RAM Concept Column and Wall Force Integration
The RAM Structural System can use the column and wall forces that are exported from RAM Concept in the RAM Concrete Analysis and Concrete Design Modules. This feature is only available with RAM Concept v1.4 or later, and applies to RAM Concept models that are created in the RAM Structural System and then imported into RAM Concept. Also, the import into RSS feature does not work for levels which are influenced by hanger column forces.
RAM Concept can import loads and geometry from any story of a RAM Structural System model. Following an analysis in RAM Concept the column and wall forces can be exported back into the RAM Structural System for consideration in the concrete analysis and design modules. Within the RAM Structural System the RAM Concept column and wall forces are integrated into the analysis results in the RAM Concrete Analysis module. When forces have been exported from RAM Concept they can then be selected to be included in the RAM Concrete Gravity Analysis. Following a successful analysis in RAM Concrete the column design module will consider the RAM Concept column forces in the design.
- Start with a model created in RAM Structural System.
- Import a story (Roof and 2nd) into RAM Concept, analyze and export the column forces back to the RAM Structural System Model.
- Import another story (2nd) into RAM Concept, analyze and export the column forces back to the RAM Structural System model.
- Invoke the RAM Concrete Analysis module and perform the analysis (selecting to use the RAM Concept Column Forces).
- Switch to the RAM Concrete Column module and design the columns.
- Import the final loads into RAM ConceptRAM Concept for Mat Foundation design.
As a result of the integration a new hyperstatic load case may be introduced into RAM Concrete. Please refer to the RAM Concept documentation for more information on the origin of this force. Where they exist in the RAM Concept analysis the hyperstatic column forces are provided to the RAM Structural System and considered in the analysis and design in the RAM Structural System.
Introduction
Concept member forces exported into the RAM Structural System are included in the analysis that is performed in RAM Concrete. As described previously RAM Concrete analyzes each story independently and carries the vertical reactions for each load case down to the story below for the subsequent analysis. During this process, if any story is selected to use RAM Concept column forces, the program will sum the Concept member force at that story with the force that is passed down from the levels above, to modify the column reactions (to be carried to the level below) and column design forces at that level. Beam forces will continue to use the RAM Structural System concrete analysis results, they are not exported back from RAM Concept. Note that the column forces from RAM Concept could produce forces in the beams in the analysis performed at the story/s below the columns. Also, the floor analysis of each story is still performed in RAM Concrete Analysis, even if it is also performed in RAM Concept and forces are passed back. This is to allow RAM Structural System to determine beam forces (which are not passed back from Concept), to distribute transfer loads and to accumulate the forces from levels above the one being analyzed.
Results
As described previously the various beam, column and wall forces from each load case are available for display on the screen following an analysis by selecting Process-Results. These forces are not affected by the RAM Concept Forces except as indicated next.
The member forces shown on the screen are all taken from the RAM Concrete analysis (RAM Concept member forces are not displayed on screen). However, when a story is selected to use RAM Concept forces two things happen. First the design forces calculated for the columns at that story add the Concept Force to the force that exists in the member due to the load on the levels above the one being analyzed. And second, the reactions that are applied to the level below are modified to include the RAM Concept column force. These are not visible on the screen except that the effect of the reactions can be observed in the analysis results (on screen) of the story below.
- Criteria Column Forces
- Refer to the Criteria Section for more information on tracking the status of the RAM Concept Force information and the RAM Structural System Model.
- Reports
- Refer to the Reports Section for more information on Concept Column Forces and Concept Wall Forces Report.
- Technical Notes
- RAM Concept Wall and Column Forces
- RAM Concept exports column moments at the base of the columns at the level above the story being analyzed, and column top moments and axial forces for the columns below the story being analyzed. The wall forces for walls located below the story are also exported back into the RAM Structural System. No beam forces are exported from RAM Concept. There is no change in the sign convention used in RAM Concrete. Refer to previous section in this manual for a description of the RAM Concrete Sign Convention and how RAM Concrete determines the design column forces for columns that span multiple levels.
