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Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000


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Improving Connectivity: The Custer Interchange Project

Appendix C Construction/Innovative Materials Skill Set

Construction

Idea Name Detailed Description Implementation Details (barriers, skills set coordination, etc.)
3-phase construction
  • Break project into 3 phases.
  • Improvements to:
    • Cedar St Overlay and widen.
    • Sanders St, connections to Custer.
    • Custer Ave. west of Sanders St.
    • Frontage Road realignment.
  • Interstate ramp/aux lanes work.
  • Custer Ave. structure and approaches.
  • Custer would only be closed or detoured for last phase.
  • Further alleviate traffic on Cedar, N. Montana and Washington.
  • Additional time for dissipation of fill settlement.
  • There is greater leeway to perform work based on funding available.
  • Provide better alternate route for traffic.
  • Relieve congestion.
  • Addresses emergency services, i.e. fire station on Forestvale.
Custer Avenue - Remain Open
  • Maintain existing alignment and two-way traffic on Custer Ave with existing structure until permanent structure is complete; utilizing phase construction.
  • Shift Custer alignment slightly North and maintain two-way traffic on Custer Ave with existing structure until permanent structure is complete.
  • Maintain two-way traffic on Custer Ave with a temporary structure, i.e. Bailey bridge, detour bridge.
  • Maintain two-way traffic on Custer Ave.
  • Alignment shift to North would reduce impacts to utilities on South.
  • Ease of construction phasing.
  • Construction of new ramps could be done during the early phases.
  • May be outside of the originally identified right-of-way footprint.
  • Added expense.
  • More construction over the interstate.
Custer Avenue - Closed Close Custer Ave to replace the structure, which will increase the need for accelerated construction methods, i.e. Self Propelled Modular Transport (SPMT).
  • Cut the total construction time.
  • Cut costs; road user, traffic control.
  • Increase safety for motorists and construction personnel.
  • Establishing the detour route may help to keep traffic flowing.
  • Public/business relations, impacts.
Interstate Structure vs. Custer Avenue Structure Build an Interstate bridge over the top of Cedar paralleling current I-15 alignment; single bridge with concrete barrier rail; SPMT could be incorporated.
  • Help to reduce or eliminate utility relocation/conflicts.
  • Potentially reduce fill requirements.
  • Reduced structure costs.
  • Better pedestrian access across interstate.
  • Custer Ave. would be at grade or lower (earthwork could be balanced).
  • Reduce right-of-way needs.
  • May require permanent and/or temporary MSE walls.
  • Ramp C2 may require extension of aux lane; vehicles getting up to speed.
  • Would need to revisit drainage.

Materials

Idea Name Detailed Description Implementation Details (barriers, skills set coordination, etc.)
Flowable Fill Use flowable backfill for storm drain, utilities trenches and bridge ends.
  • Decreased construction time.
  • Less likely to have settlement at bridge ends.
  • Reduces settlement of trench backfill and improves pavement performance.
  • Increased construction costs.
  • Increased lateral pressure on the backwall.
Pre-cast bridge Elements Fabricate bridge Elements off-site, i.e. caps, deck panels, beams, etc.
  • Accelerate construction.
  • Better quality product.
  • Increased costs.
  • Contractor inexperience.
Portland Cement Concrete Pavement (PCCP) Full depth PCCP or White Topping, could be used on Cedar, Custer and interchange ramps.
  • Longer life cycle of pavement, i.e. maintenance.
  • Increased construction time; cure time of concrete.
Pulverize and Widen Existing Roadway Pulverize and widen Cedar and potentially Custer west of Sanders.
  • Longer service life.
  • Uniform section, more opportunities for better ride.
  • Increased cost.
A-1-a(0) Borrow Better borrow material in the top two feet of the sub-grade.
  • Reduce surfacing section.
  • R-60 or better readily available.
  • May require excavation in thin sections.
  • May only use on new construction.

Contract Administration

Idea Name Detailed Description Implementation Details (barriers, skills set coordination, etc.)
Contract Administration
  • Lane rental.
  • A+B.
  • Incentive/Disincentive (I/D).
  • Internal milestones w/ A+B or I/D.
  • Construction inspection during utility moves.
  • Night work; limited work hours in some areas, see local ordinances.
  • Potential to reduce construction costs.
  • Potential to reduce contract time.
  • Reduce impacts to traffic and the public.
  • Increase safety due to shorter exposure.
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Updated: 10/31/2013
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000