Gravity Load Capacity of Earthquake Damaged Slab-Column Connections

PI：詹姆斯·吉尔萨，德克萨斯大学奥斯汀分校。本项目的目的是确定钢筋混凝土板柱建筑的临界剪力、弯矩和变形相互作用。平板和平板楼板系统广泛应用于低重力荷载的住宅和商业建筑中。平板和平板楼板的双向抗剪能力或冲剪能力较低。这种连接的抗剪强度计算是复杂的，涉及弯矩和剪切传递之间的相互作用。抗剪能力受到连接处发生的非弹性作用的不利影响。必须控制变形或漂移以限制损坏。在1985年墨西哥城地震和此后的其他地震中，建筑物的不良性能证明了这些结构的弱点。在重力荷载作用下，由于结构侧向位移引起的非弹性变形对随后的剪切传递能力的影响知之甚少。研究计划的重点是实验测试，以确定重力载荷下板-柱连接的冲剪能力与地震（或其他严重载荷，如爆炸、风或沉降）对结构的破坏程度之间的关系。这些信息将有以下用途：通过目视观察、测量局部或整体变形或采用非破坏性技术来确定结构遭受地震破坏后，由于重力载荷而发生的冲孔剪切破坏的条件。2. 开发板柱连接的响应特性，用于新结构或现有结构的推覆或其他地震分析。3. 为既有板柱结构修复方案的评估和设计建立合理的变形限值。4. 评价加强板柱连接的可行性。该项目将在一个新的专业领域创造知识，对了解地震期间和地震后的结构性能至关重要。很少有实验证据可以指导研究和设计界评估和修复系统，这些系统在地震（或其他严重载荷，如爆炸、风或沉降）期间的损坏会对结构在不同载荷组合下的后续行为产生有害影响。PI将向NEES网络提供数据。研究结果将通过向地震工程界提供的报告、技术期刊上的文章和技术会议上的报告来传播。实践工程师将参与项目细节的制定。我们将做出特别努力，从得克萨斯大学的研究生和本科生群体中争取学生，CE项目中有很大一部分是女性和西班牙裔学生。这项研究的结果将立即用于关于评价和修复现有钢筋混凝土结构的研究生课程。PI将利用现有的大学课程和与当地高中科学教师的直接联系，鼓励高中生选择工程作为职业。

PI: James Jirsa, UT-Austin.The objective of this project is the determination of critical shear, moment, and deformation interactions for reinforced concrete slab-column buildings. Flat plate and flat slab floor systems are widely used in residential and commercial buildings with low gravity loads. Two-way or punching shear capacity of flat plate and flat slab floors is quite low. Shear strength calculations for such connections are complex and involve interaction between moment and shear transfer. Shear capacity is adversely affected by inelastic action that occurs at the connection. Deformation or drift must be controlled to limit damage. The poor performance of buildings in the 1985 Mexico City and other earthquakes since then has demonstrated the weaknesses in these structures. Little is known about the effect of inelastic deformations due to lateral displacements of the structure on subsequent shear transfer capacity under gravity loadings. The keystone of the research program is experimental testing to determine the relationship between punching shear capacity of the slab-column connection under gravity loads and the level of previous damage to the slab by earthquake (or other severe loading such as blast, wind, or settlement) actions on the structure. The information will be valuable for the following uses: 1. Determining the conditions under which punching shear failures due to gravity loads will occur after the structure has suffered earthquake damage by determining the degree of damage through visual observations, measured local or global deformations, or with non-destructive techniques. 2. Developing response characteristics for slab-column connections for use in pushover or other seismic analyses of new or existing structures. 3. Establishing reasonable deformation limits for evaluation and design of rehabilitation schemes for existing slab-column structures. 4. Evaluating the feasibility of strengthening slab-column connections. The project will create knowledge in an area that is new to the profession and essential to understanding the performance of structures during and after an earthquake. There is very little experimental evidence available to guide the research and design community in evaluating and rehabilitating systems where damage during an earthquake (or other severe loadings such as blast, wind, or settlement) can have deleterious impact on the subsequent behavior of the structure under different load combinations. The PI will make data available to the NEES network. Results will be disseminated through reports made available to the earthquake engineering community, articles in technical journals, and presentations at technical conferences. Practicing engineers will be involved in the development of the project details. Special efforts will be made to secure students from the graduate and undergraduate student bodies in the UT, CE program that has large fractions of women and Hispanic students. The findings from the research will be utilized immediately in a graduate course on evaluation and rehabilitation of existing reinforced concrete structures. The PI will use existing University programs, and direct contacts with local high school science teachers, to encourage a high-school student to choose engineering as a career.