History of the Washington National Monument and of the Washington National Monument Society

by Frederick L. Harvey

ADMINISTRATION.

Under the authority of the act of Congress of August 2, 1876, and joint resolutions of June 14, 1878, and June 27, 1879, the Monument is being constructed under the direction and supervision of a Joint Commission, consisting of the President of the United States, the Supervising Architect of the Treasury Department, the Architect of the Capitol, the Chief of Engineers of the United States Army, and the First Vice-President of the Washington National Monument Society.

PROJECT.

The project or design of the work is an obelisk 550 feet in height, faced with white marble mid hacked with dressed granite rock. Of this structure 156 feet is already finished.

The base of the Monument is 55 feet square, the top will be 34 feet 6 inches square, and it will be crowned with a pyramidion, or roof, 50 feet in height.

The proportions of the parts of this obelisk are in exact accordance with the classic proportions of parts of this style of architecture, as determined after careful research by the Hon. George P. Marsh, American Minister at Rome.

The shaft, as proportioned, both in dimensions and weight, will be entirely stable as against winds that could exert a pressure of one hundred pounds or more per square foot upon any face of the structure.

The project includes the preparation of the foundation so as to enable it to carry this structure. This preparation, or strengthening, consists in making the existing foundation wider and deeper, in order to distribute the weight over a greater area, and in bringing upon each square foot of the earth pressed no greater weight then it is known to be able to sustain.

CONDITION OF THE WORK.

1. Preparation of foundation.—This consisted in placing a mass of Portland cement concrete beneath the existing foundation, extending downwards 13-1/2 feet; underneath and within the outer edge of the old foundation 18 feet; and without this edge 23 feet; then, of taking out the old foundation from beneath the shaft, for a sufficient distance back to obtain a good bearing upon the new masonry which is built out upon the slab first mentioned.