Diagonal (SH 119) Reconstruction from 28th Street to Independence

The City of Boulder Transportation Department collaborated with CDOT on this local agency project to design an impressive new “Gateway” into Boulder. This section of SH 119, also called the Diagonal Highway, used to be in the outskirts of the city, but has become a very busy area with what was a deteriorated asphalt road and no pedestrian or bike facilities in 2015.

To solve this problem Castle Rock Construction managed and built a complex project with an extensive new drainage system, off-street bike lanes, multi-use path, improved transit facilities, various colored concrete aesthetic components, durable concrete roadway, incredible landscape features and art plazas for the community to enjoy. Coordination with the multiple departments within the City of Boulder, CDOT, RTD, contractors on adjacent projects and the 20 subcontractors onsite was key to CRCC’s success on this job.

Some of the unique elements on the Diagonal Reconstruction include:

• 4,700 LF of reinforced concrete pipe installed by J2 Contracting
• 31,000 SY of full depth reclamation of the existing roadway to be recycled into road base for the new concrete paving a collaboration of ARS and CRCC crews
• 11,600 SY of asphalt and concrete pavement removal
• 14,000 CY of embankment material moved
• 10,700 SY of flat work including cycle track, multi-use path, sidewalk, exposed aggregate, colored sidewalk and colored median curb skirt
• 31,000 SY of 8.5” doweled concrete roadway paved by CRCC
• 3,500 SF of Rosetta Stone Retaining Walls built by Slaton Brothers
• 300 SF of Boulder Retaining Wall and 600 SF of Grouted Rock Wall built by Rock and Company
• 1,900 SF of Weathering Steel Landscape Walls built by Standard Metal Works
• 1,400 SF of colored Cast-in-Place Concrete Retaining Wall built by Standard Concrete
• New signals, electrical boxes and corresponding infrastructure installed by Sturgeon Electric
• 400 trees, 4,400 shrubs and 2,000 perennials planted with corresponding new irrigation installed by Green Earth Environmental
• 3 Rain Gardens were built which are defined by the City of Boulder as “low-lying areas landscaped with plants, mulch, and soil on the surface, and sand beds and drains underneath. These rain gardens will collect, store, and filter rain water and storm water runoff, naturally removing pollutants.”
• Monument foundations and drainage systems for art features

In order to accommodate the public during construction, lane closures were only utilized during off-peak times throughout the week, bicycle routes for both eastbound and westbound were maintained at all times and intersection reconstruction was limited to weekend work.

The Diagonal Reconstruction project is a compilation of numerous talented contractors coming together to build a job that the people of Boulder and those that visit can appreciate and enjoy for a very long time. We appreciate the City of Boulder and Colorado Department of Transportation’s hard work and innovation on the preparation for and execution of this project.