Principle XXXVI.

In trestles and elevated railroads every column should be anchored so firmly to its pedestal that failure by overturning or rupture could not occur in the neighborhood of the foot if the bent were tested to destruction.

As long ago as 1891 the author designed pedestals which involved truly fixed ends for column feet; but it is only within the last three years that such a detail has begun to come into general use. The ordinary connection of columns to pedestals by an anchor-bolt at each of the four corners of the bed-plate is extremely weak and ineffective.

Principle XXXVII.

All pedestals for trestles, viaducts, and elevated railroads should be raised to such an elevation as to prevent the accumulation of dirt and moisture about the column feet, and all boxed spaces in the latter should be filled with extra-rich Portland-cement concrete.

The neglect of these precautions causes the rapid deterioration of the metal at bases of columns, and thus shortens the life of the structure.

Principle XXXVIII.

In designing short members of open-webbed, riveted work, it is better to increase the sectional area of the piece from ten to twenty-five per cent than to try to develop the theoretical strength by using supplementary angles at the ends to connect to the plates.

This principle is based upon the results of some late tests of the author's on the strength of single angles and pairs of angles connected by one leg only, by which he found that 6" X 3 1/2" angles thus connected developed ninety per cent of the ultimate strength of a flat bar of equal net section, and that 3" X 3" angles developed seventy-five per cent of same.