City Council candidate Ken Wilson says West Seattle Bridge could be opened much sooner than next summer
City Council Candidate Ken Wilson PE SE contends that the West Seattle High Rise bridge could be opened much sooner than next summer and that the reports prepared by SDOT show conclusions about the bridge condition, but whose notes are copies from previous inspections.
Wilson, a structural engineer and bridge inspector, "someone who trains bridge inspectors" was the engineer for the Northgate pedestrian and bicycle bridge set to open Oct. 2.
He maintains that the existing "Jersey Barriers" as the concrete and steel dividers are called, already outweigh the weight of cars in a one lane either direction configuration. If these and some side curbing were removed, work could still proceed on the bridge but traffic could be moving on it.
His explanation, while technical, is backed by his 28 years of engineering experience.
Wilson explains, "My proposal specifically is that the median rail’s superimposed DL (Dead Load) should be removed immediately and entirely, (replaced with candle stick dividers such as SR99's Aurora Bridge) and the two edge barriers should also be replaced with lightweight barriers where beneficial to this critical zone as determined by simple engineering influence line. This reduces current demands at the critical location by 1.5*(3 barriers *427 lbs/ft – 2 temp barriers*100 lbs/ft)) = 1,620 lbs/ft) and will further enhance repaired beneficial pre-compression."
To prevent large trucks from accessing the bridge Wilson states, "Parking garage type clearance steel bars at 8’-2” maximum will be added at each of the four entrances to the bridge and access will be opened to one lane of car traffic each direction with a reduced weight demand of only (1.75* 2 lanes *400 lbs/ft = 1,400 lbs/ft). Buses and trucks continue to cross the lower bridge as they have.”
This idea was sent to SDOT for response and they shared quotes from a West Seattle Bridge Community Taskforce meeting with Bridge Safety Program Manager Heather Marx stating, "Allowing traffic on the bridge now would cause more cracking and further harm the condition of the bridge that we are relying on for the repair."
Wilson maintains, "The statement that my proposed net reduction in loading of -200 lbs per linear foot (making the bridge lighter), would cause additional cracking is false and without engineering basis. The bridge "Stabilization" repair included epoxy injection of cracks, added focused fiber reinforcing and throughout the main center span, as well as longitudinal post-tensioning of the system. Per SDOT's Report, 92% of the 108,179 Average Daily Traffic vehicles are cars that would greatly benefit from access as detailed below since completion of the "Stabilization" in December 2020. Buses and trucks would continue to use the lower bridge as they have.
Furthermore, as stated on Wednesday 9/15/21 by SDOT's engineer Greg Banks PE SE of WSP on Slide 25 (slides were due 8/23/21) in the Western Bridge Engineer's Seminar session 8D Emergency Stabilization: West Seattle High-Rise Bridge, the "Stabilization" design assured "Zero tension under permanent and environmental loads. Adequate capacity for a single lane of live loading." A single lane of AASHTO live loading at completion of the "Stabilization" meant that the bridge was adequate for an additional 951,200 lbs of total added LL (Live Load) weight or approximately an added 709 lbs per linear foot even without removal of the bridge rails' superimposed dead load."
SDOT's Marx also said in the task force meeting, "There are holes in the deck of the bridge that we don’t want people to drive over, especially not at speed."
Wilson replies, " Statements that temporary "holes in the deck of the bridge" are a concern that they do not want people to drive over requires further clarification. It is unreasonable to believe that these holes could not be readily covered, patched, or plugged as necessary given that we are now in the rainy season. The "holes", if not covered, create direct access to fill the bridge with further weight of storm water and cause corrosion. The "holes" are likely square top access holes cut into the deck and typical of box girder bridges, used to provide access within the PT Box Girder for internal work (likely two north bridge girder and two south bridge girder). These typical access holes can easily be covered with temporary steel plates, if not already covered. Such covered access holes will not be a problem in any way to car traffic wheel loading which represents 1/14th of the typical truck wheel design load. Also, a single lane of cars each way can be located within the 50-foot half bridge widths to not cross "holes in the deck", if they are a concern. Without specific details, I do not accept that SDOT is being forthright with the level of concern for this typical construction item, but I am willing to accept further clarification details and photographs for consideration."
The "holes" in question are actually 3 inches deep and were used to provide anchor points for the work platforms that hung below the bridge during the first phase of the stabilization of the bridge. Crews used the platforms to apply carbon fiber wrap to the girder exterior, and to fill in cracks with epoxy to seal them against moisture. These anchor points are easily filled in.
Further on in the SDOT response Marx states, "Cracking occurred in both the center and tail spans. So far, we have added post-tensioning to strengthen the center span, but not yet reinforced the tail spans."
Wilson said, " Again, per Bridge Inspection Report - 7/23/2019 (downloaded from the Seattle website) the 1,500LF of end approach spans (4 spans * 375-ft per span=1500LF) labeled as tail spans and Element 105 and are shown by the inspectors to be in Condition State 1 which is "satisfactory" (NBI 5) or better condition. Concrete cracking is routine in bridges. Observed narrow cracking does not require bridge closure or necessarily added reinforcing. These "tail spans" were not a load reducing concern per the documented condition state and originally were designed for SIX LANES of AASHTO loading (see above), including an allowance for added deck overlay weight that was never constructed, and therefore do not limit the bridge's usage as proposed by two lanes of cars, one each direction, in any way. Again, the response statements to my proposed usage are false and without engineering basis."
When asked about the idea during a media tour of the bridge on Sept. 23 Marx pointed to "another reason we could not remove the barriers" an existing fire department water source to provide water on the bridge in the event of an accident.
