Slabs in tunnel formwork projects You should apply a semi-rigid diaphragm solution as it does not fit on the beams in every eye and the curtain/flooring system must be solved together."cagatayk":2617lwup" said:When I choose analysis with semi-rigid slabs in my project, the computer gets very stiff and I have to wait for hours for analysis. If I do the analysis rigid instead. Would it be a problem if I don't do it together with slabs?