To design and check floor slabs and walls, StruBIM Design processes the results from their analysis based on the finite element method. This analysis provides solutions at specific points of the 2D structure, depending on the established discretisation. Based on these solutions, the design values required for the design and reinforcement are obtained by generating integration strips in the two-dimensional element and the calculation of the resultant in the corresponding design section.
As of the 2017.a version, StruBIM Design offers users the possibility to calculate this resultant by applying the “Internal forces integration method” or “Nodal forces integration method”.
Evaluation of the integration methods
The first premise is to have the internal and/or nodal forces in the 2D elements considered, to be able to apply one method or another. Depending on the origin of the analytical model which is being worked on (xml, sbar, etc.), the available design data may vary. Obviously, when only one of the types of data is available, only the corresponding method can be applied. If both the internal forces and nodal forces are available, it is the user’s choice which method is most adequate. The following observations on the methods can be used to guide users as to which method they should apply:
- Integration of nodal forces
The nodal forces integration method provides very good results when the width of the integration strip to calculate the resultant, is the entire width of the 2D element, regardless of the discretisation size used, as occurs when treating walls in StruBIM Design. When the width is smaller, and this method is being applied, it is recommended a more reined discretisation of the two-dimensional element be used. - Integration of internal forces
The internal forces integration method provides very good results when the integration strip width is small, as occurs when calculating the required slab reinforcement in StruBIM Design.
