Attached is a model of a floor in an industrial building that is part of my purview. The model was started by a contractor we enlisted in creating it and doing a floor load analysis of it. His contract was closed and he is no longer available, but I have been given this model and am being asked to perform the analysis.
Information on the building floor…it was designed in the early 1960’s. As can be seen, there are z-axis purlins and x-axis girders, but looking at the drawings, the original designers obviously believed that a one-way slab design was the way to go. I was also remember a professor in grad school stating that if you have a 2 to 1 panel ratio or greater, it will "mostly" act as a one-way slab.
If this were done correctly, the loads should be spanning along the global X axis with exception some small areas in the corners of the purlin/girder intersection. However, it is “seeing” fairly large moments in the longitudinal direction, so it is definitely acting like a two-way slab. I have never used the “One-Way Load” specification, and if I understand it you should be able to force the direction of the loads to make it a one-way slab. I have been unsuccessful because the moments aforementioned longitudinal moments. Below are the loading commands I used for the oneway action…can you help me? I have no problem in sending you the file if you'll give me a link to do so.
LOAD 10 STRUCTURE SELFWEIGHT
ONEWAY LOAD
YRANGE -0.1 0.1 ONE -0.1 XRANGE 0 129 ZRANGE 0 100 GY
PERFORM ANALYSIS PRINT STATICS CHECK
FINISH
