Showing papers by "Zdenek P. Bazant published in 2015"
TL;DR: In this article, the authors present a novel approach to solve the problem of plagiarism in the context of biomedical data analysis, which is accepted for publication, but it is copyrighted by RILEM, and readers must contact Riellem for permission to reprint or use the material in any form.
Abstract: The original publication is available at the publisher’s web site: http://link.springer.com/article/10.1617/s11527-014-0485-2/fulltext.html#copyrightInformation.
This article is accepted for publication, it is copyrighted by RILEM, and readers must contact RILEM for permission to reprint or use the material in any form.
162 citations
01 Jan 2015
TL;DR: In this article, the authors present Model B4, the improved and extended successor of the 1995 RILEM recommendation Model B3, and compare it statistically to a wide set of previous models, such as Model B 3, Model Code Models 90/99 and 2010, the 1992 ACI 209 Model, and the Gardner-Lockman Model 2000.
Abstract: The multi-decade creep and shrinkage prediction for modern high–performance concretes poses a significant challenge. Here we present Model B4, the improved and extended successor of the 1995 RILEM recommendation Model B3. We demonstrate its strength by comparing it statistically to a wide set of previous models, such as Model B3, the fib Model Code Models 90/99 and 2010, the 1992 ACI 209 Model, and the Gardner–Lockman Model 2000. The calibration of Model B4 is based on a new laboratory database, developed at Northwestern University, and additionally on multi-decade deflections of 69 large-span prestressed bridges. The multi–decade creep behavior is updated using a joint optimization of the laboratory and bridge deflection databases. Two sets of equations to predict the parameters of the creep and shrinkage model, one utilizing solely strength, and one based on composition information, have been calibrated. They include the effects of admixtures, aggregates, and cement type.
6 citations
DOI•
01 Jan 2015TL;DR: In this paper, a series of studies at Northwestern University led to the establish- ment of a theory of probability distributions of short-time strength, residual strength after static preload and lifetime of structures made of quasibrittle materials such as concrete, fiber composites and tough ceramics.
Abstract: The paper reviews a series of studies at Northwestern University which led to the establish- ment of a theory of probability distributions of short-time strength, residual strength after static preload and lifetime of structures made of quasibrittle materials such as concrete, fiber composites and tough ceramics. The theory is based on the frequency of probability of interatomic bond breaks on the atomic scale and on the multi-scale transition of power-law probability tail. The conclusion is that if the failure is not perfectly brittle, the probability distribution of strength and lifetime is a graft of Gaussian and Weibull distributions and varies from nearly Gaussian at the scale of one RVE to Weibullian for very large struc- tures consisting of many RVEs. As a consequence, the safety factors should depend on structure size. Numerous experimental comparisons and computational simulations are given.