City council candidate Ken Wilson says the West Seattle Bridge could be opened much earlier than next summer
City council candidate Ken Wilson PE SE argues that the West Seattle High Rise Bridge could be open much earlier than next summer and that reports prepared by SDOT show conclusions about the condition of the bridge, but whose ratings are copies of previous inspections.
Wilson, a structural engineer and bridge inspector, “someone who trains bridge inspectors” was the engineer for the Northgate Pedestrian and Cycle Bridge which was scheduled to open on October 2.
He maintains that the existing “Jersey barriers“As the concrete and steel separators are called, already exceed the weight of the cars in a one-way two-way configuration. If these and some side curbs were removed, work could still continue on the bridge,” but traffic could circulate there.
His explanation, although technical, is based on his 28 years of engineering experience.
Wilson explains, “My proposal is precisely that the superimposed DL (dead load) of the middle rail be removed immediately and entirely (replaced by stanchion dividers such as the Aurora bridge from SR99) and that the two edge barriers also be replaced with light barriers where beneficial for that critical area as determined by a simple line of engineering influence. This reduces current demands at the critical location by 1.5 * (3 barriers * 427 lb / ft – 2 barriers thermal * 100 lb / ft)) = 1,620 lb / ft) and further improve the repaired beneficial pre-compression. “
To prevent large trucks from accessing the bridge, Wilson states that “parking garage type steel bars at a maximum of 8′-2” will be added to each of the four entrances to the bridge and access will be open to one lane. vehicle traffic in each direction. with a reduced weight demand of only (1.75 * 2-way * 400 lbs / ft = 1,400 lb / ft). Buses and trucks continue to cross the lower deck as they did.
This idea was sent to SDOT for response and they shared quotes from a West Seattle Bridge Community Task Force meeting with Heather Marx, Head of the Bridge Safety Program, stating: Count on repair. “
Wilson maintains: “The statement that my proposal for a net reduction in load of -200 lbs per linear foot (making the deck lighter) would cause further cracking. it’s wrong and without an engineering basis. The bridge “stabilization” repair included epoxy injection into the cracks, the addition of focused fiber reinforcement and throughout the main center span, as well as longitudinal post-tensioning of the system. According to the SDOT report, 92% of the 108,179 average daily traffic vehicles are cars that would greatly benefit from access as detailed below since the completion of “Stabilization” in December 2020. Buses and trucks would continue to use the lower deck as they did.
Also, as reported on Wednesday 09/15/21 by SDOT Engineer Greg Banks PE SE of WSP on slide 25 (slides were to be shown on 08/23/21) at the Engineers Seminar session from the western bridge. 8D Emergency Stabilization: West Seattle High Bridge, the “Stabilization” design ensured “Zero voltage under permanent and environmental loads. Adequate capacity for a single dynamic loading lane. A single dynamic loading lane of the AASHTO at the end of the “stabilization” meant the deck was adequate for an additional 951,200 lbs of additional total LL (live load) weight or approximately 709 additional lbs per foot linear, even without removing the rails from the bridge. ‘superimposed dead load. “
SDOT’s Marx also said at the working group meeting: “There are holes in the bridge deck that we don’t want people to drive on, especially not at high speed. “
Wilson responds, “Claims that ‘temporary holes in the bridge deck’ are a concern they don’t want people to drive by need further clarification. It is unreasonable to believe that these holes could not be easily covered, repaired or plugged. if necessary given that we are now in the rainy season. The “holes”, if not covered, create direct access to fill the deck with additional weight of storm water and cause corrosion. The “holes” are probably square access holes cut into the deck and typical of box girder bridges, used to provide access to the inside of the PT box girder for internal works (probably two bridge girders). These typical access holes can easily be covered with temporary steel plates, if not already covered. traffic wheels which is 1 / 14th of the rated load of typical truck wheels. In addition, only one car lane in each direction can be located within the 50 foot hectare. If the bridge widths do not go through the “holes in the deck”, if they are a problem. Without specific details, I do not accept that SDOT is frank with the level of concern for this typical building element, but I am prepared to accept further details and photographs for review. “
The “holes” in question are actually 3 inches deep and were used to provide anchor points for the work platforms that were hanging below the bridge during the first phase of stabilization of the bridge. The teams used the platforms to apply a carbon fiber wrap to the exterior of the beam and to patch the cracks with epoxy to seal them against moisture. These anchor points are easily filled.
