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Project Preparation and Administration

Project Preparation and Administration

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Project Preparation and Administration

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  1. Project Preparation and Administration Bridge Module

  2. Why are bridges part of this training? • Big cost. • Long Process • Design is complicated • Tough Decisions R1 Trails Project Preparation

  3. But they are Fun! Proud crew! Trails do nothing more than connect the Bridges! R1 Trails Project Preparation

  4. Training Focus • Bridge Design Process • Decisions to be made. • How to make those decisions! R1 Trails Project Preparation

  5. Training Focus • Northern Region Standard Trail Bridge Plans • Intended uses • Limitations, Inappropriate Uses • Costs • Maintenance • Wilderness Bridges • Helicopter Usage • Preservative Treatments If there is time – NP Wilderness Bridge Project Presentation R1 Trails Project Preparation

  6. Authorities • All Decisions – Line Office • Approval of Bridge Design – Director of Engineering • Unless using Regional Standard Trail Bridge Designs – Forest Engineer. • All Trail Bridges need to be designed! Bridge in Bob Marshall Wilderness R1 Trails Project Preparation

  7. Authorities • Design Resources Available. • Forest Engineer • Regional Bridge Group • John Kattell • David Scovell • Our job is to provide technical assistance to Forest personnel and complete and/or approve all bridge designs. R1 Trails Project Preparation

  8. Bridge Design Process • Function (To bridge or not? Replace or remove?) • Who is User? ROS? TMO? • Force Account/Contract? ProjectScope** **Contact FE and /or RO during Project Scope Location/Survey • Where is best spot? • Many decisions. • Project Funding and Scope finalized. Preliminary Design Final Design • Plans, Specs, Estimates. Construction • COR R1 Trails Project Preparation

  9. Project Initiation and Scope • Function • To Bridge or Not to Bridge? • Replace or remove? • Preliminary Engineering needed? • Factors? • TMO & ROS • User Safety • Resource Protection • Others? Funding Feasibility Aesthetics Wilderness Albino Trail Bridge Site - Gal R1 Trails Project Preparation

  10. Bridge Design Process • In general, more complicated than road bridges. Why? • Defining the User • Location • Access • Wilderness • Size? R1 Trails Project Preparation

  11. Bridge Design Process • Dome Mtn. On Ktn. • 24-foot span • Wilderness • 6-mile from TH but 4000 ft elevation gain. • Force Account • Dangerous work. R1 Trails Project Preparation

  12. Bridge Design Process • Iron Springs on D-P • 50-foot span • Easy access • Total cost -~$35,000 • Contract Maah-Taah-Hey Trail R1 Trails Project Preparation

  13. Project Initiation and Scope Define the User (TMO & ROS) • Pedestrians • Stock • ATVs • Bicycles • Administration vehicles • Outfitters / other permittees • User affects size, design and cost. • Bridge many times limits the user! R1 Trails Project Preparation

  14. Project Initiation and Scope • Force Account or Contract? (Effects design decisions!) • Design (in house or A/E) • Complexity of bridge project. • Availability of Forest or RO Engineers • Funding • Typically, R1 designs are done in house. • Construction • Safety • Force Account capability, skill level, and availability. • Complexity of bridge. • Funding • Pros and Cons R1 Trails Project Preparation

  15. Force Account or Contract? • Remote site required packing all materials. • Simple construction • NP has trained Crews. • Force Account Goat Creek on NP R1 Trails Project Preparation

  16. Force Account or Contract? • Bridge part of a larger trail construction project. • Short distance from trailhead. • Complicated construction • Contract Yellow Mule on Gallatin R1 Trails Project Preparation

  17. Force Account or Contract? • Site at trailhead. • Working over large water penstock and tracks. • Needed large equipment Mystic on Custer Contract R1 Trails Project Preparation

  18. Project Initiation and Scope • Summary • Function (To bridge or not to bridge) • Define Users. • Force Account versus Contract • Funding. Project a go or no go? • May need some preliminary engineering this early. Who makes these decisions? R1 Trails Project Preparation

