3 ms·
As a layman, the difference I notice between "modern" and older bridges is, less exposed steel and more concrete.
by WatchDog 9y ago
As a layman, the difference I notice between "modern" and older bridges is, less exposed steel and more concrete.
- kevin_thibedeau 9y ago> more concrete That will be heavily spalled 50 years from now. Almost as dumb as building thin flexible skyscrapers with reinforced concrete.
- ggcdn 9y agoI fail to see what's dumb about using concrete for skyscrapers. Tall buildings have been built this way for over 50 years without issue.
- kevin_thibedeau 9y agoIt's fine for skyscrapers. The Empire State Bldg isn't going anywhere. It's dumb for thin flexible skyscrapers that will accumulate microfractures in a relatively short time span and whose steel structure is insufficient to support the building in the face of significant concrete degradation.
- ggcdn 9y agoMicrofractures =/= global strength loss. Additionally, the concrete itself tends to strengthen over time. I guess I just don't understand what failure mode you are worried about. There are thousands of slender concrete structures that have been in service (thus far) without issue.
- treerock 9y agoThe Forth crossing (north of Edinburgh) seems to show this progression quite nicely. https://commons.wikimedia.org/wiki/File:Forth_Replacement_Crossing_Artist%27s_impression.jpg https://commons.wikimedia.org/wiki/File:Forth_Replacement_Cr... Three bridges built in 1890, 1964 and 2017 respectively (from right to left in the picture above).