Time-dependence, load relaxation and performance aspects of polyester resin grouted reinforcing bars in sedimentary rocks : Whittaker, B N; Grant, A S Proc International Conference on Structural Foundations on Rock, Sydney, 7–9 May 1980, P77–85. Publ Rotterdam: A A Balkema, 1980

Abstract

The present paper is an extension of previous work at nottingham and is specially directed towards time- dependence and load relaxation aspects of polyester resin grouted anchorages; the nature of the stress conditions associated with such anchorages has been observed to be of importance in relation to creep characteristics and this aspect is also discussed with respect to finite element analyses. Finally, localised fracturing arising from over- stressing conditions of reinforcing bar anchorages has been examined with reference to foundation engineering and excavation stability. The main conclusions drawn from the research findings reported are:- (1) the resin anchorage design formulae investigated with respect to bond creep show insignificant time- dependent displacement for loads up to the recommended maximum value given by each formula. (2) The u.K. Design formula, p = (l-50)/ 25 was found to have an appreciable inherent factor of safety against anchorage creep. (3) The design formula, p = 0.1.Sc.Pi.D.L was also found to be satisfactory regarding anchorage creep, but it does not possess such an inherently high factor of safety since unstable bonds were observed at 100-200 per cent of the recommended maximum design value. (4) The effect of load relaxation on a resin bonded bar followed by subsequent reapplication of loading (within the maximum design load) was found to have an insignificant effect on anchorage displacement. (5) The results from the computer predictions proved useful in relating stress concentrations to anticipated localised failure of the host rock.