Apparently, there was some warning that the bridge was failing because there are amateur videos showing roadway gaps and uplift followed by the actual collapse. Be careful when searching because there's a suspension bridge (which didn't collapse) that has the same or very similar name, Juscelino Kubitschek de Oliveira Bridge. See image of bridge here: https://www.folhadobico.com.br/wp-content/arquivo/2023/09/2-13.jpg The stains on the structure mid-span imply long-term lack of maintenance on the sixty-year-old bridge.
Is there anything they could have done over the years to prevent this from happening, or was the design/construction so bad that collapse was inevitable?
Does Brazil have a robust bridge inspection program? If not this sort of collapse is inevitable. Even with the US's relatively robust inspection system where collapses are rare, we still have them (ex Fern Hollow).
I suspect that the time where any tendons could be safely detentioned for replacement is long past.
Well in 2015 the bridge looked like this and even up to 2022 it looked pretty flat or slightly upward curve.
In 2024 it looked like this
Visible sagging in the middle and also visible from the banks. I'm kind of guessing here, but the extra staining of the concrete barriers and guard rails is possibly due to ponding of water and splashing from trucks and cars when it rained due to the sagging of the central section?
You would hope that any sort of regular inspection would have spotted that.
The deterioration over the east and west supports is rather astonishing. It's not as though informed persons were unaware of what was happening. Even the satellite imagery (Google Maps) captured the repair crew putting lipstick on the pig.
Closest alternate river crossing 64 km detour, this is going to be painfully slow given the observed traffic on the collapsed bridge. Ignore the google travel times. Waze correctly marks the bridge as closed, but only provides car travel times.
Message posted on Waze (google translate), (closest bridge)
DNIT warns of total interdiction on BR-226/TO, on the bridge over the Tocantins River. As an alternative route: Tocantins (195 km): Users must access the road that goes from Darcinópolis/TO to Luzinópolis/TO, arrive at BR-230/TO and continue until km 101 (city of São Bento/TO). Then take the right, towards Axixá/TO and Imperatriz/MA. Maranhão (125 km): Users must access BR-226/MA in Estreito/MA to Porto Franco/MA. From Porto Franco/MA, users should take the BR-010/MA to Imperatriz/MA.
The 'inclined elements' may be post-construction shear strengthening. Also, if you look at some of the collapse photos, there appears to be external PT tendons running under the bridge deck and that may suggest post-construction flexural strengthening too.
Long-span concrete bridges built before/around the 70's by the balanced cantilever were often designed with a midspan shear joint to preserve the structural intent - i.e.. free cantilever. However, many of them constructed in that time period by that method suffered excessive midspan deformation. Parrott's Ferry, Koror-Babeldaub bridges etc. Long-term creep and shrinkage properties of the concrete were often underestimated (especially for Parrott's Ferry where they used light-weight concrete), resulting in significantly greater deflections. Bridge constructed beyond the 80's - whilst built using the balanced cantilever method - they eliminated the midspan shear joint and included continuity tendons to act as a continuous multi-span bridge. This may explain the midspan deflections of this bridge and why they possibly strengthened it.
I am assuming (guessing?) that tendon corrosion of the original in-deck PT tendons was the root cause of this collapse.
Thanks for your insightful post. Where did you find the photo and what was the context. It looks like it was pre collapse with extraordinary damage to the strengthening elements. (There was more of a left over stub than I thought)
