Using CSiBridge, initial cable forces may be obtained for a cable-stayed bridge by following the process outlined in this article.

Modify undeformed geometry

• Model the final geometry of the bridge in its deformed configuration.

• On the Cable Shape Definition menu, select the option for Relative Undeformed Length.

• Use a nonlinear load case to analyze the bridge under applied dead loads.

• Run analysis again by selecting Analysis > Shape Finding > Modify Geometry. Iterate until deformed shape converges to the geometry desired.

• Extract the cable forces.

Verify cable forces

The procedure used to verify these cable forces is as follows:

• Apply the dead loads and the cable target forces (previously determined), then run a nonlinear static analysis for this loading condition.

• If the cable forces are optimal, then the structure, when modeled in its final configuration, should experience negligible deflection under dead-load and target-cable forces.

Use the unit-load method to tune cable forces

• If deflection is not negligible, then the unit-load method may be manually applied to determine how cable forces should be adjusted.

See Also

• Accounting for deformed shape in staged construction article

• Cable-stayed bridge first steps tutorial

• Cable-stayed bridge FAQ article