I'm fairly confident that the span in this post I just wrote was built before 1910. Trouble is that I can't find an exact year of construction:
https://www.facebook.com/gribblenation/posts/pfbid02xRtUWgNB8THhunqawbRjMabfrHWYJVYFpDx8pJZvrZoyTcXs5rGPaKmuGGZWMBWAl
Text from the post:
"Pictured in photos 1-3 is the Fine Gold Creek Bridge located near the site of the mining community of Fine Gold along Madera County Road 200 between O'Neals and North Fork. The exact year of construction of this concrete structure is unknown. This span is similar to the 1905 Pollasky Bridge which is now located in ruins on the Madera County side of the San Joaquin River across from Friant (previously Pollasky and Jones Ferry).
Mining claims were staked at Fine Gold during the Mariposa War during 1850. The community was never very large but became a stopping point on the stage road between the original Fresno County seat at Millerton and Fresno Flats (now Oakhurst). The stage road eventually bypassed Millerton when the Fresno County seat was moved to Fresno in 1874. The Fine Gold Post Office can be seen on the Fresno-Fresno Flats Road on the 1882 Bancroft's Map in Photo 5. During 1893 Madera County would be formed from what was Fresno County north of the San Joaquin River.
As noted above, the exact year the bridge in Photos 1-3 was constructed is not known. That said, the structure can be seen on the 1912 United States Geological Survey map crossing Fine Gold Creek immediately west of Mountain View Peak. A replacement bridge was constructed by Madera County during 1947. The 1947 era structure was recently demolished when a new bridge carrying Road 200 over Fine Gold Creek was completed in 2023."
For clarity, here is photos of the Fine Gold Creek Bridge. The structure has a facade almost identical to the 1905-era Pollasky Bridge. If it was part of the same construction period, this possible would be the oldest intact concrete bridge in California.
(https://live.staticflickr.com/65535/53885829413_518470d2ea_4k.jpg) (https://flic.kr/p/2q6GXJn)IMG_6750 (https://flic.kr/p/2q6GXJn) by Max Rockatansky (https://www.flickr.com/photos/151828809@N08/), on Flickr
(https://live.staticflickr.com/65535/53885598881_16113d5e24_4k.jpg) (https://flic.kr/p/2q6FMcF)IMG_6749 (https://flic.kr/p/2q6FMcF) by Max Rockatansky (https://www.flickr.com/photos/151828809@N08/), on Flickr
(https://live.staticflickr.com/65535/53886019185_d0a0dcd9f5_4k.jpg) (https://flic.kr/p/2q6HW9i)IMG_6751 (https://flic.kr/p/2q6HW9i) by Max Rockatansky (https://www.flickr.com/photos/151828809@N08/), on Flickr
(https://live.staticflickr.com/65535/53885828778_c6e230d340_4k.jpg) (https://flic.kr/p/2q6GXxq)IMG_6754 (https://flic.kr/p/2q6GXxq) by Max Rockatansky (https://www.flickr.com/photos/151828809@N08/), on Flickr
(https://live.staticflickr.com/65535/53885829288_9218dffad1_4k.jpg) (https://flic.kr/p/2q6GXGd)IMG_6756 (https://flic.kr/p/2q6GXGd) by Max Rockatansky (https://www.flickr.com/photos/151828809@N08/), on Flickr
Interestingly the western side of the span clearly had a Portland Cement surface:
(https://live.staticflickr.com/65535/53886018525_cb6db1bccb_4k.jpg) (https://flic.kr/p/2q6HVWV)IMG_6755 (https://flic.kr/p/2q6HVWV) by Max Rockatansky (https://www.flickr.com/photos/151828809@N08/), on Flickr