Retaining walls: report on discussion

The Chairman discussed the anchorinq effect of different types of reinforcement and described the results of research work at Sheffield University into the performance of 2m lonq reinforcinq elements buried in a tank with a surcharge capacity of 200 kN per square metre.

In the case of steel strip reinforcement, the ultimate pulling resistance was found to be directly proportional to the overburden pressure. With smooth steel strip failure could be induced and the steel strip pulled out after very few cycles. The use of ribbed steel strip increased the number of cycles to failure by a factor of

10. A very marked difference was noted in the performance of Tensar SR2, The Tensar SR2 was subjected to 100,000 load cycles with the pullinq load varyinq from between the limits of 70 per cent of ultimate and zero. The results show that the system became stiffer and stiffer as the number of load cycles increased. Polymer grid reinforcement was therefore believed to provide excellent performance if subjected to severe repeat loadings, as one might well get in bridqe abutments.