Abstract

The paper investigates the flexure behaviour and cracking pattern of reinforced concrete beams utilizing steel and GFRP reinforcement using a judicious combination of non-destructive testing techniques of Acoustic Emission (AE) and Digital Image Correlation (DIC). AE parameters including amplitude, number of AE hits, average frequency (AF) and rise angle (RA) successfully correlate with cracking initiation and its progression in steel reinforced concrete (RC) and GFRP RC beams. The plot between AF-RA value effectively classifies the different failure modes in the two types of beams. Simultaneous drop in AF and a significant jump in AE duration at the same instant give a fair indication of critical failure points. AE-XY plots and longitudinal strain profiles obtained from DIC give a real-time representation of progressive AE activity and strains respectively. While AE is proposed to characterize the onset and propagation of the cracking pattern and mode of failure in the beams, DIC assists to visualize the displacement and strain fields while highlighting discontinuities in the displacement field. The work is aimed at developing a health monitoring strategy for RC beams with steel or GFRP bars which is in-situ, non-invasive and provides pre-emptive warning in real-time so that catastrophic failures can be completely avoided.

摘要

本文采用声发射 (AE) 和数字图像相关 (DIC) 无损检测技术的明智组合，研究了使用钢和 GFRP 钢筋的钢筋混凝土梁的弯曲行为和开裂模式。AE 参数包括振幅、AE 命中次数、平均频率 (AF) 和上升角 (RA) 成功地与钢筋混凝土 (RC) 和 GFRP RC 梁的开裂起始及其进展相关。AF-RA 值之间的图有效地分类了两种梁的不同失效模式。AF 的同时下降和 AE 持续时间的显着增加在同一时刻给出了关键故障点的公平指示。从 DIC 获得的 AE-XY 图和纵向应变曲线分别给出了渐进式 AE 活动和应变的实时表示。虽然提出了 AE 来表征梁中开裂模式和失效模式的发生和传播，但 DIC 有助于可视化位移和应变场，同时突出位移场中的不连续性。这项工作旨在为钢筋或 GFRP 钢筋的 RC 梁制定一种原位、非侵入性的健康监测策略，并实时提供先发制人的警告，从而完全避免灾难性故障。DIC 有助于可视化位移和应变场，同时突出位移场中的不连续性。这项工作旨在为钢筋或 GFRP 钢筋的 RC 梁制定一种原位、非侵入性的健康监测策略，并实时提供先发制人的警告，从而完全避免灾难性故障。DIC 有助于可视化位移和应变场，同时突出位移场中的不连续性。这项工作旨在为钢筋或 GFRP 钢筋的 RC 梁制定一种原位、非侵入性的健康监测策略，并实时提供先发制人的警告，从而完全避免灾难性故障。