O129-00-00-X002 Headwall Replacement

O129-00-00-X002 Headwall Replacement

Last Modified: 08/27/2020 03:43 PM

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PROJECT DESCRIPTION 

In August 2019, the Flood Control District began removing and replace a failed headwall structure on the downstream end of a pipeline corridor channel crossing along HCFCD Unit O129-00-00, a tributary of Goose Creek. 

The project repairs 30-year old infrastructure and restores conveyance to the drainage channel as originally designed. The completed project also ensures that the buried refinery pipelines remain functional across the channel.  

The structural design of this sixteen foot tall headwall requires 12' wide continuous footings x 1.5' thick along the entire 146' of the headwall. For a period following the demolition effort of the old wall, the project site will have a 16' deep by 30' wide hole in the ground extending the full 200' distance between East and West Hutto Blvds. This temporary excavation has been carefully designed with a safe layback slope and a protective shotcrete overlay that serves to protect both the workers and the integrity of the active pipelines buried in the crossing behind the new wall. Pedestrian and bicycle traffic will be routed to the far sides of East and West Hutto Boulevards as a safety measure during construction. 

Construction equipment for the demolition phase will operate from a temporary earthen dam constructed a safe distance downstream of the failed headwall. Ramps will be cut into the existing channel banks to allow from heavy equipment to access the earthen dam. Excavation equipment will operate from a position on the upstream edge of the excavation. Heavy timber mats will be placed on the ground to protect the buried pipelines from potential equipment track/wheel damage.