Economy of Steel Concrete Bridges Delongs Learn Earn
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)
Mo. DOT Bridge Construction Between January 2009 to May 2018: How Many Total Concrete Bridges Did Mo. DOT Built? 378 • • Prestressed NU PC I Beam PC Box PC Bulb T, Dbl T & Slab How Many Typical Steel Bridges? 16 (39 Total) 15 Plate and 1 Wideflange, Excludes: • Major River Crossings • Tight Horizontal Curves • Widenings • And Special Configurations
Problem Statement Preconception that Concrete is Always Less Expensive Than Steel for Bridges
Problem Statement Preconception that Concrete is Always Less Expensive Than Steel for Bridges
Problem Statement Preconception that Concrete is Always Less Expensive Than Steel for Bridges v o m e TR m e c e ed D Mo. DO 7 1 0 2 ber But Many States Have Similar Policies - Or At Least Similar Mentalities
Another Problem Design Process Concrete Bridge Design Tables Steel Original Piece of Art
Today’s Presentations Short Span Steel Bridge Alliance e. SPAN 140 Initial Costs – Dealing with the Preconception Audrain County Bridge Economies Mo. DOT Bridge Costs Local & State Bridges Another Two Near Identical Mo. DOT Bridges Recent Mo. DOT Bridges Similar Short Span Bridges Life Cycle Cost Comparison Steel vs Concrete – Long Term Costs
Short Span Steel Bridge Alliance – Who we Are Fasteners Coaters Producers Service Centers Fabricators Contractors Design Firms Trade Organizations Bridge Owners Universities
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 (e. SPAN 140) • Answer Questions (Bridge Technology Center) • Access to Industry Partners (industry contact list) • Innovative Design - PBTG
Website • e. SPAN 140 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 / Linked. In / Facebook) • Email Newsletter (sign-up to receive it) • Calendar of Industry Events www. Short. Span. Steel. Bridges. org
Free Online Design Tool for Short Span Steel Bridges Developed by the Short Span Steel Bridge Alliance http: //www. espan 140. com/
Providing Economical Steel Solutions to 140 Feet (40 Meters)
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)
e. SPAN 140 • e. SPAN 140 is an easy-touse and free resource for bridge engineers & owners. • In 3 easy steps, multiple steel solutions are recommended!
• Step 2: Project Information
• Step 2: Project Details (general dimensions)
• 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
Design Example • Sample plate girder (homogeneous) elevation:
Design Example • Sample rolled beam (lightest weight) elevation:
Practical and Economical Detailing Typical stiffener details Typical diaphragm details Typical bearing details
Durability Solutions • Weathering, galvanized, and painted steel
Manufacturer’s Solutions
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.
A Few e. SPAN 140 Designed Bridges
1 st Direct Application of e. SPAN 140 – start to finish Jesup South Bridge, Buchanan County, Iowa • Buchanan County Iowa • Count Crew Built Bridge • Replacement using W 36 x 135 rolled beams • 65 feet length, 40 width • Better Roads (February 2014) County Crew Accomplishments: • Longest Bridge Built • First Steel Bridge Built • First Concrete Deck • First Integral Abutment • Galvanized Steel • Galvanized Rebar • County Equipment
Other e. SPAN 140 Bridges • 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 e. SPAN 140 for preliminary design • Constructed in summer 2014
First Costs Steel & Concrete Examples
Missouri County Bridges – Where the SSSBA Began Steel Concrete Audrain County, MO Bridge 411 Built 2012 Steel 4 Girders 47. 5 ft. Span 24 ft. Roadway Width 2 ft. Structural Depth No Skew Audrain County, MO Bridge 336 Built 2012 Precast 6 Hollowcore Slab Girders 50. 5 ft. Span 24 ft. Roadway Width 2 ft. Structural Depth 20 o Skew
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. )
Case Study Bridges: Superstructure Only Comparison (Remove Site Prep, Abutment, Grading & Finishing, Guardrail, Engineering, Rock, Etc) Steel Concrete 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 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 = $37. 54 / sq. ft. 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. )
