RIA: Three-Dimensional Nonlinear Cyclic Analysis of Concrete-Filled Tube Beam-Columns and Composite Subassemblies

这是一项研究启动奖，用于研究无支撑框架复合组件的力位移响应和极限强度行为。结构工程师越来越意识到在中低层建筑中使用钢管混凝土（CFT）梁柱的经济效益，他们预计未来十年对CFT的需求将显著增长。详细而有效的数值模拟，加上实验研究，是理解CFT行为的唯一实用手段。然而，迄今为止，对cft的研究还不够充分。在这个项目中要研究的组件包括钢梁框架成矩形CFT梁柱承受单调或循环加载。该项目的目标是：1)开发一个实用的、三维的、非线性的、基于纤维的有限元公式来表示CFT梁柱；2)建立兼容的非线性模型来表示梁-柱连接和面板区域；3)在现有的复合框架分析系统中实现这些公式，并根据实验数据对公式进行校准；4)对单个CFT梁柱和复合组件进行全面的参数研究。将进行参数化研究，以提供所需的数据，以提高当前非地震和地震设计规范规定的准确性和范围。这种纤维分析也将有助于研究新的复合CFT系统，并允许实验人员预测和解释他们的测试结果。＊＊＊

9410473 Hajjar This is a Research Initiation Award to study the force displacement response and ultimate strength behavior of composite subassemblies of unbraced frames. Structural engineers are increasingly realizing the economic benefits of using concrete filled steel tube (CFT) beam-columns in low and medium-rise construction, and they expect the demand for CFTs to grow significantly in the next decade. Detailed but efficient numerical simulation, coupled with experimental research, is the only practical means of understanding CFT behavior. Yet only insufficient research has been conducted on CFTs to date. The subassemblies to be studied in this project consist of steel I girders framing into rectangular CFT beam-columns subjected to either monotonic or cyclic loading. The project's objectives are: 1) to develop a practical, three-dimensional, nonlinear, fiber-based finite element formulation to represent CFT beam columns; 2) to develop compatible nonlinear models to represent the girder-to-column connection and panel zone region; 3) to implement these formulations in an existing composite frame analysis system, and to calibrate the formulations against experimental data; and 4) to conduct comprehensive parametric studies of individual CFT beam- columns and composite subassemblies. The parametric studies will be conducted to provide the data required to improve the accuracy and scope of current non-seismic and seismic design specification provisions. This fiber analysis will also facilitate investigation of new composite CFT systems, and permit experimentalists to both predict and interpret their test results. ***