Replies

More Discussion: Looking at the Radial Gate Outlet Blueprints, it's possible that all of the Anchors to the tendons are accessible for "side coring" removal & new tendon installation repair if the Radial Trunnion Gate is fully raised.

This would greatly simplify the project as only "stop logs" would be needed to dewater the entrance to the spillway gate. (No coffer dam).

I suspect they would have to sequence the timing of tendon removal & replacement as some "alignment support" is required to keep the trunnion pin secure (via the trunnion anchor beam). Before the new Anchor Tendons may be post-tensioned to tensile loads, the anchor concrete must reach curing to "design strength". Any staggering of the "curing to design strength" timing could widen a completion window.

Then there is the "parallel factor". To do all of the anchor tendons in an optimized window of time requires teams of workers working in parallel on all of the gates simultaneously. Big bucks in equipment & expertise all at the same time...... A challenge in Logistics.

That would be a much larger undertaking than I had thought. My conception of the project was simply to unbolt and remove one rod at a time, re-bore and prep the hole, and slide in a new one.

I wasn’t fully aware of the design and in my mind, the other end of the anchor tendon was an exposed bolt/plate type assembly where it could be accessed. I suppose that if that were true, they could have been systematically replacing them over the last few years (provided they felt like doing maintenance prior to an incident).

Graphic of Anchor Tendons (to scale) imbedded within the Gate Concrete Column - 2 sets of 12 for each Trunnion Pin - 48 anchors to each column

Removal of the aged steel rod tendons requires coring of the concrete column slab from the side to remove the "Tee" anchors, nuts, washers imbedded in the concrete. Precise Coring down the length of the steel rod tendon is another requirement to facilitate replacement of a new steel tendon. Drawing altered to show Radial Gate in full upward retraction. This scale drawing reveals that all of the Anchor Tendons would be accessible for repair/replacement construction with the Radial Gate fully raised.