Cyclic load capacity and endurance limit of multi-ring masonry arches
Cyclic load capacity and endurance limit of multi-ring masonry arches
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多环砌体拱的循环承载能力及耐久性极限
DOI：
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发表时间：
2004
期刊：
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通讯作者：
Jinyan Wang
中科院分区：
文献类型：
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作者：
C. Melbourne;A. Tomor;Jinyan Wang
索尔福德大学对多环砌体拱进行了一系列大规模测试，以评估其耐久性极限和循环荷载能力。多环拱占英国桥梁存量的很大一部分，其中大部分已有 100 多年的历史。由于公路和铁路交通的重量不断增加，需要预测其预期寿命和循环负载下的容量。尽管已经对砌体拱进行了许多小型和大型试验，但大多数都是在静载荷作用下进行的。然而，在循环负载下的负载能力方面所做的工作却很少。目前的工作需要在不同荷载水平的循环荷载下进行一系列 3m 跨度两环和 5m 三环砖砌拱测试，直至失效。负载循环次数、损坏传播和失效模式已被记录，并且已考虑对此类拱的耐久性极限的建议。还进行了一些静态加载试验以进行比较。虽然静态载荷下拱的经典失效模式是四铰链机构，但当前测试系列中循环载荷下的所有拱都因拱中间部分的环分离而失效。因此，循环载荷会影响失效模式。已经讨论了一些描述故障原因的理论方法。 C. 墨尔本，A.K. Tomor 和J. Wang 2 1 背景和背景 英国有超过40000 座砖石拱桥，需要承受不断增加的荷载和不断增加的交通量。桥梁桩基必须不会受到这些荷载状态变化的不利影响，并且必须采用适当的评估、修复和加固技术。在过去的十年里，英国和国外开展了广泛的研究计划，考虑了砖石拱门行为的各个方面。结论之一是，多环砖砌拱桥中的环分离（分层）是一个主要问题，因为它的存在降低了桥梁的承载能力。然而，迄今为止所有的实验工作都是在单调荷载条件下进行的，人们担心在循环荷载下，这些现象可能会因砖砌体的逐渐恶化而加剧。本文报告的当前研究解决了一些问题并提供了一些指导。 2 材料性能 整个测试过程中均使用“A”级工程砖（215 x 102.5 x 65mm），平均抗压强度为 154N/mm，密度为 23.7 kN/m。采用1:2:9（水泥：石灰：砂）砂浆，平均抗压强度为1.7N/mm，密度为15.5 kN/m3。砖砌体的平均抗压强度为25N/mm，密度为20kN/m。
A series of large-scale tests have been carried out at the University of Salford on multiring masonry arches to assess their endurance limit and cyclic load capacity. Multi-ring arches represent a significant proportion of the UK bridge stock most of which is over 100 years old. Due to the increasing weight of road and rail traffic their life expectancy and capacity under cyclic loading needs to be predicted. Although there have been a number of small and large scale tests carried out on masonry arches, most of them have been under static loading. There has been however very little work done on load capacity under cyclic loading. The present work entails a series of 3m span two-ring and 5m three-ring brickwork arch tests under cyclic loading at various load levels until failure. The number of load cycles, damage propagation and failure modes have been recorded and recommendations to an endurance limit of such arches have been considered. A few tests under static loading have also been carried out for comparison. While the classical mode of failure of arches under static loading is the four-hingemechanism, all arches within the present test series under cyclic loading have failed by ring separation over the middle section of the arch. Cyclic loading therefore influences the mode of failure. Some theoretical approaches describing the causes of failures have been discussed. C. Melbourne, A.K. Tomor and J. Wang 2 1 BACKGROUND AND CONTEXT There are over 40000 masonry arch bridges in the UK which are being called upon to carry ever increasing levels of loading and increasing volumes of traffic. It is imperative that the bridge stock is not adversely affected by these changes in the loading regime and that appropriate assessment and repair and strengthening techniques are available. Over the past 10 years there has been an extensive programme of research in the UK and abroad which considered various aspects of masonry arch behaviour. One of the conclusions has been the identification of ring separation (delamination) in multi-ring brickwork arch bridges as a major source of concern because its presence reduces the load carrying capacity of the bridge. However, all the experimental work to date has been under monotonic loading conditions and there is a fear that under cyclic loading these phenomena may be aggravated by the incremental deterioration of the brickwork. The current research reported herein addresses some of the issues and offers some guidance. 2 MATERIAL PROPERTIES Class “A” Engineering bricks (215 x 102.5 x 65mm) were used throughout the tests with an average compressive strength of 154N/mm and density of 23.7 kN/m. 1:2:9 (cement:lime:sand) mortar was used with an average compressive strength of 1.7N/mm and density of 15.5 kN/m3. The average compressive strength of the brickwork was 25N/mm and the density 20 kN/m.