Load Properties
One of the key features of the RAM Structural System is the ability to automatically determine the loads to each individual member based on user-defined surface, line, and point loads. In the RAM Modeler, loads are defined by first creating a list of load properties and then assigning these load properties to the layout with the use of polygons, lines, and points as appropriate. A load property consists of a Label, a Dead Load, a Construction Dead Load, a Live Load with its associated Live Load Reduction flag, a Partition Live Load, a Construction Live Load, and a Mass Dead Load.
The following load types are considered by the program:
| Setting | Description |
|---|---|
| Dead Load | The total dead load such as slab, deck, partitions, miscellaneous, etc. Member and slab self-weights can be included in this value automatically. See Section 10.3.2, Self-Weight Calculations. |
| Construction Dead Load | Also referred to as the Pre-composite Dead Load, is a temporary condition load and is that portion of the Dead Load that is applied to the beam prior to composite action. It must be less than or equal to the Dead Load. This value is only used when designing unshored (i.e., "unpropped") composite beams and need not be specified for non-composite beams or shored ("propped") composite beams. This is in addition to the Construction Live Load described below. When a column is supported by a composite beam, RAM Steel Beam assumes that the full column load is applied to the post‑composite section; the column induces no Construction Dead Load on the pre‑composite section. |
| Live Load |
The total live load appropriate for the particular building based on the applicable Building Code and use of the building. Live Loads may be defined as Reducible, Storage, Unreducible, or Roof. Roof loads may be treated as Reducible or Unreducible. Live Load Reduction is discussed in Section 10.3.9 |
| Partition Load | An additional Live Load; it is treated as an unreducible Live Load and will not be reduced. It is in addition to the loads specified as Live Load. Partition loads are defined variously by the Codes, some as Dead Load and some as Live Load. For those codes that define Partition loads as an unreducible Live Load, those should be specified here. For those Codes that define Partition loads as a Dead Load or as part of the regular Live Load, those should be included as part of the Dead Load or Live Load accordingly. |
| Construction Live Load | A temporary load that is applied to the beam prior to composite action. It represents the temporary load due to workers and equipment on the bare beam prior to composite action. This load is combined with the Construction Dead Load when investigating the pre-composite beam. Its magnitude is independent of the Live Load value. This value is used only when designing unshored ("unpropped") composite beams and need not be specified for non-composite beams or shored ("propped") composite beams. |
| Mass Dead Load | The load that will be used in calculating the diaphragm mass properties used in RAM Frame. It is not used in the design of gravity steel beams. |
| Snow Loads | Snow loads, including varying drifting snow loads can also be applied. A current limitation in the program is that Roof Live Loads and Snow Loads cannot be considered simultaneously. Both types of loads can exist simultaneously in the model, but only one or the other will be considered. In the command in the RAM Manager there are two options: Consider Snow Loads, Ignore Roof Live Loads and Consider Roof Live Loads, Ignore Snow Loads. This is used to specify which set of loads is to be considered. If both types of load need to be considered, it may be necessary to design the members twice, once with each option selected. Note that this limitation is only between Snow and Roof Live loads; Snow and Reducible, Storage or Unreducible and Partition Live loads can be considered simultaneously by the program. |
Surface load properties are assigned to the model by defining the boundaries of the load polygon. Virtually any number of load polygons may be assigned to a given layout. Additionally, overlapping polygons are permitted. The last polygon assignment will over‑ride all previous assignments rather than be additive.
Polygon boundaries need not coincide with beam locations; boundaries can fall within a bay. Such changes in loads will result in multiple uniform or trapezoidal loads generated on the beam and will be shown individually on the Beam Output. Care should be taken in the RAM Modeler when laying down load polygons, especially those whose sides should coincide with a beam line, so that extraneous minuscule loads are not generated on the beam.