Earthquake-proof Buildings.

Progress, Volume II, Issue I, 1 November 1906, Page 28

Earthquake-proof Buildings.

That is what American architects and engineers are in search of just now Their technical press has been full of discussions lately on the best type of building to employ in the rebuilding of San Francisco, in order that there may be no possibility of a repetition of such a terrible calamity as lately befell the city. No one, of course, can guard against earthquake, but the Americans think it is quite possible to build a city which shall be, at any rate to a very great extent, earthquake proof. The Scientific American, for instance, declares that it will be within the power of the engineer and architect to build a second San Francisco, which, if called upon to do so, could pass through such another seismic disturbance without being completely overturned or utterly ravaged by fire. The most hopeful promise for the future (the writer goes on to say) is found in the admirable manner m which the steel skeleton of the modern steel and masonry building has passed through the terrific shock and wrenching of the earthquake. Although this result has been a matter of surprise to the average layman, it is not so to the engineer. Modern structural steel is possessed of such elasticity and toughness that it will submit to the most severe and complicated stresses before it can be brought to the point of rupture According to information at present available, it would seem that m buildings of this type at San Francisco the wreckage directly due to the earthquake was confined to the loosening, and in some cases throwing down, of the brick or stone facades with winch the buildings were covered in. Probably, also, it will be found that the interior partitions and floors have m many cases suffered a similar fate. The loss of the walls or panelling, was due to the fact that they were not homogeneous with the steel frame, but were merely attached to it by methods which were never intended to resist the enormous inertia stresses that were set up when the old building was rocked by the earthquake. Evidently, if this disruption of the walls is to be prevented, they must either be bonded in more completely with the steel frame, or, better yet, they must be made homogeneous with the frame. Now, the last-named conditions are ideally present m the new form of concrete steel or armoured concrete construction, which has made such rapid strides of late years in structures of the larger and more important class. As the results of most elaborate engineering tests, concrete steel has been proved to possess in the highest degrees those qualities of elasticity, toughness, and homogeneous strength which, when combined in a monolithic mass present a structure as nearly earthquake-proof as our present methods and materials can make it.