The fifty-year-old "Nuselák" is one of the busiest bridges in the Czech Republic

Prague – Around 160,000 cars and 750 subway trains carrying nearly 300,000 people pass daily over the Nusle Bridge, one of the key transport structures in Prague. The bridge over the Nusle Valley, which is one of the busiest in the Czech Republic, is not only a functional transportation structure but also an interesting technical and architectural piece, as well as a place where at least three hundred people have ended their lives. The bridge, which won the Construction of the Century award in the Transportation Structures category in 2000, was opened half a century ago, on February 22, 1973.

The plan to bridge the deep Botič Valley dates back to the early 20th century. In 1903, engineer Jaroslav Marjanko proposed a steel bridge to replace the steep and uncomfortable ascent via the Vyšehrad serpentine. However, the ambitious project failed.

During the interwar period, this possibility was of particular interest to Stanislav Bechyně, a pioneer of Czech concrete construction. He submitted several proposals, the most interesting of which was from 1938, which he collaborated on with architect Bohumír Kozák. The similarity of their solution back then to the current appearance of the bridge is striking.

The appearance of the structure, which spanned the Nusle Valley and connected Pankrác with Karlov, is the result of an architectural competition that took place at the turn of the 1950s and 1960s. The winning design was created by a trio of architects from the Institute for Transportation and Engineering Structures: Vojtěch Michálek, Stanislav Hubička, and Svatopluk Kobra.

"Their project closely resembles the winning competition design of architect Bohumír Kozák from 1938. It is designed very similarly, with a tube for trams. In fact, Kozák proposed glazing the station, as was later done at the Vyšehrad station. It is a reinforced concrete frame construction that has four supports," said architectural historian Zdeněk Lukeš.

The project envisioned a two-level reinforced concrete structure, with the upper part reserved for road traffic, while the hollow bridge body concealed the subway tracks or underground trams. The technical and aesthetic solutions proved successful, and in 2000 the Nusle Bridge even received the Construction of the Century award in the transportation structures category.

Construction of the bridge began in 1965. It progressed relatively quickly, allowing for a load test in the autumn of 1970 using 66 tanks lined up on the still-incomplete deck. However, the ceremonial opening did not take place until the end of February 1973, attended by leading representatives of "party, state, and public life," as reported by the press at the time. The structure was named after Klement Gottwald until May 1990.

"It became a work that is interesting both from an engineering standpoint – in that it combines motor and pedestrian traffic with the metro, which is in the tube beneath the roadway – as well as from an architectural perspective. I think it is a very successful structure that appears elegant and airy," said Lukeš.

The bridge, which is 485 meters long and 26 meters wide, represented and still represents one of the largest prestressed concrete structures in the Czech Republic. Five bridge spans with a trapezoidal cross-section are supported by four pillars, the construction of which necessitated the demolition of 17 buildings on Svatoplukova Street and the surrounding area. The construction consumed around 20,000 cubic meters of the highest quality concrete.

The tube, which has walls only 30 centimeters thick in some places, carries a dual-track subway line. However, the operation on line C posed a serious problem for the structure. Original plans accounted for significantly lighter trains than the Soviet-made cars that were eventually purchased. The result was increased stress on the bridge's structure, which the designers attempted to alleviate by installing a steel grid to better distribute the weight of the subway trains. However, cracks began to appear in that as well over time, leading to extensive repairs at the end of the 1990s.

However, it is not the interesting past or technical solution that regularly draws media attention to the Nusle Bridge. The structure became a popular spot for suicides shortly after its opening. As a result, the railing was gradually increased. The original railing was one meter high (in 1990, a 1.5-meter-wide net was hung beneath the railing), and between 1996 and 1997, it was raised to 2.7 meters. In 2007, it was supplemented with a smooth metal plate, which even climbers attempted to overcome, and which succeeded in halting the wave of suicides. It is estimated that at least three hundred people have taken their lives by jumping from the bridge, but an exact number does not exist.

Since 2011, a memorial titled "By Their Own Choice," created by Krištof Kintera, has commemorated them in Folimanka Park.

Between 2012 and 2017, the bridge underwent reconstruction: the bridge deck was repaired, and the concrete parts of the substructure and load-bearing structures were renewed. The repairs cost 288 million crowns and are expected to last another 20 to 25 years of operation.