  19. Location Narrowest spot? Not necessarily Stable stream reach. Where users want it! Good trail approaches for user (function for hikers vs stock vs snomobiles vs ATV’s) Survey - Varies Simple small creek Profile of trail and stream with few x-sections. Sketches Complex Full site survey of area. Geotechnical (drilling) In general, experienced bridge engineer may get by with less. Location / Survey R1 Trails Project Preparation

  20. Location / Survey • Holter Cut on Btr. • No survey done. R1 Trails Project Preparation

  21. Location / Survey • Little Salmon on Flathead in Bob Marshall. • Full site survey completed. • Needed for hydraulic analysis. R1 Trails Project Preparation

  22. Determine Span Height Width Bridge Type Foundations FA or Contract Cost Factors Crossing and height Flood waters, Clearance User Span, location, aesthetics Site geology See earlier slide All of the above. Preliminary Design R1 Trails Project Preparation

  23. Preliminary Design Two biggest problems in R1 Bridges too short. Abutments scour and fail Resource damage R1 Trails Project Preparation

  24. Preliminary Design Bridges are too low! R1 Trails Project Preparation

  25. Preliminary Design • Sill-Thru Configuration • Little work in water. • Hydraulically efficient. (less susceptible to scour). • More $ in superstructure, less in abutments. • No wingwalls needed. R1 Trails Project Preparation

  26. Preliminary Design • Vertical Wall Configuration • More work in water. • Hydraulically less efficient. (more susceptible to scour). • Less $ in superstructure, more in abutments. • Need wingwalls R1 Trails Project Preparation

  27. Preliminary Design • Span Length • Field Estimate (Rule of Thumb) typicalspill-thru bridge. Estimated Span Length (L) = BW + 3 x BH • BW – Channel bottom width • BH – Bridge height from channel bottom to trail tread. BH Span Length (L) R1 Trails Project Preparation

  28. Preliminary Design • Span Length • Field estimate must be verified on paper. • Do not undersize. • Better to spend more on span than abutments. • Evaluate existing bridge (did it function OK) • Iterative process with what? • Bridge height • What controls bridge height? R1 Trails Project Preparation

  29. Preliminary Design • What controls bridge height? • Trail height • Bridge structure depth • Rule of thumb 1/20 x span • Clearance for debris • Minimum 2 feet above high water (100 yr flood) to bottom of bridge. Little Salmon on Flathead R1 Trails Project Preparation

  30. Preliminary Design • Span Length – Vertical Wall abutment • Span Length = Bankfull +. Must be able to pass flood without damage to bridge or stream. • Footings must be ‘below stream bed as minimum unless on bedrock. BH Span Length (L) R1 Trails Project Preparation

  31. Preliminary Design Factors for Bridge Width - Users - Railing Bridge w/o railing R1 Trails Project Preparation

  32. Preliminary Design Variable widths • Single log – 14” • Stock w/railing – 8’ • Snowmobile – 16’+ • Manual guidance but can be anything. Bridge with railing R1 Trails Project Preparation

  33. Preliminary Design • Bridge Types • Single Log • Timber stringer • Glu-lam stringer • Truss • Suspension • Packable • Factors Span Access AestheticsMaterials R1 Trails Project Preparation

  34. Foundations Spread footings Gabions Geocell Walls Generally we use spill-thru configuration with timber sill on gabion or geocell. Factors Site geology Site materials Access Scour Potential Preliminary Design R1 Trails Project Preparation

  35. Preliminary Design • Costs • Very difficult to estimate. • No rules of thumb. • Procedure • Take off and price materials (variable) • Crew up labor. • $2500/day for crew of 4 with • Or use Davis Bacon rates • Estimate Equipment needed (cranes, backhoe, helicopter) R1 Trails Project Preparation

