civeng80
Structural
- Dec 21, 2007
- 745
I have a large canopy structure which are two end portal frames 25m wide and a mid rafter supported on girders which are in turn carried by the two end portal columns.
I have modeled the structure in microstran for cases of 1. Self weight, 2. imposed Dead Load 3. Live load (amongst other wind loads cases). I then have a combination load with load factor of 1 for Self weight + imposed Dead load + Live load
As a check I am comparing deflection of the central rafter and cases 1, 2 and 3 added do not come to the combination case. Could this be because the analysis is non linear and superposition does not apply ? (microstran does not do the linear analysis because there are non linear elements (bracing) in the structure.
The difference I get in deflection is 34mm which is quite significant.
I have modeled the structure in microstran for cases of 1. Self weight, 2. imposed Dead Load 3. Live load (amongst other wind loads cases). I then have a combination load with load factor of 1 for Self weight + imposed Dead load + Live load
As a check I am comparing deflection of the central rafter and cases 1, 2 and 3 added do not come to the combination case. Could this be because the analysis is non linear and superposition does not apply ? (microstran does not do the linear analysis because there are non linear elements (bracing) in the structure.
The difference I get in deflection is 34mm which is quite significant.
