I am going to do a quick analysis for a steel box girder of 20 ft wide top flange, 14-2/3ft bottom flange and 8 ft deep.
The bridge is of 11 spans (each span approx. 165 ft long) and several spans are curved in plan on a radius of 1000 ft. Over each pier, the box is strengthened with a plate diaphragm and is seated on a pair of bearings, spaced at 8-10/12 ft only.
For this quick analysis, I want to model the whole structure with a spine beam. A layer of mesh, assigned with nominal/low stiffness, is supported off the spine beams with outriggers and studs. This mesh is to help distribute the loads acting on the spine beam and not to add any extra stiffness to the spine beam as the spine beam is to be assigned with section properties of the whole box section, the attached file refers but it shows a model for 2 cells girder bridge. Hence, I need the half of the model.
So, my question is that if the whole box structure is represented by a line beam and the bearings at each piers are spaced at 8-10/12 only < spacing of the webs at bottom flange level, can I assume that there is only vertical support at each pier and bearings don’t provide any torsional restraint at all?
The bridge is of 11 spans (each span approx. 165 ft long) and several spans are curved in plan on a radius of 1000 ft. Over each pier, the box is strengthened with a plate diaphragm and is seated on a pair of bearings, spaced at 8-10/12 ft only.
For this quick analysis, I want to model the whole structure with a spine beam. A layer of mesh, assigned with nominal/low stiffness, is supported off the spine beams with outriggers and studs. This mesh is to help distribute the loads acting on the spine beam and not to add any extra stiffness to the spine beam as the spine beam is to be assigned with section properties of the whole box section, the attached file refers but it shows a model for 2 cells girder bridge. Hence, I need the half of the model.
So, my question is that if the whole box structure is represented by a line beam and the bearings at each piers are spaced at 8-10/12 only < spacing of the webs at bottom flange level, can I assume that there is only vertical support at each pier and bearings don’t provide any torsional restraint at all?
