In-plane and out-of-plane behaviour of concrete masonry infills

砌体墙通常用于填充钢或钢筋混凝土框架，作为现代建筑结构中的内部分隔或外部覆层。由于缺乏科学的信息，在评估填充物和框架之间的相互作用的程度，砌体填充物往往被视为非结构元素和边界框架的重力和横向荷载的设计。因此，砌体填充物对框架刚度和强度的贡献被忽略。然而，忽略填充的贡献是一种保守的方法，这是一种误解。填充墙显著地包围框架，这反过来又将更大的力吸引到结构中的填充区域。设计不当的填充墙已被确定为地震中灾难性结构故障的一个促成因素。另一方面，适当设计的填充物已经显示出在抵抗各种类型的侧向载荷方面为框架系统提供显著的强度和延展性，即使在相当大的开裂之后。 框架系统的非线性、非弹性行为以及砌体填充物的各种材料和几何特征使得准确评估填充物对填充系统的侧向刚度和强度的贡献成为一项挑战。尽管在过去的三十年里进行了大量的实验测试和数值分析，但结果分散，这些研究的一些结果要么是不确定的，甚至是相互矛盾的。加拿大砌体设计标准CSA S304.1-04（2004）中包含的砌体填充设计指南是基于40多年前进行的工作。使用这些指南获得的设计值与现有的实验结果以及从其他公认标准（如美国规范MSJC 2013、新西兰砌体设计规范NZS 4230和欧洲规范8）获得的值存在显著差异。这些不一致性导致了研究结果在很大程度上没有转化为行业实践的情况。 为了将砌体填充物纳入结构的横向和重力荷载抵抗系统中，经过科学验证和行业认可的设计指南（涵盖填充物的实际应用）至关重要。因此，这一建议的动机是调查，无论是实验和分析，行为和能力的混凝土砌体填充框界定，以促进合理的设计方法。研究完成后，预计将量化填充物和框架的行为与一系列参数的点，适用于行业实践的建设性建议。这将填补现行标准中的差距，这将最终影响现行砌体填充施工实践。

Masonry walls have been commonly used to infill steel or reinforced concrete frames either as interior partitions or exterior cladding in modern building construction. Due to a lack of scientific information in assessing the extent of interaction between the infill and the frame, the masonry infill is often treated as non-structural element and the bounding frame is designed for both gravity and lateral loading. The contribution of masonry infills to the frame stiffness and strength is therefore ignored. It is, however, a misconception that ignoring the contribution of the infill is a conservative approach. Infill walls significantly stiffen the frame, which in turn attracts larger forces to the infill region in a structure. Improperly designed Infill walls have been identified as a contributing factor to catastrophic structural failures in earthquakes. On the other hand, properly designed infills have shown to provide significant strength and ductility for the frame system in resisting various types of lateral loads-even after considerable cracking. The nonlinear, inelastic behaviour of the frame system coupled with the various material and geometric characteristics of masonry infills has made accurate evaluation of the infill contribution to the lateral stiffness and strength of the infilled system a challenge. Despite that much experimental testing and numerical analysis have been conducted in the past three decades, the results have been scattered and some findings from these studies were either inconclusive or even conflicting. The design guidelines for masonry infills contained in the Canadian masonry design standard, CSA S304.1-04 (2004), are based on work conducted more than 40 years ago. The design values obtained using these guidelines are found to be in significant disparity with existing experimental results and also with values obtained from other recognized standards such as American code MSJC 2013, New Zealand masonry design code NZS 4230 and Eurocode 8. These inconsistencies have resulted in the situation that research findings have not been transferred to industry practice to a large degree. In order to incorporate masonry infills in the lateral and gravity load resisting systems of a structure, scientifically verified and industry-accepted design guidelines that cover practical applications of infills are crucial. This proposal is hence motivated to investigate, both experimentally and analytically, the behaviour and capacity of concrete masonry infills bounded by frames so as to contribute to advancement of rational design approaches. The research, upon its completion, is expected to quantify the infill and frame behaviour with a range of parameters to a point that constructive recommendations applicable to industry practice can be made. This will fill in the gap in the current standard which will ultimately impact the current masonry infill construction practice.