| Bridge Name: | Alsea Bay Bridge |
| Crosses: | Alsea Bay |
| Locale: | near Waldport, Oregon |
| Design: | concrete arch bridge (both) |
| Mainspan: | 450feet |
| Length: | 3011feet (1st) 2910feet (2nd) |
| Below: | 70feet (2nd) |
| Begin: | 1988 |
| Open: | 1936 (1st) 1991 (2nd) |
| Closed: | 1989 (1st) |
| Coordinates: | 44.4319°N -124.0705°W |
The Alsea Bay Bridge is a concrete arch bridge that spans the Alsea Bay on U.S. Route 101 (US 101) near Waldport, Oregon.
There have been two bridges on this site.
The first bridge was designed by Conde McCullough and opened in 1936. It was a 3011feet long, reinforced-concrete combination deck and through arch bridge.The hostile environment caused significant corrosion to the steel reinforcements. In 1972 the Oregon Department of Transportation began projects aimed at extending the life of the bridge. By the mid-1980s it was decided to replace the bridge rather than continuing costly rehabilitation efforts.[1] The first bridge was demolished in 1991.Construction of the second bridge, designed by HNTB, began in 1988, and it was opened in the fall of 1991 at a cost of $42.4 million. The bridge is 2910feet in total length, with a 450feet main span that provides 70feet of vertical clearance. The bridge has a latex concrete deck and the piers are significantly thicker than normal in an attempt to thwart corrosion. Its life expectancy is 75 to 100 years.