The purpose of this test problem on acceleration loading is outlined as follows:
- Demonstrate acceleration-load application
- Demonstrate absolute/relative acceleration, velocity, and displacement
- Verify SAP2000 results with those obtained from the Acceleration to displacement record spreadsheet
- Check the ALTADENA-1 acceleration record
- Check one 10-cycle sinusoidal acceleration record
The attached SAP2000 file features a massless cantilever subjected to a vertical force which represents a concentrated mass located at its free end. A sinusoidal acceleration time history, defined as the SINE time-history load case, is applied to the system.
The absolute acceleration, velocity, and displacement of the restrained joint are plotted to obtain the applied ground-acceleration time history, along with its corresponding velocity and displacement records. For the test model given, these records are plotted in Figure 1:
Figure 1 - Sinusoidal acceleration, velocity, and displacement plot
These plots match the values obtained through manual calculation, displayed in the attached Excel file . This manual calculation follows formulation J.2 of Appendix J in Dr. Edward L. Wilson’s text Static and Dynamic Analysis of Structures.
This test problem yields non-zero displacement at the end of the time-history record. Correction using the base line correction algorithm is therefore necessary to establish zero absolute displacement at the unrestrained joint upon conclusion of the record.
- SAP2000 V12.0.1 model (zipped SDB file)
- Spreadsheet calculation (zipped Excel file)
- Hand calculations (PDF)