Moment redistribution capacity in prestressed concrete continuous beams

IF 1.8 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Magazine of Concrete Research Pub Date : 2024-08-10 DOI:10.1680/jmacr.24.00138

Da Luo, Bing Li

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Abstract

In prestressed concrete continuous beams, building code provisions often allow for a reduction in the moment at a critical section (calculated through elastic analysis). This reduction is permitted as long as the moments in all other sections are adjusted to maintain equilibrium and support the designated loads. However, the allowable moment redistribution percentage (MRP) for prestressed concrete beams (PCBs) remains a topic of debate. Many codes currently assign a similar MRP limitation to both PCBs and reinforced concrete members. This approach might be over-simplistic for PCBs due to their unique behaviour. This paper proposes a method for identifying the maximum available MRP. An in-depth study was conducted on the maximum available MRP of PCBs based on calibrated finite element models. The results show that the parameters such as passive reinforcement ratio, steel yield strength, slenderness ratio, eccentricity of prestressing tendons, concrete grade, and load pattern, which were not considered in the codes, influence the maximum available MRP to an extent. Using the same permissible MRP as reinforced concrete beams may be inappropriate. Finally, an equation is proposed to estimate the maximum available MRP for PCBs.

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预应力混凝土连续梁的弯矩再分布能力

在预应力混凝土连续梁中，建筑规范通常允许减少关键截面的弯矩（通过弹性分析计算）。只要调整所有其他截面的弯矩以保持平衡并支撑指定荷载，就允许减少弯矩。然而，预应力混凝土梁（PCB）的允许弯矩重分布百分比（MRP）仍然是一个争论不休的话题。目前，许多规范对 PCB 和钢筋混凝土构件都规定了类似的 MRP 限制。由于多氯联苯的独特行为，这种方法对于多氯联苯来说可能过于简单。本文提出了一种确定最大可用 MRP 的方法。根据校准的有限元模型，对多氯联苯的最大可用 MRP 进行了深入研究。研究结果表明，规范中未考虑的被动配筋率、钢屈服强度、细长比、预应力筋偏心率、混凝土等级和荷载模式等参数在一定程度上影响了最大可用 MRP。使用与钢筋混凝土梁相同的允许最大可承受力可能并不合适。最后，提出了一个估算多氯联苯最大可用 MRP 的公式。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Magazine of Concrete Research 工程技术-材料科学：综合

CiteScore

4.60

自引率

11.10%

发文量

102

审稿时长

5 months

期刊介绍： For concrete and other cementitious derivatives to be developed further, we need to understand the use of alternative hydraulically active materials used in combination with plain Portland Cement, sustainability and durability issues. Both fundamental and best practice issues need to be addressed. Magazine of Concrete Research covers every aspect of concrete manufacture and behaviour from performance and evaluation of constituent materials to mix design, testing, durability, structural analysis and composite construction.