SDOT: High bridge repair: Pre-tensioning epoxy injection and carbon-fiber wrap work complete; post-tensioning prep continues
information from Seattle Department of Transportation
This week marks the completion of our pre-tensioning phase of epoxy crack injection and carbon-fiber wrapping that began back in February. This work was necessary to strengthen sections of the bridge’s concrete that had weakened over time and reinforce the areas that surround the new structural components for the post-tensioning system.
Injecting cracks with epoxy and wrapping sections of the bridge in carbon-fiber (seen above) were an important first step in strengthening and reinforcing the bridge. After tensioning the bridge, we will complete a final round of epoxy injection and carbon-fiber wrapping work.
We continued assembling protective ducts that will encase the post-tensioning cables. We are working to position the assembled ducts inside the bridge by using temporary rigging lines and support towers. Once the ducts are in their final position, we will be able to start installing the cables in them using specialized equipment. When the cables are installed, we will begin the tightening process to compress the bridge structure’s concrete.
We built temporary support towers to elevate and brace the ducts that will encase the post-tensioning cables.
We continue to make progress on major maintenance work. We wrapped up concrete grinding and surface preparation work on the Fauntleroy Expressway this week. With the top half inch of concrete removed on about 2 acres of the expressway, we will start pouring new concrete overlay in the coming weeks.
Low bridge rehabilitation: east span platform hoist complete
Two platforms were hoisted to the underside of the low bridge’s eastern span. This allows us to begin our low bridge rehabilitation work.
Last weekend, we successfully hoisted two platforms to the underside of the low bridge’s eastern span. This effort begins our low bridge rehabilitation work that will strengthen the low bridge to keep it strong for years to come.
We will begin epoxy crack injection and carbon-fiber wrapping to reinforce the concrete on the low bridge in the coming months. This is the same concrete strengthening method we’ve been using on the high bridge.
We’ll hoist work platforms on the bridge’s western span in the next few weeks so that crews can easily access the underside of the bridge’s girder.