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| Brian Tannehill, Mar 2019 |
The lampposts indicated where the piers are from which the arches launch. So about an eighth of the rainbow arch is under the deck on both ends of the arch.
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| Street View, Sep 2023 |
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| Historic Alabama Online posted Opening of the Bibb Graves Bridge over the Coosa River in Wetumpka, Alabama.1931 |
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| HistoricBridges This 878' (240m) long bridge has spans of 140' (43m). "This large multi-span rainbow arch bridge is the only one of its kind in Alabama, and one of the top historic bridges in the state. The bridge retains excellent historic integrity. Overall the bridge is in good condition as well, although for unknown reasons a single through arch span is suffering from ASR [Alkali-Silica Reaction] cracking." |
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| GlobalGilson, photo credit: ASR Identification Handbook "Although Alkali-Silica Reactivity (ASR) has created problems in concrete mixtures for centuries, the mechanism was not understood and documented until the mid-1930s. Thomas Stanton, an engineer with the California State Division of Highways, identified the issue. By 1940, he had completed his research showing that alkali content in cement, the amount of reactive silica in the aggregate, and the availability of moisture caused the expansion of sample mortar bars in laboratory tests. ASR is now recognized as a significant cause of concrete deterioration anywhere in the world where siliceous aggregates are found." A diagram shows that the problem in the aggregates is SiO2. [I thought that sand was used as one of the aggregates in concrete mixtures. But I guess not because I just confirmed that SiO2, or silica, is the primary chemical in sand. [CivilToday]] |
Bonus
This had to be a lock. Note the notches for the gates.
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| Satellite |
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