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Load Combination

SS

The LoadCombination class is designed to define and manage load combinations defined in MIDAS CIVIL NX.
It supports classification-specific combinations such as Steel, Concrete, Seismic, etc., and provides functionality for creating, syncing, retrieving, and deleting these combinations.

Constructor

LoadCombination(name, case, classification="General", active="ACTIVE", typ="Add", id=0, desc="")

Parameters

  • name (str): Name of the load combination.

  • case (list[tuple]) : List of tuples with load case names and factors.
    ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ Example: [('Dead Load(CS)', 1.5), ('Live Load(ST)', 0.9)]

  • classification (str) : Category of the load combination.
    ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ Must be one of : General   |   Steel   |   Concrete   |   SRC   |   Composite   |   Steel Girder   |   Seismic
    ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ ‎ Defaults to General.

  • active (str) : Activation status. ACTIVE, INACTIVE, STRENGTH, or SERVICE.

  • typ (str | int) : Combination type: "Add", "Envelope", "ABS", "SRSS" or corresponding integers 0–3.

  • id (int) : Unique identifier. Auto-incremented if set to 0.

  • desc (str) : Optional description.

Object Attributes

NAME: Name of Load Combination

CASE: Load Case and Scale factors in the Load Combination

CLS: Classification of the Load Combination (General, Steel, Concrete, SRC, Composite Steel Girder, Seismic)

ACT: Activation status of the Load Combination ('ACTIVE' , 'INACTIVE, 'STRENGTH', 'SERVICE')

TYPE: Type of the Load Combination (Add, Envelope, ABS, SRSS)

ID: ID of the Load Combination

DESC: Description of the Load Combination

Class Attributes

LoadCombination.data -> List of all Result combination data.

NOTE :

  • Load case names must include their analysis type in parentheses, e.g., "Load1(ST)".
  • Supported analysis types: ST, CS, MV, SM, RS, TH, CB, CBC, CBS, CBR, CBSC, CBSM.

Methods

json

Returns a JSON dictionary of the defined load combinations.

  • Filters by classification or includes all if "All" is passed.
Load_Case('USER','SelfWeight','SIDL') # Static Load cases
LoadCombination('LCB1',[('SelfWeight(ST)',1.5),('SIDL(ST)',1.35)],'Steel') # Load Combination for Steel design
LoadCombination('LCB2',[('SelfWeight(ST)',1.5),('SIDL(ST)',1.35)],'Concrete') # Load Combination for Concrete design

print(LoadCombination.json('Steel')) # Printing only steel design load combination
# Output
# {'Steel': {'Assign': {1: {'NAME': 'LCB1', 'ACTIVE': 'STRENGTH', 'iTYPE': 0, 'DESC': '', 'vCOMB': [{'ANAL': 'ST', 'LCNAME': 'SelfWeight', 'FACTOR': 1.5}, {'ANAL': 'ST', 'LCNAME': 'SIDL', 'FACTOR': 1.35}]}}}}

create

Creates (or replaces) combinations in the MIDAS model.

Load_Case('USER','SelfWeight','SIDL')
LoadCombination('LCB1',[('SelfWeight(ST)',1.5),('SIDL(ST)',1.35)],'Steel')

Load_Case.create()
LoadCombination.create()

get

Gets load combinations from the MIDAS CIVIL NX model.

  • Returns combinations as a dictionary grouped by classification.
print(LoadCombination.get())
# Output
# {'Steel': {'LCOM-STEEL': {'1': {'NAME': 'LCB1', 'ACTIVE': 'STRENGTH', 'bES': False, 'bCB': False, 'iTYPE': 0, 'DESC': '', 'iSERV_TYPE': 0, 'nLCOMTYPE': 0, 'nSEISTYPE': 0, 'vCOMB': [{'ANAL': 'ST', 'LCNAME': 'SelfWeight', 'FACTOR': 1.5}, {'ANAL': 'ST', 'LCNAME': 'SIDL', 'FACTOR': 1.35}]}}}}

sync

Synchronizes internal Python data with what's present in the MIDAS CIVIL NX model.

LoadCombination.sync()

for comb in LoadCombination.data:
    print(f'Name -> {comb.NAME}  | Design -> {comb.CLS}  | Cases -> {comb.CASE}')

# Output
# Name -> LCB1  | Design -> Steel  | Cases -> [{'ANAL': 'ST', 'LCNAME': 'SelfWeight', 'FACTOR': 1.5}, {'ANAL': 'ST', 'LCNAME': 'SIDL', 'FACTOR': 1.35}]

delete

Deletes specific combinations from the MIDAS model.

LoadCombination.delete()

Example Usage

# Define a new load combination
lc = LoadCombination(
    name="LCB1",
    case=[('Dead Load(CS)', 1.5), ('Live Load(ST)', 1.0)],
    classification="General",
    active="ACTIVE",
    typ="Add"
)

# Export combinations to JSON
print(LoadCombination.json())

# Create combinations in the MIDAS model
LoadCombination.create()