roads, thereby provoking much animated discussion; and, as the subject is one of great importance to the designer of future similar structures, that portion of the paper which includes this list will be reproduced here verbatim.

I.   INSUFFICIENCY OF RIVETS FOR CONNECTING DIAGONALS
TO CHORDS OF OPEN-WEBBED, RIVETED GIRDERS.

This defect is more noticeable in old structures than in later ones, especially as the tendency nowadays is very properly to substitute plate-girder for open-webbed construction. In many of the older elevated roads there is no connecting plate between the diagonal and the chord, but one leg of each of the angles in the diagonal is riveted directly to the vertical legs of the chord angles. This detail involves the use of either two or four rivets to the connection, which is evidently very bad designing, as there should be more rivets used, even if the diagonal stresses do not call for more on purely theoretical considerations. Where the theoretical number of rivets is very small, additional rivets should be used for two reasons, viz.: first, one or more of the rivets are liable to be loose, and, second, there is nearly always a torsional moment on each group of rivets, owing to eccentric connection.

II.   FAILURE TO INTERSECT DIAGONALS AND CHORDS OF
OPEN-WEBBED GIRDERS ON GRAVITY LINES.

It is very seldom indeed that the designer even attempts to intersect at a single point all of the gravity lines of members assembling at an apex. The failure to do so involves large secondary stresses, especially in the heavier members. By using connecting plates, it is always practicable to obtain a proper intersection; and it is always better to do this than to try to compensate for the eccentricity by the use of extra metal for the main members.

III. FAILURE TO CONNECT WEB ANGLES TO CHORDS BY
BOTH LEGS.

Some standard bridge specifications stipulate that in case only one leg of an angle be connected, that leg only shall be counted as acting, although this stipulation is generally ignored by the designer working under such specifications.