The creation of story force cases for in-plane analysis in RAM Frame and the analysis of individual load cases is no different than previous versions of RAM Structural System.

After the load cases have been analyzed, the elastic second order analysis is performed in the RAM Frame Analysis – Load Combinations mode. The Combinations menu has Custom, Strength, and Service Combinations. The Custom Combinations are the superimposed load case results that are not analyzed. The Strength and Service combinations are considered in the Advanced Analysis. The engineer should only create advanced analysis combinations for conditions where an iterative analysis is required. For example, assume that a single wind pressure case was created for the components and cladding forces that will control the out-of-plane design, and generated story force wind cases were created for the main force resisting system in-plane design. Small p-delta effects are negligible for the in-plane design and the P-Delta implementation in Frame Analysis Load Cases mode is adequate for any big P-Delta effects that impact in-plane behavior. Therefore, the advanced analysis combinations can only include combinations that include the out-of-plane pressure case as shown below.

The criteria defined in Load Cases mode is used in the load combination analysis, as well. Some criteria will cause the analytical model for a gravity case to be different than a lateral load case. This would present a problem for the analysis of a load combination that contains both cases. Errors will be thrown when these conditions occur. The user will need to change the selections in Load Cases mode before proceeding with the load combination analysis.

Additional criteria that is only relevant to elastic second order analysis can be found in the Advanced Analysis Criteria dialog in RAM Frame Analysis -Load Combinations mode by selecting Criteria > Advanced Analysis. As discussed previously, the cracked section factors entered in RAM Modeler are intended to be used for a strength analysis. When analyzing service conditions, the crack factors can be relaxed. Rather than entering separate cracked factors for strength and service combinations, a single cracked factor modifier is entered for service combinations (see Service Analysis section below). Live load reduction can be turned enabled or disabled. Trouble shooting criteria for the iterative analysis is available to assist in achieving convergence.

The advanced analysis is performed by selecting Process > Advanced Analysis, selecting the combinations to consider, and then clicking OK. If advanced combinations have not been defined or no valid combinations are selected, the combination type will have a red status light.

Viewing and reporting of load combination analysis results requires selection of the appropriate load combination type to consider. Reports and onscreen results only consider the active output mode load combination type. Similarly, the Frame Shear Wall Forces module has a dialog to select the combination type for envelope results.