Responses to questions received following I-526 Wando Bridge closure As of May 31, 2018 Structurally Deficient: 1. What is the definition? Bridges are considered structurally deficient where significant load carrying elements are found to be in poor or worse condition due to deterioration and/or damage, or the adequacy of the waterway opening provided by the bridge is determined to be extremely insufficient to the point of causing intolerable traffic interruptions. The fact that a bridge is "structurally deficient" does not imply that it is likely to collapse or that it is unsafe or that it has to be restricted or closed. It means the bridge must be monitored, inspected and maintained more closely. 2. Who determines if a bridge is structurally deficient? The SCDOT, as with all states, follows the National Bridge Inspection Standards (NBIS) as contained in federal law. In addition the FHWA provides criteria for defining whether a bridge is Substandard (structurally deficient and/or functionally obsolete). The condition of different parts of a bridge is rated on a scale of 0 to 9 (with 9 being excellent and zero being failed ). A structurally deficient bridge is one for which the deck (riding surface), the superstructure (supports immediately beneath the deck) or the substructure (foundations) are rated in condition 4 or less. These ratings for the individual bridges are determined by nationally-certified bridge inspectors. 3. What criteria are used to determine which bridges need to be replaced and who determines? Objective and quantifiable factors are used to rank bridge replacement projects by SCDOT s engineers. These analytical lists are approved by the SCDOT Commission and receive public comment. The criteria used to rank the bridge projects are: Major Criteria Structural Condition Traffic Status (closed, load-restricted, or recommended for load restriction). Average Daily Traffic (ADT) Average Daily Truck Traffic (ADTT) Detour Length Minor Criteria Route Continuity and River Basin Upgrades District Repair Feasibility Improved Emergency Services and Emergency Evacuation Routes State Freight Network Strategic Corridor Network New Schools and/or Changes in Bus Routes Known Commercial Routes Future Economic Development (Residential/Commercial) SCDOT s 10-year plan and focus is to reduce the number of structurally deficient bridges in the State. The SCDOT Commission has established two bridge replacement programs, both focusing on structurally deficient bridges: Load-Restricted Bridge Program and the National Highway System (NHS) Bridge Replacement Program.
4. What is the cost of replacing the 465 bridges identified in the 10-year plan? Can you identify the projected most-expensive and most-expensive project? The SCDOT Commission has approved an average annual bridge replacement program at $151 Million annually for a total of $1.51 Billion over the next 10 years. Beginning in year 2024, this number is expected to be increased to $166 Million annually based on the February 2018 Commission action to invest more in bridges. The more expensive bridges are expected to be those involving bridges on the National Highway System and the least expensive would be anticipated to be those associated with the load restricted bridge program. 5. What are the DOT s plans for the remaining 300 +/- structurally deficient bridges that are not slated for repairs under the 10-year plan? Repairs only, eventual replacement? The SCDOT Commission approved, in February 2018, allocating an additional $15 Million annually to the bridge program once the tax credit sunsets and those IMTF funds return to SCDOT s budget. Even with this additional investment, there remains an estimated $31 Million annually in unfunded bridge needs in the State. The replacement projects will be ranked based on objective and quantifiable factors and advanced accordingly. Bridge preservation (repairs) must also continue to be a part of the overall bridge program as well. 6. What are the main funding sources for the bridge replacement program? It is a combination of federal and state funding with a combined average annual planned investment of $151 Million. Beginning in year 2024, this number is expected to be increased to $166 Million annually based on the February 2018 Commission action to invest more in bridges. The split varies over time, but this predominately federally-funded program ranges at values of approximately 80% federal funds annually in the projected 10-year bridge program. 7. How much IMTF funds are expected to be committed to the bridge program? Accounting for the February 2018 Commission action to add future funding (through the tax credit sunset) to the bridge program, it is forecasted that approximately $31 Million annually on average from the IMTF will be utilized to assist in funding the bridge replacement program. 8. What would qualify the bridge as deficient if a cable that holds it together being compromised doesn t? The National Bridge Inspection Standards rates bridges based on three components: substructure, superstructure and deck. A damaged cable associated with this particular bridge type and design would be associated with the superstructure rating. The most recent NBIS inspection and rating of the bridge occurred just prior to the rupture of the cable and therefore was not considered as part of the rating. 2016 Cable Damage: 9. Why wouldn t the bridge be considered deficient if the cable damage in 2016 triggered increased inspections? The damaged cable in 2016 was replaced. 10. What was the date that the weekly monitoring started in 2016 after the issue was found? September 29, 2016 11. What was the issue in 2016 and was the cause determined? While some other repairs to the bridge were being completed, a damaged tendon (cable) was discovered in the main span of the westbound bridge. Forensic testing has confirmed that the 2016 cable failure was due to corrosion.
