Niwot Loop Concrete Bridge Approaches

Boulder County Parks & Open Space Department is requesting proposals for concrete bridge approach construction at the Niwot Loop Trailhead (7901 Mineral Road, Unincorporated Niwot, Colorado), with proposals due October 8, 2026 at 3:00 p.m. via electronic submittal through the Boulder County Bonfire portal and public bid opening via Microsoft Teams.

The project replaces unsustainable crusher-fines approaches at two bridges (Bridge 1811 and 1812, each 40 feet long and 8 feet wide with 10,000-pound gross vehicle weight capacity) with concrete construction to address drainage, trail sustainability, and accessibility for all users including those with mobility challenges. The contractor must complete all work within thirty consecutive calendar days following issuance of a Notice to Proceed, with a minimum fourteen-day advance notice required to BCPOS for public notifications and trail closures. Work hours are restricted to Monday through Friday, 6:00 a.m. to 7:00 p.m.

Key deliverables include mobilization and demobilization, excavation and subgrade preparation, six-inch Class 6 aggregate base course installation, concrete placement conforming to CDOT Class B specifications (minimum 4,500 psi compressive strength at twenty-eight days) totaling approximately 24 cubic yards, proctor density testing at 95 percent standard compaction for three locations, seven-day and twenty-eight-day compressive strength testing, Emergency Management Plan, Field of Debris Sediment track-out control, temporary fencing and barricades, portable restroom facilities, site restoration, and utility locates. The contractor must possess experience in civil and concrete construction, CDOT Class B flat work, and heavy and light equipment operation.

Payment and performance bonds equal to 100 percent of the proposed cost are mandatory and must be included in the total bid amount. The contractor will receive payment as a single lump sum upon project completion and inspection approval. Contractors must submit a W-9 form dated within the past twelve months and, if awarded, provide a current Certificate of Good Standing from the State of Colorado. Insurance requirements include Commercial General Liability ($1,000,000 per occurrence, $2,000,000 aggregate), Workers' Compensation at statutory limits with $100,000 Employer's Liability, and Pollution Liability ($1,000,000 per occurrence and aggregate), with Boulder County named as additional insured. No pre-bid meeting will be held. All questions must be submitted through the Bonfire portal.