FEASIBILITY STUDY OF GRS SYSTEMS FOR BRIDGE ABUTMENTS IN OKLAHOMA: INFLUENCE OF FACING AND AGGREGATE FILL ON PERFORMANCE (FHWA-OK-19-09 2262)

Abstract

This document reports a study where load-bearing capacity, deformations and construction speed of different GRS abutment models were compared in the laboratory at full scale. Six 8 ft-high, instrumented abutment models were constructed inside an outdoor test station in order to study the influences that the choice of facing type, reinforcement spacing, fill aggregate and compaction effort could have on the structural performance and construction speed of GRS bridge abutments in the field. Results of the study show that even though facing is not considered a structural member in GRS bridge abutments, the choice of facing can influence their structural performance and construction speed. Models with large block facing tested in this study (i.e. Models #2 and #3) were easier to compact during construction and consistently showed smaller deformations relative to the control model (Model #1). The influence of backfill compaction on the structural performance of GRS abutments is also demonstrated and quantified. It is shown that models built using the recommended compaction effort (i.e. Models #4 and #5) are significantly stiffer relative to their settlement under the loading beam (simulating bridge load) and facing lateral deformation when compared to the control model with reduced compaction effort (Model #1).