Tag Archives: cast in place

This Bridge is Getting Very Advanced

A work-related post for today.  One of our projects is a light rail expansion and part of it involves the construction of a long span bridge.  This was not the original plan, but it is what we ended up having.  It is constructed by having forms for pouring a section of the bridge in one place and then, when that section is cured, a traveler moves out with the forms to pour the next section.  This is all done from a central column so the weight balances out as the bridge expands in each direction.

It is now very close to the final pours, and they will soon be done.  I got to go and see the progress recently and that included looking at the center section of the bridge where the gap between the two sections coming from each direction are close to meeting.  The bridge section is hollow, and you can see across and into the other half.  The final pours involve joining each end to the rest of the right of way and then, when they have been post-tensioned, this center section will be poured.  There will be more to do but this is a major milestone in the project.

Building a Bridge One Bit at a Time

One of our work projects includes the construction of a long span bridge for the light rail line to run over.  I have been down on many occasions since the construction started on this section but much of the early work was the preparation of the ground and the creation of the foundations for the final bridge.  We now have the piers in place and the construction of the bridge itself is underway.

This type of construction involves casting the bridge in sections in place rather than offsite and then bringing them in.  Steel supporters called travelers, hold the formwork in place as each section is cast.  When it is cured, the traveler moves out onto the new section and the process is repeated.  This happens symmetrically about the pier, so the bridge grows out in both directions at once keeping everything balanced.

The process moves quite quickly so, each time I go down, the bridge has got noticeably larger.  There are actually to sections happening at once to make the two halves of the bridge.  They grow towards each other, and the final casting will connect the two cantilevered spans to complete the bridge.  That will happen later in 2024.  The section of the bridge is hollow so it will be possible to access the insides of it in the future.  If I get a chance to go inside at some point, expect more images here.