PSI - Issue 62

A. Lupoi et al. / Procedia Structural Integrity 62 (2024) 963–971 A. Lupoi, F. Romano / Structural Integrity Procedia 00 (2024) 000–000

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2.2. Repair activity

The damaged girder was taken off from the bridge by cutting the top slab and the transverse beams; then, the remaining portion of slab attached to the girder was demolished before the cracks repair took place. The repair activity was conducted in collaboration with MAPEI and consisted in restoring the concrete cover of the web and filling the full-depth crack by high-pressure injection of specific mortar, as shown in Fig. 3. In particular, the repair procedure was made by the following steps: • Removal of deteriorated concrete areas through a sander in correspondence with the cracks; • Cracks cleaning by high-pressure air jet and high-pressure washing (Fig. 3(a)); • Arrangement of injection pipes and bonding to the girder through MAPEI two-component Adesilex PG4 adhesive (MAPEI, 2016, in Fig. 3(b); • Restoration of web concrete by applying MAPEI Mapegrout Easy Repair thixotropic cement mortar (MAPEI, 2023) in Fig. 3(c); • Full-depth crack sealing by high-pressure injection of MAPEI two-component Epojet LV epoxy resin (MAPEI, 2021) in Fig. 3(d); the injection also aims to fill the eventual void due to absence of mortar in post-tensioning ducts.

It is worth noting that the repair intervention was realized by one side only of the girder, due to the impossibility to operate on the other one.

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(b)

(c)

(d)

Fig. 3. Repair activity: (a) Girder preliminary cleaning ; (b) injection pipes arrangement; (c) web concrete restoration ; (d) high-pressure crack filling (courtesy of MAPEI).