## 2 Bridge Description  
The Filomena Delli Castelli bridge is a steel-concrete composite cable-stayed bridge with three spans of 42.6, 103.4, and 42.6 m, for a total bridge length of 188.6 m. The bridge allows the road and cycle-pedestrian connection between the municipalities of Montesilvano and Citta Sant'Angelo (in Central Italy) by crossing the Saline River (Figure 1). The overall deck width varies between 19.2 m and 22.8 m and includes a 11.5 m wide carriageway, two 0.75 m wide curbs to accommodate barriers, two technical paths for the stay connections, and a cycle-pedestrian path of variable width (Figure 2a). The deck structure is constituted of two 1.2 m high I-shaped girders that are connected by I-shaped cross-beams with variable heights ranging between 0.8 and 1.2 m, and by a 25 cm thick concrete slab. The cross-beams have cantilevers that extend for a length of 1.1 m on the upstream side of the bridge, while they vary between 4.0 and 7.6 m on the downstream side. The cross-beams are 4.3 m spaced along the longitudinal direction in the lateral spans, and 4.7 m spaced in the central span. The concrete slab is connected to the main girders and cross-beams by Nelson studs and it is casted using 7 cm thick precast predalles, lightened with expanded polystyrene blocks in correspondence of the cycle-pedestrian path. The pylons consist of four inclined steel tubes with diameter of 1.9 m and height of 33.45 m on the upstream side and 36.4 m on the downstream side, respectively (Figure 2b), filled with concrete for the first 16 m on the bottom part, and transversally connected by a 1 m wide and 2 m high steel box-girder (Figure 2b). The pylons are anchored at the base by means of 20 5.5 m long Dywidag steel bars having diameter of 40 mm, and by four shear keys that are embedded into a truncated cone-shaped concrete shaft. The foundation of each couple of pylons consists of 2 m thick and 9.2 m large square concrete plates that are transversally connected to each other by a 3 m wide and 2 m high tie beam. Each pylon basement is founded on nine 35 m long drilled piles with diameter of 1.2 m.  
Stay cables are realized with bundle of 19, 25, 30, and 37 waxed and biplated parallel strands with seven galvanized wires that are made of low relaxation harmonic steel, and they are protected by a high-density polyethylene sheath. The stays are anchored to the pylons by means of forks and pin connections that are arranged on five levels at a distance of about 2.5 m from each other (Figure 2c), while, on the other side, they are equipped with adjustable anchorages that are connected to the deck by means of ribbed plates that are directly welded to the main girder webs. The two pairs of external stays spread outwards, passing from 14.1 to 26.1 m of transverse distance, to anchor to the abutment wing walls by means of 7 m long Dywidag bars having diameter of 40 mm, thus ensuring a reduction of the transverse bending in the pylons. The abutments have a total height of about 5 m above the ground. The front walls are 1.9 m thick, while the back walls, set back of 2.25 m from the front walls, have thickness of 0.5 m. The side walls, which are connected to the frontal walls with 34.2\({}^{\circ}\) inclined sections, consist of 5.85 m long walls with a thickness of 3 m, on which the outermost stays of the pylons are anchored through an inclined projection. The abutment foundations are  
Figure 1: Overview of the Filomena Delli Castelli bridge. constituted by 16 drilled piles with diameter of 1.2 m arranged in three transversal rows and the cap has an almost rectangular shape of dimensions 10.3 \(\times\) 16.3 m, with thickness of 1.4 m. Multidirectional negative-load pot bearings are adopted for the supports of the main girders. Lead rubber bearings (LBRs) are located at the two pylon cross-beams in the middle position. The latter control the horizontal displacements of the deck and ensure the seismic protection of the bridge through the isolation technique, by adding benefits of the period elongation to those of the energy dissipation.