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Economy of Steel & Concrete Bridges

Economy of Steel & Concrete Bridges. Delong’s Learn & Earn St. Louis November 1, 2018 Michael Barker, PE University of Wyoming & SSSBA Bridge Technology Center (Formerly at University of Missouri – Columbia). MoDOT Bridge Construction. Between January 2009 to May 2018:

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Economy of Steel & Concrete Bridges

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  1. Economy of Steel & Concrete Bridges Delong’s Learn & Earn St. Louis November 1, 2018 Michael Barker, PE University of Wyoming & SSSBA Bridge Technology Center (Formerly at University of Missouri – Columbia)

  2. MoDOT Bridge Construction Between January 2009 to May 2018: How Many Total Concrete Bridges Did MoDOT Built? 378 How Many Typical Steel Bridges? 16 (39 Total) • Prestressed NU • PC I Beam • PC Box • PC Bulb T, Dbl T & Slab 15 Plate and 1 Wideflange, Excludes: • Major River Crossings • Tight Horizontal Curves • Widenings • And Special Configurations

  3. Problem Statement Preconception that Concrete is Always Less Expensive Than Steel for Bridges

  4. Problem Statement Preconception that Concrete is Always Less Expensive Than Steel for Bridges

  5. Problem Statement Preconception that Concrete is Always Less Expensive Than Steel for Bridges MoDOT Removed December 2017 But Many States Have Similar Policies - Or At Least Similar Mentalities

  6. Another Problem Design Process Concrete Bridge Design Tables Steel Original Piece of Art

  7. Today’s Presentations Short Span Steel Bridge Alliance eSPAN140 Initial Costs – Dealing with the Preconception Audrain County Bridge Economies MoDOT Bridge Costs Local & State Bridges Another Two Near Identical MoDOT Bridges Recent MoDOT Bridges Similar Short Span Bridges Life Cycle Cost Comparison Steel vs Concrete – Long Term Costs

  8. Short Span Steel Bridge Alliance – Who we Are Coaters Fasteners Producers Service Centers Fabricators Contractors Design Firms Trade Organizations Universities Bridge Owners

  9. Short Span Steel Bridge Alliance - What do we do? Education (webinars, workshops, forums, conferences) Technical Resources (standards, guidelines, best practices) Case Studies (economics: steel is cost-effective) Simple Design Tools (eSPAN140) Answer Questions (Bridge Technology Center) Access to Industry Partners (industry contact list) Innovative Design - PBTG

  10. Website • eSPAN140 Web-based Design Tool • Bridge Technology Center • Technical Design Resources • Catalog of Short Span Steel Solutions • Project Case Studies • Video & Photo Gallery • News Updates & Social Media (Twitter / LinkedIn / Facebook) • Email Newsletter (sign-up to receive it) • Calendar of Industry Events www.ShortSpanSteelBridges.org

  11. Free Online Design Tool for Short Span Steel Bridges Developed by the Short Span Steel Bridge Alliance http://www.espan140.com/

  12. Providing Economical Steel Solutions to 140 Feet (40 Meters)

  13. Standards for Short Span Steel Bridge Designs • Goals: • Economically competitive • Expedite & economize the design process • Simple repetitive details & member sizes. • Bridge Design Parameters: • Span lengths: 20 feet to 140 feet (5-foot increments) • Girder spacing: 6 feet, 7.5 feet, 9 feet and 10.5 feet • Homogeneous & Hybrid plate girders with limited plate sizes • Limited Depth & Lightest Weight Rolled Beam Sections • Selective cross-frame placement/design (AASHTO/NSBA)

  14. eSPAN140 • eSPAN140 is an easy-to-use and free resource for bridge engineers & owners. • In 3 easy steps, multiple steel solutions are recommended!

