## 3 Results of Strengthening According to the Author  
### Characteristics of the Diagonal Stay Cable According to the Author  
In 1993, the author of the paper was a participant of the 31 st IRI (Istituto per la Ricostruzione Industriale) course organized in Italy for bridge experts from different countries. During several months of the course, he had the opportunity to familiarize himself with the work of design and construction companies in Italy. In April 1993, he stayed at the Italstrade company in Milan. Since the company was involved in the reconstruction of the Polcevera Viaduct, the author was sent to Genoa as part of the visit to  
Figure 8: **(a)** Support No. 11 with strengthened north-eastern concreted cable (photo by [PERSON]; April 1993). **(b)** Strengthening of the concreted cable with long external tendons—view from the deck (photo by [PERSON]; April 1993). **(c)** The north-western concreted cable after strengthening—view from the top of pylon No. 11 (photo by [PERSON]; April 1993). **(d)** Steel cap on pylon No. 11 (photo by [PERSON]; April 1993). **(e)** The south-western concreted cable before strengthening—view from the top of pylon No. 11 (photo by [PERSON]; April 1993). **(f)** View from the top of pylon No. 11 to pylon No. 10 with scaffolding (photo by [PERSON]; April 1993). the company. During this period, the diagonal stay cables of the viaduct were strengthened according to the design by [PERSON]. Table 1 summarized data characterizing the structure of the diagonal stay cable before and after strengthening with the use of the long external tendons. These are cross-sectional area and tensile stiffness. The cables were not strengthened at two supports of the viaduct, Nos. 9 and 10. The structure of the stay cable at those supports was constructed according to the design by Prof. [PERSON]. Assuming that:  
internal forces specified in the report of Prof. [PERSON] ([PERSON], March 1992) are correct,  
the longitudinal modulus of elasticity of the tendon E = 180,000 MPa,  
the modulus of elasticity of concrete E = 32,000 MPa,  
the length of the cable is 92.2 m (based on Figure 3b),  
the cross-sectional area and the tensile stiffness are calculated and specified in Table 1, it can be calculated that in the non-strengthened cable:  
Under permanent load:  
the tensile stress in internal tendons was 515.1 MPa (26.1:0.05067),  
the compressive stress in concrete was 6.1 MPa (7:1.14493),  
the elongation of the cable transferring the load as a steel-concrete section was 38.5 mm (19.1 \(\times\) 92,200:45,758.4),  
the elongation of the cable transferring the load only through internal tendons would be 193.1 mm (19.1 \(\times\) 92,200:9120.6);  
Under live load equal to 6.0 MN:  
the tensile stress in internal tendons was 23.6 MPa (6.0:0.05067 \(\times\) (9120.6: 45,758.4)),  
the compressive stress in concrete was 4.2 MPa (6.04:1.14493 \(\times\) (36,637.8: 45,758)),  
the elongation of the cable transferring the load as a steel-concrete section was 12.1 mm (6.0 \(\times\) 92,200:45,758.4),  
the elongation of the cable transferring the load only through internal tendons would be 60.7 mm (6.0 \(\times\) 92,200:9120.60). In summary, in the non-strengthened cable under total load (permanent and live load):  
the tensile stress in internal tendons was 538.7 MPa (515.1 + 23.6),  
the compressive stress in concrete was 10.3 MPa (6.1 + 4.2),  
the elongation of the cable transferring the load as a steel-concrete section, was 50.6 mm (38.5 + 12.1),  
the elongation of the cable transferring the load only through internal tendons would be 253.8 mm (193.1 + 60.7),  
the increase in elongation of the cable transferring loads only through internal tendons would be 203.2 mm (253.8-50.6); such an increase in elongation of the cable would cause vertical displacement equal to 108.9 mm (sin32.4o \(\times\) 203.2; the value of the angle was assumed based on Figure 3b). The non-strengthened diagonal stay cable can be characterized as follows.