Assessment of the Bill Emerson Memorial Bridge - FTP Directory ...

4.5. Details of the bridge modelThe overview of the bridge model and the global coordinate system used in modeling arepresented in Figures 4.4 to 4.7. The origin of the global coordinate system is located at themiddle of Bent 1 or the intersection of the first floor beam and center strut. The bridge wasmodeled based on the geometries and material data from as-built drawings with necessaryupdated modifications in consultation with the Missouri Department of Transportation. Inthe FE model, frame elements were adopted for steel girders, floor beams, and the centerstrut connecting any two adjacent floor beams. The main components of the bridge towersand pile caps were also represented by frame elements. The precast, concrete panel/slab of279 mm thick, which is supported by the steel girders, was modeled with shell elements.Cables were modeled with cable elements. The sags at the middle of the cables weredetermined from the bridge drawings. In this study, the wind effect on the cable-stayedbridge is beyond the scope of consideration. Therefore, the cross ties on the cables, whichare designed to mainly reduce wind-induced vibration, are not included in the FE model.The complete FE model of the entire bridge has a total of 3,075 joints, 3,622 frameelements, 106 shell elements, and 853 2-D solid elements, resulting in 15,926 degrees offreedom.(a) View of the entire bridge32 31 30 29 28 27 26 25242322 21 2019 18 17 16 15543276 11110 98121413Figure 4.4(b) Close-in view of tower and cablesElevation of the cable-stayed bridge48