth of the cross section,
2. Perfect bond between steel, concrete, and CFRP, i.e., perfect
composite action and no slippage,
3. Elastic-perfectly-plastic behavior for steel~« ,0.025!,
4. Hognestad’s parabola for concrete stress-strain relationship
~Park and Paulay 1975 !, and
5. Linear elastic behavior for CFRP.