12. Are engineers exploring similarities between the recent cable break and the one in 2016? Yes. 13. Please provide all records from 2016 to present which document all engineering, metallurgical and other testing performed on the Wando Bridge s cables. Please include all data, reports, evaluations and recommendations as well as SCDOT document related to its investigation and repair of the cable defect. Included in the documents. 14. What is the date the first damaged cable was discovered? Were any other damaged cables discovered before that date? September 29, 2016. No other slack or ruptured cables were discovered prior to that date. 15. What were the repair costs for the 2016 cable repair? Approximately $1.8 Million 1990 and 1991 issues 16. Any/all letters and/or memos to /from the SCDOT from 1990 and 1991 concerning the Edwards Bridge. We are providing what information we have found to date. 17. Any/all change orders between 1990 and 1991 concerning the Edwards Bridge. We are providing what information we have found to date. 18. Any/all scope or work documents from 1990 and 1991 concerning the Edwards Bridge inspection Records. We are providing what information we have found to date. 19. All inspection records for the Interstate 526/Edwards Bridge. We are providing what information we have found to date. We are also providing a summary of the NBIS inspection findings for the bridge. 20. Any and all records, investigation reports, investigation materials, notes, witness statements or any other materials or documents relating to the enhanced inspection schedule. We are providing what information we have found to date. 21. All inspection records for the Interstate 526 (Governor Edwards Bridge) between 2017 and present date. We are providing what information we have found to date. Some items are being provided in draft form. 22. Records related to all inspections of the bridge, including video, drone footage, and photo documentation. We are providing what information we have found to date. 23. Any forensic analysis about the Governor Edwards Bridge from the SCDOT between 01/01/17 and present date. We are providing what information we have found to date. Some items are being provided in draft form.
10/11/2002 memo 24. Authenticity of October 11, 2002 memo from D.H. Freeman to Robert L. Lee. We acknowledge the authenticity of this memo requesting FHWA grant funding for the innovative bridge research and construction program. However, based on the current review of the information, we have not found any evidence in the grant application or files that it was requested because of any specific concerns with active corrosion but rather as a way to avoid inspecting the bridge by destructive methods. 25. Memos and other correspondence related to an October, 2002 SCDOT letter to the Federal Highway Administration regarding the potential installation of acoustical monitoring equipment on the Edwards Bridge. We acknowledge the authenticity of this memo requesting FHWA grant funding for the innovative bridge research and construction program. We have also identified a nearly identical request for grant funding in 2005. 2010 Briefing by Lee Floyd 26. All memos, communications and studies related to 2010 concerns raised by SCDOT bridge maintenance engineer Lee Floyd about problems with the Edwards Bridge, including corrosion of the cables. We are providing what information we have found to date. Construction of Bridge 27. When was the contract ordered for the Wando Bridge When was the contract awarded? When did actual construction begin? The earliest records we have been able to locate are the construction diaries, the earliest of which is dated May 29, 1985. 28. Who were the contractors? This was a design-build contract. The design-build team for the project was T.L. James (contractor) and Figg Muller (engineer). 29. Who decided on the design firm? This was a design-build contract. The design-build team for the project was T.L. James (contractor) and Figg Muller (engineer). 30. Who selected the design firm? SCDOT selected the design-build team. 31. How much did it cost? What was the contract amount? SCDOT paid $42,481,088.36 for the completed project. 32. When was bridge officially opened to traffic in 1991? We have not been able to determine the exact opening date within our current records. 33. All Bridge delays Were there any delays in the construction? On time? Unknown at this time. 34. The engineering design manual for the bridge. Please include engineer's notebooks. This information includes the design plans and will be available for review at the Charleston District Office or Columbia Headquarters Office because it cannot be released due to security concerns.
