Information from Seattle Department of Transportation

This week, we finished installing and positioning protective ducts for the new post-tensioning system and began the process of installing nearly 250,000 feet of new strands inside the bridge.

Using specialized equipment, we feed the woven steel cable strands into the protective ducts on one side of the bridge’s span and push them through to the other side. In each of the bridge's 3 spans, we will complete this process 8 times.

A spool of steel cable that will be threaded through the West Seattle Bridge’s newest post-tensioning system.

We also began compressing the concrete anchor blocks that will secure the new post-tensioning strands. This includes inserting large bolts into the block and tightening them. This process reinforces the connection between the concrete anchor block and the existing structure, allowing it to withstand 760,000 pounds of force.

The bolts shown in the bottom of this photo will be inserted into the openings in the concrete anchor block. We’ll then tighten the bolts to strengthen the concrete and prepare it for the forces of the post-tensioning strands that will make the West Seattle Bridge stronger.

These stacks of a fiber reinforced polymer material, shown above, will be used to build permanent inspection platforms inside the bridge’s girders. These platforms will allow inspectors to monitor the bridge’s concrete.

We are also preparing to install permanent inspection platforms throughout the bridge’s interior. Inspectors will use these new platforms and the bridge’s movement sensors to closely monitor the bridge’s concrete for decades to come.