When requests for bids on a paving contract came in higher than expected in 1920, Downer investigated whether the BPC could save money by using its own forces to operate the new construction equipment. After studying the matter Downer reported that the savings would not justify the added work involved in organizing the project. The BPC would have to comply with civil service requirements when hiring the additional workers and then deal with all the possible difficulties that might arise during the course of the project, including bad weather and accidents. The BPC decided to reject all bids and postpone the project.(197)

While the BPC stayed away from actual paving activities, the equipment obtained from the War Department allowed the commission to organize its operations on a large scale with work proceeding simultaneously in two and sometimes three areas of the parkway. The pace of the work picked up when Downer exchanged several pieces of used equipment for the latest Bucyrus dragline excavator mounted on caterpillar traction. Other equipment was modified to suit BPC needs. Downer’s excavation operation consisted of four dragline excavators and four steam shovels supplemented by a derrick truck, two hand derricks, a ten-ton stiff-leg derrick and eleven caterpillar tractors with accompanying dump trailers. This equipment was supplemented by a full quota of trucks, including five one-half ton dump trucks.(198)

The Rigid-Frame Bridge

The construction of bridges and grade separations was another expensive element of BRPR project costs. The parkway had twenty-seven driveway bridges over the river, two bridges over railroad tracks, and six grade-separations. The early bridges built on the parkway were reinforced concrete arch structures embellished with granite arch rings and rubble facing for the spandrels. The bridge parapets were constructed of rough stone with native granite copings. These traditional arch bridges were attractive but expensive. Realizing that it could not afford to construct all the required bridges in this manner, the BPC began to use alternative technologies that mimicked the appearance of traditional arches, but did not require as much concrete or excavation work. The first attempt to reduce the cost of bridge construction employed simple reinforced concrete girder and slab construction, dressing up the inelegant utilitarian structures with native grant arch rings and rubble facing for the approach walls, spandrels, and parapets. Five bridges were constructed using this design, which substantially saved on construction costs. In some locations, the new design was used, but no effort was made to give the bridges an arched appearance. Instead, the BPC saved money by facing the outside girders with hewn timbers to resemble old-fashioned timber-beam bridges. Girder bridges were also well suited to locations where the grade of the road at river crossings was too low for an arched bridge, which would make an objectionable hump in the road profile.(199)


 

(197)Bronx Parkway Commission, Minutes, March 16, 1920, 35-37.
(198)Bronx Parkway Commission, Report, 1922, 41-42.
(199)Bronx Parkway Commission, Report, 1922, 43-44; Bronx Parkway Commission, Minutes, July 24, 1920, 107-109.

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