  36. Preliminary Design • Costs - continued • Materials • Sawn Timber $1350/mfbf • GL timber $2500/mfbf • Bolts/hardware $3.00/lbs. • Concrete $600 - $1000/cy • Reinforcing Steel $1.25/lb • Gabions $125/cy • Geocell $15/cy • Geocell fill $25-$75/cy R1 Trails Project Preparation

  37. Preliminary Design • Costs - continued • Equipment • Excavator $130/hr • Backhoe $80/hr • Dump Truck $75/hr • Crane (Light) $350/hr • Crane (medium) $650/hr • Helicopters See later slides • Packing $225/mule trip (180 lbs per mule) R1 Trails Project Preparation

  38. Typical work items to accomplish for labor. Project Management Mobilization Excavation Build Abutments Install Superstructure Build Approach walls Build Approach fills Less Common Work Items Helicopter use. Packing Materials Supply Camp Install Falsework. Preliminary Design R1 Trails Project Preparation

  39. Preliminary Design • Nail Lam built 15 years ago. • Replace with glu-lam stringer bridge. • On sills. • Wilderness • Use Helicopter to fly in stringers. • Estimate based on Contract Construction Flood Creek – Custer R1 Trails Project Preparation

  40. R1 Trails Project Preparation

  41. Preliminary Design Whose Responsibility / Authority for preliminary decisions? Forest! • However, Engineering must assist! • Why? • Call FE and or RO during Project Scope for assistance with alternatives and options. • Meet with Rec staff and Ranger to discuss preliminary design options and alternatives. R1 Trails Project Preparation

  42. Preliminary Design • At this point • Re-evaluate Project Scope! • Re-evaluate Funding! • Why? • Many times each site has several alternatives being evaluated. • Must select Final Design Alternative. R1 Trails Project Preparation

  43. Final Design, PS&E Typically done by Engineering • Plans (as a minimum) • Title Sheet (signatures) • Bridge Layout (Plan and Elevation) • On site plan from survey. • Abutment/foundation details • Superstructure details • Miscellaneous details R1 Trails Project Preparation

  44. Final Design, PS&E • Specifications • FP-03, Standard Specifications for Construction of Roads and Bridges on federal Highway Projects. • Special Project Specifications as needed. R1 Trails Project Preparation

  45. Final Design, PS&E • Estimates • Estimated Construction Costs • Update of preliminary estimate • Estimated Schedule for Construction R1 Trails Project Preparation

  46. Final Design, PS&E • Plans, Specs and Estimates • All 3 required. • Any difference for Force Account vs Contract? • Shouldn’t be! • Authorities • Regional Engineer must approve PS&E package, UNLESS • Using Standard Plans, then FE has authority to approve PS&E package. R1 Trails Project Preparation

  47. Construction • All Trail Bridge Construction is to be administered and inspected by • Certified COR, Level III • With appropriate technical endorsements. • Any difference for Force Account vs Contract? • NO! • RO will assist as needed or requested. R1 Trails Project Preparation

  48. Trail Bridge Standard Plans • Pre-designed and detailed drawings for: • Typical Trail Bridge Superstructures • Typical simple substructures (sills). Iron Springs on Maay-Daay-Hey Trail R1 Trails Project Preparation

  49. Trail Bridge Standard Plans • Intended Uses • Simple, single spans • Spans less than 60 feet • Adapted for each site. • FE can approve. • Limitations • At discretion of FE only. • Not for complex bridges. • Not for difficult abutments. • Still requires, survey, hydraulic analysis, soils, etc. R1 Trails Project Preparation

  50. Trail Bridge Standard Plans Typical Superstructures: Drawing # • Solid Sawn Timber Stringer R1920 • Log Stringer R1921 • Glu-lam timber stringer R1922 • Glu-lam longitudinal slab R1923 • Single log R1924 • Nail-lam longitudinal slab R1925 • Prefabricated steel truss R1926 • Packable spliced stringer R1927 R1 Trails Project Preparation