Understanding the cracking behaviour of reinforced concrete elements subjected to the restraint of imposed strains

了解受外加应变约束的钢筋混凝土构件的开裂行为

基本信息

批准号：
EP/T004185/1
负责人：
John Forth
金额：
$ 85.56万
依托单位：
University of Leeds
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FT004185%2F1
关键词：
Understanding cracking behaviour reinforced concrete

项目摘要

Concrete is the most widely used construction material and is essential to the global programme of infrastructure updating (global estimate ~$100tn including UK National infrastructure plan £400bn) (www.oxfordeconomics.com/publication/open/283970). Excessive cracking due to restraint in poorly designed reinforced concrete (RC) structures is a widespread problem in the concrete construction industry and leads to many instances of costly remedial measures and delays. For example, a recent project in England was delayed due to excessive cracking caused by the restraint of imposed strains (from early thermal and shrinkage actions). Subsequent changes recommended by the applicants during the construction programme to limit the edge restraint of early thermal and shrinkage strain produced a real cost saving to the client of approximately £1.75M. The design guidance developed in this research will increase the performance and efficiency of new RC infrastructure as well as prolong the life of existing infrastructure through improved understanding of cracking. There are many situations when cracking due to the restraint of imposed deformations may be difficult to avoid. In fact, cracking from the restraint of early thermal movements (often referred to as 'non-structural' cracking) is the most common form of restraint induced cracking. In design, cracking is managed by the provision of reinforcement intended to distribute internal strains in such a way as to control the cracking pattern and limit crack widths. Current UK/EU design guidance on restraint induced cracking is encapsulated in EN1992-3:2006 and CIRIA report C660/766. The underlying design methodology in these documents has been used for over 30 years and is flawed. This is reflected in field observations identifying cracking patterns contrary to - and crack widths in excess of - those predicted by EN1992-3:2006. It is apparent that such 'non-compliance' cases result from erroneous basic assumptions; in particular; the boundary (restraint) conditions play a more significant role in determining the crack pattern than assumed in the current design guidance. The outcome of this research will provide practising engineers with the ability for the first time in three generations of UK/EU codes to correctly design RC elements for the restraint of short and long-term imposed strains. Planned dissemination routes will significantly aid the reduction in frequency and overall number of non-compliance cases, which currently result from the poor understanding of restraint induced cracking and affect all aspects of concrete construction in the UK.

混凝土是使用最广泛的建筑材料，对于全球基础设施更新计划至关重要（全球估计约 100 万亿美元，其中包括 4000 亿英镑的英国国家基础设施计划）（www.oxfordeconomics.com/publication/open/283970）。设计不良的钢筋混凝土（RC）结构的约束是混凝土建筑行业的一个普遍问题，并导致许多昂贵的补救措施和延误的情况，例如，英国最近的一个项目因这一原因而被推迟。由于施加应变的限制（来自早期热和收缩作用）而导致的过度开裂，申请人在施工计划期间建议进行后续更改，以限制早期热和收缩应变的边缘限制，从而为客户节省了大约大约的成本。这项研究开发的设计指南将提高新的 RC 基础设施的性能和效率，并通过加深对裂缝的了解来延长现有基础设施的寿命。在许多情况下，由于施加变形的限制而可能会出现裂缝。很难事实上，早期热运动约束引起的裂缝（通常称为“非结构性”裂缝）是约束引起的裂缝的最常见形式，在设计中，通过提供旨在分布内部的钢筋来控制裂缝。 EN1992-3:2006 和 CIRIA 报告中包含了当前英国/欧盟关于约束诱发裂纹的设计指南。 C660/766。这些文件中的基本设计方法已经使用了 30 多年，并且在现场观察中反映了这一点，该方法识别出与 EN1992-3:2006 预测相反的裂缝模式，并且裂缝宽度超过了这些预测。显然，这种“不合规”情况是由于错误的基本假设造成的，特别是边界（约束）条件在确定裂纹模式方面发挥的作用比当前设计中的假设更为重要；这项研究的成果将首次为实践工程师提供三代英国/欧盟规范中正确设计 RC 元件以限制短期和长期施加应变的能力。不合规案例的频率和总数减少，这是目前由于对约束引起的裂缝了解不足造成的，并影响了英国混凝土施工的各个方面。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Understanding the cracking behaviour of reinforced concrete elements subjected to the restraint of imposed strains

了解受外加应变约束的钢筋混凝土构件的开裂行为

DOI：
发表时间：
2021
期刊：
影响因子：
0
作者：
Elwakeel;A
通讯作者：
Elwakeel;A

Imposed loading effects on reinforced concrete walls restrained at their base

对钢筋混凝土墙施加的荷载效应在其底部受到限制

DOI：
10.1680/jstbu.17.00179
发表时间：
2020
期刊：
Proceedings of the Institution of Civil Engineers - Structures and Buildings
影响因子：
0
作者：
Shehzad M
通讯作者：
Shehzad M

Current Perspectives and New Directions in Mechanics, Modelling and Design of Structural Systems

结构系统力学、建模和设计的当前观点和新方向

DOI：
10.1201/9781003348443-204
发表时间：
2022
期刊：
影响因子：
0
作者：
Ridley I
通讯作者：
Ridley I

INDUCED CRACKING IN EDGE RESTRAINED WALLS - FEA PARAMETRIC STUDY

边缘限制墙中的诱发裂纹 - 有限元分析参数研究

DOI：
发表时间：
2022
期刊：
影响因子：
0
作者：
Elwakeel A
通讯作者：
Elwakeel A

Experimental assessment of crack prediction methods in international design codes for edge restrained walls

DOI：
10.1016/j.istruc.2023.06.087
发表时间：
2023-09
期刊：
Structures
影响因子：
4.1
作者：
Karim El Khoury;Imogen Ridley;R. Vollum;J. Forth;M. Shehzad;A. Elwakeel;N. Nikitas;B. Izzuddin
通讯作者：
Karim El Khoury;Imogen Ridley;R. Vollum;J. Forth;M. Shehzad;A. Elwakeel;N. Nikitas;B. Izzuddin