Case Study Bridges: Audrain County, MO Steel: Superstructure $37. 54 per sq. ft. Concrete: Superstructure Cost $50. 61 per sq. ft. 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
Case Study Bridges: Other Bridges in Audrain County Steel Superstructure Concrete Bridge Number 061 140 149 152 710 AVG 028 057 069 520 AVG Year Built 2008 2009 2010 AVG 2009 2010 2011 2006 AVG Span Length 50 50 40 62 64 53. 2 36 36 38 40 37. 5 Skew 0 0 0 30 35 13 0 15 20 30 16. 25 Cost Summary - Labor $14, 568 $21, 705 $15, 853 $24, 765 $31, 949 $21, 768 $12, 065 $15, 379 $14, 674 $19, 044 $15, 291 - Material $56, 676 $53, 593 $46, 282 $92, 821 $69, 357 $63, 746 $51, 589 $54, 450 $50, 576 $46, 850 $50, 866 - Rock $6, 170 $6, 216 $3, 694 $8, 235 $6, 163 $5, 135 $7, 549 - Equipment $7, 487 $12, 026 $7, 017 $19, 579 $15, 266 $12, 275 $5, 568 $10, 952 $11, 093 $14, 742 $10, 589 - Guardrail $4, 715 $7, 146 $3, 961 $7, 003 $4, 737 $4, 663 Construction Cost CONST. COST PER FT 2 $6, 501 $7, 003 $5, 966 $5, 378 $5, 356 $3, 621 $3, 323 $5, 421 $4, 520 $89, 616 $100, 686 $76, 807 $152, 403 $130, 076 $109, 918 $79, 094 $92, 993 $87, 077 $87, 580 $86, 686 $74. 68 $83. 91 $80. 01 $102. 42 $84. 68 $86. 09 $91. 54 $107. 63 $95. 48 $91. 23 $96. 32
County Bridge (Designed by e. SPAN 140) • 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
State Bridge (also Designed by e. SPAN 140) Kansas Department of Transportation • Shawnee County • 112 feet (5 plate girder bridge) • Competitive bid process (steel vs. concrete) • DOT used e. SPAN 140 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
What about Mo. DOT’s OLD 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
Mo. DOT 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
Net Cost and $/ft 2 Costs
Statistical Results (costs $/ft 2) NU: Mean = $ 94. 89 St. Dev = $ 22. 92 Steel: Mean = $ 101. 06 St. Dev= $ 14. 92 No Consideration of Year Built Span Lengths Number of Spans Etc Just Raw Net Numbers
Statistical Work – Assuming Normal Distribution What is the Probability that a Bridge Will Cost Less than $105/ft 2 ? Concrete = 68% Steel = 61%
Here’s a Good Question For a Bridge Project, What is the Probability that a Steel Bridge Will Cost Less than a Concrete Bridge?
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(-(m. S – m. C)/sqrt(s. S 2 + s. C 2)) = 40. 0% Probability that Steel Costs Less than Concrete 0
Using Old Mo. DOT Policy Concrete: Mean = $ 95. 00 St. Dev = $ 22. 92 Steel: Mean = $ 120. 00 St. Dev= $ 14. 92 The Probability that Steel Costs Less than Concrete = 18. 0% Probability that Steel Costs Less than Concrete 0
Two Mo. DOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Route H (Columbia Airport) Steel Plate Girder: 98 ft – 98 ft Discovery Parkway (Columbia)
Two Mo. DOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Route H (Columbia Airport) Steel Plate Girder: 98 ft – 98 ft Discovery Parkway (Columbia)
Two Mo. DOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Route H (Columbia Airport) Steel Plate Girder: 98 ft – 98 ft Discovery Parkway (Columbia)
Two Mo. DOT Bridges Crossing US 63 in Boone County Concrete P/S: 92 ft – 92 ft Route H (Columbia Airport) Steel Plate Girder: 98 ft – 98 ft Discovery Parkway (Columbia) Using ENR CCI Index Increase of 2. 7%/yr For 2018 Concrete = $ 93. 64/ft 2 Steel = $ 85. 84/ft 2
More Recent Bridges (2014 through 2018)
Similar Short Span Bridges (2017 & 2018) Competitive
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
The Bottom Line… Steel bridges are competitive on first costs!
Summary & Conclusions Competition Between Steel & Concrete is Healthy For: Costs Quality of Bridges Industry Responsiveness Industry Capabilities Steel and Concrete are Competitive on First Costs Steel or Concrete May Be the Lowest Cost for a Particular Project Owners, Designers & Contractors Should Consider Both Concrete & Steel for Bridge Projects
Questions & Discussion
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