WENDEL BOLLMAN'S 



Patent Iron Suspension Kailroad Bridge. 



The undersigned would inform the officers of 

 Railroads and others, that lie is prepared to fur- 

 nish Drawings and Estimates for Bridges, Roofs, 

 etc., on the plan 01" Bollman's Patent. 



The performance of these bridges, some of 

 which lia\ '■ been in use for six year.-, has given 

 entire satisfaction. Their simplicity of construc- 



tion renders repairs easy and cheap, and by a pe- 

 culiar connection of the Main and Panel Rods at 

 the bottom of the Posts, all danger from the ef- 

 fects of expansion, which has heretofore been the 

 chief objection to Iron Bridges, is entirely remov- 

 ed. 



J. II. TEGMEYER, 



Baltimore, Md. 



Figure la. Advertisement in the Raili I v. 



eventually to l>c replaced. In this regard it is not 

 surprising thai Latrobe, a man oi considerable fore- 

 sight, had, at an early date, given serious thought to 

 the possible application of iron here. 



The world's first major iron bridge, the famed cast- 

 iron arch at Coalbrookdale, England, had been 

 constructed in 1779. Its erection was followed 1>\ 

 rather sporadic interesi in tins use of the material. 

 The first significant use of iron in thiscountr) was in a 

 series of small trussed highway arches erected l>\ 

 Squire Whipple over the Erie (anal in the earl) 

 1840's. over 60 years later. In these, as in most of the 

 earlier iron structures, an arch of cast iron was the 



primary support. I he thrust ol the arches was 

 counteracted l>\ open wrought-iron links with other 

 wrought- and cast-iron members contributing to the 

 truss ,n lion. 



The Whipple bridges promoted a certain amount of 

 interest in the material. In the B. & O.'s annual 



for the fiscal yeai ars the Hi si i 



of Latrobe's interest in this important matter. In the 

 president's message is found the following, rather 

 offhand, statement: 



16,183. ig have been expended tow. ml the renewal ol 

 the Stone Bridges 011 the Washington Branch, carried off 

 by the fli 0< 7th, 1847. Preparations are mad 



PAPER 36: ENGINEERING CONTRIBUTIONS Ol WENDEI BOLLMAN 



87 



