Wood I-Joists with Excessive Web Openings: An Experimental and Analytical Investigation
Wood I-Joists with Excessive Web Openings: An Experimental and Analytical Investigation
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DOI：
10.1061/(asce)st.1943-541x.0000013
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发表时间：
2009-02
期刊：
影响因子：
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通讯作者：
G. C. Morrissey;D. Dinehart;W. Dunn
中科院分区：
文献类型：
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作者：
G. C. Morrissey;D. Dinehart;W. Dunn
通过两组不同深度的工字型木托梁试验，研究了圆形和方形腹板开孔以及角钢加固位置对工字型木托梁性能的影响。所有的测试配置的有限元分析，以提高理解如何网络开口和改造影响的刚度，开口周围的应力分布，和最终的失败机制。试验结果表明，失效载荷远高于规定的设计载荷;然而，腹板开孔的存在影响了失效模式的类型。控制托梁在受拉翼缘处失效，而腹板开孔的托梁通过腹板开孔或直接由于开孔的存在而在剪切中失效。极限承载力和刚度通常会因腹板开孔的存在而降低，开孔位置越靠近高剪切区域，结果越差。当位于相同位置时，方形腹板开口比圆形开口的极限承载力降低约10%。如果使用足够的改造长度来重新分布应力集中，则角钢改造可以提高承载力。有限元模型准确地预测了由于腹板开孔而导致的刚度降低;然而，该模型预测了由于钢结构改造的存在而导致的刚度提高，而钢结构改造在实验结果中并未确定。
Two series of tests with different depth wood I-joists were conducted to study the effects of circular and square web openings and the placement of steel angle retrofits at openings. Finite-element analysis of all test configurations was used to improve understanding of how web openings and retrofits affect the stiffness, stress distributions around openings, and ultimate failure mechanisms. Test results show failure loads well above prescribed design loads; however, the presence of web openings affected the type of failure modes. Control joists failed at the tension flange, whereas joists with web openings failed in shear through web openings or by means directly attributable to the presence of an opening. Ultimate capacity and stiffness was generally reduced by the presence of a web opening, with openings located closer to high shear areas producing worse results. Square web openings lowered the ultimate capacity approximately 10% more than circular openings when located at the same location. Steel angle retrofits improved capacity if an adequate retrofit length was used to redistribute stress concentrations. Finite-element models accurately predicted decreases in stiffness due to web openings; however, the models predict an improvement in stiffness due to the presence of steel retrofits that was not ascertained in experimental results.