1. Scope

The question of how best to join the many parts of a building structure isas old as building construction itself. Close examination of traditional stone,masonry and timber construction methods reveals the various and ofteningenious solutions developed to transfer load from one part of a structureto another. Modern building structures, whether made of wood, masonry,concrete or steel, likewise comprise interconnected parts. The connectionstake many forms.

In the design of concrete and masonry structures, attachments for theintroduction of concentrated loads as well as primary structural connectionsfor prefabricated components involve the use of fastening systems. Thesesystems are also increasingly employed in the repair and strengthening ofexisting structures. The term 'fastening system' as used here encompassesthe numerous methods and products currently available to facilitate theintroduction of concentrated loads into concrete and masonry structures. Thedemands of the building industry for more flexible and dependable constructionmethods, and efforts to improve the performance of building structures, havein recent years focused particular attention on the design, installation andperformance of fastening systems.

Fastening systems can be classified into cast-in-place systems and post-installed systems.

Cast-in-place systems are placed in the formwork before casting of theconcrete. The element to be fastened is connected to the embedded part eitherby the use of mechanical fasteners or by welding. Forces acting on cast-in-place systems are often distributed into the concrete member by means ofsuitably placed reinforcement.

Post-installed systems may be installed in masonry or hardened concrete.Advances in drilling technology have led to the development of increasinglydependable post-installed systems which are widely used in new constructionas well as for repair and strengthening work.

Each fastening system is by design suited for particular applications. Theselection of the appropriate system is based on engineering, economic andarchitectural considerations. Modern fastening technology offers architectsand engineers new versatility in that it provides systems for an increasinglywide range of uses and load levels. In order to choose the correct systemfor a given application and to design the fastening properly , comprehensiveknowledge of the broad range of fastening systems and their behaviour isrequired. However, because the design of a particular fastening may be criticalfor the behaviour of the structure in which it is used, it should be based onsound engineering models that describe the real behaviour under load as closelyas possible.

The present state of the art cannot quantitatively account for all factorsthat influence the load-bearing behaviour of fastening systems. Theoreticalmodels up to now have been based primarily on empirical test data. Theselimitations notwithstanding, this report compiles and compares the availableexperimental and theoretical research results concerning fastening systems.In a further report, a consistent approach based on current empirical andtheoretical models for the design of fastenings will be proposed, and the effectsof fastenings and the loads they carry on the behaviour of the structure towhich they are attached will be addressed.

The various test methods for the assessment of the proper functioning(suitability) of fastening systems are reviewed by the appropriate regulatorybodies, e.g. UEAtc, EOT A and ASTM.