Timber Building Modeling and Static Analysis with StatiCAD
In the current version of the StatiCAD program, you can perform operations such as modeling timber buildings, calculating earthquake forces, obtaining cross-sectional effects of elements using the finite element method, obtaining plan drawings, and performing foundation analyses.
Create architectural axes in the program.
Timber columns can be drawn by clicking the Vertical Tie Beam command and specifying the dimensions.
Multiple copying of elements at specific intervals can significantly shorten the modeling time.
The order of modeling operations you perform in the program does not matter. The sequence below is given as an example; you can perform operations in any order you wish.
After modeling the timber columns, select all timber columns, right-click on one of them, and use the "Modify Properties of Selected Vertical Tie Beams" command. In the form that appears, click the "Select Material" button and assign one of the timber materials from the list or define a new material.
After drawing the columns, you can proceed to drawing the beams. The base beam, header beam, horizontal band beams, and all diagonals are drawn using the K.Hatıl (Horizontal Tie Beam) button on the left toolbar. After clicking the K.Hatıl command, make the material selection, enter the beam dimensions and elevations (left elevation, right elevation) to create the desired elements between the columns.
An important point to note is that beams must be entered in segments between columns. If separate beams are not placed between each column, sufficient accuracy may not be achieved in the finite element analysis.
Another important point is that having the header and base beams at the column top elevation allows for more proper finite element analysis, because nodes created very close to each other can slightly affect the equation solution accuracy in the finite element method due to having very large and very small numbers in the same equation.
After the beams are created, you can proceed to slab placement. To define the slab material as timber, select "Timber" in the slab concrete class section on the material tab of the project general settings form, or type the material name such as OSB, Plywood, etc. Select "---" for the reinforcement class, and enter the values for the modulus of elasticity and unit weight for the material to be used. If two different timber materials are to be used, make similar settings in the 2nd slab section.
Slabs should be placed separately between each beam, with slab edges aligned to the beam center axis.
In cases such as roof floors where you need to give a slope to some elements, the slope can be applied by changing the right and left elevation values of the elements. An easier method is to select the elements you want to slope, right-click on a selected element, and click the "Apply Slope to Selected Elements on Floor" option, or click the slope button on the right toolbar. Select the reference node point followed by the target node point to determine the elevations and direction. The form that appears shows default values assuming the first point of the line will be -100 cm below floor level and the right point will be +100 cm above. Change the values according to your project and press the OK button. The form will not close automatically when the OK button is pressed, but the operation will be performed according to the given options. Check from the 3D view how the desired operation was performed; if satisfactory, close the form with the X button; if not, change the parameters and press the OK button again.
Analysis Settings:
To set the project analysis settings, go to Project General Settings. In the form that appears, enter the earthquake parameters related to the soil, location, etc. (SS, S1 values). Enter the R and D values according to the ductility level of your timber structure from TBDY2018 Table 4.1 Section F.
On the Method 2 page, select the "Finite Elements" option for element normal force calculation. If you select "Classical Method" for Load Transfer from Slabs to Walls, you do not need to precisely adjust slab elevations to beam elevations; however, when finite elements is selected, slab elevations must exactly coincide with beam elevations. The finite elements option for Load Transfer from Slabs to Walls reduces the possibility of load transfer errors and provides more precise calculations.
For element shear force and moment calculation, select the finite elements method. Uncheck the "Reset Rotational Degrees of Freedom at Bar Element Ends (RYTEIE 2019 required)" option below. In our opinion, resetting rotational degrees of freedom in slender bar elements is not appropriate.
Including slabs in the system stiffness and performing load transfer from slabs to beams using finite elements may slightly extend the analysis time.
Also under the Method 2 page, change the Finite Element FEM Precision value (Precision for Treating Close Nodes as Identical in Finite Elements) to 1. The FEM precision value enables consolidation of node points, and an appropriate value prevents errors in finite element calculations. (If errors occur, the error ratio is displayed in the analysis warning.)