Western Washington University Communications Facility and Student Recreation Center

wwu-com5Merit Engineering received the “Best in State” Gold Award for Technical Value to the Engineering Profession (Engineering Excellence Awards – 2004) from the American Council of Engineering Companies of Washington (ACEC Washingtion). The following paragraph was taken from the ACEC web site:

Gold Award for Technical Value to the Engineering Profession

Merit Engineering, Inc. – Western Washington University Communications Building and Student Center – Bellingham

wwu-com7Western Washington University’s planned Student Recreation Center required construction on an erratic bedrock subsurface that would most likely cause construction change orders and cost overruns. With impressive mathematic derivations, Merit Engineering recalculated the capability of drilled shaft and rock socket pillars to more closely match field conditions, proving their technical and economical feasibility. The firm’s new equations set an important baseline calculation for other projects to effectively use drilled shaft and rock socket pillars, and enabled Western Washington University to complete the project under budget and without construction change orders.

wwu-com2Merit Engineering conducted a geotechnical investigation of Western Washington University’s South Campus. The focus of the study included complete geotechnical analysis of surface and subsurface soil and groundwater conditions, as well as a feasibility study of foundation options and recommendations, with an emphasis on determining the strength properties of the bedrock beneath the University. The Student Recreational Center is a multi-story building with a footprint of 80,000 sq. ft., while the Communications building is five stories tall with a two story basement and a footprint of about 100,000 sq. ft.

The proposed Student Recreational Center and a Communications Building was to be anchored to bedrock, but the bedrock at this location is found at various depths across campus. The bedrock profile is so erratic that in one area it may be found 10′ below the surface, and then 10′ away, the bedrock may be 30′ feet below the surface. This kind of bedrock profile is common in the Chuckanut Formation, which consists of various layers of young sedimentary rocks that have been highly folded and faulted.

wwu-com4Two methods were used to explore the subsurface. Standard Penetration Tests (SPT) were conducted in order to determine the depth to unweathered bedrock and rock coring was carried out with a 6″ auger drilling down to the unweathered bedrock and then using a mud rotary drilling system to bore into the bedrock and extract 5-ft long, 2.5″ diameter core sections of the rock. The bedrock was sampled in sixteen locations, with each core being 10′ long. The rock cores were analyzed to determine the unconfined and confined compressive strength, shear strength,

Young’s modulus, Poisson’s ratio, tensile strength, and were classified using the CSIR Geomechanics Classification of Jointed Rock Masses. The cores were also examined to determine the joint spacings, condition of the joints, dip and wwu-com6strike of the joints, and dip and strike of any visible bedding. Using the information from our investigation and previous investigation, Merit Engineering was able to accurately map the depth to bedrock under both buildings using 200 data points. With this much data, a precise representation of the subsurface conditions was rendered.

For this particular project, a high capacity piles known as “shaft with rock socket” foundation was recommended. The advantage of this foundation system lies in that the quality of pile is better assured than a driven pile because it is observable when unweathered, competent bedrock is reached and it has 2-3 times more bearing capacity than normal end-bearing on rock piles. With knowledge of the bearing capacity of the bedrock and specified strengths of the concrete used for the piles, these piles will wwu-com3absorb the weight of the structure and provide necessary integrity to the foundation. This procedure involved drilling 18-inch diameter shafts socketed in unweathered, competent bedrock. Ultimately, almost 300 piles were installed by drilling through the clay subsurface and into the bedrock.

Merit Engineering was also rigorously involved in the construction phase of the project. Merit was there to observe drill pile installations, groundwork, and any backfill and/or structural fill placed at the site. We provided laboratory work and material testing services throughout the construction phase.