Instrumentation of a reinforced earth wharf Newcastle, N. B.

Abstract

The predominant use of reinforced earth has been in dry land retaining structures. Recent research has led to the development commercial applications of reinforced earth walls constructed partially "in the wet". Previous marine applications of reinforced earth were restricted to shore erosion protection structures (breakwalls) constructed in shallow water, taking advantage of low tide. The Newcastle wharf represents the "next generation" of reinforced earth marine walls. Since there have been few structures built, there are presently very little data available on their performance. The Newcastle wharf was therefore instrumented in order to measure its structural performance as part of a research project undertaken by the U. N. B. Civil Engineering Department. Specifically, the purpose was to generally compare the measured performance of the structure with the field performance of reinforced earth walls constructed "in the dry", which is reported extensively in the literature. A summary of the unique construction techniques used for the Newcastle wharf, an overview of the previous research in the study area, and a brief description of analysis and design procedures for reinforced earth walls is also presented herein. The basic instrumentation consisted of (i) strain gauges on three reinforcing strips to monitor the tensile stress distribution, (ii) a total load pressure cell in the backfill to measure the vertical overburden pressure, and (iii) an inclinometer casing installed close to the wall face in order to allow for the use of an inclinometer in determining the wall deflection profile. An extensive monitoring program, from June to October 1991, was implemented after the instrumentation. The results indicate that the structural performance of the wharf is similar to the structural performance of dry land retaining structures. However, it is recommended that further research on this topic be conducted, due to the need for a large database to make a generalised comparison.