As parkgoers will have noticed, the historic Alvord Lake Bridge, famous for being the oldest rebar-enforced bridge of its kind in the United States, is in a state of disarray.

The west-facing half of the bridge—which dates to 1889 and used to be the main entrance to Golden Gate Park—is collapsing. And as pedestrians have likely noticed, the area is roped off with metal guardrails.

As shown below, a broad chunk of the bridge's retaining wall, which transitions to the roadbed above, has broken free of the rest of the structure. The bridge survived the 1906 earthquake intact, and the integrity of the rest of the bridge is in good shape, but nothing lasts forever.

When can we expect some maintenance work? Joey Kahn, spokesperson for San Francisco Rec & Parks, said that the job is about to go out to bid "in the very near future," but it's going to be a long haul.

"Because this is an historic bridge," he said, "this is a really complex process. Strangely enough, the process involves pulling off the broken piece, building a structural wall behind it, pushing the broken piece back in, and reattaching it."

And the historic nature of the bridge, he said, means "we will create a backup mold of the piece in case it becomes impossible to remove and reattach the piece in one part."

Kahn added that part of the delay was the result of necessary coordination with historic preservation teams.

Thanks to tipster Jeff T.

See something interesting while you’re out and about? Text Hoodline and we’ll see what we can find: (415) 200-3233.