What makes it interesting?
The project had difficult elements, including multiple stakeholders, limited access, existing utilities, and deep excavation to be completed within 40 hours. It required two teams working 12-hour shifts in order to safely reach the deadline and open the rail and the highway on time.
How HCSS Software assisted with this project
The project was estimated using HeavyBid and managed using HeavyJob. HeavyJob helped make fast work of job tracking, cost, and reporting. However, HeavyBid is the most powerful tool our estimating department posesses and is responsible for much of the successes.
The North Meadows Extension – Tributary B Outfall in Castle Rock, CO involved the installation of a 10-foot by 6-foot CBC at a depth of 23 feet and a length of 236 feet. Challenges included crossing under a railroad and a parallel major highway (50 feet apart), thus connecting a detention pond with a stream channel. The Union Pacific Railroad allowed an open cut of the Class A tracks (30 trains daily) if assured that there would be a maximum of only 30 hours between trains.
In cooperation with Colorado Department of Transportation, the Town of Castle Rock, and the CMAR team, approval and use of a temporary detour was agreed to allow the safe construction of this congested crossing. This was all accomplished through partnering, construction review and collaboration, planning, and stakeholder buy in. The construction window for this work included shutting down and removing of rail and detouring the highway beginning on Halloween Night.
The staging area was limited, and since the quarries were closed during the weekend, the specified backfill materials were required to be previously stockpiled on site. The lack of lay-down area required the precast supplier to deliver the CBC segments as they were installed. This required the precast yard to load and deliver 40 precast boxes during a straight 24-hour period.
The rail was first to shut down, creating valuable time to start the excavation/placement of the first three boxes prior to the detouring of Hwy 85. The depth of the excavation required a trench shoring box. Due to the weight of the precast segments, a 400-ton crane was used to place the CBC. The precast boxes below the railroad prism specified AREMA boxes which had a different outside dimension compared to the boxes used under the highway.
The backfill requirements under the railroad were substantially different compared to the highway requirements. As luck would have it, the transition where the material types switched was the same location that a major fiber line ran in between the rail and the highway. The fiber had to be exposed for a length allowing available slack to work around. Care of the fiber included protecting and tracking the production excavator over the line, digging around the line, and placing the precast box without incident.
Roughly a month of pre-planning was required for this 40-hour project. It required two teams working 12-hour shifts in order to safely reach the deadline and open the rail and the highway on time. The construction schedule had hourly milestones that were evaluated and adjusted due to varying issues. Within the 30-hour rail window and the 40-hour highway window, time was allowed for the reinstallation of the ballast and rail as well as time to place three lifts (10.5-inch HMA) with cooling time for lift placement and traffic. In the end, it was a great success and with many personal and professional accomplishments.