Hamon Infrastructure, working with stake holders: Colorado DOT, RTD, City of Arvada and the BNSF Railroad constructed a grade separation between the Wadsworth By-Pass and both Grandview Ave and the BNSFRR thus relieving a dangerous bottleneck on this major arterial roadway. Hamon Contractors lowered the Wadsworth By-Pass 30 feet under both Grandview Ave and the BNSFRR. To accomplish this, Hamon constructed a permanent detour for Wadsworth Ave. Hamon then assisted the BNSFRR with the construction of a complete 960 foot long shoofly including new switches, signals and track.
Background
The Wadsworth Bypass was built in the 1950’s and included an at-grade railroad crossing with the BNSFRR. Over time, the volume of traffic on Wadsworth Bypass has increased dramatically making an at-grade railroad crossing at this location unacceptable. An average of 5 trains per day cross Wadsworth Bypass – often during peak traffic periods. Prior to the grade separation, traffic was stopped each time for eight to ten minutes, with a traffic recovery period lasting as long as 20 minutes. 50,000 vehicles travel through this area each day resulting in 24,100 vehicle delay hours annually.
Importing nearly 40,000 cy of embankment, Hamon Infrastructure built a complete detour allowing the Bypass to be constructed with little or no additional inconvenience for the 50,000 vehicles that drove through the project each day.
Project Benefits
Innovations
The Wadsworth Bypass project combined innovations in both design and construction means and methods:
RAILROAD SHORING – Hamon Contractors used an innovative connection technique between the soldier beams and lagging allowing the lagging to be removed from the bottom up not only assuring the safety of the craft personnel at the face of the work but also assuring the structural integrity of the contractor designed system supporting the BNSFRR.
SECANT CAISSONS – CDOT’s design for shoring the roadway lowering utilized 361 interlocking secant caissons as a permanent retaining wall. Hamon Contractors used laser measurement devices and levels attached to the caisson rig to continuously monitor the drilling operations to achieve the stringent tolerances necessary to successfully construct the nearly 2 miles of caissons required by this innovative design.
VALUE ENGINEERING COST PROPOSALS – Hamon Contractors proposed replacing portions of the secant caisson retaining wall with cast-in-place cantilevered retaining walls. This VECP not only improved constructibility and helped accelerate the schedule but it also saved CDOT over $300,000.
Construction of Recreational Parks and Public Spaces
For over 50 years two historic neighborhoods, Olde Town Arvada and the Stocke-Walter neighborhood, were separated by a major highway. The Wadsworth Bypass Grade Separation project reunited these two neighborhoods and created a gateway to Olde Town Arvada along Grandview Avenue. A portion of the Grandview Avenue Bridge was constructed as a pedestrian promenade including planters, streetscaping, paver covered walkways and sandstone pylons crowned with distinctive copper-clad lights. This pedestrian promenade, with custom lighting, terraced planters, architectural railings and custom signage creates a stunning gateway to Old Towne Arvada.
Environmental Compliance
The Grade Separation project was constructed in a part of Arvada that was historically used for both commercial and industrial purposes. The project included the creation and execution and continual monitoring and maintenance of a Storm Water Management Plan (SWMP) and Permit protecting the local environment from storm water run-off during the course of construction. In addition to Stormwater Management, plans were developed and permits were secured for mitigating fugitive dust emissions and safely performing necessary construction dewatering.
During the course of construction, Hamon forces captured and safely disposed of contaminated soils and groundwater, asbestos materials, creosote railroad ties and underground storage tanks. Hamon installed ground water monitoring wells and performed continual sampling and testing as a part of our overall Health and Safety Management Plan.
