Anchorage of reinforcement bars in Hennebique structures

Abstract

A crucial aspect of the assessment of existing r.c. structures is the efficiency of the anchorage of the bars. This is specifically true for historic pre-code concrete, when the basic principles of r.c. structures were either not well understood nor set in a code practice. This is true also for the Hennebique-type structures that make use of a shape of the anchorages that falls outside modern codes. In spite some tests performed by Hennebique and his concessionaries at the times of their activity, it seems that nobody noticed that the shape of anchorages was a weak point of their system.In this paper a series of tests have been performed on two typical Hennebique anchorages: fish-tail ends and plate stirrup bends. Tests have been performed using a Hennebique-type concrete, with similar sieve curve, low to medium strength, large round aggregates and an excess of water. The outcomes outline the collapse mechanisms of these anchorages and allow to set assessment type formulas that may be of common use in practical applications. It has to be noted that direct verifications, as large as possible, are needed when assessing a pre-code structures due to the lack or standards that characterizes pre-code r.c. structures.