Engineering and Contracting . o trav-eling cranes, each crane carrying two 55-tonmain hoists and two auxiliary gantry cranes(see Fig. 1). On each auxiliary gantry cranethere arc two 5-ton hoists. All motions aremotor-driven, except the bridge travel of the On each side of the river, high tension hy-droelectric power is stepped down by trans-formers, and is converted into 250-volt, directcurrent at two sub-stations, one on each sideof the river. These sub-stations are suppliedby separate systems, and arc connected by sub-marine cables. Each sub-station is of suffi-cient capacity to operate all
Engineering and Contracting . o trav-eling cranes, each crane carrying two 55-tonmain hoists and two auxiliary gantry cranes(see Fig. 1). On each auxiliary gantry cranethere arc two 5-ton hoists. All motions aremotor-driven, except the bridge travel of the On each side of the river, high tension hy-droelectric power is stepped down by trans-formers, and is converted into 250-volt, directcurrent at two sub-stations, one on each sideof the river. These sub-stations are suppliedby separate systems, and arc connected by sub-marine cables. Each sub-station is of suffi-cient capacity to operate all the motors onboth sides of the river, including those re- Engineering and Contracting Vol. XLI. No. 1. quired for the air compressors, which requiresabout HP. Direct current is used exclusively on theerection towers, a: it affords better control anchor arm over falsework, using one of thetravelers. After this arm has been erected thesouth anchor span will be erected by using thesecond traveler. At the same time that the. Fig. 5. View Showing Construction Equipment for Reinforced Concrete Piers. than alternating current, and permits the ready employment of dynamic braking for the low-ering machinery. The lowering of some ofthe heavy members used in the construction ofthe cantilevers would generate an excessive south anchor arms is being erected the firsttraveler will be at work on the north canti-lever arm, and this will be finished at aboutthe same time that the south anchor arm iscompleted. The first traveler will then be takendown and reassembled at a point about twomiles below the bridge site, where it will beused for erecting the suspended span onbarges. In the meantime the second travelerwill be at work erecting the south cantileverarm, and it is planned to complete the erectionof this arm and the suspended span (onbarges) at the same time. The suspended spanthen will be transported to the bridge site andraised into place. An operating platform will be built on eacht
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