Why are the creep and secondary moments unequal in all the girders of an integral 2 span bridge (grillage model) with 23.6m effective span and 17 pretensioned composite girders in each span, despite having the same dead loads and prestress?
Answer:
The transverse deck is transferring the load to the longitudinal girders. For end girder, the transverse elements are on the one side, while for other girder, the transverse elements are on the both side.
Secondly, uniform load due to dead load of slab and fill is different for end girders and mid girders.
Thirdly, middle girder is rigidly connected to the pier (diaphragm and middle girder intersecting node) and while other girders are connected to Diaphragm which in turn is connected to pier using rigid link.
Further, transverse deck elements are provided with time-dependent properties. Generally, we don't use time dependent properties on transverse deck elements. These transverse elements generate additional forces which are distributed unequally to end and middle girders.
The above factors collectively are the reason why the creep secondary are different for each girder
1-R0-DRT-AOP-10.50m Ht-ks-156080-check 14.mcb
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