NEESR II; System Behavior Factors For Composite And Mixed Structural Systems

该奖项是NSF 06-504项目征集“小乔治·E·布朗地震工程模拟研究网络(NEESR)”竞赛的结果。智能优点：这项建议将开发组合框架结构体系的系统性能系数(R、CD和WO)，并为此类结构的分析和设计提供实用指南。该项目将使用明尼苏达大学的NEES桅杆设施来测试一系列全尺寸细长组合梁柱，以开发这些构件在承受大的横向位移时的刚度和强度演变的数据。该项目将产生一套独特的数据，以验证先进的分析模型，并为开发复合材料和混合结构的简化和先进分析技术提供支持。这些数据将填补当前数据库中的空白，并提供一系列独特的受控良好的测试，以允许校准先进的、基于纤维的组合梁柱分析模型。将收集关于组合梁柱与梁和基础的连接的性能和性能的试验数据，以校准构件模型。一些需要解决的更具挑战性的任务包括：建立组合框架内梁柱及其节点的强度和刚度的逐步循环劣化模型，徐变和收缩等长期效应的影响，沿组合界面和柱脚和连接处的力传递，以及正确理解组合梁柱体系的行为所必需的许多强度、刚度和变形能力机制的必要工具。主要成果将是：(1)以代码语言格式的一系列设计建议，以便直接纳入为ASC7和AISC地震规定编制的2010/11年度订正结构体系表，以及说明和澄清其适用性的设计实例；以及(2)对开发的高级模型的详细说明，这些模型将帮助研究人员对其他组合和混合结构体系进行类似研究。本研究直接针对NSF 06-504征集中引用的建筑地震安全委员会研究需求文件中的基础研究需求#1(制定合理的弹性设计参数)、#4(与柱脚的连接)、#12(使用高强度钢)、#19(混合和组合结构)以及#22和#23(组合柱)。更广泛的影响：该项目的结果将采用一种可以直接纳入设计规范的格式，并将涵盖多种材料特性(3 ksi f‘c 15 ksi和36 ksi f’c 80 ksi)，这是目前设计规范未考虑到的一系列材料强度。其目的是鼓励在低、中、高地震活动区的5到20层范围内的建筑物中使用复合系统。此外，该项目将与佐治亚理工学院的FACES/AGEP项目对接，为少数族裔本科生提供研究经验。最后，该项目将提供适用于现有结构升级的初步指导方针，方法是对封闭部分使用外部约束(玻璃钢或类似材料)，并对空心结构部分填充轻质胶凝材料。

Abstract 0619047LeonThis award is an outcome of the NSF 06-504 program solicitation "George E. Brown, Jr. Network for Earthquake Engineering Simulation Research (NEESR)" competition. Intellectual Merit: This proposal will develop system performance factors (R, Cd, and Wo) for composite frame structural systems and provide practical guidelines for the analysis and design of such structures. This project will use the NEES MAST Facility at the University of Minnesota to test a series of full-scale slender composite beam-columns to develop data on the evolution of the stiffness and strength of these elements when subjected to large lateral displacements. The project will produce a unique set of data to verify advanced analytical models and provide support for the development of both simplified and advanced analysis techniques for composite and mixed structures. This data will fill gaps in the current databases and provide a unique series of well-controlled tests to allow for the calibration of advanced, fiber-based analytical models for composite beam-columns. Experimental data will be collected on the behavior and performance of connections of composite beam-columns to beams and foundations to calibrate component models. Some of the more challenging tasks to be addressed include development of models for the progressive cyclic deterioration of strength and stiffness of beam-columns and their connections within composite frames, the effect of long term effects such as creep and shrinkage, the force transfer along the composite interface and at column bases and connections, and the necessary instrumentation to discriminate between the many mechanisms of strength, stiffness, and deformation capacity that will be necessary to properly understand the behavior of composite beam-columns systems. The main deliverables will be: (1) a series of design recommendations formatted in code language for direct incorporation into the revised structural system tables being developed for the 2010/11 cycle of ASCE 7 and the AISC Seismic Provisions, along with design examples to illustrate and clarify their applicability; and (2) a detailed description of the advanced models developed that will help researchers pursue similar studies for other composite and mixed structural systems. This research addresses directly Basic Research Needs #1 (development of rational elastic design parameters), #4 (connections to column bases), #12 (use of high strength steel), #19 (mixed and composite structures), and #22 and #23 (composite columns) in the Building Seismic Safety Council Research Needs document referenced in the NSF 06-504 solicitation. Broader Impacts: The results of this project will be in a format that can be directly incorporated into design codes and will span a wide range of material properties (3 ksi f'c 15 ksi and 36 ksi Fy 80 ksi), a range of material strengths that is not currently contemplated by design specifications. The objective is to encourage the use of composite systems in buildings in the 5 to 20 story range in areas of low, moderate, and high seismicity. In addition, the project will interface with the FACES/AGEP project at Georgia Tech to provide minority undergraduates with research experience. Finally, the project will provide preliminary guidelines suitable for being adapted to the upgrading of existing structures through the use of external confinement (FRP and similar) for encased sections and infilling with lightweight cementitious materials for hollow structural sections.