A general model for the nonlinear analysis of sequentially constructed reinforced , prestressed and composite concrete structures

Abstract

A general step by step model for the nonlinear and the time dependen analysis of reinforced concrete, prestressed concrete and composite plane frame structuras is presented. The model can take into account many aspects of sequential construction processes, such as changes of longitudinal and cross sectional geometry or material properties, the placement or removal of elements, internal or external boundary conditions, prestressing tendons and stays. In addition, the nolinear time dependent properties of the constitutive materials of the structure, the structural effects of time dependent deformations, and the second order effects are considered in the srtuctural analysis under loads and imposed deformations. The model can trace the structural response not only during the construction of the structure but also throughout its service life. The consideration of nonlinear gemoetry and material behavior (cracking, yielding, crushing) allows the structural response to be traced through the elastic, cracked and ultimate load level, providing valuable imformation about the influence which the construction process may have on the short and long term loading capacity of the structure. The model is also appliacble to damaged, repaired and retrofitted structures, using both passive and acive retrofitting schemes. In order to show the capabilities of the model, several examples are presented, one of them consisting on an actual cantilever constructed prestressed concrete bridge.