Merit Engineering has provided complete geotechnical engineering services for construction of the project. Subsurface conditions at the Western Washington University’s Bellingham Campus are so unique that similar subsurface conditions are rarely found in other Bellingham areas. From our past experience in various projects on the campus, we knew that the soils at the campus area are mostly soft, loose and unsuitable for building foundations. Therefore, most of the buildings on campus are founded on bedrock including Haggard Hall and Wilson Library.
However, bedrock elevations are so extremely erratic that accurate prediction of profile of bedrock surface has never been achieved before. For instance, bedrock is present at one location at a shallow depth, two feet away, bedrock may be located at 20 or 30 feet deeper. This dramatic variation of bedrock elevation caused significant difficulties in construction cost estimate and schedules in the past. Expensive test borings further prohibited comprehensive field investigation to determined bedrock depths.
Other consultants have tried various methods such as seismic deflection/reflection, but none of them produced acceptable results. Merit Engineering proposed and used an innovative subsurface investigation method on this project, both economically and successfully determined bedrock profiles by combining test borings with cost-effective dynamic cone penetration test (DCPT). When the site was excavated, the exposed bedrock profile very closely resembles the bedrock profiles predicted by Merit Engineering both in shape and in elevation. Merit Engineering derived soil and especially rock properties and classifications, analyzed pile and footing capacities and foundation settlement.
The significant achievement in geotechnical engineering in this project is that for the first time, bedrock profile has been accurately predicted and thus the construction cost estimate for earthwork and construction schedule were ensured. We also provided construction earthwork inspection and soil testing services for this project.
Another geotechnical engineering excellence we have achieved in this project is our innovative approach for solving difficult technical problems for excavations adjacent to existing load columns within a existing building. With our sound geotechnical engineering knowledge and experience, we proposed an innovative approach using rock bolts and shotcrete instead of traditional concrete retaining wall avoiding excavation in an area within the load influence of the column footing. With our approach, safety in excavation adjacent to existing load columns was ensured and the need for temporary shoring support eliminated. Thus, our approach cost-effectively solved the problem.