KB 001793 | Modal Analysis in RFEM 6 Using a Practical Example

In CRANEWAY, the action of a rail as "statically effective" or "statically ineffective" is defined under "Rail‑Flange Connection" in the Details dialog box. This setting controls the calculation of the load introduction length according to EN 1993-6, Tab. 5.1.

In the event of converting or extending a hall, the building owner may want to add a second or third crane to an existing crane runway. Since the original design usually does not consider other cranes, a common solution is to design a minimum distance between the cranes. This is done via the crane technology settings.

When using interrupted welds between the rail and flange, make sure that the applied weld length does not exceed the length of the rigid load application of the wheel load according to Equation 6.1 in [1].

All results are arranged in result windows sorted by different topics. The design values are illustrated in the corresponding cross-section graphic. The design details cover all intermediate values.

General Stress Analysis

CRANEWAY performs the general stress analysis of a craneway girder by calculating the existing stresses and comparing them with the limit normal, limit shear, and limit equivalent stresses. Welds are also subjected to the general stress analysis with regard to parallel and vertical shear stresses and their superposition.

Fatigue Design

Fatigue design is performed for up to three cranes operating at the same time, based on the nominal stress concept according to EN 1993-1-9. In the case of fatigue design according to DIN 4132, a stress curve of crane passages is recorded for each stress point and evaluated according to the Rainflow method.

Buckling Analysis

Buckling analysis considers the local introduction of wheel loads according to the EN 1993-6 or DIN 18800-3 standards.

Deformation,

Deformation analysis is performed separately for the vertical and horizontal directions. The available related displacements are compared to the allowable values. You can specify the allowable deformation ratios individually in the calculation parameters.

Lateral-torsional buckling analysis

The lateral-torsional buckling analysis is performed in accordance with the second-order analysis for torsional buckling considering imperfections. The general stress analysis has to be fulfilled with the critical load factor greater than 1.00. As a result, CRANEWAY displays the corresponding critical load factor for all load combinations of the stress analysis.

Support forces

The program determines all support forces on the basis of the characteristic loads, including dynamic factors.

During the calculation, crane loads are generated in predefined distances as load cases of the crane runway. The load increment for cranes moving across the crane runway can be set individually.

The program analyzes all combinations of the respective limit states (ULS, fatigue, deformation, and support forces) for each crane position. In addition, there are comprehensive setting options for specification of the FE calculation, such as length of finite elements or break-off criteria.

The internal forces of a crane runway girder are calculated on an imperfect structural model according to the second-order analysis for torsional buckling.

Geometry, material, cross-section, action, and imperfection data are entered in clearly arranged input windows:

Geometry

• Quick and convenient data input
• Definition of support conditions based on various support types (hinged, hinged movable, rigid, and user-defined, as well as lateral on upper or bottom flange)
• Optional specification of warping restraint
• Variable arrangement of rigid and deformable support stiffeners
• Possibility to insert hinges

CRANEWAY Cross-Sections

• I-shaped rolled cross-sections (I, IPE, IPEa, IPEo, IPEv, HE-B, HE-A, HE-AA, HL, HE-M, HE, HD, HP, IPB-S, IPB-SB, W, UB, UC, and other cross-sections according to AISC, ARBED, British Steel, Gost, TU, JIS, YB, GB, and others) combinable with section stiffener on the upper flange (angles or channels) as well as rail (SA, SF) or splice with user-defined dimensions
• Unsymmetrical I-sections (type IU) also combinable with stiffeners on the upper flange as well as with rail or splice

Actions

It is possible to consider the actions of up to three simultaneously operated cranes. You can simply select a standard crane from the library. You can also enter data manually:

• Number of cranes and crane axles (maximum of 20 axles per crane), center distances, position of crane buffers
• Classification in damage classes with editable dynamic factors according to EN 1993-6, and in lifting classes and exposure categories according to DIN 4132
• Vertical and horizontal wheel loads from self-weight, hoist load, mass forces from drive, as well as loads from skewing
• Axial loading in driving direction as well as buffer forces with user-defined eccentricities
• Permanent and variable secondary loads with user-defined eccentricities

Imperfections

• The imperfection load applies in compliance with the first natural vibration mode - either identically for all load combinations to be designed, or individually for each load combination, as mode shapes may vary depending on the load.
• Convenient tools available for scaling the mode shapes (rise determination of inclination and precamber).