Creep and shrinkage of HPC in prebended composite structures. Part II: in situ case study

A prefabricated, prebended and prestressed railway bridge deck was instrumented in June 2000 with strain gauges and vibrating wire extensometers. It is a kind of structure in which large time-dependent stress redistributions between steel and concrete are expected to occur. The purpose of this paper is to report on the comparison between strains recorded in situ on an instrumented bridge deck of this kind up to four years after its construction with values computed within the framework of four different time-dependent analyses: (a) a pseudo-elastic analysis with variable modular ratios for concrete used for the design of these bridge decks; (b) a step-by-step method applying the principle of superposition; (c) a step-by-step method incorporating a recovery function; and (d) an original modelling method. This final analysis is presented in Part 1 of this paper, which is based on the evolution of three fundamental local parameters: the temperature, the degree of advancement of reaction of hydration and the water content in concrete.