North Shore Road Bridge Retaining Wall Improvements

During a July 2021 inspection, the City discovered cracks and movement in the retaining wall on the east side of the northern approach to the North Shore Road Bridge, which supports the approaching roadway. To maintain public safety, since July, the bridge has remained closed to all vehicular traffic.

Since that time, the City has contracted with DOWL for design services and Emery and Sons for construction services under a Construction Manager/General Contractor project delivery approach.

Project Updates - Construction has been delayed until fall 2022

March 30, 2022

This week, the contractor mobilized to the North Shore Road retaining wall work site, to start setting up the bladder bags for dewatering the work zone around the bridge. Upon deployment, the contractor discovered pockets of the lake bed that were deeper than originally anticipated. This has pushed the dewatering bags out of the depth of their safe operating condition.

The initial survey that was conducted in the design stage did not catch some of the lower points in the lake. This was unforeseen and a localized issue that was discovered this week by the contractor.

Out of an abundance of caution, we are deferring this work until the water level can be lowered to a safe operating level for crews.

We plan to resume the repair later this fall, when we can lower the water levels in the lake slightly enough so it is safe to resume work.  Coordination with the Lake Corp will be on-going.

Pedestrian, boat and bike access to the bridge will be restored as soon as possible, but the roadway and bridge will remain closed to vehicular traffic until the work can resume this fall.

March 21, 2022

Considering the feedback received from the March 16 community meeting, the project team has since reviewed the schedule, confirmed availability of labor and materials, and has developed contingency plans. The City is proceeding with construction of the wall replacement this spring, instead of waiting until later this fall. Safety is our number one priority.

 Key information: 

  • Crews and equipment will begin mobilizing to the site the week of March 28. Construction is expected to be complete by late spring.  
  • To maintain safety, starting the week of March 28, the bridge and roadway will be temporarily closed to ALL traffic. This includes boats, pedestrians, bikes, and vehicles. This will be an active work zone and unsafe for the public to access.
  • There will be no boat access under the bridge in to or out of Lakewood Bay. Passage under the bridge will be blocked as crews will be dewatering the work zone around the bridge and walls.
  • Boat access will be open by mid-May, if not sooner, and open for the summer months.
  • Pedestrian access will be open for the June Lake Run.
  • There will be no public parking on the south side of the bridge. Crews will be staging equipment in the public right-of-way.
  • Work hours are Monday to Friday, 7 a.m. – 7 p.m. and Saturday 8 a.m. – 5 p.m. During work hours, please expect an increase in noise and truck traffic as excavators and dump trucks will be accessing the site.

March 18, 2022

On March 16, the City held a community meeting with residents to share more about the project and what to expect during upcoming construction; particularly related to boat, pedestrian, vehicle and bike access.

An audio recording of the meeting can be found here.  

March 10, 2022

  • Construction is expected to start in late March/early April, and be complete by late spring.
  • To maintain safety, the bridge and roadway will be closed to ALL traffic. This includes boats, pedestrians, bikes, and vehicles. This will be an active work zone and unsafe for the public to access. Please use alternate routes.
  • There will be no boat access under the bridge into or out of Lakewood Bay. Passage under the bridge will be blocked as crews will be dewatering the work zone around the bridge and walls.
  • During work hours, please expect an increase in noise and truck traffic as equipment including excavators and dump trucks will be accessing the site.

Schedule Commitments

  • We will commit to having boat access open by mid-May and open for the summer months. 
  • A final go/no-go decision on whether to proceed with construction this spring will be made a few days before construction starts. Information will be posted on the project website.
  • If needed, we will delay the work to start in the fall of 2022, after the summer boating season.

March 7, 2022

Currently, the bridge and roadway remain closed to vehicular traffic only. To maintain safety, during construction, the bridge and roadway will be closed to ALL traffic: including boats, pedestrians, bikes, and vehicles. There will be no boat access under the bridge into Lakewood Bay.

More information will be shared the week of March 14, 2022.

December 16, 2021

Project team staff will be presenting an update to City Council on Tuesday, December 21, 2021. View the council report and recommended actions. 

October 12, 2021

Starting the week of October 18, a test pit will be excavated within the closed area, so crews can conduct more thorough geotechnical investigations. In addition, crews will begin removing extensive invasive vegetation on the retaining wall on the west side of the northern approach.

What to expect over the coming months (prior to major construction):

  • Surveyors and crews may be visiting the site intermittently to conduct investigations.
  • Work hours are 7 a.m. – 6 p.m.
  • Pedestrian access is expected to remain open during most times. There may be short periods where traffic is held to accommodate crews and equipment.
  • A small floating dock/barge will be located next to the wall. At times, excavators and dump trucks will access the site and the test pit location. Please expect an increase in noise and truck traffic.

Frequently Asked Questions 

[updated March 30, 2022]

Background

Why has the North Shore Road Bridge been closed since summer 2021?

