Bridges and Viaducts

KUDE'S BRIDGE

Since the dawn of time, people have been dealing with the problem of crossing natural obstacles, larger or smaller watercourses, deep gullies and similar. The effort to overcome the obstacle has usually been motivated by some lucrative incentive, such as hunting, exchanging goods, stealing or robbing neighbours, military campaigns and similar. But in the case of the Kude's Bridge or, better said, the crossing, it is about a stimulus motivated by a sublime category: love. According to tradition, this crossing (which includes several small bridges and embankments with dry stone walls) was built at the end of the 18th and the beginning of the 19th century by a young man named Kude motivated by great love for his girlfriend. He built it to make it easier and faster to go see her. Some say he built it so that his wedding entourage could come for a proposal or a wedding with dry feet. It is not known who Kude was and where his idea of ​​how to build the crossing came from, but he probably saw a vaulted bridge somewhere, a construction logical for stone construction, and may have been inspired by the construction of the Marmont Road along the Adriatic coast built at that time.

The 109-meter-long crossing bridges the River Krupa, a tributary of the River Zrmanja, and consists of 12 smaller arched bridges with openings of approximately three to four meters in size, two culverts and connecting embankments of stone-lined sides between the mentioned structures. The width of the crossing is approximately 1.5 meters.

The crossing was built using tufa – a limestone relatively easy to process that is usually found at the foot of waterfalls, so the construction material was located next to the site. At the location of the Kude's Bridge, the Krupa River meanders among the steep stone slopes. There are several waterfalls upstream from the Kude's Bridge. "The nine" stand out among them due to 9 travertine cascades with a total height of about 10 meters. The entire river surrounding and the bridge location is extremely attractive and, therefore, is an integral part of the Velebit Nature Park, and it is also the goal of many hikers.

The bridge can be reached on foot from the village of Golubić, about 6.5 kilometres away on a hiking trail, which takes about an hour and a half, given the altitude difference of approximately 320 meters. The Kude's Bridge crossing is protected as a cultural good. However, there are fears that it could be endangered due to the excessive number of visitors.

ZEČEVE DRAGE VIADUCT

On the A6 Rijeka - Zagreb Motorway, between the Bosiljevo 2 and Vrbovsko junctions, the x-viaduct of Zečeva draga was built, followed by the Veliki Gložac tunnel in the direction of Zagreb. The viaduct has a total length of 939.23 meters and consists of two identical parallel structures, each for a separate direction of travel. They were being built from 2002 to 2004 (now in the direction of Rijeka) and from 2005 to 2007 (today in the direction of Zagreb). The project was made at the Engineering Project Institute in Zagreb, and the responsible designer was Zoran Lončarec, B.Sc. Civil Engineering. The works were performed by the company Viadukt.

The total length of the viaduct consists of two abutments 8.7 and 15.6 meters long and 19 spans measuring 2x 39.75 meters + 16x 49.73 meters + 39.75 meters. The width of both structures is 12.2 meters. Traffic widths at each structure are 2x 3.5 meters for the traffic lane and 2.5 meters for the stop lane, and the rest up to a full width of 12.2 meters are fences and protective spaces. The pillars of the viaduct are up to 50 meters high. The viaduct has a floor plan curve of R = 2505 meters and a vertical curve of R = 26,500 meters. The longitudinal slope is 4.25% on the higher and 0.77% on the lower abutment.

The span structure is a box-shaped cross-section made of prestressed concrete, sloping sides, and a height of approximately 4.0 meters. The walls of the structure are reinforced above the bearing points. The pillars of the bridge are box-shaped with a wall thickness of 0.3 meters (0.6 meters at the bottom), and are based on shallow reinforced concrete foundations measuring 12x13x3 meters.

This structure is especially interesting because of the way its span construction was executed using the segmental pushing technique. The segments of the span structure were concreted in front of the abutment and, with the help of a metal "beak", pushed by hydraulic presses until the pillar was reached. In doing so, they had to be complied with due to the longitudinal slope of the building. The total mass of the span structure at the end of the thrust was 22,000 tons. To make the work even more complex, the complicated geometry of the structure should be emphasized due to the vertical and horizontal curvature of the level. Prior to that, the Bajer Viaduct was built using the same technology on that highway near Fužine which was built by the same contractor, the company Viadukt from Zagreb.

Zvonimir-Zdenko Šimunjak,

B.Sc. Civil Eng.