International Scientific Conference "Preservation of Cultural Heritage" BASA'2019

DANUBE BRIDGE BETWEEN RUSE AND . CONSTRUCTION AND MAINTENANCE.

Eng. IVAN GOGEV, NRIC, Republic of Associate Prof. D-r Eng. LAZAR GEORGIEV, UACEG, Republic of Bulgaria Prof. D-r Eng. DONCHO PARTOV, VSU L. Karavelov, Republic of Bulgaria Prof. D-r Eng. MILTCHO LEPOEV, UACEG, Republic of Bulgaria International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The Bridge connecting Bulgaria (Ruse) and (Giurgiu) is built between 1952 and 1954 for only two years. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019

The Danube Bridge connecting Bulgaria (Ruse) and Romania (Giurgiu) is built between 1952 and 1954 for only two years.

The bridge is with combined road and railway traffic. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Ø Before building the bridge connection between Ruse and Giurgiu was realised by means of ferryboat, opened in 1940, built by MAN-Werk Gustavsburg, Wayss & Fraytag, Hojgaard & Schultz, Gutenhoffnungshütte Werft in Walsum, Danube buiding section - Ruse. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The chronology of decision for building the bridge follows several steps: Ø In 1951 a Protocol for erection of “Bridge of friendship over Dadnube” between Bulgaria and Romania is signed in Moscow between members of UEMH (Union for Econcomic Mutual Help); Ø Special agreement for participation of Soviet Union in the project is also signed. The bridge was named “Object 889” and designed and erected in top secret condition because of its strategic and military significance.

Ø In present times the traffic capacity of the bridge is insufficient so building of additional bridge is discussed. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The total length of the bridge is 2224 m and the spans are (12х34,5)+(4х80)+(2х160)+86+(2х160)+(4х80)+(12х34,5).

Perspective view of the bridge. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The total length of the bridge is 2224 m and the spans are (12х34,5)+(4х80)+(2х160)+86+(2х160)+(4х80)+(12х34,5).

General view of the bridge with rised movable span. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The Danube Bridge connecting Bulgaria (Ruse) and Romania (Giurgiu).

Opening of the bridge traffic at 27 January 1954. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The approaches are composite steel and concrete plate girder bridges L=34,5m. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The approaches are composite steel and concrete plate girder bridges L=34,5m. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The 4x80m spans are continuous girder riveted trusses with road at the upper cord and railway deck at the lower cord and slenderness of the superstructure h/L=1/7. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The 4x80m spans are continuous girder riveted trusses with road at the upper cord and railway deck at the lower cord and slenderness of the superstructure h/L=1/7. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 2x80m spans from Bulgarian side. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The 2x160m are continuous girder 3 cords riveted trusses with road level at middle cord and railway at lower cord and slenderness of the superstructure h/L=1/7. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 The 2x160m are continuous girder 3 cords riveted trusses with road level at middle cord and railway at lower cord and slenderness of the superstructure h/L=1/7. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 General view of the 86m movable span. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Cross section of the 86m movable span. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Ø The piers in large span region are reinforced concrete with caisson foundations approach spans are on pile foundations.

Ø For the superstructure of the bridge 19200 ton of steel Cт.3 мостова are used. Ø Steel consumption is around 502kg/m2 (concerning the total surface of the road and railway deck). Ø The 80m trusses are fabricated in Hungary. Ø Two of the 160m steel riveted two level truss bridges and the movable span are fabricated in Czech Republic. Ø The other couple of 160m riveted trusses are fabricated in Poland. . International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 International Scientific Conference "Preservation of Cultural Heritage" BASA'2019

Scheme of the erection technology International Scientific Conference "Preservation of Cultural Heritage" BASA'2019

Scheme of the erection technology International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Side 34,5m spans of the bridge consists of simply supported composite steel and concrete main girders. They are steel riveted beams with prefabricated reinforced concrete plate over the upper flange. Steel girders and reinforced concrete panels are lifted and positioned by means of relevant cranes.

Lifting 40 ton steel plated riveted girder by means of crane ДК-35 International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Positioning of the prefabricated reinforced concrete panels. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Erection of the first of the 80m spans with small size elements. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 160m span, 2026 ton, is erected at the coast and prepared to be transported by means of floating supports. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 160m span, 2026 ton, is erected at the coast and prepared to be transported by means of floating supports. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Transporting of the 160m span to the piers by means of floating supports. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 First of 2x160m spans is positioned on the supports and the erection of the second one by DK-35 crane is started using small part elements and balanced console launching. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 First of 2x160m spans is positioned on the supports and the erection of the second one by DK-35 crane is started using small part elements and balanced console launching.

The console is 110m long at the presented stage International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 86m span, 1264 ton, is erected at the coast and transported to the floating supports. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 86m span, 1264 ton, is erected at the coast and transported to the floating supports. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Load tests are realized to prove the correspondence of the behavior of the superstructure with the design project parameters. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 It must be noticed that due to high quality of the erection first serious rehabilitation works for the bridge were realized in 1999-2004. There are high number of complex steel riveted details in the bridge superstructure and problems with corrosion and delamination are registered. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 Rehabilitation works include: Ø torkreting 5709m2 concrete surfaces Ø anticorrosion coating of steel surfaces – 72363m2 Ø repair of delamination in corroded zones – 460m Ø strengthening of longitudinal girders Ø replacement of parts of the railway track Ø controlling geodetic surveying and analysis Ø others. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019 During 2012 refubrishment of the movabale span of the bridge is done including electrical part, autoblocking system, command cabin, regulation of steel ropes, check and repair of the mechanisms . International Scientific Conference "Preservation of Cultural Heritage" BASA'2019

CONCLUSIONS: Ø The Danube Bridge between Ruse and Giurgiu for its 65 years of exploitation and in spite of high intensity of the traffic is in relatively satisfactory condition from technical point of view. Ø General revisions for estimating the technical condition are provided with a frequency of several years. Ø The first serious preservation and rehabilitation works began 45 years after bridge competition due to high quality of erection. Ø In spite of the serious importance of the bridge the detailed technical documentation and drawings of the bridge elements are missing in the relevant authorities in Republic of Bulgaria which is problem in respect to the estimation of the load bearing capacity for present live loads. Ø In present times UACEG and NRIC has the idea to provide scientific research project focused on measuring and recalculation of parts of the superstructure in accordance with Eurocodes and evaluation of the remaining fatigue life with respect to relevant critical details. International Scientific Conference "Preservation of Cultural Heritage" BASA'2019

LITERATURE: [1] Gogev, I. Tsenov P., Ivanova S., Bairov I, (1999): “60 years Danube bridge between Ruse and Giurgiu”, Vip Style, 2014, (in bg). [2] Building bridge over Danube between Ruse and Giurgiu, Technical Report, Volume 1, 1954. [3] NRIC, General Revision, 2008. [4] Brainov M., “Bridge of the friendship”, Journal of Science and Technics, 9-10, 1954, (in bg).