Frame Analysis

Substructure uses a state-of-the-art three-dimensional frame analysis. The structure is modeled as straight lines using nodes and members.

Nodes and members are assigned physical properties to simulate the real structure. If there is a tapered member, the sizes of the start section and end section are averaged to obtain the average size for this member. The remaining properties, such as section area and moment of inertia for a tapered member, are computed based on the calculated average sizes. Analysis is done to the top of the footing excluding any footing depth.

Analysis is done to the top of the footing excluding footing thickness.

Columns are set to be fixed at bottom unless a drilled shaft or spring matrix is defined. For defined spring matrix, program will compute nodal deformations for the dof in which springs are provided.

Factor of Reduced Moment of Inertia

There are many situations that would require the design of a cracked member. For example, if you design a column with its section 30% cracked, you will need to adjust the member section properties in order to simulate the cracking effect.

With this regard, Substructure allows you to reduce the moment of inertia of any members. When you define the cap and column geometry, specify the Factor of Reduced Moment of Inertia (MI). By default, this factor is one. However, for a cracked member, you can specify the value equal to or less than one. For instance, if you input 0.75 in the Factor of Reduced (MI) field, Substructure will use 75% of the moment of inertia of the original section without cracking in the frame analysis.

Service Load Analysis Design and (Working Stress)

Substructure can perform analysis and designs under service load (working stress design) according to IRC Standard. The service load design provided by Substructure is in accordance with IRC 21-2000.