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原文传递 Improved Noncompact Web-Slenderness Limit for Steel I-Girders

题名：	Improved Noncompact Web-Slenderness Limit for Steel I-Girders
正文语种：	英文
作者：	Lakshmi Subramanian;Donald W. White, M.ASCE
作者单位：	Georgia Institute of Technology
关键词：	Structural steel; Plate girders; Structural stability; Beams; Flexural strength; Metal and composite structures.
摘要：	The noncompact web-slenderness limit in current design specifications is based on an assumed value of the plate buckling coefficient for a web subjected to flexure that is between the values for fixed and simply-supported edge conditions. While the limit provided in current specifications is a good representation in many situations, there is evidence that the limit overestimates the magnitude of the restraint provided by smaller flanges. This paper shows that the ratio of the area of the compression flange to the area of the web in compression is a good indicator of the restraint provided to the bend-buckling of the weh plate. The overestimation of the plate buckling co-efficient can result in the classification of cross sections having relatively small flanges as noncompact web sections when their behavior is more akin to that of slender web sections. Slender web sections have a maximum possible flexural resistance, referred to as the plateau strcngth, less than the yield moment Mvc, because of load shedding from the web. Furthermore, the St. Venant torsional stiffness contribution to the lateral torsional buckling resistance is neglected for these sections due to web distortional flexibility. This paper evaluates the appropriate noncompact web-slenderness limit via test simulation of a targeted set of short girder specimens in which the calculated resistance is governed by the plateau strength and proposes a modified equation to rectify the problem. The impact of this change on the prediction of a broad range of member limit states is illustrated via comparison to other test simulations and to experimental results. DOI: 10.1061/(ASCE) ST. 1943-541 X.0001722. © 2016 American Society of Civil Engineers.
出版日期：	2017.04
出版年：	2017
期刊名称：	Journal of Structural Engineering
卷：	Vol.143
期：	NO.04
页码：	04016216