The story modeling 'Without | Original Stiffness' corresponds to the well-known modeling from RFEM. No floor set and no load transfer area is generated.
Nevertheless, the Building Model provides a variety of improved and simplified information:
- Centers of mass and rigidity
- Mass per story
- Center of mass
- Cumulative mass / center
- Story actions
- Story forces
- Delta story forces
- Location of the resultant story forces
- Interstory drifts
- Displacement
- Delta interstory drift
- Story centroid
Center of Mass and Rigidity
The center of mass, as well as the mass in the table Static Analysis – Results by Story – Centers of Mass and Rigidity, refers to the mass including the applied vertical loads. For the example here, a surface load of 2.7 kN/m² is applied in load combination 2. With an area of 6m x 6m, this results in a mass of 9.72 tons. The center of mass is located in the center of the building. This output is helpful with many different loads in a story. The center of mass and the mass are calculated for each defined story.
Mass of 1st story for the example used here:
- 2 concrete walls à 0.9 t
- 2 CLT walls à 0.151 t
- Concrete slab 14.4 t
- 2*0.9+2*0.151+14.4=16.5 t
The cumulative mass and its center refer to the story above.
Story Centroid
The story centroid is the centroid in each story. The point is output both in the Building Stories dialog and in the table Structure – Building Model – Building Story.
For the 1st story of this example in the Y-direction:
In the following image, a comparison with the result from the Building Model
Story Actions
The Story Actions result table contains the story forces, the difference of story forces per story, and the location of the resultant story forces.
The story forces are always output for the upper and lower point of a story. For the example in this chapter, a horizontal force in the Y-direction of 2 kN/m x 6m = 12 kN is applied in load case 2, which is introduced into each story. With an appropriately refined FE mesh setting, this result is achieved well, as shown in the following image.
The minor deviations from the manual calculation result from the warping or rotation of the wall panels at the line hinges and line supports.
Interstory Drifts
Analogous to the Story Actions table, the Interstory Drift table lists the displacements of each story and the difference in displacement for each story.
In the attached example, the maximum displacement in the topmost story LC2 is 8.25 mm in the global Y-direction. Since the displacement in the story below is 3.4 mm, a difference value of 4.85 mm is output here.
Vertical Result Lines
As soon as a Building Story is defined, vertical result lines are available in the Navigator – Results for this story. Thus, all deformations and forces in the respective story can also be displayed graphically.
Walls
The definition of walls and wall-like beams is described in earlier chapters of this manual. Here, in the example, a wall panel is defined on the cross-laminated timber wall of surface 11 and 12.
Once wall panels are defined, two additional result tables are output.
In the table –Forces in Walls–, the total forces and the forces per unit length are shown.
These forces are converted into axial forces in the table Axial Forces in Walls by means of a result beam. These forces are also used for the design of the wall panels in the Concrete Design or Timber Design add-on. In addition, these forces are available like normal member internal forces in the Navigator – Results.
Furthermore, the wall panels automatically generate result sections at the upper and lower points of the story. Here, among other things, the resultant force of a wall is also displayed graphically.
In the Axial Forces in Walls table, the percentage critical compressive load and the compression are specified. For this example, this is calculated in load case 1 as follows:
ηNcr=N/Ncr=22.3 kN/1737 kN=1.28%
The column ηNc is calculated from the permissible compressive force divided by the existing compressive force.
ηNc=N/Nc=22.3 kN/2520 kN=0.89%
Nc=fck=2.1 kN/cm²*1200 cm²=2520 kN
