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Nonzero abutment moment can be caused also by abutment skew, because the total abutment moment is obtained by summing up all reactions about a line perpendicular to the layout line at the abutment location. If the loading is not symmetrical, the total moment may be nozero, because reactions closer to the more heavily loaded portion of the bridge are contributing more moment than the other reactions.

For results reported for individual girders, the moments reported on the "Bridge Object Response Display" form are obtained from section cuts that include both the girder and the tributary section of the deck. When there is a skew at the abutment, the skew also causes twisting of the deck and the interaction with the adjacent girder or the deck of the adjacent girder may cause negative section cut moment at the abutment. In other words, the reported moment is not solely caused by the vertical reaction at the support, but the contribution of all joints included in the section cut must be accounted for.

See also

• Effect of insertion point on beam reactions test problem

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