Create Patterned Loads

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 loading that needs to be considered. Details of this methodology are covered in the technical note Patterned Load Analysis.

Definition

Elements

Only these elements will be considered for pattern loading. This allows the technique to be applied to one part of the model, for example a single floor.

Dead and Imposed Load Factors

This specifies the adverse and beneficial factors (γG,sup and γG,inf) for dead and the adverse and beneficial factors (γQ,sup and γQ,inf) imposed loads. These are used to set up mean and difference loads

$$\begin{aligned} f_{\text {mean }}&=\frac{\gamma_{G, \text { sup }}+\gamma_{G, \text { inf }}}{2} f_{G}+\frac{\gamma_{Q, \text { sup }}+\gamma_{Q, \text { inf }}}{2} f_{Q}\\ \Delta f_{i}&=\frac{\gamma_{G, \text { sup }}-\gamma_{G, \text { iff }}}{2} f_{G, i}+\frac{\gamma_{Q, \text { sup }}-\gamma_{Q, \text { inf }}}{2} f_{Q i} \end{aligned}$$

Case Descriptions for Dead/Imposed Loads

These are the descriptions of the loads cases that specify the dead and imposed load patterns. This allows for the specification of the spatial distribution of these loads.

Include Loads

Determines which loads should be included in the load patterns. Only beam force/moment loads, face loads on load panels and gravity loads are considered.

The loads specified in the relevant load cases are factored according to the equations above. One load case for the mean loads and one load case for each element considered for pattern loading. A set of load case titles are set up for these with the title “Mean load” for the means load and “Difference load L#” for the difference loads when # is the element number. These new load cases should then be included in the analysis task.

See also Create Patterned Load Combinations.