Design

Reconstruction of the I-25 Corridor through the City of Trinidad will replace the existing aging infrastructure with a facility that meets current highway design and safety standards. The new facility will provide a safe highway that accommodates current and future traffic demands.

Reconstruction of I-25 will include multiple construction projects. CDOT has completed the Phase I construction project, Phase II NB began in April 2007, Phase II SB and Phase III will follow as construction funding becomes available.

Phase I	Construction of the SH 12 (Highway of Legends) Extension Construction of the SH 12 extension from I-25 across the Purgatoire River to Main Street began in September of 2003 and was completed August 2004. This section of SH 12 was officially open to the public in a ribbon cutting ceremony on August 3, 2004. The new extension provides a safe connection from SH 12 to I-25 via the Main Street interchange. This connection also guides motorists traveling from the west to downtown Trinidad, via Main Street, into the El Corazon de Trinidad Historic District. (More info: Archive: Phase I Construction History and Photographs)
Phase II NB	Reconstruction of Northbound I-25 During Phase II NB approximately 1.3 miles of the I-25 northbound lanes from Van Buren Drive to Commercial Street will be realigned both horizontally and vertically to improve driver’s safety; the Main Street and Commercial Street interchanges will be reconfigured to accommodate the shift in I-25 alignment; and the I-25 NB viaduct and structures at Main Street and the Purgatoire River will be replaced. Street level improvements will include replacement of the existing AMTRAK depot, construction of a paved parking area adjacent to the new depot, construction of a water quality detention pond, and improvements to Purgatoire River Park. I-25 Trinidad construction project - Phase II NB Design Aesthetics - click to view enlargement Design took into account many factors in addition to the safety of the traveling public. Because the project bisects the City of Trinidad, project aesthetics was an important consideration during design. Architectural elements of the historic downtown buildings as well as the naturally occurring sandstone bluffs influenced project aesthetics. For example the arch form found in many of Trinidad’s buildings was replicated in an arch-shaped reveal on the viaduct piers. Trinidad’s famous brick street pavers were incorporated in local street cross walks. Finish treatment on project retaining walls replicates sandstone blocks. Minimizing right-of-way purchase also influenced the final design. Retaining walls were used extensively to minimize encroachment of roadway side slopes onto properties adjacent to the highway. During most of Phase II NB construction, all I-25 traffic will be shifted to the existing southbound I-25 lanes. For the duration of construction, I-25 will have one lane of traffic in each direction from just north of Goddard to just south of Van Buren. CDOT and local agencies have an incident management plan in the event of partial or full closure of I-25 within the construction zone. Detours have been predetermined to route I-25 traffic onto local roadways for various closure scenarios. Phase II NB consists of the following features: NB I-25 will be reconstructed from Goddard south to Van Buren. Bridges carrying NB I-25 over Main Street and the Purgatoire River, and the NB viaduct will be replaced. The NB I-25 on ramp at Van Buren will be removed. NB I-25 on and off ramps at Main Street will be reconstructed. At Commercial Street, the NB I-25 on-ramp will be reconstructed and a NB I-25 off-ramp will be added. Highway lighting will be LED guidance lighting mounted on the inside face of guard rail in lieu of the traditional high mast lighting. This will be the first instance in the Country of LED guidance lighting being utilized on an interstate highway. Ramp lighting will be traditional mid-mast lighting. This project will be a CDOT Research test case for the use of self-consolidating concrete (SCC). SCC will be utilized in the Purgatoire River and Main Street bridge abutments. The BNSF depot building will be replaced with a new structure. A paved parking lot adjacent to the new depot will be constructed. The Amoco Station at Commercial Street and the Pizza Hut on Nevada Avenue will be removed to accommodate the realignment of I-25. Railroad crossing arms will be installed at University Street, Nevada Avenue, and Commercial Street. Improvements will be made to Purgatoire River Park including an addition of a foot path, benches, trash receptacles and landscaping. A water quality pond will be constructed near the viaduct to filter stormwater runoff from the viaduct before discharging into the Purgatoire River. Phase II NB Map Coming soon...
Phase II SB	Reconstruction of Southbound I-25 Phase II SB Reconstruction will be similar to Phase II NB. This phase will reconstruct all elements of southbound I-25, which includes the viaduct, the mainline bridge over the Purgatoire River, the Main Street overpass bridge, and entrance and exit ramps at the Main Street and Commercial Street interchanges. Work also includes removal of the southbound exit ramp at Van Buren Drive interchange. Funding and the construction schedule are not yet finalized, this phase is expected to begin following completion of Phase II NB. Phase II SB consists of the following features: SB I-25 will be reconstructed from Goddard south to Van Buren. Bridges carrying SB I-25 over Main Street and the Purgatoire River, and the SB viaduct will be replaced. Decorative brick bases will be added to the NB & SB viaduct pier columns. The viaducts, bridges and walls constructed in both NB & SB phases will be stained colors to match the surrounding environment. The SB I-25 off-ramp at Van Buren will be removed. SB I-25 off and on ramps at Main Street will be reconstructed. At Commercial Street, the SB I-25 off-ramp will be reconstructed and a SB I-25 on-ramp will be added. Highway lighting will be similar to NB I-25. Commercial Street under the viaduct will be repaved with Trinidad bricks. The Purgatoire River Trail will be extended from where it currently ends near the I-25/Purgatoire River bridges south to Van Buren Drive. A parking lot with landscape features will be constructed under the viaducts. A pocket park with picnic tables will be added south of Commercial Street between the NB off-bound ramp and the railroad tracks. Phase II SB Map Coming soon...
Phase III	Construction of New Interchange At MP 12. Phase III will reconstruct I-25 from Van Buren Drive south to Sopris Road, remove the remaining portion of the Van Buren interchange, and construct a new interchange at MP 12. Design and construction of Phase III will occur as funding becomes available.

