Absurd stress results

Question:
My bridge is PSC simply supported standard cross section without any camber. LL envelope is symmetrical, but when I am checking stress at extreme left and right, it is not symmetrical on span 1 to 3 as BMD. Also, nature of stress is reverse in many location ( that is in ptn 1 it is compression but in ptn 2 its tension though both are top fiber and should be exactly same.) Kindly resolve as I cannot do my prelim iterations of cables until the stresses are trustworthy.


Answer:

Dear sir,

The model was unstable and there were abnormal deformations as it could be noted from the analysis message window. Hence, it won't be right to extract results from this model. Kindly restrain all components except Ry at the location of Pin support for structural stability about longitudinal direction and then check the results. Unsymmetric loading about global X axis (like moving load) will cause Mx moment, which wasn't being restrained before and hence the inappropriate results. For a simply supported span, kindly restrain Rx and Rz at the pin support location.
Creation date: 10/27/2017 6:12 AM ()      Updated: 10/27/2017 3:47 PM ()