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

9410473 Hajjar这是一个研究启动奖，旨在研究无支撑框架的组合组件的力、位移响应和极限强度行为。结构工程师们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钢管混凝土梁柱的需求将显著增长。详细而高效的数值模拟，加上实验研究，是理解CFT行为的唯一实用手段。然而，到目前为止，对CFT的研究还不够充分。本项目中要研究的部件包括框架成矩形钢管混凝土梁柱的工字形钢梁，承受单调或循环荷载。该项目的目标是：1)开发实用的三维、非线性、基于纤维的有限元公式来表示钢管混凝土梁柱；2)开发兼容的非线性模型来表示梁柱连接和板区区域；3)在现有的组合框架分析系统中实施这些公式，并根据试验数据对公式进行校准；以及4)对单独的钢管混凝土梁柱和复合材料部件进行全面的参数研究。将进行参数研究，以提供所需的数据，以改进当前非抗震和抗震设计规范规定的准确性和范围。这种纤维分析还将促进对新的复合材料CFT系统的研究，并允许实验者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. ***