The tension stiffening model generally predicts the response for instantaneous loads, so some extensions are necessary to account for the effects of the load history on the member.

• Creep and shrinkage strains are included in the calculated uncracked and cracked cross section curvatures.
• Creep strains for the cracked curvature calculations consider the actual cracking history of the cross section.
• While calculating cracked section curvatures, creep is only applied to portions of strain change in compression.
• Once a cross section is determined to be cracked during a particular load history step iteration, it is assumed to be cracked for all future iterations and load history steps.
• The mean curvature calculated for any loading level is assumed to be proportional to the mean curvature calculated at the peak loading level.