Seismosoft | Earthquake Engineering Solutions

How i could modelling one way slab type ribbed as in etabs 2015? because in my country (Perú) is very frecuently used slab lightened with hollow brick.

There is no specific ribbed slab element in SeismoStruct. The only way to model them is to model separately each rib as a beam.
Note however that in seismic analysis the slabs behave elastically and do not participate in the energy absorption mechanisms. This is why slabs are typically modeled as rigid diaphragms and loads on the supporting beams (as is the modelling process in the Building Modeller of SeismoStruct).

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