Create patterned load combinations

In most design codes there is a need to consider different load factors on different parts of the structure. This dialog assists in creating the combination cases that needs to be considered. Details of this methodology are covered in the technical note Patterned Load Analysis.

Definition

Analysis case for mean loads

This is the analysis case that contains the mean loads (fmean)

Analysis cases for load differences

These are the analysis case that contains the difference loads (Δfi). These are assumed to be contiguous.

Description of other cases

This allows any other cases to be added to the description.

The combination cases to be considered are:

$$\begin{aligned} f_{Amax} &= f_{mean}+\sum_i \left|\Delta f_i \right|\\ f_{Amin} &= f_{mean}-\sum_i \left|\Delta f_i \right| \end{aligned}$$

This will set up a series of combination cases that correspond to the Δfi analysis cases. The absolute value of these are then combined with the analysis case corresponding to the mean loads to give the maximum and minimum cases. So for example if the mean case is A3 and the difference cases are A4 to A8. Then assuming no other cases the combination cases will be defined as follows:

C1	A4
C2	A5
C3	A6
C4	A7
C5	A8
C6	A3 + (C1abs + C2abs +C3abs + C4abs +C5abs)
C7	A3 - (C1abs + C2abs +C3abs + C4abs +C5abs)

See also Create patterned load.