Practical Cement Work; An Elementary Treatise on Cement Construction (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...of aggregate, showing a mixture of one part cement to '12 1-2 parts properly proportioned sand and gravel, are in fact sronger than a mix of C 1. S 4., even nearly as strong as a mix of C 1. S 3. Pr'oportions by measure---Cement per eube Compressive Strength. Cement. Sand. Gravel. By Volume. Per sq. in. Under this heading will be included footings and foundation construction; also such walls as are constructed to retain banks of earth, etc. ' The object of foundation footingsis to distribute the weight of structures over a safe area of surface. Some earth foundations by their nature are not sufficiently compact to resist without yielding the great weight imposed by the weight of their walls. To overcome this the surface bearing of the walls is extended by the footing until the surface covered is ample to bear up witha factor of safety, any load it may be wished to impose on them. The safe bearing load per square foot on the different earth foundations is estimated as fol lows: Loam Soil, per square foot, 1 ton Wet Clay, " " " 2 tons Sand, " " " 4 tons Gravel, " " " 5 tons Dry Clay, " " " 6 tons-Hard Pan, " " " 8 tons Bed Rock, " " " 35 tons First, the nature of the earth upon which a structure is to be built must be ascertained, next the weight--dead and live load--it is wished to impose on the walls. This then must be so calculated that the load applied to the footing will be safely within the limits given above per square foot. In walls and columns extending above ground the footings supporting them must extend equal distance from a perpendicular line of the imposed load; while in retaining walls, abutments, dams, and basement...