Hi
I am designing a steel grating with a chequered plate and cross members.
I am trying to model it in 2 ways
1. Neglecting the effect of cross members, i am modeling a composite beam (ISMB with a top plate) for the complete span. I am using BM and deflection values to design the member using composite section modulus. Further, these values matches with my manual calculations.
2. Second way i am trying to model is along with cross beams. But as soon as i apply cross beam, the length of main member reduces (as per staad) and thus there is extreme decrease in the deflection values, bending moment remains unchanged. While there would be some increase in stiffness of structure, there is no way to check such decrease in deflection is correct or not.
If someone can shed light on issues with 2nd way of modeling or can tell ways to overcome this issue in staad, that would be really appreciated.
A sample of what i am trying to do is enclosed as follows (without chequered plate)
Regards.
Please let me know if you need any additional information
I am attaching a typical 3 element model. 2 members are connected with small angles, while 3rd element is standalone. The huge difference in deflections can be seen here.
I am mainly concerned with the analysis part, so want to refer BM and deflection from the model.
Hatch typical.std
Hello,
For the second case can you please upload the STAAD model? Are you only looking into the analysed results or the design results as well?
If you are interested in the design results, you need to use proper design parameters to simulate the actual conditions depending on the code used. Please refer the help file to know more about the available parameters and their effect. Specifically for deflection, you need to use DJ1,DJ2 and DFF parameters.