Marx went on to say, "I understand where this is coming from. People's lives have been disrupted, and in some cases turned upside down, so I understand that they are looking for any solution they think might work. But we are acting out of an abundance of caution and putting public safety first. We can't open the bridge to traffic because the work on the approaches is not done yet and would cause cracks. It would set us back to square one."
More seriously Wilson charges that the engineering inspection conclusions have been reached regarding the condition of the bridge with notations that have been copied from previous reports. The data comes from publicly available reports and recent engineering presentations regarding the bridge. He found numerous mistakes in the notes as well.
He charges, "looking in Report 07/05/2013 page 3 of 4 and Report 10/8/2014 page 3 of 4 the “Notes” for Element 105 is exactly the same. No change, yet National Bridge Inventory coding for Superstructure Condition page 1 at left is changed from very good (NBI 8) to good (NBI 7). This theme continues again in Report 9/23/2015 where looking at page 3 of 4 under Notes for Element 105 the information is exactly the same, yet now on page 1 Superstructure Condition at the left has been changed from previous good (NBI 7) to now fair condition (NBI 5) with no explanation or change in Notes of Element 105 girder conditions. Again Report 8/3/2016 page 3 of 4 is exactly the same. Here at least in 2016, the Bridge Management System (BMS) quantities of page 1 are now added, but are incorrect. Deck area is too low, girder length is half, railing is wrong and only including two rails instead of three, etc. Also, it is important to understand that the box girder is a prestressed concrete system and also post-tensioned segmentally constructed so that this is Element 100 not Element 105 for a cast in place standard reinforced concrete box girder, an error that has still not been corrected even through the current May 27, 2020 reporting. Then in 8/8/2018 page 3 of 4 Notes for Element 105 are updated in format only with no new notes added.
All the Work Orders and numbers are the same as had been on the report for years requesting work order maintenance. Note that this update to format was only likely because the WSBIS system was updated. Reviewing the 7/23/2019 “Special” inspection report page 4 of 5 you can see the exact same notes and format from 8/8/2018 and same notes unchanged since 7/05/2013 even though girder Superstructure condition has changed from NBI 8 to NBI 7 to NBI 5 without new information conveyed under Notes for superstructure girders. The BMS quantities for girders were corrected in this 7/23/2019 special inspection report to two girder lines, but no other mistakes corrected. Under Special Inspection Notes (Element 3) page 2 of 5 it is apparent that between 5/30/2019 and 7/23/2019 the longterm cracks at the 11th and 12th panels East of Pier 16 (West Seattle side) and similar cracks at the 11th and 12th panels West of Pier 17 (SODO side) were prepared and made ready for epoxy injection. Routine interim inspection 11/14/19 showed under Element 3 Special Inspection notes that “All injected cracks on both boxes were checked and no apparent re-cracking was found.” While again on page 4 of 6 Element 105 Concrete Box Girder notes were unchanged. Inspection report from 5/19/2020 (date on page 1) showed the Superstructure condition at critical (NBI 2) reduced from previous fair (NBI 5), but again without girder Element notes for why the changes and only on page 2 of 6 does it say “5/23/2020 Bridge closed to all traffic effective 7 pm due to worsening conditions”, which is mistaken as the bridge appeared to have been closed 3/23/2020. “
The Presentation on crack width for the West Seattle Bridge made before the American Society of Civil Engineers is linked here.
Wilson, running for City wide Council District 8, has other issues he's concerned about too. Homelessness, Critical Green Canopy, Public Safety & Support for Police. Wilson states, "We cannot continue to watch in frustration as Seattle becomes lawless, 911 response times increase, or go unanswered due to Council caused losses in police staffing. Homeless challenges are extreme and unaided, while parks and schools are made inaccessible. High school track teams can no longer use Green Lake and Woodland parks." He also says, "It is not compassionate to allow homeless to continue living at the edge of roads where they struggle with additions and mental problems." Finally, he asks consideration of his campaign web site (www.KenForCouncil8.com) stating that "we must plan and develop smarter to protect our critical green canopy and old trees that are so valuable for capturing carbon, reducing heat, and the health of our built environment."
You can watch a series of videos produced by the Wilson campaign, including one regarding the West Seattle Bridge on his campaign site here. https://www.kenforcouncil8.com/video-links
Not surprising. What are they waiting for: more Federal funding? Thank you, Westside Seattle. All the more reason for newspaper support in this era of mis-information.
Did Ken pay for this advert, or are you just uncritically posting whatever reckless nonsense he sends you?
No, Ken Wilson did not pay for this. You are entitled to your opinion. In a presentation made before an engineering society, Greg Banks of WSP, not Ken Wilson, shared that in fact the bridge is capable of handling a single lane of traffic right now. The slides that show that have not been released for public viewing but we are satisfied from what we were shown that this has been verified. Wilson, with his vast engineering and bridge expertise, merely extrapolated that fact with the existing dead load on the bridge which would in fact outweigh that of another single lane of cars, meaning two lanes of traffic could be on the bridge in short order. Far from reckless, he's making an educated assertion about the bridge. We have yet to hear from SDOT or any other bridge engineer who will say he's wrong. What SDOT has asserted is not that cracks would get worse at midspan. but that cracks (never mentioned by them) in the approaches to midspan would worsen. What cracks? These were never shown, brought up in Community Task Force meetings, or by the Expert Panel. Wilson is pointing out that the repairs could in fact continue as 18,000 vehicles per day are no longer diverted into neighborhoods. That assertion is worthy of a serious response. Not a casual dismissal by people with zero engineering expertise.