. Bulletin - United States National Museum. Science. Figure 2i. Im Harpers Ferri bridgi toward the end of its career, carrying a common road ovei the P ai I he westernmost line ol trussing and span no. i had been re- moved long before. View through the Winchestei span looking toward Maryland in P H â ⢠Ferry National Historical Pc standing flanges for riveting together. The circular sei nun is theoretically the mosl efficient to bear compressive Loading. A column of any required diameter could be produced by simply increasing the number of segments, the individual size of which never exceeded
. Bulletin - United States National Museum. Science. Figure 2i. Im Harpers Ferri bridgi toward the end of its career, carrying a common road ovei the P ai I he westernmost line ol trussing and span no. i had been re- moved long before. View through the Winchestei span looking toward Maryland in P H â ⢠Ferry National Historical Pc standing flanges for riveting together. The circular sei nun is theoretically the mosl efficient to bear compressive Loading. A column of any required diameter could be produced by simply increasing the number of segments, the individual size of which never exceeded contemporary rolling mill capacity (see fig. 16). The design exhibits the inspired combination of perfection and simplicity thai seems to ( haracterize most great inventions. It may have been because he had no facilities for rolling that Bollman communicated his idea to Reeves, although this seems illogical. At am rate, Reeves and his associates patented the system exten- sively, .nul the Phoenix column was eventually employed to the virtual exclusion of cast-iron and other types of wrought-iron columns. H\ the end of the 1 'ih century it began to pass from use, as mills became capable of producing larger sections with IH i iperties relatively favorable to column use and more adaptable to connection with other members. Final Use oi the Bollman Truss The Bollman truss found occasional use elsewhere than on the B. & O. lines, but generally only when erected on contract by Patapsco Bridge and Iron Works. However, the fact t Bollman could prof- \ ereel this bridge in the severely competitive I870's indicates that the harsh criticism of the system by authorities of such stature as Whipple was not necessarily justified. Bollmai i ements, in fact, refer to the favorable recommendations of other l'AI'IR 36: ENGINEERING t:n\ I RIB! 1 IONS < IF WENDEL HOI I \l \\ 95. Please note that these images are extracted from scanned page images that may have been
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