NEESR-CR: An Innovative Seismic Performance Enhancement Technique for Steel Building Beam-Column Connections

NEESR-CR：一种创新的钢结构梁柱连接抗震性能增强技术

基本信息

批准号：
0936547
负责人：
Tasnim Hassan
金额：
$ 59.04万
依托单位：
North Carolina State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2010
资助国家：
美国
起止时间：
2010-01-01 至 2013-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0936547&HistoricalAwards=false
关键词：
NEESR CR Innovative Seismic Performance

项目摘要

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This award is an outcome of the NSF 09-524 program solicitation "George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)" competition and includes the North Carolina State University (NCSU, lead institution) and the University of North Carolina at Pembroke (UNCP, subaward). This project will utilize the NEES equipment site at the University of Minnesota to experimentally validate an innovative technique for enhancing the seismic performance of steel building beam-column connections.Intellectual Merit: The proposed seismic enhancement technique involves heat treating sections of beam flanges by exposing these sections to a very high temperature for certain amount of time before slow air cooling. Such a heat treatment process reduces the strength of steel in the heat treated areas of the flange. Consequently, under seismic loading, a plastic hinge develops at the heat treated beam section (HBS). A connection enhanced by this technique will have the advantages of the popular reduced beam section (RBS) connection, but the HBS will have better energy dissipation than the RBS connection. In RBS connections, "weakening" of the beam flanges induces a plastic hinge away from the welds. In HBS connections, a plastic hinge develops at the heat treated section because of the reduced strength of steel. Moreover, as the beam flange remains intact and the inelastic modulus of steel is not altered at the HBS, the lateral and torsional buckling resistances of the HBS connection will be higher than those of the RBS connection. Consequently, the HBS connection will dissipate a larger amount of energy with a minimum loss of strength or stiffness compare to the RBS connection. Through a pilot study at NCSU, the seismic performance enhancement technique is validated analytically. This project will validate the technique by conducting full-scale connection experiments. Currently, RBS is the most popular connection design because of its seismic performance and cost effectiveness. The HBS connection is anticipated to be more seismically robust and economical than the RBS connection. The research will be performed through integrated experimental and analytical studies. Material experiments of heat treated and unconditioned coupons will be conducted and data will be analyzed to quantify the influence of heat treatment parameters (peak temperature and hold time) on the reduction of strength and to determine the constitutive model parameters. Detailed structural analyses of HBS connections will be performed to determine the optimum heat treatment parameters and geometry of HBS. Beam-column connections with and without HBS will be built and tested to demonstrate seismic performance enhancement of the modified connections. Detailed measurement of strains, displacements and rotations at various locations will be recorded for investigating both the local and global failure modes of HBS connections. Experimental and analytical results will be used to refine the technique and to develop a methodology for practical application of the technique.Broader Impacts: The research results will be integrated into professional development courses, and the research will involve faculty and students from a predominantly undergraduate Native American institution in the experimental activities. A methodology for application of the novel technique will be developed and disseminated. The heat treatment concept is applicable to steel building or bridge connections; the proposed heat treatment technique will benefit industries that use welded joints. Experimental data from this project will be archived and made available to the public through the NEES data repository.

该奖项根据 2009 年《美国复苏和再投资法案》（公法 111-5）提供资金。该奖项是 NSF 09-524 计划征集“George E. Brown, Jr. 地震工程模拟网络 (NEES)”的结果研究（NEESR）”竞赛，包括北卡罗来纳州立大学（NCSU，牵头机构）和北卡罗来纳大学彭布罗克分校（UNCP，子奖项）。该项目将利用明尼苏达大学的 NEES 设备现场，对增强钢结构梁柱连接抗震性能的创新技术进行实验验证。智力优点：所提出的抗震增强技术涉及通过暴露梁翼缘部分来对梁翼缘部分进行热处理。在缓慢空气冷却之前，将部分加热到非常高的温度一段时间。这种热处理工艺降低了法兰的热处理区域中的钢的强度。因此，在地震载荷作用下，热处理梁部分 (HBS) 处会形成塑性铰链。通过该技术增强的连接将具有流行的减小梁截面（RBS）连接的优点，但HBS将比RBS连接具有更好的能量耗散。在 RBS 连接中，梁翼缘的“弱化”会导致塑性铰链远离焊缝。在 HBS 连接中，由于钢的强度降低，在热处理部分会形成塑料铰链。此外，由于梁翼缘保持完整且HBS处钢材的非弹性模量没有改变，HBS连接的横向和扭转屈曲阻力将高于RBS连接的横向和扭转屈曲阻力。因此，与 RBS 连接相比，HBS 连接将消耗更多的能量，同时强度或刚度损失最小。通过北卡罗来纳州立大学的试点研究，抗震性能增强技术得到了分析验证。该项目将通过进行全面的连接实验来验证该技术。目前，RBS 因其抗震性能和成本效益而成为最流行的连接设计。预计 HBS 连接比 RBS 连接具有更强的抗震性能和经济性。该研究将通过综合实验和分析研究进行。将进行热处理和未调节试样的材料实验，并分析数据，以量化热处理参数（峰值温度和保持时间）对强度降低的影响，并确定本构模型参数。将进行 HBS 连接的详细结构分析，以确定 HBS 的最佳热处理参数和几何形状。将建造和测试带有和不带有 HBS 的梁柱连接，以证明修改后的连接的抗震性能增强。将记录不同位置的应变、位移和旋转的详细测量结果，以调查 HBS 连接的局部和全局失效模式。实验和分析结果将用于完善该技术并开发该技术实际应用的方法。更广泛的影响：研究结果将纳入专业发展课程，研究将涉及以本科生为主的本土教师和学生美国机构从事实验活动。将开发和传播新技术应用的方法。热处理概念适用于钢结构建筑或桥梁连接；拟议的热处理技术将使使用焊接接头的行业受益。该项目的实验数据将被存档并通过 NEES 数据存储库向公众开放。