FOUNDATION DESIGN/IMPROVEMENT OF SUBSURFACE CONDITIONS

Foundation design requires a thorough understanding of structural loads and settlement limits as well as the characteristics of soil and rock at the construction site. D'Appolonia routinely plans and executes site exploration programs to identify key soil and rock strength parameters and to collect other key data related to the depth of the ground water table and variation of subsurface stratigraphy over the site. We design foundations that meet design requirements in a cost-effective manner. Often it is economically prudent to improve site conditions prior to construction. We have developed and implemented programs for many types of foundation improvement technologies including dynamic consolidation, stone columns, soil mixing, and grouting.


Installation of stone columns using vibro-compaction methods.



Some project profiles for D'Appolonia projects involving foundation design and improvement of subsurface conditions are provided in the following:


EXAMPLE PROJECTS


Coal Terminal Foundation Improvements (PDF-1143K)

D'Appolonia performed foundation evaluations for a 100-acre coal transhipping facility adjacent to the James River in Newport News, Virginia. The site was underlain by a 25-foot-thick layer of sand, silt and clay dredged from the river and placed by hydraulic filling over sand sediments. Unequal placement of coal in piles caused severe local lateral ground displacements and intolerable distortion of rail tracks. D'Appolonia developed a design to eliminate the problem utilizing 300 stone columns installed to an average depth of 20 feet.

Stabilization of Undermined Building Site at College (PDF-1704K)

D’Appolonia was retained to perform foundation investigations for expansion of a recreation building complex that was undermined. D'Appolonia's project responsibilities included determination of the extent of undermining; developing remedial measures; preparing design drawings, construction specifications and bid documents; screening potential construction contractors; selecting grout materials compatible with mine water chemistry; and providing construction management for all phases of a mine filling program.

Ground Improvement Using Dynamic Consolidation (PDF-838K)

D’Appolonia was retained by a client seeking to build a 90-MW cogeneration plant near Yuma, Arizona. The proposed plant site was characterized by loose to medium dense, well-rounded sands to a depth of 20 feet below the ground surface. Surficial soils needed to be compacted sufficiently to support a boiler, turbine generator, and fuel storage tanks. D’Appolonia developed and implemented a soil consolidation program that involved dropping a 13-ton weight from a height of 82 feet using a large crane.

Foundation Recommendations for Microwave Towers (PDF-231K)

D’Appolonia directed subsurface explorations and prepared recommendations for the design of foundations for 37 microwave communication towers for Allegheny Power Systems. The 3-legged and 4-legged unguyed towers ranged in height from 30 to 280 feet. The project sites were located in five states and exhibited widely varying subsurface conditions.


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