Strength and Long-term Behaviour of Masonry Structures

砌体结构的强度和长期性能

• 批准号: 4210-2013
• 负责人: Shrive, Nigel
• 金额: $ 2.55万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=636417
• 关键词: Strength; Long; term; Behaviour; Masonry

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.

砌体由于其美观性和耐久性而广泛用于结构中。加拿大的许多遗产建筑是用砖石建造的，有必要保护这些建筑。《国家建筑法》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，建议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（在负载下变形随时间缓慢增加）和风化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开裂，从而导致结构的损坏。如果了解了原因，就可以设计适当的补救措施。第二个主题涉及使用跨墙锚来加固墙，目的是开发一种预测这种锚的最佳方向的方法，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。提案的第二部分涉及砌体的面内抗剪性。我们没有一个很好的理解如何砌体抵抗这种类型的负载，所以有很大的分歧，估计剪切强度时，审查世界各地的代码。然而，许多建筑物采用砌体剪力墙来抵抗这种荷载（例如由风产生的荷载）。由以前的补助金支持的工作表明，钢筋砌体的主要强度是由砌体的强度，钢筋只有在砌体开裂后才有显着的效果。因此，我建议剪力墙的强度将取决于砌体的强度以及墙与建筑物其他部件之间的连接强度。我的目标是开发一种方法来预测剪力墙强度的基础上，这一观点，并比较结果与那些从我自己的测试和文献报道。特别感兴趣的主题是砌体墙，其中钢筋间隔很宽，在地震风险低的地区很常见，但强度预测特别差。我将与澳大利亚同事合作。