Later in the SDOT response, Marx states: “Cracks have occurred in the center and rear spans. So far we have added post-tensioning to strengthen the center span, but not yet strengthen the rear spans.
Wilson said: “Again, according to the Bridge Inspection Report – 7/23/2019 (downloaded from Seattle website), the 1,500 LF of end approach spans (4 spans * 375 feet per span = 1500LF) labeled as tail spans and item 105 and Inspectors have shown that the condition of condition 1 is “satisfactory” (NBI 5) or better. Concrete cracking is common in bridges. The narrow cracking observed does not require the closure of the bridge or necessarily the addition of reinforcement. These “back spans” were not a load reduction problem according to the documented condition and were designed to l ‘origin for SIX WAYS of AASHTO loading (see above), including allowance for the additional weight of the deck covering which has never been built, and therefore does not limit the use of the bridge as proposed by two lanes of cars, one in each direction in any way. The statements of response to my proposed use are false and without technical basis. “
Asked about the idea during a media tour of the bridge on September 23, Marx pointed to “another reason why we couldn’t remove the barriers” from an existing water source for firefighters 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 upset, so I understand that they are looking for any solution that they think might work. But we are taking action. “function of great caution and priority to public safety. We cannot open the bridge to traffic because the work on the surrounding area is not yet finished and will cause cracks. This would bring us back to square one.”
More seriously, Wilson accuses that the conclusions of the technical inspection were drawn regarding the condition of the bridge with notes which were copied from previous reports. The data comes from publicly available reports and recent technical presentations about the bridge. He also found numerous errors in the notes.
it loads, “Looking at report 05/07/2013 page 3 of 4 and report 8/10/2014 page 3 of 4, the ‘Notes’ for item 105 are exactly the same. No change, but the coding of the national inventory of bridges for the state of the superstructure page 1 on the left has been changed from very good (NBI 8) to good (NBI 7). Notes for the element 105 the information is exactly the same, but now on page 1 Condition of the superstructure on the left has been changed from old good (NBI 7) to now fair (NBI 5) without explanation or change in the notes of the conditions of the beams of the element 105. Again, the 8/3/2016 page 3 of 4 report is exactly the same. Here at least in 2016, the Bridge Management System (BMS) quantities on page 1 are now added, but are incorrect. The area of the bridge is too small, the length of the beams is half, the railing is incorrect and only includes two rails instead of three, etc. Also, it is important to understand that the box girder is a pre-stressed concrete system and also built in post-stressed segmentation so that it is element 100 and not element 105 for a beam- standard box in reinforced concrete poured in place, an error which has still not been corrected even in the current report of May 27, 2020. Then, in 8/8/2018, page 3 of 4 Notes for the element 105 are updated only in the format with no new notes added.
All work orders and numbers are the same as those that appeared on the report for years requesting work order maintenance. Note that this format update was only likely because the WSBIS system has been updated. Examination of the “special” inspection report of 23/07/2019 page 4 of 5 you can see exactly the same notes and the same format from 8/8/2018 and the same notes unchanged from 5/7/2013 even though the state of the beam superstructure has changed from NBI 8 to NBI 7 to NBI 5 without new information transmitted under Notes for superstructure beams. BMS quantities for beams have been corrected in this special inspection report from 07/23/2019 for two beam lines, but no other errors have been corrected. Under the Special Inspection Notes (Item 3) on page 2 of 5, it is evident that between 05/30/2019 and 07/23/2019, the long term cracks at the 11th and 12th panels to the east from Pier 16 (West side of Seattle) and similar cracks to the 11th and 12th panels west of Pier 17 (SODO side) were prepared and prepared for epoxy injection. The routine intermediate inspection of 11/14/19 showed, under the special inspection notes of item 3, that “all the cracks injected on the two boxes have been checked and no new apparent cracks have been found. found ”. Again on page 4 of 6, the element 105 concrete box girder notes remained unchanged. The inspection report of 19/05/2020 (date on page 1) showed the critical condition of the superstructure (NBI 2) reduced compared to the previous fair (NBI 5), but once again without beam Item notes explaining why the changes and only on page 2 of 6 it says “2/3/2020 Bridge closed to all traffic from 7:00 PM due to deteriorating conditions” is incorrect because the bridge appeared to have been closed 3/23/2020. “