PSI - Issue 78

Stefano Bozza et al. / Procedia Structural Integrity 78 (2026) 1213–1220

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c)

a)

b)

Fig. 1: Planimetric view (a), lateral view (b) and element cross sections (c) of the case study bridge.

The shear keys on the mid-span joint are steel pins rigidly connected to one side of the joint via Dywidag bars and inserted in cavities appropriately created on the other side of the joint; these pins restrain differential displacements along one direction between the two sides of the joint, and thanks to the different orientation of the three shear keys, both horizontal and vertical differential displacements are restrained, while both longitudinal displacements and rotations along vertical and horizontal axes are free. The role of the Dywidag bars is merely to anchor the metallic part to the concrete block. The prestress in the Dywidag bars, if present, does not significantly affect the shear strength of the device and is therefore neglected in the following.

3. Analysis 3.1. Numerical modelling

A FE model of the entire structure was built using the software SAP2000 ® v25.2.0 (CSI 2016), see Fig. 2. The box girder was modeled with elastic frame elements, using one frame for each precast segment and defining the actual section of the deck in every frame, taking advantage of the FE software API and Python to import the geometry of the bridge (both for nodes coordinates and cross section geometry). The piers were modeled using elastic frame elements and nonlinear hinges: elastic frames with the actual cross

Fig. 2: General view of the FE model of the case study bridge.