依据规范设计的钢板剪力墙的抗震性能
|
摘要
目前美国钢结构协会(AISC)抗震设计规范纳入了钢板剪力墙(SPSWs)的设计要求。钢板剪力墙由薄钢板中夹着被称为水平边界单元(HBEs)的钢梁和被称为竖直边界单元(VBEs)的钢柱组成。无加劲薄钢板在较低剪力作用下屈曲并发展变形,通过屈服变形达到延性和耗能的目的。HBEs的作用是加劲和提高整体强度,并将屈服局限于薄钢板内。VBEs的作用是促进梁端塑性铰的形成。研究依据规范设计的钢板剪力墙的性能,设计了一系列钢板剪力墙试件,采用不同震级的地面震动反应谱的非线性时程分析对其进行性能研究。研究发现,依据现行规范设计的试件能满足各种地震烈度下最大层间位移的要求,并且在最高地震烈度下最大层间位移比小于5%。由于高阶振型对反应的影响,低层钢板剪力墙的延性要求比高层钢板剪力墙要高。由钢板承担的楼层剪力与由边界框架承担的楼层剪力之比为60%～80%,此比值与板的长宽比和地震烈度无关,而与板的厚度有关。9层或以上钢板剪力墙在低烈度地震下对VBEs的需求比规范计算方法要小很多。
The AISC Seismic Design Provisions now include capacity design requirements for steel plate shear walls,which consist of thin web plates that infill frames of steel beams,denoted horizontal boundary elements(HBEs),and columns,denoted vertical boundary elements(VBEs).The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action,providing ductility and energy dissipation through tension yielding of the web plate.HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates.VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs.This paper assesses the behavior of code designed SPSWs.A series of walls are designed and their behavior is evaluated using nonlinear response history analysis for ground motions representing different hazard levels.It is found that designs meeting current code requirements satisfy maximum interstory drift requirements considering design level earthquakes and have maximum interstory drifts of less than 5% for maximum considered earthquakes.Web plate ductility demands are found to be significantly larger for low rise walls than for high rise walls where higher modes of vibrations impact the response.The percentage of story shear resisted by the web plate relative to the boundary frame is found to be between 60% and 80% and is relatively independent of panel aspect ratio,wall height,or hazard level,but is affected by transitions in plate thickness.Maximum demands in VBEs in design level shaking are found to be considerably less than those found from capacity design for SPSWs with 9 or more stories.
The AISC Seismic Design Provisions now include capacity design requirements for steel plate shear walls,which consist of thin web plates that infill frames of steel beams,denoted horizontal boundary elements(HBEs),and columns,denoted vertical boundary elements(VBEs).The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action,providing ductility and energy dissipation through tension yielding of the web plate.HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates.VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs.This paper assesses the behavior of code designed SPSWs.A series of walls are designed and their behavior is evaluated using nonlinear response history analysis for ground motions representing different hazard levels.It is found that designs meeting current code requirements satisfy maximum interstory drift requirements considering design level earthquakes and have maximum interstory drifts of less than 5% for maximum considered earthquakes.Web plate ductility demands are found to be significantly larger for low rise walls than for high rise walls where higher modes of vibrations impact the response.The percentage of story shear resisted by the web plate relative to the boundary frame is found to be between 60% and 80% and is relatively independent of panel aspect ratio,wall height,or hazard level,but is affected by transitions in plate thickness.Maximum demands in VBEs in design level shaking are found to be considerably less than those found from capacity design for SPSWs with 9 or more stories.
引文
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心