During a July 2021 inspection, the City discovered cracks and movement in the nearby retaining wall, which supports the approaching roadway. To maintain public safety, the North Shore Road Bridge has remained closed to all vehicular traffic as the City conducted structural analysis of the retaining wall and approaching roadway. There are concerns with the retaining wall and roadway, not the bridge itself.

What did you base your decision for closure on?

The decision to close the retaining wall (and adjacent bridge) was based on visual assessments from geotechnical and structural engineers, and our own field investigations that indicated cracking and movement between the wall and the roadway.

The survey data showed that the NE corner approach of the retaining wall appeared to have moved about an inch in the past two years, and is bowing outward. 

How long will the bridge and road be closed for?

To maintain safety, the bridge and roadway are expected to remain closed until repairs are completed.

How often is the bridge inspected?

As a part of managing our roadways and bridges, the City has routine analysis done on our transportation system. ODOT inspects our bridges typically every other year. The North Shore Road Bridge specifically has been routinely monitored and surveyed since 2014.

Geotechnical Assessment Findings  

What did the structural analysis find?

The design team has performed detailed testing and analysis of the retaining wall and surrounding area to determine the extent of the defects. In late 2021, the project team and City staff explored alternatives and selected a preferred alternative.

The geotechnical and structural findings support replacing the retaining walls on the northeast and northwest approach with Mechanically Stabilized Earth (MSE) type walls. This is an economical solution that should provide structural stability and complement the existing retaining walls on the south side of the bridge.

What will the new retaining wall and handrail look like?

The retaining walls will be replaced with Mechanically Stabilized Earth (MSE) type walls using lock and load components that are 32” x 16”. Below is an example of the blocks to be used for the wall:

A parapet protective wall and handrail will also be installed. The project team is finalizing the aesthetic details of the wall and handrail. These will be shared shortly.

Will the bridge also be replaced?

The bridge itself does not appear to be of concern based on the latest bridge inspections performed by DOWL.

Construction Schedule 

When is construction expected to start?

Work was originally expected to take place in spring 2022. Crews and equipment are now expected to begin work in fall 2022.  

Why are you delaying the work until fall 2022?

In late March, the contractor mobilized to the North Shore Road retaining wall work site, to start setting up the bladder bags for dewatering the work zone around the bridge. Upon deployment, the contractor discovered pockets of the lake bed that were deeper than originally anticipated. This has pushed the dewatering bags out of the depth of their safe operating condition.

The dewatering bags are not sufficient for the current depth of water, and it would be unsafe to take the risk of putting them in at this time.

Out of an abundance of caution, we are deferring this work until the water level can be lowered to a safe operating level for crews.

How did this occur?

The initial survey that was conducted in the design stage did not catch some of the lower points in the lake. This was unforeseen and a localized issue that was discovered when the contractor mobilized to the site.

What is the revised plan for construction?

We plan to resume the repair later this fall, when we can lower the water levels in the lake slightly enough (a partial drawdown) so it is safe to resume work.  Coordination with the Lake Corp will be on-going.

What will happen to public access?

The bridge will be reopened to pedestrian, bike and boat access until fall. It will remain closed to vehicular traffic until the repair can be completed.  

Was this part of the contingency plan?

Our contingency plans for construction included returning the bridge and closure to its previous condition, so in the event that the retaining walls were not progressing on schedule, pedestrian, bike and boating traffic could resume through the spring and summer months, and the walls could be completed in the fall or winter.

During construction, will the bridge remain open to people walking, rolling, biking, and boating?

No, to maintain safety, the bridge and roadway will be closed to ALL traffic. This includes boats, pedestrians, bikes, and vehicles. This will be an active work zone and unsafe for the public to access. Please use alternate routes.

How will boat access be restricted by construction?

There will be no boat access under the bridge in to or out of Lakewood Bay. Passage under the bridge will be temporarily blocked.

A work zone will be set up on the lake around the bridge and retaining walls. This area will be blocked off with barriers and water will be removed from the work zone. This will create a dry area in order for the crews to begin excavating, removing the existing retaining walls, and replacing the new walls.

I live in the local area, can’t I travel over the bridge and through the road closure signs?

No, the road closed signs are there for a reason – to keep you safe and vehicles out of the closure area. Please do not attempt to move the barricades or travel past the signs, even if you live in the local area. 

Will my trash or mail service be interrupted?

The City notified Republic Services and USPS about the closure. If you have additional work at your home (landscaping, construction, etc.), please let them know to use an alternate route.

What about emergency vehicle access?

The bridge closure will not impact emergency vehicle access. There will be no interruption to emergency response – Police and Fire will be able to access the area from the north or the south.

Costs

What is the cost of the repair? How is it being funded?

Given this was an emergency situation, the project is not funded in the current budget. However, in December 2021, City Council directed staff to use American Rescue Plan Act funding for the unanticipated expense. The total estimated cost for the project including design, construction, and administration is between $1,000,000 and $1,250,000.

 

 

Project Details
ID: 
WO 324
Year: 
2021
Status: 
Active
Project Contact: 

David Kudna

Project Manager

503-635-0261

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