For this project both the wall foundation and the wall face utilized precast double tee segments that were post tensioned together in the field. In addition, to eliminate shoring that would have been required for conventional wall options, the double tee footing extended in front of the wall. To increase sliding resistance a cip grade beam was linked to the double tee foundation segment following wall erection. Due to the post tensioning the wall tee stems are always in compression thereby eliminating the possibility of tension cracks forming on the fill side of the wall which can occur with typical cip walls.
El Cajon Calif.
||Denver Public Schools Client
||28' Parking Lot Wall Scope Of Work
This essentially vertical wall supports high E 80 loads (night traffic) and LRT commuter rail traffic during the day. By using reverse batter counterforts a planting space is provided between the wall tiers. Internal wall landscaping is unique to the Stresswall System and softens and aesthetically blends the wall face into the environment while eliminating the possibility of graffiti on the wall surface and associated removal costs.
Fletcher Parkway at Jackson Dr. La Mesa, Calif.
||National Projects Client
||E 80 & LRT Tiered Wall Scope Of Work
This ASCE award winning wall is the result of a value engineering proposal submitted to SANDAG (formerly MTDB) by the contractor. The original plan design was a typical MSE wall that required very specific wall fill. All of the wall components are precast/prestressed elements and were made locally. The essentially vertical wall with internal planting offset between the counterfort tiers are possible due to the unique revers batter counterfort configuration. Morrison Knudsen was the engineer for the wall.
Brad Lewis (with KTU&A), the landscape architect, selected indigenous plants that alternatively bloomed continuously so that the wall face always has a variable color pallet. Since emitters are used for irrigation water use is at a minimum.
One of the factors that added VECP was the reduced cost of fill for the counterfort wall compared to the MSE wall. By utilizing construction debris from a landfill substantial savings were realized. In addition, the erection rate for the counterfort wall was substanially faster than would have been the case for an MSE wall.
The MSE wall also required internal cip foundation supports for the catenary poles for rail power lines. Due to the structural capacity of the precast counerforts special counterforts were designed to support both the top tier wall panels and to be utilized as foundation support members for the catenary poles.
This wall, as well as other Stresswalls supplied to SANDAG, are designed for locomotive E 80 traffic. During the day the rails are used by LRT lines whereas at night freight lines utilize the line.
||Herzog Construction Client
||32' High Rail Wall Scope Of Work
This project is the result of a VECP proposed to the Bureau of Reclamation by the contractor. The wall supports the access road to the Theodore Roosevelt Dam Power Station.
The original design was a typical massive cip wall. Field testing determined that ground anchors would be required to both pre-compress the insitu soil as well as enhance wall stability. Therefore the wall has a unique foundation configuration. By including a cip grade beam with vertically oriented mini piles over which the counterforts were placed provided adequate foundation bearing capacity for the wall. In addition, following placement of the base counterforts, ground anchors (tie backs) where inserted through the cip grade beam that was cast over the tails of the counterforts.
Following the installation of the base tiers and anchors the subsequent upper tier components were placed. Site excavated cut material was used for wall fill.
||Bureau of Reclamation Client
|| Scope Of Work
This 1.5 mile 8′ high wall was constructed in the spring when there are typically no hurricanes or major storms. Although unfortunately that was not the case the wall components were placed quickly and reaches filled between high wave events.
The other bid option was a panel MSE wall system. Due to the fact that the counterfort wall can be designed to use a wide range of wall fill including the “clayey” site material the low bidder selected Stresswall partially due to the fill savings compared to the spec. fill for the MSE wall option
The 8′ high ‘seawall counterforts” were cast at Manco in San Antonio and delivered to the site. The shots show the counterfort elements stored on the beach in front of the wall. By working off of the existing embankment excavators placed the counterforts into slots cut into the existing slope. The excavation costs were therefore substanially less for Stresswall than would have been the case for the MSE option.
The “elevated base seawall” counterfort has a unique configuration which results in the minimum excavation volume as well as providing the counterfort support base at a higher elevation than the bottom of the wall elevation. This element geometry facilitates an efficient component erection even in high tide conditions. Also, since the counterfort base is elevated compared to the bottom of the counterfort face, the resultant earth and surcharge loads passes through the counterfort base so the overturning moment is at a minimum. Due to the elevated base the wall foundation loading approaches the minimum value of gamma times h where h is the wall height.
||Matagorda County Client
||1.5 mile 8' high seawall Scope Of Work