Enhancement of the behaviour of reinforced concrete dapped end beams including single-pocket loaded by a vertical concentrated force

IF 0.7 Q3 ENGINEERING, MULTIDISCIPLINARY Engineering Review Pub Date : 2023-01-01 DOI:10.30765/er.1853

Qasim M. Shakir, Sara A. Hamad

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引用次数: 2

Abstract

In precast building construction, some beams are designed to support one or several concentrated loads resulting from the reactions of the attached cross beams. Consequently, the pocket beams without or with dapped ends may represent one of the innovative solutions to constitute the joints between the two attached members. In the present research work, the behaviour of dapped end beams that included rectangular opening loaded with in-plane force, have been investigated. Several detailing have been proposed, in addition the vertical stirrups, to improve the strength of the opening region including the use of steel fibre concrete (SFC),Configuration of the inclined crossed bars, jacketing with steel plates and the composite section technique with two arrangements of the reinforcement of the dapped end . Ten specimens have been tested under gradually increased vertical static loading. The tested specimens are categorized into two sets based on the configuration of dapped end reinforcement. Two variable have been considered which are the strengthening configuration of the opening region and the configuration of the dapped end reinforcement. The response has been discussed in terms several indicators including, the cracking and failure loads, maximum deflection, mode of failure, load-deflection curves, crack patterns, crack width, to recognize the optimum strengthening proposal of the opening. Results revealed that using the inclined steel bars (modified arrangement) yield better response than the conventional (standard) reinforcement (vertical stirrups) within the dapped end. For beams with pockets strengthened with crossed inclined bars, failure load enhanced in range of (8.5-11%) whereas the enhancement was in ranged in (8-10%) for the steel SFC method. Moreover, an improvement by about (11-13%) in load capacity increased when the jacketing with steel plates was applied. The maximum improvement was obtained when using the embedded rolled section within the opening with values of (21-23%).

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增强钢筋混凝土端梁的性能，包括单袋垂直集中力加载

在预制建筑结构中，一些梁被设计用来支撑一个或几个由连接的横梁的反作用力产生的集中荷载。因此，无端或端部有缺口的口袋梁可以代表构成两个连接构件之间的连接的创新解决方案之一。在本研究工作中，研究了面内力作用下带矩形开口的端梁的受力特性。除了垂直箍筋外，还提出了一些细节，以提高开口区域的强度，包括使用钢纤维混凝土(SFC)，倾斜交叉杆的配置，钢板护套和复合截面技术，两种安排的补强端。10个试件在逐渐增加的垂直静载荷下进行了试验。根据端部配筋的配置，将试件分为两组。考虑了两个变量，即开口区域的强化构型和缺口端钢筋的构型。从开裂和破坏荷载、最大挠度、破坏模式、荷载-挠度曲线、裂缝模式、裂缝宽度等几个指标对响应进行了讨论，以确定开口的最佳加固方案。结果表明，斜筋(改进布置)比常规(标准)配筋(垂直箍筋)在搭接端产生更好的响应。对于带有斜杆交叉加固袋的梁，破坏荷载的增强范围为8.5-11%，而钢的SFC方法的增强范围为8-10%。此外，当采用钢板护套时，承载能力提高了约(11-13%)。在开口内采用预埋轧制截面时，改善效果最大，改善值为(21-23%)。

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Engineering Review ENGINEERING, MULTIDISCIPLINARY-

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1.00

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期刊介绍： Engineering Review is an international journal designed to foster the exchange of ideas and transfer of knowledge between scientists and engineers involved in various engineering sciences that deal with investigations related to design, materials, technology, maintenance and manufacturing processes. It is not limited to the specific details of science and engineering but is instead devoted to a very wide range of subfields in the engineering sciences. It provides an appropriate resort for publishing the papers covering prior applications – based on the research topics comprising the entire engineering spectrum. Topics of particular interest thus include: mechanical engineering, naval architecture and marine engineering, fundamental engineering sciences, electrical engineering, computer sciences and civil engineering. Manuscripts addressing other issues may also be considered if they relate to engineering oriented subjects. The contributions, which may be analytical, numerical or experimental, should be of significance to the progress of mentioned topics. Papers that are merely illustrations of established principles or procedures generally will not be accepted. Occasionally, the magazine is ready to publish high-quality-selected papers from the conference after being renovated, expanded and written in accordance with the rules of the magazine. The high standard of excellence for any of published papers will be ensured by peer-review procedure. The journal takes into consideration only original scientific papers.