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| Applies To | ||

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| Product(s): | STAAD.Pro | |

| Version(s): | ALL | |

| Environment: | ALL | |

| Area: | Modeling Solutions | |

| Subarea: | Geometry | |

| Original Author: | Sye Chakraborty, Bentley Technical Support Group | |

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**Can I analyze and design a hollow core slab or a voided slab using STAAD.Pro ?**

When it comes to modeling/analysis, although there is no direct way to model hollow core slabs in STAAD.Pro but here are some suggestions which may help.

You may use a finite element mesh to model the slab. You would need to determine a suitable thickness to assign to the mesh of plates so that it represents the stiffness of the hollow core slab. Imagine a solid slab of an equivalent thickness (De). Equivalent Moment of Inertia (Ie) for a unit width of such a slab = 1/12 x 1 x De^3. Now calculate the Moment of Inertia of a unit width of the actual hollow core slab. You will possibly have the data from the manufacturer or would need to calculate manually. Let’s say this is represented by Ih. Then equating Ie=Ih you can find out De which is the thickness you can assign to the plates. You would also need define and assign special material to these plates with appropriate density so that the weight due to the hollow slab is correctly accounted for in the analysis through the plate mesh.

Similar type of approaches of modeling such slabs by adjusting the stiffness and material density could be used when modeling such slabs in other Bentley products like RAM Concept.