- Concept Story Status (State)
- To coordinate the RAM Structural System model and the various RAM Concept models, the program attempts to track how Concept as interacted with each story, and what the status of the shared data is. This is so as to provide feedback to the user as to whether a particular set of column and wall results for a story are one of the following:
| Result/Color | Description |
|---|---|
| Current (Green) | The RAM Structural and Concept Models are identical and in synch. |
| Not Current (Yellow) | There is some potential minor difference between the RAM Concept model and the RAM Structural model. This is typically caused by a reframe of a story in the RAM Structural System model at a point in time after Concept has imported the loads and geometry for the story. It could however also refer to a change in member size in RAM Structural System, which again has not been recognized in the data that RAM Concept already has for this story. |
| Not Available (Red) | Typically indicates either RAM Concept has not imported any data for this story, has not exported forces for this story, or that a significant (major) change has occurred to this story in the Structural System model since either the import or export occurred. A significant major change could be any of: Addition or deletion of columns or walls, or the deletion of stories or changing the floor type on a story. |
- The status of a particular story is determined using the following rules and definitions:
| Status | Definition |
|---|---|
| Source Story | Story whose model geometry and loads are imported into RAM Concept from. |
| Target Story | Story that RAM Concept has exported forces to. |
| Floor type | The floor that is assigned to a story in RAM Structural System. One or more stories can be assigned the same floor type in the RAM Modeler. |
| Major Change Time | The most recent time that a significant change occurred to the story in the RAM Structural System model. This change could be as a result of the addition or deletion of columns or walls at a story, the addition or deletion of stories or the changing of a story's floor type. |
| Minor Change Time | The most recent time that a minor change occurred to the story in the RAM Structural System model. This change could be as a result of any reframe of a story (moved framing, other model changes such as slab edge, load changes etc). |
| Major Read Time | The most recent time at which RAM Concept imported the geometry and member properties from the RAM Structural System for the particular story. |
| Minor Read Time | The most recent time at which RAM Concept imported the story loads. |
- RAM Concept will export results back into the RAM Structural System providing the RAM Structural System with the Target Story, the Source Story and a set of flags (values) related to actions made in RAM Concept. These flags, which represent any difference between the RAM Concept and RAM Structural System model, are used as the last criteria on which the story status is determined. Given this information RAM Structural System determines the story status as follows.
- Transfer loads
- All transfer loads are distributed during the RAM Concrete analysis. That is, if a transfer situation exists the forces exported by RAM Concept for the transfer story, do not include the contribution of the transfer load. The forces are transferred in RAM Concrete based on the support framing as modeled in the Structural System model.
- Self weight
- The self-weight of slabs and beams is typically considered in the RAM Concept analysis. The column/wall forces provided by RAM Concept account for the effects of self-weight as specified in RAM Concept. It is the engineer's responsibility to ensure the self-weight settings of the RAM Structural System and RAM Concept are in synch. The self-weight (when indicated to be included) of walls and columns below a story being analyzed are calculated with RAM Concrete analysis and not provided by RAM Concept.
- Missing Member Forces
- In some circumstances RAM Concept may only import a subset of the columns/walls at a story. This typically occurs at partial levels where some of the columns/walls may not be enclosed in the slab and hence are not considered in the Concept Analysis. Forces can then only be exported back to the RAM Structural System for those walls and columns that were imported. In these cases the program will report the columns and walls for which no Concept forces are provided during the analysis in RAM Concrete. In the case of the situation described this should not be a concern as the forces in these members are still carried down from the levels above where they were actively supporting slab or beam.
- Column Design Forces
- Column design forces are calculated as previously described in this manual. Skip loading forces provided by RAM Concept are utilized when the skip load condition is specified in RAM Concrete Analysis Criteria. Concept provides column forces for any/all of the following: Dead Load, Hyperstatic Load, Roof Live, Storage Live, Floor Live and unreducible (includes partition) Live loads. The live loads (excluding the roof) can be skip loaded and are shown as cumulative values in the design report (considering the appropriate live load reduction factors).