Each of the Building Codes has provisions for reducing the live loads under certain conditions. When appropriate, the RAM Structural System automatically calculates these reduction factors and reduces the loads accordingly. On the outputs, these reduction factors are listed as a percent of allowable reduction. For example, if the output lists a reduction of 60%, the unreduced load is multiplied by 0.40 to obtain the reduced load. The RAM Structural System recognizes four types of live loads: Reducible, Storage, Unreducible, and Roof. Roof Live Load can be further specified as either Reducible or Snow using the Criteria - Member Loads command in the RAM Manager. These options are explained in the Technical Notes chapter in the RAM Steel Beam Design, RAM Steel Column Design and the RAM Frame manuals.

Live load reduction factors are a function of the area associated with the loads acting on a member. In calculating the reduction for a given load, the RAM Structural System only uses the area on the member associated with that live load type. For example, if part of the load on a member is Reducible and part is Storage, only the area associated with the Reducible loads will be included in the calculation of the reduction factor on the Reducible loads and only the area associated with the Storage loads will be included in the calculation of the reduction factor, if permitted, on the Storage loads.

Some reduction criteria are based on whether the member receives load from a single level or multiple levels. The loads being transferred from other levels onto a given member may or may not need to be of the same type as those loading the member at the current level in order for the RAM Structural System to consider the member as receiving load from multiple levels. This can be controlled by selecting or de-selecting Live Load types using the Criteria - Member Loads command in the RAM Manager.

Some Roof Life Load reduction criteria are based on the slope of the roof. Sloped framing conditions can be created by using the Layout - Columns - Modify Elevation command.

You can limit the live load reduction on beams by specifying a Maximum Live Load Reduction Percent with the Layout - Beams - LL Reduction command. The limit is assigned on a beam by beam basis. For example, you can specify that for purlins, the live loads not be reduced, but for girders the live loads get the full allowable reduction. If a limitation is assigned using this command, the more stringent of the code-required value and the user-specified value will be used. Similarly, you can limit the live load reduction on columns by specifying a Maximum Live Load Reduction Percent with the Layout-Columns-LLReduction command.

The requirements for live load reduction are different for each Building Code. For a discussion of Live Load reduction as it pertains to each building code, see the Technical Notes chapter in the RAM Steel Beam Design, RAM Steel Column Design and the RAM Frame manuals.