RockSol Consulting Group, Inc.
  • SH 93 Shoulder Widening

    SH 93 Shoulder Widening

  • SH 93 Shoulder Widening

    SH 93 Shoulder Widening

  • SH 93 Shoulder Widening

    SH 93 Shoulder Widening

SH 93 Shoulder Widening, SH 128 to SH 170


Client:

Boulder County & Colorado Department of Transportation

Services:

Structural & Geotechnical Engineering, Construction Management, Inspection & Materials Testing

Location:

Boulder County, Colorado

Project Description:

RockSol performed structural and geotechnical engineering services for the design of the SH 93 highway widening between SH 128 to SH 170. Boulder County, in coordination with City of Boulder and Colorado Department of Transportation (CDOT), determined that the roadway needed wider shoulders and a grade-separated crossing for the Community Ditch Trail to improve safety and enhance the multimodal user experience. The goal of this 1.75-mile project was to design the widening of SH 93 to accommodate 6-foot paved shoulders on both sides of the highway from SH 128 to SH 170 and to add an underpass for the trail. In order to widen the shoulders, new embankment, culvert extension, cut slope, and retaining walls were designed. The project also included box culvert replacement; recreational trail realignment for Community Ditch Trail, including a grade-separated underpass structure; stormwater drainage improvements; and relocation of utilities. Michael Baker Jr., Inc. was the prime consultant to Boulder County.  RockSol, as sub-consultant to Michael Baker Jr., Inc., performed geotechnical and structural engineering services. RockSol prepared the Structure Selection Report and was responsible for design calculations for a reinforced concrete cantilever retaining wall, founded on bedrock for part of its length and on a deep foundation for part of its length; and providing quantities, independent design check, plans check, and quantities check.


RockSol’s geotechnical investigation included drilling 38 boreholes and six coreholes; assigning the laboratory testing; and providing the geotechnical recommendations for the pavement design, underpass structure, and retaining wall and wing wall structures. Geotechnical design considerations included historical coal mining activities within the project limits and their associated geological hazard potential/risk for new development constructed over abandoned coal mines. Other unique challenges included new construction adjacent to an irrigation canal/ditch, bedrock outcrops, and steep slopes. RockSol also performed a geological hazards study of the project site, which included researching historic coal mine maps, state records, aerial images, and deep drilling/coring operations.


Under a separate contract with CDOT, RockSol performed construction quality assurance services for the construction of this highway widening and underpass structure project. RockSol provided construction management services and was responsible for administering the construction contract, managing consultant forces, running monthly pay estimates, performing erosion control inspections and traffic control reviews, and monitoring daily construction activities to ensure the project was completed in accordance with project plans and specifications. Additionally, RockSol conducted materials sampling, testing, inspection, and documentation for all materials produced and used on this project.