The Use Of Resin Adhesives In The Repair OfStructural Timber Members

Abstract

Structural adhesive bonding of metal parts began in the European aircraft industry in the early 1940's and is now regarded as well established. More recently, building and civil engineering applications have become accepted, with resin adhesives, principally but not exclusively epoxy-types, to the fore. Onerous repair applications have included the strengthening of existing concrete highway bridges. In the repair of timber structures, where metal inserts are commonly bonded into the parent material, resin adhesives have been known for over 20 years. However, only relatively recently has systematic research been conducted, aimed at establishing the durability of these repairs, and at formalising design procedures. Investigations have shown that epoxy resin adhesives can produce efficient durable repairs, provided that the repairs are well designed, detailed and performed under strict quality control guidelines. Resin repairs can be carried out either in-situ or to individual members in buildings which have been dismantled. Even though resins can produce highly efficient repairs to buildings, other considerations may apply. Care should be taken not to over-stretch the technology to a point where it is either uneconomic or it is conservationally undesirable, and alternative repair methods should always be considered. TRADA Technology Ltd (TTL) have undertaken case studies, where resin repairs have been carried out successfully. These include repairs to a 500 year old trussed rafter roof, which is also the subject of long-term monitoring.