  15. Step 2: Project Information

  16. Step 2: Project Details (general dimensions)

  17. Step 3: Customized Solutions Book is Provided (pdf) • Standard Design and Details of Short Span Steel Bridges Solutions • Rolled Beam Recommendations • Plate Girder Recommendations • Standard Design and Details of Corrugated Steel Pipe and Structural Plate Solutions • Manufacturer’s Steel Solutions (SSSBA Partners) • Customized Solutions from Members of the SSSBA • Durability Solutions (SSSBA Partners) • Galvanized & Paint • Weathering Steel • Additional Contact Information

  18. Design Example • Sample plate girder (homogeneous) elevation:

  19. Design Example • Sample rolled beam (lightest weight) elevation:

  20. Practical and Economical Detailing Typical diaphragm details Typical bearing details Typical stiffener details

  21. Durability Solutions • Weathering, galvanized, and painted steel

  22. Manufacturer’s Solutions

  23. The Bridge Technology Center • Free resource available to bridge owners and designers with questions related to: • Standard design and details of short span bridges (plate & rolled beam) • Standard design and details of corrugated steel pipe and structural plate.

  24. A Few eSPAN140 Designed Bridges

  25. 1st Direct Application of eSPAN140 – start to finish County Crew Accomplishments: • Longest Bridge Built • First Steel Bridge Built • First Concrete Deck • First Integral Abutment • Galvanized Steel • Galvanized Rebar • County Equipment Jesup South Bridge, Buchanan County, Iowa • Buchanan County Iowa • Count Crew Built Bridge • Replacement using W36x135 rolled beams • 65 feet length, 40 width • Better Roads (February 2014)

  26. Boone County, Missouri (Local) High Point Lane Bridge 102 feet (2 lane rural road plate girder bridge) 44” weathering steel plate girders (4 lines) Constructed in summer 2013 Kansas Department of Transportation (State) Shawnee County 112 feet (5 plate girder bridge) Competitive bid process (steel vs. concrete) DOT used eSPAN140 for preliminary design Constructed in summer 2014 Other eSPAN140 Bridges

  27. First Costs Steel & Concrete Examples

  28. Missouri County Bridges – Where the SSSBA Began Audrain County, MO Bridge 411 Built 2012 Steel 4 Girders 47.5 ft. Span 24 ft. Roadway Width 2 ft. Structural Depth No Skew Steel Concrete Audrain County, MO Bridge 336 Built 2012 Precast 6 Hollowcore Slab Girders • 50.5 ft. Span • 24 ft. Roadway Width 2 ft. Structural Depth 20o Skew

  29. Case Study Bridges: Side-by-Side Comparison Total Cost of Structure Steel Concrete • 19.3% Total Bridge Cost Savings with Steel Total Bridge Costs Material = $41,764 Labor = $24,125 Equipment = $21,521 Guard Rail = $ 7,895 Rock = $ 8,302 Engineering = $ 8,246 TOTAL = $111,853 ($97.48 / sq. ft.) Total Bridge Costs Material = $67,450 Labor = $26,110 Equipment = $24,966 Guard Rail = $ 6,603 Rock = $ 7,571 Engineering = $21,335 TOTAL = $154,035 ($120.83 / sq. ft.)

  30. Superstucture Costs Material Girders = $21,463 Deck Panels = $ 7,999 Reinf Steel = $ 3,135 Concrete = $ 4,180 Labor = $ 5,522 Equipment* = $ 500 SUPER TOTAL = $42,799 SUPER TOTAL = $37.54 / sq. ft. Case Study Bridges: Superstructure Only Comparison (Remove Site Prep, Abutment, Grading & Finishing, Guardrail, Engineering, Rock, Etc) Steel Concrete Superstructure Costs Material Slab Girders = $50,765 Deck Panels = $ 0 Reinf Steel = $ 724 Concrete = $ 965 Labor = $ 4,884 Equipment* = $ 4,000 SUPER TOTAL = $61,338 SUPER TOTAL = $50.61 / sq. ft. • *Added cost to use galvanized steel = $5,453.80 or $0.22 / lb. (includes est. 10% fabrication fee) • ** Cost to use weathering steel is approximately $0.04 / lb. (already included in cost in example) *County Crane (30 Ton) used for Steel, Larger Rented Crane (100 Ton) Required for Concrete (Equivalent County Crane Cost is $1520, would result in Steel Cost of $38.88 / sq. ft. )

  31. Case Study Bridges: Audrain County, MO • 25.8% superstructure cost savings • Same bridge conditions: • Structural Depth = 2 ft. (No Difference in Approaches) • Roadway Width = 24 ft. • Same Abutments for Both Can be Used (Steel Could Use Lighter) • Same Guard Rail System • Same Work Crew Steel: Superstructure $37.54 per sq. ft. Concrete: Superstructure Cost $50.61 per sq. ft.

