over a range of one hundred and fifty (150) degrees Fahrenheit.

Spans up to eighty-five (85) feet in length, or in certain cases, up to even one hundred (100) feet, may slide on planed surfaces; but those of greater length must move on nests of turned rollers. Occasionally a rocker end is permissible; but this method of expansion is always to be avoided if practicable.

ANCHORAGE.

Every span must be anchored at each end to the pier or abutment in such a manner as to prevent the slightest lateral motion, but so as not to interfere with the longitudinal motion of the trusses or girders due to changes of temperature or loading.

NAME-PLATES.

The names of the designer, manufacturer, and builder of every bridge or trestle, also the date of erection, must be attached thereto in a prominent position and in a durable manner.

LOADS.

The loads to be considered in designing bridges, trestles, and elevated railroads are the following; and all parts of same are to be proportioned to sustain properly the greatest stresses produced thereby for all possible combinations of the various loads.

A. Live Load.

B. Impact Allowance Load.

C. Dead Load.

D. Direct Wind Load.

E. Indirect Wind Load, or Transferred Load.

F. Traction Load.

G. Centrifugal Load.

H. Effects of Changes of Temperature.

In calculating the stresses caused by a uniform moving load, the load shall be assumed  to  cover  the  panel  in advance of the panel point  considered;  but  the half-panel load going