Vertical Deformation of Multi-Axial Geogrid Stabilized Working Platform Design Using Conventional Techniques and Back-Analyses Using Composite Approach

ABSTRACT: Presented is a comparison of the estimated vertical deformation using conventional techniques for the design of a multi-axial geogrid stabilized working platform to the results of back-analysis using actual deformation measurements during operation. Satisfying very stringent criteria for allowable load and differential settlement was the major challenge in designing this working platform for a large ringer crane. Platform design and construction was 1.8 m thick and composed of five layers of multi-axial geogrid and aggregate material. The vertical deformation back-analyses of the platform incorporated a hybrid adaptation of a composite material model for the geogrid and aggregate layers. Composite material modeling considers the interaction of geogrid and aggregate which results in enhancement of the strength of the composite material, and this strength enhancement is not considered in typical models for stabilized aggregate layer design. Although the back-analyses were not rigorous finite element calculations, the hybrid adaptation of the geogrid/aggregate composite material used with a conventional deformation analysis approach provided results significantly less conservative and more closely predicted the actual deformation measurements. The comparison of vertical deformation modeling and back-analyses to initial pre-construction design provides important insight into material modeling and numerical techniques.