  32. Case Study Bridges: Other Bridges in Audrain County

  33. Boone County, Missouri (Local) High Point Lane Bridge 102 feet (2 lane rural road plate girder bridge) 44” weathering steel plate girders (4 lines) Constructed in summer 2013 County Bridge (Designed by eSPAN140)

  34. Kansas Department of Transportation Shawnee County 112 feet (5 plate girder bridge) Competitive bid process (steel vs. concrete) DOT used eSPAN140 for preliminary design Constructed in summer 2014 1 Steel Bridge Bid 3 Concrete Bridge Bids Steel = $ 1.240 mil Concrete = $ 1.243 – $ 1.425 mil State Bridge (also Designed by eSPAN140)

  35. What about MoDOT’sOLD Policy…But Still Policy or Mentality in Other States? Assumes Concrete is 20% less (1-95/120) or Steel is 26% more Expensive (120/95-1) Let’s look at Some Data

  36. MoDOT NU and Plate & W Shape Bridges Built 2009-2018 • 148 NU Bridges; 15 Plate & 1 W Shape Girder Bridges • Excludes: • Major River Crossings • Tight Horizontal Curves • Widenings • And Special Configurations • All Had New Substructures

  37. Net Cost and $/ft2 Costs

  38. Statistical Results (costs $/ft2) • NU: Mean = $ 94.89 Steel: Mean = $ 101.06 • StDev = $ 22.92 StDev= $ 14.92 No Consideration of Year Built Span Lengths Number of Spans Etc Just Raw Net Numbers

  39. Statistical Work – Assuming Normal Distribution • What is the Probability that a Bridge Will Cost Less than $105/ft2 ? Concrete = 68% Steel = 61%

  40. Here’s a Good Question • For a Bridge Project, What is the Probability that a Steel Bridge • Will Cost Less than a Concrete Bridge?

  41. Here’s a Good Question • For a Bridge Project, What is the Probability that a Steel Bridge • Will Cost Less than a Concrete Bridge? • Probability Theory Prob(S<C) = Prob(S-C<0) then standardize • Prob(S<C) = F-1(-(mS – mC)/sqrt(sS2 + sC2)) = 40.0% Probability that Steel Costs Less than Concrete 0

  42. Using OldMoDOT Policy • Concrete: Mean = $ 95.00 Steel: Mean = $ 120.00 • StDev = $ 22.92 StDev= $ 14.92 • The Probability that Steel Costs Less than Concrete = 18.0% Probability that Steel Costs Less than Concrete 0

  43. Two MoDOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Steel Plate Girder: 98 ft – 98 ft Route H (Columbia Airport) Discovery Parkway (Columbia)

  44. Two MoDOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Steel Plate Girder: 98 ft – 98 ft Route H (Columbia Airport) Discovery Parkway (Columbia)

  45. Two MoDOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Steel Plate Girder: 98 ft – 98 ft Route H (Columbia Airport) Discovery Parkway (Columbia)

  46. Two MoDOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Steel Plate Girder: 98 ft – 98 ft Route H (Columbia Airport) Discovery Parkway (Columbia) Using ENR CCI Index Increase of 2.7%/yr For 2018 Concrete = $ 93.64/ft2 Steel = $ 85.84/ft2

  47. More Recent Bridges (2014 through 2018)

  48. Similar Short Span Bridges (2017 & 2018) Competitive

  49. Summary on Initial Costs Case Studies of County Bridges 10 Years of State Bridge Data Recent Cost Data Similar Bridge Comparison Competitive Bids Bridges over US 63

  50. The Bottom Line… Steel bridges are competitive on first costs!

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