I-5, Skagit River Bridge Collapse First Annual Missouri Bridge Conference April 9, 2015 Columbia, MO Jugesh Kapur, PE, SE

I-5, Skagit River Bridge Collapse Bridge collapses on May 23, 2013 Struck by over height truck I-5 the only N-S interstate in WA state w/ ADT = 71,000 $14 billion of US-Canada commerce passes thru I-5 annually Courtesy: WSDOT

Collapsed Bridge Courtesy: WSDOT

I-5, Skagit River Bridge Collapse Courtesy: WSDOT

First Steps 1.Within 24 hrs – Assembled team to evaluate replacement options 2.Within 24 hrs – Selected contractor (force acct.) to remove debris 3.Within 48 hrs – Options for temp. bridge alternatives evaluated – 30 day emergency contract executed 4.Within 72 hrs – Governor and Secretary of Transportation announce plans to install temp. span w/in 30 days and reopen I-5 Courtesy: WSDOT

Next Steps Coordination w/ NTSB investigation Inspection of remaining trusses & piers Repairs to remaining trusses ACROW temp bridge ordered and pier supports modified Courtesy: WSDOT

Temp. Span Details Acrow panels – arrived w/in 5 days Two temp. bridges placed side by side using launching technique Speed reduced to 40 mph Opened to traffic in 27 days Courtesy: WSDOT

Perm. Span Contract Details 1.Accelerated RFP Process 2.A+B+C = Best Value Approach A= # hours of total closure x $660K/day B= Days past Sept 4 th x $50K C= Price proposal 3.Two week proposal period – from RFP to award 4.Best value award $6.9M – Max J. Kuney & PB team 5.Anticipated opening of Sept 5 th w/ 12 hr. total closure Courtesy: WSDOT

Perm. Span Options 1.Precast, prestressed deck bulb tee girders (59” deep) 2.Lightweight concrete deck bulb tee girders (65” deep) 3.Steel girders (6’ deep) w/ 3.5” precast stay-in-place panels w/ 5” CIP concrete topping 4.Steel plate girders (5’-6” deep) with CIP slab 5.WSDOT obtained all environ. permits, ROW, detour permits, etc. Courtesy: WSDOT

Preferred Alternate Modified deck bulb tees (lightweight concrete) chosen for: 1.Shorter fabrication time 2.Greater schedule control 3.Conventional construction 4.Concrete wt. = 133pcf Challenges : 1.Concrete superstructure weight less than 915 tons 2.Weight for shipping and erection Courtesy: WSDOT

Girder Connection Details 1.Headed bars used between girders (first use in WA, based on NCHRP research); staggered between girders 2.Full moment connection Courtesy: WSDOT

Camber Challenges 1.Predicted camber – 5.5” 2.Vertical profile - 1.5” 3.Pre-cambered the girder forms ” 4.Used 1.5” modified concrete overlay Courtesy: WSDOT

Perm. Span Details Replacement Scheme – Lateral Slide Courtesy: WSDOT

Lateral Slide Details 1.Push & reset system 2.2 – 150 M-ton jacks one on each side for lateral move; 4 – 150 M-tons for vert. movement 3.Total lateral move – 75 ft 4.Skid beam w/ clad stainless steel sheets; support beams w/ Teflon surface Courtesy: WSDOT

Temp. Bents – Special Feature Special truss span = 77 ft. Courtesy: WSDOT

Skid Track Details Courtesy: WSDOT

Modified Concrete Overlay 17 1 ½” modified concrete overlay 42 hours cure time Deck temperature between F Courtesy: WSDOT

Placement Details Courtesy: WSDOT

Lowering Span To Final Position Courtesy: WSDOT

Bridge Move Summary 1.19 hours full road closure 2.Temp. span out in 25 minutes 3.Permanent span into place in 45 minutes 4.Superstructure lowering in 30 minutes Courtesy: WSDOT

NTSB’s Findings (failure mechanism) 21 1.Truck hits the sway brace 2.Vertical member L4-U4 is deformed 3.Upper chord U3-U5 pulled downward 4.Bucking failure in upper chord at node U4

NTSB’s Findings 1.Load 2” taller than permitted. 2.Pilot car distracted by cellphone (although hands-free); claimed that clearance pole never struck the bridge. 3.Insufficient distance between pilot car and truck (less than 1/2 of what it should be). 4.States should have better warnings for low-clearance bridges. 5.Provide lane specific guidance for bridge clearance.

Vertical Clearance Upgrade Courtesy: WSDOT

Thank you.