The design-build project involved the widening, reconstruction, and resurfacing of 3.6 miles of Route 50 from Sully Road (Route 28) to Poland Road (Route 628). Construction included adding two lanes to the roadway, two new single-span bridges, lengthening and adding turn lanes, six stormwater management (SWM) ponds, a shared-use path, and a 500-foot long retaining wall.
GeoConcepts provided geotechnical engineering design and construction inspection and testing services. The field investigation was challenging to complete along the congested roadway so GeoConcepts carefully coordinated schedules with the traffic control and drilling crews to complete the investigation safely and efficiently, minimizing disruptions to roadway operations.
Subsurface conditions were investigated by drilling a total of 274 test borings. Due to the presence of unsuitable soil at expected subgrade elevations, GeoConcepts developed an unsuitable soils table based on station numbers that provided expected undercut depths, and possible alternative remedial measures to limit undercuts. During construction, GeoConcepts was responsible for documenting the removal of this unsuitable material. Due to their knowledge of the local subsurface conditions which indicated the potential for sulfate attack for poured in place concrete, GeoConcepts conducted additional laboratory tests to determine if excessive sulfate was present in the soils and made recommendations accordingly.
GeoConcepts provided its design recommendations in the form of project memoranda as the field investigation was completed to expedite the design process for their fellow team members. GeoConcepts personnel were responsible for obtaining the subsurface data, quickly evaluating the engineering properties and conducting the engineering analyses so that they could provide design recommendations to meet the accelerated schedule of the contractor.
During construction, GeoConcepts provided full-time quality control staff to monitor construction and conduct quality control testing with regard to compaction of structural fill, proofrolling of subgrades, concrete placement, and asphalt placement. The quality control staff submitted their field generated paper work daily to senior personnel at GeoConcepts for review. The senior personnel would then provide monthly summary reports to the client.