STRUCTURAL REPAIR OF REINFORCED-CONCRETE PORTAL FRAME

The Paper describes repairs carried out on a reinforced concrete porta l frame that had suffered damage over the previous 25 years as a resul t of alkali-silica reaction (ASR). This particular structure has been the subject of intense study since 1978 and several previous papers ha ve described its behaviour.3,5 The repair consisted of partly demolish ing and rebuilding the upper beam of the portal, while keeping the mot orway it supports open to traffic. Results are given for the shrinkage of the replacement concrete, and for depropping movements and surface strain measurements taken on the structure over the year following th e repair.