analysis performed. This is done to show which specific parameters in each group of parame-ters the S-BIM tools must be able to handle in order to make a structural analysis according to Eurocodes.
The calculations are made both by hand and by a suitable software application. StaadPro is used for both the steel and the timber structure, whereas the application Column and beam design from NordSoft ApS [Rasmussen and Rasmussen, 2010] is used for the concrete structure. The choice of software applications is not important for the employed method.
3.3 Simply supported steel beam
The first structure, for which the tests are performed, is a 6 m simply supported steel beam, subjected to an arbitrary line load of q = 5 kN/m as shown in Figure 3.2. The beam is an IPE200-profile of steel type S235.
The statical system of the steel beam and the cross section are shown in Figure 3.2.
q
Figure 3.2 Left: Simply supported beam. Right: Cross section of an IPE profile.
The chosen cross section and magnitude of the line load provides sufficient bending and shear strength but insufficient lateral torsional buckling resistance. This choice is made to ensure that the S-BIM tools not only check the most simple design criteria.
Relevant design criteria for the steel beam are found by a code check cf. BS EN 1993-1-1:2005 [2005] in StaadPro and hand calculations cf. DS/EN 1993-1-1 [2007]. The design criteria are:
• EC3: 6.2.5 Bending moment
• EC3: 6.2.6 Shear
• EC3: 6.3.2 Buckling resistance
The parameters needed to evaluate the three design criteria are presented in Appendix C.1.
No partial factor is applied to the load, since the size of the load is irrelevant in order to evaluate the S-BIM tools and the results obtained. In principle also no partial factors should be applied to the material properties. However partial factors according to BS EN 1993-1-1:2005 [2005] are applied since they are defined by default in both StaadPro and Robot.
In order to test the applicability of updating backwards to Revit changes are made one at a time in Robot and StaadPro, respectively. The tests contain the following changes:
• The cross section is changed from IPE200 to IPE220
• The length of the beam is changed with 1 m
• The material is changed from steel S235 to S355
• The line load is changed from 5.0 kN/m to 6.0 kN/m
• The supports are changed from pinned and roller to fixed
The changes are chosen to show how well the S-BIM tools handle the groups of parameters presented in Section 3.2 when updating backwards to Revit.
3.3.1 Results of tests
Based on the above described design criteria and the design parameters in Appendix C.1 the applicability of the S-BIM tools are tested by means of the simply supported steel beam. The results are given in Table 3.1 on page 32. Where needed a note is given after the table.
The procedures leading to the results in Table 3.1 demand different choices from the user. The procedures in connection with each S-BIM tool are described in Appendix C.2.
A screendump of the steel beam modelled in Revit is shown in Figure 3.3. After using the add-on tool and the direct links to Robot and StaadPro the steel beam appears as shown in Figure 3.4, 3.5 and 3.6.
Analytical line
Figure 3.3 Steel beam with line load in Revit. Figure 3.4 Steel beam with line load in the Revit add-on tool.
3.3 Simply supported steel beam
Figure 3.5 Steel beam with line load in Robot. Figure 3.6 Steel beam with line load in Staad-Pro.
Note that the coordinate system in StaadPro is different from the coordinate systems in Revit and Robot.
As shown in Figure 3.3 the analytical line is placed in the top of the beam which is default in Revit. In Robot and StaadPro the analytical representation of the beam is convergent with the centreline. This difference has no influence of the results for the simply supported beam.
However the difference needs to be kept in mind in connection with more complex structures where it can be important.
RVT RVT RVT RVT RVT RVT RVT
Table 3.1 Test results for the simply supported steel beam. 3 means no problems and÷means that it does not work or that the parameter/feature is not available.
3.3 Simply supported steel beam
Notes to Table 3.1:
1) This parameter is not available in Revit.
2) By default set to 235 MPa in StaadPro. Must be defined manually if different from this value.
3) Due to the limitations of the IFC Coordination View, cf. Section 2.5.3.
4) The degrees of freedom should be fxxfff† in Revit coordinates corresponding to xxffff in StaadPro coordinates but the degrees of freedom are ffxfff in StaadPro coordinates.
5) In Robot the lateral torsional buckling curve is set to “b”, but should have been “a”. Thus the imperfection factor and reduction factor and thereby the lateral torsional buckling mo-ment capacity are different from the hand calculations. Furthermore the critical momo-ment for lateral-torsional buckling is calculated accordingly to another theory (ENV311) than used in the hand calculations and StaadPro.
6) The deflection is 18 mm without code check, but 22 mm at code check. The correct result is 22 mm cf. Table C.7 in Appendix C.1
3.3.2 Evaluation of tests
Based on the results presented in Table 3.1 an evaluation of the tests performed for the steel beam is made.
Revit add-on tool (RVT add-on) H I I I I
In the first test the Revit add-on tool Revit Extensions, Simulation - Static Analysis of Frames gets one star because it is useful in relation to compute the section forces and deflection. On the other hand it is not possible to assess the design criteria with the Revit add-on tool.
Direct link from Revit to Robot and backwards (RVT↔RSA) H H H H I
The direct link from Revit to Robot and backwards gets four stars because it is possible to exchange all relevant data from Revit to Robot. However, only the section properties are up-dated backwards from Robot to Revit. Note that a code check in Robot does not include shear, however this has nothing to do with the link and therefore does not influence the evaluation.
Direct link from Revit to StaadPro and backwards (RVT↔SPro) H H H H I
Like the link between Revit and Robot the direct link from Revit to StaadPro and backwards gets four stars. All the relevant parameters are exchanged from Revit to StaadPro which makes the link useful as a one way link. However, only the section properties are updated backwards from StaadPro to Revit.
Indirect link from Revit to Robot (RVTIFC→ RSA) I I I I I
The last test with the steel beam is performed with an indirect link from Revit to Robot. The IFC-link gets zero stars because only the length of the steel beam was exchanged from Revit to
†f marks a free degree of freedom whereas x marks a fixed degree of freedom. The three first positions are related to the translations in the three directions (x, y and z) and the three last positions are related to the rotations about the three directions.
Robot. Thus the only optimisation in connection with the IFC-link is that it is possible to reuse node and bar coordinates.