Load Cases

From the Loads menu you can select the Load Cases option to access the loading cases and the associated load combinations where combination load factors can be set up for each individual load case.

This area allows you to edit, add, delete, copy and paste, import and sort loading case titles.

To increase efficiency, you can save case titles and their load combination in a special library using the Add + button and then retrieve them from the drop list in any other project. You can delete items no longer required from this library using the Del X button.

The cluster of buttons from Dead through to (Serviceability) are quick typing buttons that insert the chosen word into the Load Case Title text box.

Adding Load Cases

To add a new loading case:

1.Press the Add Load Case  button

2.Type in the new title in the Loading Case Title text box.  Remember you can use the quick typing buttons.

3.Define the loading combination.  See instructions below on using the Loading Combination tab.

To create a Serviceability loading case from a current Ultimate loading case:

1.Press the Add Service Case to current load case button

This will generate an additional loading case with the same title, however with (Serviceability) at the end.  The load combination is also copied with all load factors for the new case set to 1.0.

2.Press the Add Service Cases to all load cases button  to generate a series of service cases, one for each ultimate case already present

To save a loading case to the standard loading cases library:

1.Select the case you wish to save

2.Make sure that you have the correct load factors in the load combination

3.Press the Add button

To add new case as a copy of an existing case:

1.Select case you want to copy from the top drop list

2.Press the Copy Case button

3.Press the Add Case button  

4.Press the Paste Case button

To import a loading case from the standard loading cases library:

1.Press the Add Case button

2.Select the appropriate case from the library

3.Press the Import selected load case from library below button

There is an Auto-Generation of Load Cases option available which takes much of the manual labour of creating a series of load cases out of the hands of the user and sets them up quickly for you – see section below on auto generation of load cases.

Deleting Load Cases

To delete a loading case:

1.Press the Delete Case button

This action will open the Delete Loading Cases panel.

2.Highlight the load case or cases (use the Ctrl key to multi select cases) that you wish to delete and click on the Delete button.

3.Confirm that you want to delete this load case.

There are options to select all cases, or all ultimate or service cases, non-critical load cases or clear all selected cases.

Suspending Load Cases

Options are provided for suspending loading cases, which means loading cases that have been set up will not be analysed.  The main benefit of this function is to save analysis time by ignoring certain loading cases that may not be needed just yet.  The benefit of suspending loading cases, rather than deleting them, is obviously that the loading cases do not have to be recreated when they are needed again.  An example of where the suspend options could be useful is if you had a model with a large number of members and numerous loading cases, and the only item you wish to investigate at this moment in time is the support reactions from loading case 10.  By suspending all cases but number 10, the analysis will complete in a fraction of the time it would take for all the cases to analyse.

You can suspend loading cases by either,

1.For an individual case, select the case you want to suspend then check the ‘Suspend this case’ box

2.For a group of cases press the Edit button.  A list of all loading cases will appear.  Select the items in the list you wish to suspend.  You can use the Select and Clear All buttons to help you.  Finally press the Suspend button in this area.

Combining Load Cases

You can combine load cases to produce new cases. The load case which is current can be a combination of the results from one or more active load cases which precede it in the list. For example, 1.25x1 + 1.5x2 is equivalent to (1.25 x Case 001) + (1.5 x Case 002).

Importing Load Cases

Load cases from other MasterSeries frames can be imported into the current frame to save having to create new cases time and time again. For example, an office may wish to have a standard set of loadcases which will be applied to all models of a certain type. A file with all these load cases already set up is opened and the load cases imported from it into the current frame. To do this:

1.Select to Import from MasterSeries File . This takes you into a directory/file structure.

2.Select the directory your file is located in.

3.Select the file that has the standard set of load cases. The list of load cases and load groups appears.

4.Highlight the load cases and load groups you wish to import.

5.You can Add them to the current list of load cases in your file or totally Replace the current set of load cases with the ones from the chosen file.

6.Once you are satisfied with your selection, click on the Apply button to import them.

