Model overview

Internal shrinkage forces are evaluated for one-span and continuous two-span bridge structures. These bridges have the following properties:


A 3D view of the one and two-span bridge models is shown in Figure 1:


Figure 1 - Bridge model


The cross-sectional geometry of the bridge deck is shown in Figure 2:


Figure 2 - Bridge deck section


Key modeling steps


For both the one-span and the two-span bridge objects, the deformed shape indicates that deck shrinkage causes shortening of deck fibers, and it causes the entire bridge to bow downwards, as expected. This behavior is shown in Figure 3:


Figure 3 - Shrinkage deflection


For the one-span bridge, since the structure is statically determinate, no internal forces are generated. However, the two-span bridge is statically indeterminate, and redundant reactions do cause internal moments. At the interior pier, tension is generated in the top fibers, as shown in Figure 4:


Figure 4 - Shrinkage moment