Shoring Review

What We Do

Shoring is a means of supporting the earth in a trench or vertical cut for construction or other activity. There are many types of shoring techniques for earth reinforcement or support. The picture below shows a vertical cut wall using soldier piles, shotcrete and tiebacks. Properly installed shoring is critical for maintaining the structural integrity of the adjacent roadway and underground utility infrastructure.

Shoring Review Process

Shoring involves collaboration between both public and private entities, and requires a permit from the Seattle Department of Construction and Inspections in order to begin. In the interest of making things easier for individuals seeking a permit, the Seattle Department of Construction and Inspections and the Seattle Department of Transportation collaborate on the shoring review process to allow for one-stop permitting. SDCI provides permits for shoring, while SDOT oversees the review process necessary for receiving a SDCI permit. Shoring review is typically initiated at SDCI. At the point of intake, the intake reviewer assigns all necessary review locations for a particular project. For any proposed excavation that would be greater than three feet deep immediately adjacent to any given public right of way, a shoring review through the Street Use division of SDOT begins. Shoring review also occurs for any proposed excavation within an imaginary 1H:1V slope (a one-foot horizontal to one-foot vertical relationship, or a 45-degree line). This point is taken from the existing grade at the public/private property line and then descends down to private property. (Please refer to Figure 1 below for clarity). Once Street Use designates a review location, a plan is routed to Street Use for review. SDCI will not issue a permit until Street Use has approved the location.

Figure 1: line drawing of where proposed excavation requires shoring review.
Figure 1

Shoring Components

Shoring components may include cantilever soldier piles, soldier piles and tiebacks, soil nail walls, slope cuts or a combination of the aforementioned. The system that would be approved depends on site specific constraints and public need considerations. Our shoring reviewers always encourage and welcome pre-design meetings. To better facilitate the review process, a direct submittal to the shoring reviewer would be beneficial. The direct submittal shall include the following:

  1. Soils report
  2. Shoring plan
  3. Building foundation plan
  4. Site survey

The City of Seattle allows for components of the temporary shoring system to be placed in the public right of way. The City will allow temporary anchorage such as soil nails and tiebacks to be installed in the public right of way under an indemnity agreement. The soldier piles may be placed in the public right of way as long as they are temporary in function and the permanent building does not rely on their presence. The augur hole may extend 24” into the right of way and the steel soldier pile component, 21”. (Please refer to Figure 2 below for clarity). Prior to the end of the project, the components of the temporary shoring system that are located in the public right of way will need to be removed as follows:

Tiebacks must be detensioned.

Soldier piles, lagging and any concrete encasement must be cut and removed to a point that is 4 feet below grade.

Figure 2: line drawing of the soldier piles.
Figure 2

Please note: Typically a designer would size the tiebacks and soil nails to be fully contained within the width of any given public right of way. If the tiebacks or soil nails extend pass the public right of way and underneath a private property, an easement from the private property owner(s) is required prior to shoring sign off.