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New add-on modules RF-/STEEL EC3
for RSTAB and RFEM |
The new add-on module for RSTAB and RFEM carries out the ultimate limit state and serviceability limit state design with the inclusion of a deflection check for members and sets of members according to
Eurocode 3 (EN 1993-1-1:2005).
The NADs of the national annexes for the following countries are an integrated part of the module:
- Germany (DIN EN 1993-1-1)
- Austria (ÖNORM B 1993-1-1)
- Czech (CSN EN 1993-1-1)
- Slovakia (STN EN 1993-1-1)
- Poland (PN EN 1993-1-1)
- Slovenia (SIST EN 1993-1-1)
- Denmark (DK EN 1993-1-1)
The user can, however, edit these parameters or create a new national annex and save it in a library.
RF-/STEEL EC3 allows the design of all types of thin-walled sections. It automatically chooses the most efficient design options offered in the code. The classification of the section into the classes 1 to 4 is done by the program according EN 1993-1-1:2005, art. 5.5.2. The required width-to-thickness ratio for compression elements according table 5.2 is automatically calculated for every stress point, which results in the classification of the section. The classification is essential for the EC3 design concept as there are different limiting values for every class. The automatic optimization of the cross-sections – a well-appreciated feature in other add-on modules of RSTAB/RFEM – has also been implemented in RF-/STEEL EC3. For the design for tension, compression, bending and shear, the maximum design values of the actions are compared with the design values of cross-section resistances. If members are subject to combined bending and axial compression, an interaction analysis is carried out. For the interaction formula, the factors are to be determined.
For every member or set of members, the parameters for buckling about the axes y and z as well as for lateral-torsional buckling can be explicitly defined. For the flexural buckling design, neither the slenderness nor the critical torsional buckling force of the decisive buckling mode have to be specified. RF-/STEEL EC3 automatically determines all required coefficients for the design value of the buckling resistanc. The design value of the maximum buckling resistance moment is dependent on the cross-section class and the reduction factor for lateral-torsional buckling. In the National Annex settings, the user can specify the equation according to which this reduction factor is to be determined.
Many structural analysis programs require the specification of for the lateral-torsional buckling design. Mcr correlates with the dimensions of the gross cross-section, the respective loading conditions, the effective moment distribution and the lateral restraints. Thus, it is hardly possible to manually calculate Mcr in complex structures. RF-/STEEL EC3 is able to determine those values automatically at all design locations x of every member.
All that remains for the user to do is to define possible lateral restraints at intermediate locations of the member or set of members. The above-mentioned specifications also have to be made for restraints of members containing plastic hinges for out-of-plane buckling. To neglect lateral-torsional buckling effects, it must be verified that the length between the restrained section at a plastic hinge location and the adjacent lateral restraint is not greater than the allowable maximum length. Above all, this refers to members with two or three flange haunches. The real length between the lateral intermediate restraints is important to calculate the taper factor and the modification factors of the moment distribution.
For the serviceability limit state design, it can be defined for every load case, load group or combination whether it is a rare, frequent or quasi-permanent design situation. The limiting values of the deflections can be defined by the user in the National Annex. To design the members or sets of members with RF-/STEEL EC3, either user-defined or automatically calculated reference lengths can be applied. If desired, it is possible to assign a specific camber to each member or set of members. For a detailed specification, the girder type (span, cantilever beam with free start or end) can be allocated individually, too. The results are presented in clearly-arranged tables that are organized by load cases, cross-sections, members, sets of members or locations x. By selecting a specific results row, detailed information on the associated design becomes accessible. All material and cross-section data, design forces and design values with their coefficients are issued in detail so that the user can easily follow the design procedure.
The governing internal forces are also presented in detail by members and sets of members, together with the corresponding design rules and equations. The graphical distribution of the internal forces can be viewed in a separate window for every design location x. Parts lists by members or sets of members which are sorted by cross-sections complete the well-organized presentation of the design results. All input and results data can be included in the global printout report of RSTAB/RFEM. If the RF-/STEEL EC3 results are to be post-processed, all tables can be exported to MS Excel.