Auto Generation of Load Cases

To reduce the amount of work required in setting up the numerous load cases applicable to your model, MasterSeries has an Automatic Load Case Generator. This is used to create or edit all loadcases.

1.To start the process click on the Create/Edit All Load Cases Edit button .

This opens up the load case generator templates box.

The buttons in the top right of the load case generator allow you to Add, Delete, Copy, Sort and Reset the load case templates in the top list. Several typical template titles are already in the list.

To define which load groups are to be included in each template:

1.Highlight the template you want to modify, eg, Dead + Live.

Note - if there is a current template you don’t want to be included in your list of load cases, then remove the tick from the tick box to the left of that template title and that combination will be omitted.

2.Tick which Load Groups you want to include in this template, eg, D0 Dead Load, D1 Dead Load and L1 Live Load. You can also designate if these load groups are to be considered Favourable or Leading or neither.

Another useful tip is to tick the box to List Used Load Groups Only. This will reduce the load group list to only those already defined in the file.

3.Under the Options, choose the Load Case Type or types, eg, Ultimate + Service. This will generate all Ultimate and Service load cases for the load groups ticked in the table above.

4.For EC design select which Ultimate Case Type to use, eg, STR/GEO Set B Eq. 6.10 a+b.

5.Select which Service Case Types to use, eg, Characteristic.

6.Horizontal Notional Forces can be added into these load cases by ticking the Add EHNF box. These can be added in the same directions as the wind directions already specified in the Wind Loading set up.

7.Carry out the same procedure for each of your load case templates entered at the top of the Load Case generator screen.

8.Click on the Preview button at the bottom of the templates box to see a list of all the load cases about to be generated. Examine the cases and then close the preview list. Modify any templates if required.

9.Select the Add button either to Add to, Update or Replace these load cases in the file.

Note that the load combinations are also generated at the same time as the load case titles.

Notional Horizontal Loading Cases

Horizontal notional loads can also be added to the load cases outside of the Automatic Generation screen.

1.Select the blue Notional Loads at the bottom of the screen.

In the list of existing load cases you can manually set up to add the NHL:

a)For each load case selected at the top of the screen, tick the Horizontal Notional Loads box.

b)Enter the Horizontal Loads percentage value, usually 0.5%.

c)Select which load case the factored vertical loads are to be taken from and

d)Which direction these loads are to be applied in relative to the X direction

Alternatively, you can generate the NHLs automatically in the Generate Horizontal Notional Loads option:

1.Set the series of directions you want the loads to be applied in, eg, 0, 90, 180 and 270 degrees.

2.Click on the Generate button to add the loads and any additional load cases that may be required.

The analysis process will calculate the HNLs for each load case in turn and then add these loads into the load case and reanalyse the case. The Elastic Critical Load Factors can subsequently be checked in the Steel Design module of the MasterSeries.

Important:  The application of horizontal notional loads should not be confused with the notional loads groups N0 to N9.  They are not connected in any way.  The notional load groups are standard load groups that are used for loads that may not be Dead, Live or Wind.  The horizontal notional loads are independent from any of the load groups and do not appear in the Load Combinations area.

After the frame has been analysed the calculated values of the horizontal notional load can be viewed in the frame data file.  From the main MasterFrame menu select Data> View Data.

Analysis Options

Select the blue Analysis Options at the bottom of the screen.

This gives access to a number of analysis options, most of which are considered in-depth elsewhere in the manual.

Second order P-Delta analysis can be carried out on individual load cases to examine the stability of a frame under the loads on that particular load combination – See Analysis chapter.

The Elastic Critical Load Factor can be found using a buckling analysis instead of the horizontal notional load method for each individual selected load case. Again, the results will appear in the steel design.

Occasionally, you may wish to carry out a plastic analysis, eg, on a portal frame. For further details see Potential Plastic Hinges in the Restraints menu.

If a frame has timber sections in it, the timber load duration terms for the various load cases can be set manually per case, by selecting each load case in turn and then the appropriate load duration for that case.

Alternatively, there is an Auto Set button where the program will set the load duration term for you, based on whether the case is a wind case, ultimate case or other type of case.