Staged Construction Analysis

The I95 Mississippi River Bridge was designed to be a record-breaking, cable-stayed structure linking the States of Illinois and Missouri in the USA, helping to relieve traffic on existing bridges across the river. 

Designed by Modjeski & Masters for its clients Missouri and Illinois Departments of Transportation, staged construction facilities in LUSAS Bridge were used to model an 800 day construction period, continuing up to a total of 10000 days to allow for creep over that length of time.

Staged construction analysis with LUSAS provides you with the means to model the step-by-step construction of your structure over time and evaluate the effects of structural changes, load applications, and, if required, time-dependent material effects. 

With LUSAS Bridge, one model file can contain all of the information needed to carry out a linear or nonlinear analysis of every stage of construction. The effects of geometric and material nonlinearity, and time-dependent material effects such as creep and shrinkage can all be included within the one analysis run.

The image above shows just a few exaggerated deformed shapes of a beam and shell model used to carry out a staged construction analysis ( incorporating creep and post tensioning) to simulate the construction of the deck.

Features

• Full activation and deactivation of elements supported
• Support and loading facilities including temporary/traveller loads
• Section property and material property changes over time
• Time-dependent material properties include stress related concrete creep and shrinkage to CEB-FIP Model Code 1990, and include creep recovery
• Steel relaxation, time effect on elastic modulus, tendon post-tensioning losses from creep, shrinkage, and superimposed loads
• Modelling of cable and tendon stressing and slackening
• Custom time dependent curves for particular material properties and codes
• Cumulative effects can be reported separately for each loadcase, such as post-tensioning effects or the effects of just creep and shrinkage
• Incremental effects can also be specified allowing you to view and assess the net changes to the structure since the previous stage.