THE PROBLEM
Low strength soils were encountered on the site required for container storage. The original construction thickness meant high costs and so savings were required to allow construction operations to take place and achieve the specified level of support for the final storage yard slab.
THE SOLUTION
A Mechanically Stabilised Layer incorporating two layers of Tensar geogrid in a well graded granular fill was designed to provide support to the initial construction operations and then to achieve the target bearing capacity required for permanent support to the concrete slab.
PROJECT DESCRIPTION
An area of container storage at Constanta Harbour on the Black Sea coast was to be extended. However, the ground conditions encountered in the proposed area of extension were of low strength. The finished surface of the storage area was to be a concrete slab requiring a level of support from the granular layer below of 200kN/m2 to support static loads from the containers.
Initial proposals were to excavate and replace the low strength soils which had typical CBR values of 2% (undrained shear strength of around 20kPa). However, contact was made with Tensar and an alternative to this expensive proposal was given. As well as being designed to provide permanent support to the slab, the Tensar MSL was designed to stabilise the area during construction operations where heavy construction vehicles were required to operate close to the low strength soils prior to the placement of the slab.
The Mechanically Stabilised Layer consisted of 2 layers of Tensar geogrid within a specifically designed thickness of well graded granular fill. Construction was successfully completed with the area becoming operational on schedule.
