MASONRY 



303 



From a great number of tests of bars and unfinished cables, 

 the committee considered that the average ultimate resistance 



ULTIMATE RESISTANCE AND PROOF TESTS OF 

 CHAIN CABLES 



and proof tests of chain cables made of the bars, whose diameters 

 are given, should be such as are shown in the accompanying 

 table. 



MASONRY 



MATERIALS OF CONSTRUCTION 



The materials employed in the construction of masonry are 

 stone, brick, terra cotta, and the cementing materials used in 

 the manufacture of mortars, namely, lime, cement, and sand. 



STONE 



Strength of Stone. In ordinary buildings and engineering 

 structures, stones are generally under compression. Occa- 

 sionally, they are subjected to cross-stresses, as in lintels 

 over wide openings. They are never subjected to direct ten- 

 sion. As a general rule, a stone should not be subjected to 

 a greater compressive stress than one-tenth of the ultimate 

 crushing strength, as found by experiment. 

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