Transportation

Seaman Bridge Replacement

City of Greeley, Colorado

During the flood event across the Front Range in September 2013, access to bridges owned by the City of Greeley were damaged due to high flows in the Cache la Poudre River. The bridges lie in Gateway Natural Area in Larimer County and provide public pedestrian access as well as private vehicle access to the Greeley-owned Seaman Reservoir. During design of the replacement bridges, subsurface investigations were used to determine the appropriate foundation designs while a hydraulic study was developed in the river channel to determine flows during major flood events. These flows were then used to ensure that the bridges were set high enough to allow large flood flows to pass under without obstructing the river or bringing damage to the bridge. The bridges themselves were designed as modular, single span vehicular bridges with concrete decking. Spanning 78 and 91 feet respectively, the two bridges will no longer require the original piers in the river for support, yet the piers are to remain in place to protect the river wildlife habitat that has developed over the past few decades.

 

Gardner Bridge Replacement

Colfax County, New Mexico

EA evaluated the hydrology, hydraulics and geotechnical conditions and developed various alternatives for replacing the existing deficient bridge along County Road A-20 (a.k.a., Gardner Road) over Dillon Canyon Creek in Colfax County, near Raton, New Mexico. After presenting the recommendations in the Preliminary Engineering Report to Colfax County, EA designed a triple cell 21’x10’ aluminum structural plate arch culvert with aluminum headwalls and wingwalls and riprap revetment. The project scope included coordinating with United States Army Corps of Engineers and New Mexico Environment Departmetn regarding the 404/401 Permit requirements. EA staff provided construction management and materials testing during construction. Construction completion is anticipated in spring 2021. Prior to bidding, the Engineer’s Estimate was $468,590. The construction contract was awarded to Mosark LLC for the low bid of $462,888. There were no cost change orders on the construction project.

 

Maryland Creek Ranch Road Cut Stabilization

Silverthorne, Colorado

The Maryland Creek Ranch development constructed north of Silverthorne, Colorado included 240 units constructed on a relic landslide complex. EA staff was the project manager for the design and provided construction oversight.  EA directed the design of the soil nail, grouted post-tensioned anchors, and MSE walls to stabilize slopes and road cuts to allow for road development.  EA also designed site subsurface drains to control groundwater and further stabilize the site. The design of stabilization features for the infrastructure included the installation of 4,500 feet of horizontal drains, 13,000 feet of underdrains, and 45,000 square feet of soil nail, ground anchor, and Hilfiker wall systems.  The design plans were reviewed by the Colorado Geologic Survey and the Town of Silverthorne. The project included obtaining geotechnical data from borings, reviewing inclinometer and piezometer data, and developing a geotechnical design report.  EA provided full construction drawings for the retaining walls and subdrain system. EA met with the Town and other review agencies to address concerns associated with the development.

 

Storm Drain Improvements Original Townsite

Raton, New Mexico

EA staff provided the design of upsizing inlets and lining manholes along Cook and Park Avenues in order to improve storm water runoff interception in the Historic Downtown Raton. EA submitted environmental documentation to New Mexico Environment Department and New Mexico Department of Transportation and successfully received environmental clearance. Additional responsibilities included producing bid documents and providing bidding and construction management services

Long Road and South Fork Mill and Overlay

Colfax County, New Mexico

EA staff developed plans and bid documents and performed construction management services for paving Long and South Fork Roads near Raton, New Mexico. The design efforts included geotechnical investigation of the existing soils and design of multiple pavement sections to reduce construction costs. Through negotiations with the contractor, value engineering, and effective construction management, EA was able to reduce the construction cost by $86,375. The original low bid was $381,337.64 (including NMGRT). Construction contract final pay application was $294,962.23 (including NMGRT).

 

Pavement Design and Rehabilitation

Springer, New Mexico

EA, in conjunction with the Town of Springer, prepared the funding application to the New Mexico Dept. of Transportation (NMDOT) for the pavement rehabilitation of 8th Street. EA designed 0.82 miles of roadway improvements from the railroad crossing near Railroad Ave. to County Road 31. The design included field reconnaissance, pavement patching, hot mix asphalt overlay, replacement of speed humps, signage, and striping for the road and the railroad crossing. EA prepared the bid documents and managed the bid process, including contractor negotiations, for both phases of construction. EA prepared and submitted all documentation required by NMDOT to satisfy the funding agreement. EA provided construction management, field observations and materials testing for both phases of construction.