I have designed a truss model as a planar frame and assigned truss specification to all the members. When i apply the moving load and run the analysis the moving load is not applied on the structure and shows the following warnings
**WARNING-NO MEMBERS IN SPECIFIED VERTICAL RANGE.
**WARNING- CONSECUTIVE ANALYSIS COMMANDS. ONLY FIRST USED.
**WARNING - THERE WERE MORE THAN 12 DOF WITH ZERO STIFFNESS.
*WARNING- ZERO STIFFNESS IN DIRECTION 6 AT JOINT 4 EQN.NO. 18
Matlab truss-1.std
1. Instability and zero stiffness warning messages are due to the member truss specification. You need to replace this with partial moment release command as --
MEMBER RELEASE1 TO 22 Start MP 0.9951 TO 22 end MP 0.995
For more details, refer to the following post --
https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/2046/staad-pro-instability-and-zero-stiffness-faq
2. 3 perform analysis commands are specified in the model. Program considers the first one and rest of the analysis commands are ignored. You need to remove rest of the analysis commands.
3. Moving load definition and load generation is not proper. You need to define the vehicle definition properly and for load generation, the number of loads generated should be calculated considering the increment value and total length covered by the load. I have modified the model with sample moving load --
Matlab truss_mod Suro.std