It was believed that to be of the greatest practical value in aiding preservation efforts that real bridges be examined. The study focused on five real – not “textbook” – structures located throughout Colorado as shown in Figures 1.1 through 1.13. All of the bridges are through-trusses, all are former highway bridges, all are pin-connected with moment-resisting portal frames at the ends, all are metal – either wrought iron or steel, and all have horizontal trusses consisting of rod X-bracing intended to resist lateral loads.
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