Journal of the Association of Engineering Societies (1881)
Association of Engineering Societies (U.S.) · New York, [etc.] Board of Managers · leaf 165
oof was formed of three stones forming a true arch, over which was a perfectly formed voussoired arch of four distinct rings, the inner ring having a span of about 1 1 feet. These arches were nearly, if not quite, semicircular. At about this time the Romans commenced the use of the voussoired arch,… … * « m m Fig. 4. Old Stone Bridge at Alcantara, Spain (105 a.d.) All records in the form of ruins, tablets, etc., fail to indicate that the true arch was employed in structures to any great extent prior to the sixth century B.C. The arched form, however, was quite common from earliest times, and…
Engineering
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