We received seven submittals for the Outstanding Project Awards competition this year, all of which were very interesting and detailed. Of course, this makes it hard for the committee to pare them down to one winner. Fortunately, the committee was able to categorize the projects into medium and large sized projects and choose one from each. The committee consisted of Directors Craig Hill and Joe Haro, and was chaired by Dave Colbaugh, CGEA Immediate Past President.
This is as good a time as any to mention that before submitting a project next year; please review all of the rules regarding the competition. Of particular note is that the committee will only consider completed/constructed projects. We had several submittals that included exhaustive investigative reports but the projects were only in the preliminary stage. As we all know, the actual construction of a project is the extension of the investigative work. This makes it all the more interesting to see the actual conditions that were encountered and what needed to be changed/augmented to actually get the project off the ground, so to speak.
The winner of this year’s mid-size project award is Wallace Kuhl Associates and the large project award went to TerraCosta Consulting Group. Congratulations!
2005-2006 Mid-Size Project Award Winner
CalPERS Headquarters Expansion
Wallace-Kuhl & Associates, Inc.
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The CalPERS project consisted of a six-story, above ground structure with two stories below ground for parking. This is the first structure in this area to accommodate a two level below ground installation. It was the below ground challenges and remediation that were of particular interest. Due to its close proximity to the Sacramento River, ground water was perhaps the major obstacle since it was both high (15 feet below street grade) with significant seasonable fluctuations. Alluvial soils added to the complexity of the site. While dewatering was obvious, the affect to the proposed and buildings in close proximity was critical. A slurry cut-off wall served as both a ground water barrier and shoring support for the structure excavation. The wall was constructed to a depth of 120 feet below the adjacent ground surface.
Foundation support for the structure consisted of 17-inch diameter, 45-feet long aurgercast piles which were drilled through the alluvium and seated in an underlying cemented soil stratum. To account for potential buoyancy affects in the event that the cut-off wall was breached, tiedown anchors were installed to depths of 50 feet below the lower parking level floor slab.
Wallace Kuhl was the geotechnical engineer of record and provided design and on-site support during the installation of all ground related improvements including the cut-off wall, sheet pile installation, tieback installation and stressing, augercast pile load installation and load testing and tiedown anchor installation and testing.
| Owner: |
California Public Employee’s Retirement System |
| Geotechnical Engineer: |
Wallace Kuhl Associates, Inc. |
| Civil Engineer: |
Nolte Associates, Inc. |
| Structural Engineer: |
CYS Structural Engineers |
| Architect: |
Kendall/Heaton Associates |
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2005-2006 Large Project Award Winner
The Point
TerraCosta Consulting Group, Inc.
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“The Point” is a roughly 15 acre commercial property which supports three office buildings and appurtenant parking. The site is roughly 100 feet in elevation above and west of Interstate 15 in the Rancho Bernardo area of San Diego. A Keystone Wall was constructed during the original construction to accommodate the easterly extension of the level pad area.
Subsequent to the development of the site, a series of cracks developed in the pavement area above and behind the Keystone wall. Additional cracks were observed well beyond the area of influence of the wall construction/backfill and several detailed geotechnical investigations ensued to evaluate the subsurface conditions. Included in these investigations were the excavation of 90 test borings and the installation and monitoring of 18 piezometers and slope inclinometers, several of which indicated movement 40 feet below the base of the Keystone wall.
TerraCosta developed repair/stabilization techniques for both the Keystone Wall as well as the global stability of the site. The stabilization of the Keystone wall consisted of a tied-back structural concrete skin. A total of 186 tie back anchors were installed in this system. Complicating matters in the global stabilization was the existence of Interstate 15 at the toe of the slope which was in the process of design consideration for widening. The final stabilization design was developed under the scrutiny of CATRANS as well as other local governing agencies. The design consists of a tied-back grade beam “wall” over 1,500 feet long which varies from 12 to 42 feet in height. A total of 974 tie-backs were installed as part of this system.
TerraCosta acted as both geotechnical and civil engineer of record on the project producing all of the plans and specifications for the stabilization efforts.
| Owner: |
Legacy Partners Commercial, Inc. |
| Geotechnical Engineer: |
TerraCosta Consulting Group, Inc. |
| Civil Engineer: |
TerraCosta Consulting Group, Inc. |
| Structural Engineer: |
TY Lin International |
| Architect: |
Schmidt Design Group (Landscape) |
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