Spans resting on drums of small diameter in proportion to the span length are to be anchored to the pivot-pier by means of a large anchor-rod in centre of pier, extending down ten (10) or fifteen (15) feet into same. This rod shall pass through the centre casting and through a box girder over the centre of the drum, which girder shall rivet into either the transverse or the longitudinal girders. The lower end of the rod shall pass through a heavy cast-iron anchor-piece embedded in the concrete of the pier. Both ends of the rod shall be provided with nuts for adjustment, and all details shall be made strong enough to develop the full strength of the anchor-rod. The upper nut shall be almost, but not quite, in contact with a large washer-plate that rests on the box girder. The size of the anchor-rod is to be determined by assuming an unbalanced upward wind load of five (5) pounds per square foot on the total area of the horizontal projection of one arm of the span.
      The cap-plate for holding down the top connection-plate for the radial struts is to be attached to the top of the centre casting by means of a bolt tapped into same. This bolt is to be at least one and one-quarter (1 1/4) inches in diameter.

The rack for turning the span is to be made in short sections, not over four feet long, so that in case of breakage only a small portion of the rack need be replaced. These rack segments are to be bolted to the lower track with tap-bolts not less than fifteen sixteenths (15/16) of an inch in diameter, and spaced not to exceed fifteen (15) inches between centres. There must be enough of them in any case in any one segment of the track to resist, with a good margin for contingencies, the entire shear (including that due to the rotating moment) caused by the effort of the pinion or pinions that engage with said segment. The least allowable thickness of metal in the rack shall be one and one-eighth (1 1/8) inches. The ends of the rack segments are to be plained so as to secure close contact, and the abutting ends are to be bolted together with turned bolts at least seven eighths (7/8) of an inch in diameter.

The bottom of the rack and that portion of lower track