Strength and Long-term Behaviour of Masonry Structures

砌体结构因其美观和耐久性而被广泛应用于结构中。加拿大的许多遗产建筑都是用砖石建造的，有必要保护这些建筑。国家建筑规范要求对这些结构进行评估并使其达到现代标准，但评估和修复这些结构并不容易。因此，提案的第一部分有两个主题。第一个目的是了解结构的当前状态，通常是在蠕变(荷载作用下变形随时间缓慢增加)和风化引起的退化的长期影响之后：这些因素的综合影响可能会导致内部裂缝，进而导致结构的危害性。如果了解了原因，就可以设计出适当的补救措施。第二个主题是利用跨墙锚固墙，目的是发展一种方法来预测这种锚的最佳方位，以抵抗地震中预期的荷载，从而帮助结构在地震中幸存下来。我们对砖石结构如何抵抗这种类型的荷载没有很好的理解，所以当人们回顾世界各地的规范时，对剪切强度的估计存在很大的分歧。然而，许多建筑都采用了砖石剪力墙来抵抗这种荷载(例如由风产生的荷载)。以前拨款支持的工作表明，配筋砌体的主要强度由砌体的强度决定，只有在砌体开裂后，加固才会产生显著的效果。因此，我建议剪力墙的强度将由砖石的强度和墙与建筑物其他部件之间的连接强度产生。我的目标是开发一种基于这种观点来预测剪力墙强度的方法，并将结果与我自己的试验结果和文献报道的结果进行比较。一个特别令人感兴趣的主题是砖石墙，其中钢筋间隔很大，这在地震风险较低的地区很常见，但强度预测特别差。我将与澳大利亚的同事们合作。

Masonry is widely used in structures because of its aesthetic appeal and durability. Many of Canada's heritage structures are constructed of masonry and there is a need to conserve these. The National Building Code requires that these structures be assessed and brought up to modern standards, but assessment and rehabilitaton of these structures is not easy. The first part of the proposal therefore has two themes. The first is aimed at understanding the current state of a structure, typically after the long-term effects of creep (the slow increase in deformation with time under load) and degradation due to weathering: the combined effects of these factors can cause internal cracking, which in turn leads to distress of the structure. If the causes are understood, suitable remedies can be designed. The second theme deals with the use of cross-wall anchors to strengthen a wall, with the aim being to develop a way of predicting the best orientation of such an anchor to resist the loads expected in an earthquake, and thereby help the structure survive that event.The second part of the proposal deals with the in-plane shear resistance of masonry. We do not have a good understanding of how masonry resists this type of load, so there is wide divergence in estimates of shear strength when one reviews codes around the world. Nevertheless, many buildings employ masonry shear walls to resist such loads (generated by wind for example). Work supported by the previous grant showed that the primary strength of reinforced masonry is dominated by the strength of the masonry, and that the reinforcement has significant effect only after the masonry has cracked. Thus I am proposing that the strength of a shear wall will arise from the strength of the masonry and the strength of the connection between the wall and other components of the building. I aim to develop a methodology to predict shear wall strength based on this view, and to compare results with those from my own tests and those reported in the literature. A subject of particular interest is masonry walls where the reinforcement is spaced at wide intervals, common in areas of low seismic risk, but where strength predictions are particularly poor. I will collaborate with Australian colleagues.