43 research outputs found
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A mathematical programming computational model for disproportionate collapse analysis of steel building frames
Disproportionate collapse analysis aims to assure that frames, a commonstructural system of buildings, can survive unforeseen local events and a central modelingtool of such abnormal deterioration is the concept of column loss. This paperformulates an appropriate computational model on the basis of mathematical optimization,using the collapse load analysis problem of steel frames with pre-existingdamage. A respective collapse load robustness measure is proposed. The model hasthe ability to consider both full and partial column/node removals. It renders to be alinear programming model, if the US steel design regulations are used. A practicalexample is presented and several aspects are discussed
A computational model for full or partial damage of single or multiple adjacent columns in disproportionate collapse analysis via linear programming
The evaluation of the sensitivity or insensitivity of structures to local damage has been a major research field during the last decades, mainly provoked due to the series of aging structures and infrastructures. Many researchers have described this property as redundancy, others as the resistance to disproportionate collapse or robustness and still others as the ability of structural systems to display alternate load paths in case of a local damage. In any case, the problem for the evaluation of this property is increasingly alarming since many systems experience similar collapses (American Society of Civil Engineers (2009). Proceedings of Structures Congress on the first international symposium on disproportionate collapse. ASCE, Austin, TX). This paper presents the numerical assessment of disproportionate collapse analysis introducing the concept of partial damage of structural elements. Global robustness measures are proposed also for the case of multiple partial losses of adjacent elements. The measures are computed on the basis of a mathematical optimization problem using collapse load analysis of steel frames with pre-existing damage. Results comparing the cases of partial losses with the full column lossesare presented and discussed
Second order cone programming approaches to static shakedown analysis in steel plasticity
The finite element method discretized static shakedown analysis of steel constructions leads to large, sparse convex optimization problems. Under the von Mises yield criterion, they lead to second-order cone programming problems, for which the most appropriate techniques are Interior Point Methods. Various approaches exploiting the specific characteristics of the shakedown problems are presented and discussed