# Indestructible

Excerpts from an article called The Monolithic Dome in the winter, 1997 issue of ROUND-UP magazine, compiled by Dr. Arnold Wilson, a leading engineer in thin wall shell concrete construction

The monolithic dome is probably the most disaster resistant building that can be built without going into a mountain or underground.

It is predicted that a wind of 70 miles per hour blowing against a 30 foot tall flat building in open flat terrain will exert a pressure of 22 lb./sq. ft. If the wind speed is increased to 300 miles per hour, the pressure is increased to 1004 lb./sq. ft. Wind speed of 300 mph is considered maximum for a tornado. It is far greater than that of a hurricane. It is predicted that a wind of 70 miles per hour blowing against a 30 foot tall flat building in open flat terrain will exert a pressure of 22 lb./sq. ft. If the wind speed is increased to 300 miles per hour, the pressure is increased to 1004 lb./sq. ft. Wind speed of 300 mph is considered maximum for a tornado. It is far greater than that of a hurricane.

Against that much pressure a Monolithic Dome 100 feet in diameter, 35 ft tall would still have a safety margin nearly 1.5 times its minimum design strength. In other words the stress created by the 300 mph wind would increase the compressive pressure in the concrete shell to 1098 psi. The normal design strength of the shell is 2394 psi, and the maximum design strength is 4000 psi. The fact is that the monolithic dome is not flat and therefore could never realize the maximum air pressure against it of 4000 psi. Neither is the concrete limited to only 4000 psi. The margin of safety is probably more like 3 or 4.

The Monolithic Dome at Port Arthur, Texas has not been hit by more than three hurricanes. A hurricane doesn't exert enough pressure on the dome to even be noticed. The Monolithic Dome can very easily withstand the stresses of a Tornado. However debris carried by the tornado could cut the surface membrane. If the tornado carried a large timber or metal object it might be possible - if conditions were just right - to puncture the dome. But the puncture would be very local and never cause any serious damage to the dome. Possible damage to the windows or doors might occur if there was a rapid decompression caused by the tornado.

For most Monolithic Domes, the likely disaster will be earthquake. The worst listed areas in the US are listed as seismic zone 4. Through analysis it is easy to prove that earthquake forces do not even approach the design strength the Monolith Dome is built to withstand under normal everyday usage. It would take an earthquake many times any that we know to even approach the design strength of just the concrete itself (let alone the dome.)