Self-Consolidating Concrete
CDOT’s Research Branch is providing funding for Phase II NB to test self-consolidating concrete (SCC) in a field condition. Advantages of SCC is that is can be placed without vibration due to it’s high fluidity, it flows well around highly congested areas of reinforcing steel and SCC typically has an excellent surface finish devoid of blemishes which minimizes the amount of finish work required on the concrete after concrete forms are stripped.

SCC is already utilized extensively in the precast concrete industry where concrete is placed in a highly controlled environment. CDOT would like to test use of this concrete in field conditions, to see if SCC can be regularly specified for projects where concrete placement may be difficult due to inaccessibility and where there is a large amount of reinforcing steel required for a structural element.

Because of the high fluidity of SCC, it creates higher pressures on formwork than normal concrete. For this project, the Contractor will be required to perform tests showing CDOT that their SCC mix design does flow readily around a congested area of reinforcing steel, and that forms can withstand the additional placement pressures.

LED Highway Guidance Lighting
One concern the City of Trinidad had with the reconstruction of I-25 was light trespass from new highway lighting. Clanton and Associates, the lighting design engineers for the project, proposed a new LED guidance lighting system that greatly reduces or even eliminates light trespass. Instead of lighting the entire surface of roadway as with conventional highway lighting, the LED fixtures wash the traffic face of guardrail with subtle lighting to guide motorists along the roadway.

Features of the LED lighting include:

• LED lamp life of 50,000+ hours
  
• Lighting is recessed into guardrail
  
• Lighting is directional with low glare
  
• Intended for “guidance” of traveling public

LED highway lighting is a new technology in the United States, the Trinidad Reconstruction Project will be the first project in the United States to utilize this technology. Implementation of this LED lighting system is being partly funded by the CDOT Research Committee. The Committee will be involved in monitoring the LED’s performance once the LED’s are installed and fully functional. Depending on the success of this project, the LED lighting system may become one of the light system standards utilized by CDOT for future projects.

Water Quality Pond
A water quality pond will be placed below the elevated portion of Interstate 25 just north of Nevada Avenue. It will collect storm drainage from the roadway, bridges and other areas of the project. This water quality pond will allow impurities to settle out of the storm water over a 40 hour period prior to discharge into the Purgatoire River. The pond will be landscaped with a variety of shrubs and native grasses with river cobbles and landscape boulders. The addition of this type of pond is one of CDOT’s ways of minimizing the environmental impacts that highways have on streams.