Ocena efektów pełzania i skurczu betonu w mostowych dźwigarach zespolonych metodą zastępczego Ec wg PN-EN
[ 1 ] Instytut Inżynierii Lądowej, Wydział Budownictwa i Inżynierii Środowiska, Politechnika Poznańska | [ P ] employee
EN Assessment of effects of creep and shrinkage of concrete in steel-concrete composite bridge girders using equivalent Ec according to PN-EN
2013
scientific article
polish
EN Creep of concrete causes stress redistribution in particular cross-sections of steel-concrete composite girder, and in statically indeterminate structures - also hyper-static variables. According to PN-EN creep effects may be assessed using equivalent relationship of elasticity module of steel and concrete: [formula]. It is shown that coefficient ,,ψL” is a function. In design constant values of ,,ψL” may be used. They depend only on the reason of creep. PN-EN gives only one value of ,,ψL” or each reason of creep. The paper shows that using two values of the coefficient is correct. In PN-EN the terms of primary creep effects and secondary creep effects are introduced. They were not used before in Polish technical and scientific literature. The paper explains meaning of the terms. Algorithms and examples of computation of creep effects in continuous composite girders due to dead loads and concrete shrinkage are given. The algorithms consist of two stages. In the first stage primary effects of creep are computed and in the second stage - secondary effects. It enables easy approach to the analysis of statically indeterminate structures.
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