Defining the load case parameters

The parameters of a load case control the way the program treats the load inserted in the load case.

Basic parameters

Name	Is used for a unique identification of the load case.
Description	May add some information about the load case.
Action type	Specifies the type of the load case.
Load group	Sorts load cases by load groups.
Load type	see later in this chapter
Load cause appreciable sidesway	(available only for IBC and LFRD codes) Determines whether the load causes transverse displacement of the structure.
Stage for composite analysis model	(available only when using the Composite Analysis Model) Defines which composite construction stage the load case is attached to

Load case Action Type

The load case type can be set to:

Permanent	Specifies the permanent loads.
Variable	Specifies the variable loads in the project.

Other parameters depend on the adjustment of the load case type.

Parameters for permanent loads

Load type (subtype)

Self weight	Specifies the load case where only self-weight of the structure can be defined.
Standard	Specifies the load case where any load can be defined.
Creep	Defines a special load case for specific calculation.
Prestress	This type is used for calculations of prestressed structures.
Primary effects	This load case is used when the primary effects are calculated.

Note: The list above may not be complete. Some types of load case may appear only for a specific type of analysis. The meaning of special load cases is explained in appropriate chapters.

Direction

This item tells the program the direction in which the generated self-weight is acting.

Parameters for variable loads

Type (subtype)

Static	The load case is used for static calculations.
Dynamic	The load case is used for dynamic calculations.
Primary effects	This load case is used when the primary effects are calculated.

Note: The list above may not be complete. Some types of load case may appear only for a specific type of analysis. The list above may not be complete. The meaning of special load cases is explained in appropriate chapters.

Specification of static load case

Standard	Defines a general static load case. Any load can be defined in such a load case.
Temperature	Defines a load case for thermal loads.
Static wind	Defines a load case for wind loads. Only load type 'force' and ' wind' can be defined in such a load case.
Earthquake	Defines a load case for seismic analysis.
Snow	Defines a load case for snow loads. Only load type 'force' and ' snow' can be defined in such a load case.

Coefficient

It defines the factor used for the load case when combinations of load cases are generated. This parameter is defined only for some codes.

Duration

For static standard loads, the duration of the load impact can be specified.

Long	Is used for non-linear calculation of deformation for concrete structures
Medium	Is used for check of timber structures.
Short	Default type.
Instantaneous	Is used for check of timber structures.

All standard static loads are considered during the generation of load case combination as a normal variable load. Loads of long and short duration are applied only to combinations for the calculation of deformation of concrete structures according to the second ultimate state. Loads of medium and instantaneous duration are taken into account only for check of timber members.

Master load case

It is possible to specify that some particular load case may be included into a combination of load cases ONLY if another specific load case is included. The item Master load case tells the program that a particular load case is bound to another load case – to the Master load case.

The  master load case is valid for all the load cases within one load group.

For example, let us define:

LC1 in LG1

LC2 in LG1

If LC3 is set as a master load case for LC2, it means that it is automatically set also for LC1.

Note: Load cases from the same group may have only one Master load case.

Imagine a load group with n load cases. If you set a master load case for one of these load cases, all other load cases of this group receive automatically the same master load case.

Other parameters

There are other parameters available for each load case. However, these additional parameters depend on the active code adjusted for the project. The meaning of individual additional parameters is based on corresponding articles of appropriate codes and it goes beyond the scope of this book.

Note: The settings may affect the functionality of the program. For example, let’s assume that the user defines a new load case and sets its specification to Static wind. If later service Loads is opened, the user may define only wind loads, nothing else.