Advanced Building Modelling

The concrete and steel material types and the frame element types that will be used to model the structural members in SeismoBuild are defined herein, together with other modelling options, such as the modelling of offsets at beam-column joints, the discretisation of the slabs, and the determination of the Control Node.

Materials Modelling
Materials that are to be used within a SeismoBuild project come defined in the Advanced Building Modelling tab. Eight material types are available in SeismoBuild, four types for concrete and four for steel. The complete list of materials is proposed hereafter:

• Mander et al. nonlinear concrete model - con_ma
• Trilinear concrete model - con_tl
• Chang-Mander nonlinear concrete model – con_cm
• Kappos and Konstantinidis nonlinear concrete model - con_hs
• Engineered cementitious composites material - con_ecc
• Kent-Scott-Park concrete model - con_ksp
• Menegotto-Pinto steel model - stl_mp
• Giuffre-Menegotto-Pinto steel model - stl_gmp
• Bilinear steel model - stl_bl
• Bilinear steel model with isotropic strain hardening- stl_bl2
• Ramberg-Osgood steel model - stl_ro
• Dodd-Restrepo steel model – stl_dr
• Monti-Nuti steel model - stl_mn
• Buckling Restrained steel brace model_stl_brb

A comprehensive description of the material types may be found here.

Frame Elements Modelling
Different frame element types may be employed for columns/beams and walls. Users may select between inelastic force-based frame elements (infrmFB), inelastic plastic-hinge force-based frame elements (infrmFBPH) and inelastic plastic-hinge displacement-based frame elements (infrmDBPH). Further, it is possible to assign the inelastic displacement-based frame element type (infrmDB) to short members, a choice that improves both the accuracy and the stability of the analysis. Users can determine the maximum length of the short members (1.0m by default). Users can also determine the maximum length of the members, below which the elfrm element type is employed (0.4m by default). The inelastic plastic-hinge force-based frame element, infrmFBPH, is selected for columns/beams and walls in the default predefined settings scheme, which should work well for most practical applications. The maximum frame element length for the discretization of Strip Footings is defined in this tab (1.0m by default).

Rigid ends Definition
The choice whether to include or not rigid ends at the frame elements to model beam-column joints is also done herein. It is noted that these rigid ends are included in the model, only when the length of a member’s rigid end is larger than the specified value, otherwise the beam is connected to the column node directly.

Slabs Discretization
Users may select the number of triangles ,to which the slabs are to be subdivided, so that their weight and mass are appropriately distributed in the supporting beams and columns. This may be done in two ways, either by assigning the exact number of triangles or by providing it as a multiplier of the slabs’ edges, which is an indication of the complexity of the slab. Obviously, an increased number of triangles leads to a better and more accurate distribution of loads to vertical members, however it also leads to longer slab analysis time.

Control Node Definition
The choice of defining the control node at the upper floor or at the floor lower to that (in the cases of a top floor mass less than 10% of that at the lower floor) is provided.

Soil-Foundation Interaction Link Modelling
When the Consider Uplifting for Inelastic Links check-box is selected, the foundation link element has zero stiffness during the uplift of the footing.