Earthquake Bolts

[rpcrowe]

A unique feature of many Charleston, SC, buildings are earthquake bolts. After the devastating 1886 earthquake (estimated at 6.9-7.3 on the Richter Scale) many buildings regained structural integrity by the addition of iron rods through the building secured at the ends by Earthquake Bolts...





While hardly up to modern earthquake standards, these bolts have done their jobs for 143-years. Of course, Charleston has not experienced a major earthquake during that time

[Rent]

We used them locally for mining subsidence
Roy

[Shadowman]

Nice shots and info.

[John 2]

Interesting set of images Richard. Takes me back to my school science classes where these were used to explain how strong the forces produced in expansion and contraction are. They were used a lot in the UK on very old buildings where the walls had begun to bulge. The technique was to remove the upper floors, wrap the rod in sacking soaked in lamp oil and set light to it. Once a rod had expanded with the heat, the bolts were tightened then as the rod cooled and contracted, the bulging wall would be pulled in. Sometimes, simple solutions are the best.

[rpcrowe]

Great information... I wonder if they used the same techniques in Charleston. There are a lot of different shaped bolt covers - from the very simple to the very ornate. Most, however, seem to be of this round pattern...

[Wavelength]

These are very informative; nice images; the angularity of view adds to the feeling of Earth quake

[Dave Humphries]

Interesting info from Richard and John,

The ones around London I had always assumed were to strengthen (WWII) bomb damaged buildings.

But now you mention it, they are prevalent on older buildings about the UK, which were less likely to have been bombed - and (thankfully) even less likely to have been subjected to an earthquake.

Examples I have seen are often a simple "X" shape, or perhaps an "S" for the older ones.

I recall as a kid it being suggested the (X) buildings had been "kissed" (to help them get better).

See ya, Dave
xx

[IzzieK]

Great info from John, thank you. I wonder if they can use those bolts in new buildings nowadays…just for the heck of having a good one…???

[Manfred M]

Great info from John, thank you. I wonder if they can use those bolts in new buildings nowadays…just for the heck of having a good one…???

Izzie - that technology is very much in everyday use. Any concrete structures you see from high rise buildings to bridges have re-enforcing steel bars in them. In certain circumstances, the bars are put under tension before the concrete is poured and once it has hardened, the external tension is released and the effect is identical to these bolts (pre-stressed concrete). All you will see are the bolts and large washers, not these fancy plates.

The technology varies; pre-stressing is quite common and post-stressing (as per Richard's pictures) is also done.

[george013]

The old Amsterdam houses have those bolds too. Different shapes. They are used to keep the outer walls connected to the beams.

George

[IzzieK]

Thanks for the further info. I learn something everyday...or try to.