GENERATION OF METEOROLOGICAL LOADS
The highly detailed verification rules of the standards often require the use of computer programs. Countless combinations and load cases must be taken into account when designing the structures and finding optimal solutions, which can no longer be handled by manual calculations. This fact is especially actual for meteorological loads. The module provides excellent assistance to designers, by automatically generating and managing the snow and wind loads according to the standard.
The module provides the ability to generate the snow and wind load on typical structures according to the standard automatically. It operates with the load panel tool of the software that must cover the affected outer contour planes of the structure since the automatically generated meteorological load can only be placed on these panels. The automatic critical load combination result can be applied efficiently to handle a significant number of possible load combinations.
In many cases, the simple schemes and design rules detailed in the standards are not applicable for the analysis of more complex structures. In the case of wind loads, it may be justified to carry out computational simulations and/or experiments to define the steady-state wind pressure for the structure. The CFD module of the AxisVM software offers support to designers for such cases by importing wind pressure results derived from external flow simulations. A detailed description of the CFD module can be found on the General purpose modules page.
Requirements / recommendations
- no requirements
DESIGN CODES
Eurocode 1
EN 1991-1-3
EN 1991-1-4
Swiss standard
SIA 261
Italian standard
NTC
CHARACTERISTICS
- automatic generation of snow and wind loads according to the standard
- individual parameters that can be specified according to the requirements of national annexes
- the meteorological loads are distributed on load panels covering the building or structure
- load zones are created based on the type and geometry of the structure
- the algorithm handles both undrifted and drifted snow load cases
- the total wind load of a complex structure can be assembled by the loads of the implemented basic structural types
- the generated meteorological loads are considered as static loads; their dynamic effect cannot be examined
DETAILES
AUTOMATIC GENERATION OF LOAD CASES
The module automatically generates the necessary load cases belonging to the snow and wind load groups. Depending on the requirements of the standard, there can be a significant number of load combinations, the handling of which is facilitated by the critical combination result.
USING LOAD PANELS
The module requires the use of AxisVM load panel tool. The boundary planes of the structure must be covered by load panels, then the snow and wind loads are distributed on these panels considering different load zones.
The load panel has no structural role in the model. It only serves to distribute the loads placed on it to the structural elements.
SNOW LOAD PARAMETERS
Snow load can be generated to pitched (or flat) or cylindrical roof. The characteristic value of the snow load and other coefficients can be defined considering the specific rules of the applied standard.
SNOW LOAD – SPECIAL OPTIONS
The module can calculate snow load shape coefficients for roofs abutting and close to taller construction works or having a parapet which acts as an obstruction. It can take into account the effect of overhanging snow on roof edges. Parameters are stored with the edges so different roof edges can have different parameters.
As the wind direction, the global X, Y directions of the model and the directions enclosing an angle of 45 degrees with them are taken into account.
WIND LOAD PARAMETERS
At the General parameters, the required basic data of wind load can be set, which may differ depending on the selected standard:
- wind velocity and pressure coefficients
- terrain category
- custom directional factors
WIND LOAD – CLASSIFICATION OF STRUCTURES EXPOSED TO WIND
In the module, wind load can be assigned and generated to substructures defined by the selected parts of the model. For each substructure, a primary structural model type according to the standard has to be assigned. In case of building type substructures: flat roof, monopitch roof, duopitch roof, hip roof and barrel roof types are available. In addition, canopies and free-standing walls and signboards can also be defined.
The implemented method allows the user to approximate the wind load of complex structure with different standard models, and the program can combine wind loads for such substructures into a general wind load for the whole structure.
TABLE OF WIND LOAD PARAMETERS
