...I have to pause at the integrity of the Washington Monument this Fourth of July.
Many of the buildings in DC are made of marble and granite. They are magnificent and the stones are huge. They are very sound buildings, but, the structural differences between the majority of DC buildings and the Washington Monument is obvious.
The stones are strong, but, they are in a spire structure rather than a sprawling structure. The heat stresses are likely to occur differently. It was obvious when there was an earthquake in DC and a crack at the capstone resulted. It is a stress fracture.
Heating can expand the stones. I haven't been to the Washington Monument since my sons were young teens so I don't know what improvements were made. But, if the structure is air conditioned, the difference between internal temperatures and external heating could result in a funky dynamic. When thick stone gets hot it stays hot for a long time. One might recall the 10 thousand deaths in France when people remained in this stone cottages through a heat event.
I am just hoping the National Park Service has been thorough in evaluating any and all stresses possible in this monument. Places like the Lincoln Memorial will be nearly impervious to damage because it is an open air structure where the temperatures outside and inside are not very different.
Sorry to be so oddly concerned on a National Holiday, but, it is one of those things most folks wouldn't think of especially when the parks might be short staffed today.
I would think the National Parks would rely somewhat on the USGS to understand the rocks themselves and the US Army Corp to understand the designs of our national buildings/monuments and their stress points.
Heat is a very big deal.
...The white Maryland marbles (click title to entry - thank you) were the first building stones to be shipped in quantity into Washington by rail. After 1840, as the expanding railway system increased the accessibility of stone from other parts of the country, the use of local building stone declined although Seneca sandstone continued to be shipped down the C&O Canal until the 1890's. The Federal Government contracted for marble from a quarry in Hawkins County, Tenn., in 1848. Marble from this quarry, one of the first areas in the country where marble was quarried commercially, was used in many buildings in Washington, most notably in three interior stairways in the wings of the Capitol built around 1855. Marble from Lee, Mass., was also used in the two wings of the Capitol built in the mid - 1850's. The columns of these wings are made from Maryland marble.
Starting in the 1850's, granite quarried at Dix Island, Maine, was shipped by sea to Washington and was used for facings and columns in the Treasury Building. Granites from New England, Georgia, and North Carolina and marbles from Vermont, Tennessee, and Georgia were used for almost all government buildings after the Civil War until the First World War....
