PSI - Issue 78

Manuel Capogna et al. / Procedia Structural Integrity 78 (2026) 1064–1070

1067

The executive design was then developed with the consultancy of Riccardo Morandi and Gino Covre. The steel deck (see Fig. 2a) is supported by mighty hollow reinforced concrete pylons, while the access viaducts are made of prestressed reinforced concrete. The viaduct was built in three stages during the years 1968 and 1969 (see Fig. 2b). Due to the exceptional nature of the work, it was baptized ‘Viadotto Italia’ (Iori and Marzo Magno, 2011). In detail, the ‘Viadotto Italia’ is 1166 m long, composed of 19 spans, including: 16 spans of approximately 47 m in prestressed reinforced concrete; 2 spans of 125 m in steel; 1 span of 175 m in steel (see Fig.3). The deck is made of steel for the 125 m and 175 m spans. It has a maximum height from the valley floor of 250 m. The larger steel spans, totaling 425 m in length, have a box section made of steel plates stiffened by ribs (the so-called orthotropic deck), the highest pylon is 145 m, while the road level rises to 260 m from the valley floor. The reinforced concrete pylons have a box section, built using telescopic box formwork (Cestelli Guidi, 1970; De Miranda, 1971; De Miranda et al., 1965).

Fig. 3. ‘Viadotto Italia’ on the Lao river - Longitudinal section and plan

Attention Class

Total sections

19

1 2 3 4 5 6 7 8 9 10111213141516171819

Structural and Foundational Seismic

5 0 0 3 0

4 0 0 0 2

3 0

2

Partial Attention Class (Sections)

1 3 0

Structural and Foundational

16

Hydraulics Landlslides

Seismic

19

0 0 8

Hydraulics Landlslides

0 3

16

6

Attention Class

1 2 3 4 5 6 7 8 9 10111213141516171819

Overall

5

4

3

2

Partial Attention Class (%) Structural and Foundational

1

0.00% 0.00% 0.00% 84.21% 15.79% 0.00% 0.00% 100.00% 0.00% 0.00% 15.79% 0.00% 0.00% 0.00% 84.21% 0.00% 10.53% 15.79% 42.11% 31.58%

Seismic

Attention Class

1 2 3 4 5 6 7 8 9 10111213141516171819

Hydraulics Landlslides

Structural and Foundational Seismic Overall Hydraulics and Landslides

Total sections

19

SI

Attention Class

1 2 3 4 5 6 7 8 9 10111213141516171819

5 3

4 2

3 8

2 6

1 0

Hydraulics Landlslides Overall Hydraulics and Landslides

Overal Attention Class (Sections)

Overal Attention Class (%)

15.79% 10.53% 42.11% 31.58% 0.00%

(b)

(a)

Fig. 4. ‘Viadotto Italia’ on the Lao river - Attention classes for each individual segment (a) and diffusion index table (b)