To simulate a two-span structure which is simply supported under dead load, and continuous under live load, a staged-construction load case is defined with five stages, outlined as follows:
Stage 1: Add two frame objects, one for each span.
Stage 2: Define frame end releases through Define > Named Property Sets > Frame Releases, then assign these moment releases to the start joint of the second span.
Additional information is available in the Staged-construction tips and Staged-construction operations articles.
Stage 3: Apply load to the structure. Response will be as though the system is simply supported.
Stage 4: Fix the moment end releases which are applied in Stage 2.
Stage 5: Apply additional load to the structure. Response will now be as though the system is continuous.
The structural response is presented in Figure 1:
Figure 1 - Structural response
SAP2000 V12.0.1 model (zipped SDB file)
Name: Two-span girder simply-supported for DL and continuous for LL
Description: Modeling demonstration for a two-span girder which is simply-supported for DL and continuous for LL.
Program: SAP2000
Program Version: 12.0.1
Model ID: 130