Earth Retention, Permanent Shoring, Temporary Shoring, Soil Nail Retention
  Earth Retention
 
  Permanent Shoring
  Temporary Shoring
  Soil Nail Retention
  Shotcrete
  Drilled Piers
 
  Cased Hole Method
  Slurry Hole Method
  Osterberg Load Cell Testing
  Micropiles
 
  Grouted Micropiles
  Helical Micropiles
  Underpinning
 
  Pit Underpinning
  Micropile Underpinning
  Rock Anchors
 
  Mat Footing Uplift
  Drilled Pier Uplift
  Dewatering
 
  Construction Dewatering
   
 
Earth Rentention
 
Permanent Shoring

The traditional method of below grade construction consisted of constructing a temporary earth retaining wall, then coming inside the temporary wall and constructing a permanent cast-in-place concrete foundation wall and interior foundations. The concept of a permanent shoring wall combines the effects of the temporary shoring wall and the permanent foundation wall. The result is that the owner of a project receives one wall for less than the price of two which serves both functions.

The permanent shoring wall also has benefits for schedule reduction and subcontractor congestion on the jobsite. This approach is particularly well suited for below grade parking deck construction in urban environments; however its application is appropriate for a wide range of projects and environments.

Our most commonly used approach to permanent shoring consists of vertical steel H-piles that are inserted into pre-drilled pilot holes which are then backfilled. The excavation then begins at the top and proceeds downward in approximately five foot lifts. As the lifts are excavated, concrete lagging is installed either between or in front of the H-piles.

Our preferred concrete placement method is by shooting the concrete pneumatically at a high velocity onto the surface, otherwise known as shotcrete. A waterproofing admixture is added to the mix for applications where impervious concrete is desired. This admixture eliminates the need for external waterproofing applications. Multiple options for finishing the shotcrete are available depending on the desired appearance, including staining for color choice.

Lateral support for a permanent shoring wall greater than approximately fifteen feet tall is typically provided by grouted tieback anchors. These anchors can either be temporary or permanent. When permanent easements behind the shoring wall are not available it is generally required to make the tiebacks temporary. In this case, the structure inside the shoring wall is designed to resist the lateral load in the permanent condition.If the required shoring wall height is less than approximately fifteen feet, generally no tiebacks are required.

Perhaps the greatest advantage to this shoring wall type is that it maximizes the available lot space. A two wall system, a temporary shoring wall and a permanent foundation wall, occupies much more space than a single permanent shoring wall system.
 
Temporary Shoring
In congested environments with significant grade changes, temporary shoring is often an economical and reliable way to create vertical grade separation for below grade construction. While these shoring walls do not allow full property line to property line use due to required interior space for cast-in-place foundation walls, they do offer advantages in specific situations.

One common method for achieving this grade separation in cut applications is steel H-pile and grouted tiebacks with wooden plank lagging. This method is favored in cases where, due to certain project restraints, a permanent shoring wall is impractical.

Similar to permanent shoring walls, temporary walls are constructed in a top-down manner allowing for foundation construction to begin immediately once the excavation is completed. Foundation walls are typically offset from the shoring wall by about four to five feet to allow for forming of the foundation wall. The space between the two walls is then backfilled and the tiebacks detensioned.
 
Soil Nail Retention
Another economical earth retention system that ABE offers is soil nail wall construction. This wall type is also appropriate for cut applications, and can be constructed either as temporary or permanent. Common applications for soil nail walls include site walls and retention walls for subgrade basements and parking decks.

This wall is constructed in a top-down manner in approximately four to five foot lifts. The soil nails consist of grouted steel bars that are installed nearly perpendicular to the excavated soil face. The nails are typically installed every sixteen to twenty-five square feet of wall area. The head of the nails are typically connected to each other at the face of the wall with lightly reinforced shotcrete facing.

If it is advantageous to the project, a permanent shotcrete layer can be placed on the initial shotcrete layer. The permanent layer contains additional reinforcing and can also contain a waterproofing admixture if required. Additionally, the permanent shotcrete layer can be finished in multiple ways to give a desired textural appearance. Concrete staining is also available to color the permanent layer to further enhance its finish.