Showing papers by "Zdenek P. Bazant published in 1972"

Prediction of Concrete Creep Effects Using Age-Adjusted Effective Modulus Method

Abstract: • IN THE CREEP ANALYSIS OF concrete structures two kinds of errors are involved. One stems from the inaccurate knowledge of the creep law, and its minimization is a problem of materials re­ search. The second error is caused by the simpli­ fication of analysis, which designers introduce to avoid the complexities of an exact analysis. In the sequel, only accuracy or exactitude in the latter sense will be of concern. The simplest and the most widespread among the simplified methods of analysis is the well­ known effective modulus method, whose error with regard to the theoretically exact solution for the given creep law is known to be quite large when aging of concrete, i.e., the change of its properties with the progress of hydration, is of significance (see Table 2 discussed below). How­ ever, a surprisingly simple way of refinement of this method has been recently discovered by Trost, 1 on the basis of approximate and mostly intuitive considerations. The intent of this paper is to present a rigorous formulation of this method and to extend it to the case of a variable elastic modulus and an unbounded final value of creep.