35. All forecasts related to vehicle traffic over the bridge from its design to present. See below. 36. Any correspondence sent to FIGG Bridge Group from the SCDOT about the Governor Edwards Bridge between 01/01/17 and present date. We are providing what information we have found to date. Structural Issues 37. Emails, letters and other correspondence from SCDOT to county and municipal officials in Charleston and Berkeley Counties from 2010 to present regarding structural issues with the Edwards Bridge and the potential for closing the span. Included are two press releases, dated December 2, 2016 and November 6, 2017 as well as an article from the Post and Courier, dated November 6, 2017 regarding damaged cables and restricted traffic conditions. 38. All records/correspondence from 2000 to present date concerning structural issues with the bridge. This includes, but is not limited to, problems identified with the corrosion and rupture of cables supporting the concrete segmental bridge. We are providing what information we have found to date. Some items are being provided in draft form.
39. Any repair plans to the Governor Edwards Bridge developed by the SCDOT between 01/01/17 and present date. We are providing what information we have found to date. Some items are being provided in draft form. May 14, 2018 closing 40. Please explain the other issues/concerns small and large found on the bridge when it was shut down after inspection on Monday May 14th besides the snapped cable. A failed tendon at Pier 27 was discovered on May 14, 2018 during a routine weekly site inspection. As a result of the failed tendon, the damaged tendon found at the same pier in 2016, and the unknown cause of the failure, SCDOT closed the bridge to all vehicular traffic. Litigation 41. Any litigation brought against the bridge? None to our knowledge at this time. Traffic Congestion due to closure of bridge 42. Is SCDOT paying for the additional cost of increased police presence due to traffic flow changes? The Secretary has committed to reimbursing our local government partners for extraordinary expenses they have incurred during this event. 43. Are there any extra resources (tow trucks, SHEP trucks, HP troopers) dedicated to 26, considering 26 between I-526 and the Ravenel Bridge is likely seeing increased traffic because of the two-lane I-526? Yes, SCDOT has made adjustments to its traffic management plan to reflect increased coverage on I-26 as well as other routes in the area. 44. Do you have any volume numbers for 26 between I-526 and the Ravenel Bridge and, for comparison purposes, an average number from before the 526 lane reversal? Yes. Please see tables providing comparative data for I 526, I 26 and Ravenel Bridge. 45. Eastbound motorists heading to the Mount Pleasant area were seeing 40-minute additions to their travel times. Do you know what that statistic are now? Real time travel time is posted on the SCDOT website and SCDOT s 511 app as shown below.
Ravenel Bridge 46. Most recent sufficiency rating for the Ravenel Bridge? 93 47. As I said the most recent data I have access to from the NBI gives it just a 77, which is a much lower score than the Don Holt and Westmoreland which are significantly older than the Ravenel. Is there a reason the Ravenel bridge scored so low comparatively? The Ravenel scores high in the sufficiency ratings. The latest sufficiency ratings for the requested structures are: I 526/ Westmoreland = 86.7 EB, 82.4 WB I 526/ Don Holt = 92 US 17 (Ravenel Bridge) = 93 I 526 / Wando = 77 EB, 77 WB 48. Also, is the SCDOT confident the Ravenel bridge can handle the increased traffic due to the Wando bridge being closed? We have no concerns about the increased traffic loading on the Ravenel bridge. 49. What may have caused the hole near pillar of bridge? And what is SCDOT doing to repair it? SCDOT is working with the Town of Mt Pleasant on both the cause and the repair. This void poses no danger to the Ravenel bridge. Bridges Statewide 50. Which bridges statewide is inspected on a frequency of 12 months or less? There are currently 1768 bridges that SCDOT is inspecting annually out of the 8423 state-owned bridge inventory. This includes the 735 structurally deficient bridges which are inspected annually. In addition, as part of our due diligence, SCDOT annually inspects a large number of H-10 bridges that were built in the 1960 s era as part of the farm-to-market program. These bridges typically have timber foundations and were constructed to accommodate lower traffic loadings versus today s standards. Attached is the list of state-owned bridges that SCDOT is inspecting on a 12 month or less frequency. 51. Would like the most recent bridge inventory statewide which is sent to federal government every year. Please see the table obtained from the FHWA Highway Statistics 2017 publication, Bridge Condition by owner 2017.