The management of post-tensioned bridges - the client's perspective

摘要

In the course of the major upgrading and extension of highway networks in the last fifty years, the use of post-tensioned concrete has been found to be an economically competitive form of construction, and enables concrete to be used for bridges with significantly longer spans than was previously possible using untensioned reinforced concrete. Despite the use of design procedures and construction practices that have been developed over many years, unexpected deterioration of post-tensioned concrete structures has become a matter of major concern in many countries. One effect of this deterioration, often identified after a considerable time, is that significant expenditure has to be diverted from capital works to the management of those structures. This paper contains a review of the need for inspections of post-tensioned bridge structures to be accompanied by well targeted testing, carried out by well qualified dedicated technical staff, with results being interpreted by experienced engineers. The condition of these structures can then be accurately assessed and the extent, severity and causes of any deterioration. Any appropriate management actions can then be identified with confidence.Case studies are presented and the implications for bridge owners are discussed in the light of the results of the investigations carried out to post-tensioned bridges.