Gravity Load Capacity of Earthquake Damaged Slab-Column Connections

这个项目的目标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。平板和平板楼板体系广泛应用于轻重力作用下的住宅和商业建筑中。平板和无梁楼盖的双向或冲切抗剪承载力较低。这种节点的抗剪强度计算很复杂，涉及弯矩和剪力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。1985年墨西哥城和此后其他地震中建筑的糟糕性能表明了这些结构的弱点。在重力荷载作用下，结构侧向位移引起的非弹性变形对后续剪力传递能力的影响知之甚少。研究的重点是试验研究，以确定自重荷载作用下板柱节点的冲切抗剪能力与地震(或其他严重荷载，如爆炸、风或沉降)对结构的先前损伤程度之间的关系。这些信息将对以下用途有价值：1.通过目测、测量的局部或整体变形或非破坏性技术来确定结构遭受地震破坏后发生重力荷载造成的冲切破坏的条件。2.开发用于新结构或现有结构的推覆或其他抗震分析的板柱连接的反应特性。3.为既有板柱结构加固方案的评估和设计确定合理的变形限值。4.评价板柱节点加固的可行性。该项目将在一个对该专业来说是新领域的领域创造知识，并对了解地震期间和地震后结构的性能至关重要。在评估和修复地震(或其他严重荷载，如爆炸、风或沉降)时的破坏可能会对结构在不同荷载组合下的后续行为产生有害影响的系统中，可用于指导研究和设计界的实验证据非常少。PI将向NEES网络提供数据。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在技术会议上的陈述来传播。执业工程师将参与项目细节的开发。将特别努力确保学生从德克萨斯大学的研究生和本科生群体中脱颖而出，该项目有很大一部分是女性和西班牙裔学生。研究结果将立即用于现有钢筋混凝土结构的评估和修复研究生课程。PI将利用现有的大学课程，以及与当地高中理科教师的直接接触，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.