Ultrasonic tomography of grouted duct post-tensioned reinforced concrete bridge beams
Ultrasonic tomography of grouted duct post-tensioned reinforced concrete bridge beams
复制标题
DOI：
10.1016/s0963-8695(00)00035-9
复制
发表时间：
2001-03-01
影响因子：
4.2
通讯作者：
Forde, MC
中科院分区：
文献类型：
--
作者：
Martin, J;Broughton, KJ;Forde, MC
英国的600座后张预应力桥梁以及世界上数量更多的此类桥梁的安全性和耐久性存在一些令人担忧的问题。本文所报道的研究工作目的是确定这些桥梁中金属预应力管道中的空洞情况。空洞会引发两类问题：(a)可能会有氯离子侵入，从而导致腐蚀；(b)梁内应力缺乏重新分布。在此背景下，首先确定后张预应力桥梁中的空洞程度是很重要的。
本文所报道的试验使用了超声层析成像新技术。对两根试验梁进行了检测：英国克劳索恩运输研究实验室（TRL）的一根10米长的梁和英国埃尔斯特里斯坦格科学与环境公司建造的一根短试验梁。TRL梁中的管道直径为40毫米，这比在后张预应力桥梁梁中通常遇到的要小。更常见的管道直径会是100 - 110毫米，保护层约为125毫米。埃尔斯特里斯坦格科学与环境公司的第二根试验梁包含直径为100毫米的管道。
所获得的飞行时间层析成像数据表明，这是一种研究后张预应力混凝土梁潜在的非常成功的方法。该方法有点耗时，所以应该与一种更简单的检测方法（例如声波冲击回波法，它可确定关注区域）结合使用。要检测的管道越小，检测点之间所需的距离就越小，这因此会大大增加检测时间。
（C）2001年由爱思唯尔科学有限公司出版
Some concern exists over the safety and durability of the 600 post-tensioned bridges in the UK, and the much larger number worldwide. The objective of the work reported herein was to identify voiding in the metallic tendon ducts in these bridges. Voiding can give rise to two sets of problems: (a) possible ingress of chlorides, which would cause corrosion; and (b) a lack of redistribution of stress within the beam. It was against this background that it was important to first of all identify the extent of voiding in post-tensioned bridges.The new technique of ultrasonic tomography was used for the trials reported in this paper. Two test beams were examined: a 10 m long beam at the Transport Research Laboratory (TRL), Crowthorne, UK and a short test beam constructed at Stanger Science and Environment, Elstree, UK. The ducts in the TRL beam were 40 mm in diameter. This is smaller than would normally be encountered in a post-tensioned bridge beam. A more usual duct diameter would be 100-110 mm with a cover of around 125 mm. The second test beam at Stanger Science and Environment, Elstree contained 100-mm diameter ducts.The time-of-flight tomography data obtained demonstrated that it is a potentially highly successful method of investigating post-tensioned concrete beams. The method is somewhat time consuming and so should be used in conjunction with a simpler testing method, e.g. sonic impact-echo, which identifies areas of interest. The smaller the ducts to be investigated, the smaller the required distances between testing stations. This therefore significantly increases the testing time. (C) 2001 Published by Elsevier Science Ltd.