Title: Local Bond-Slip Relationships by Means of the Moire Method

Author(s): T.P. Tassios and E.G. Koroneos

Publication: Journal Proceedings

Volume: 81

Issue: 1

Appears on pages(s): 27-34

Keywords: bonding; bond stress; composite construction (concrete and steel);cyclic loads; loads (forces);slippage; strains;stresses.

DOI: 10.14359/10637

Date: 1/1/1984

Abstract:
An overall optical method (the differential Moire method)is used to visulaize the full field of stresses, strains, and slips at the interface between concrete and a steel tensioned from outside. The interface is simultaneously loaded in the transverse direction by a compressive force. From the induced mechanical interference pattern between a 20 lines per mm grating, glued on the specimen, and an external (underformed)grating, the longitudinal displacement s is determined at grid points on the interface. Similarly, the steel strains are determined, allowing for steel stress evaluation. Consequently, by differentiation of the steel stress diagrams, local bond stresses t are evaluated. By compliation of coupled t and s values, a local-bond verses load-slip curve is found, which constitutes abasic tool for analytical treatment of a series of bond degredation problems, under both monotonic and cyclic loading.