“He appears fragile. An expert criticizes the design of the bridge that collapsed in Baltimore

“The bridge has a so-called continuous beam support structure, with a dominant main span field of 366 meters. As a result of the impact of the ship on one of the piers, this span increased by about 1.5 times, for which the support structure is not and cannot be designed. The bridge pier was probably not sufficiently protected against the impact of a ship and at the same time appears to be relatively fragile,” said Pavel Ryjáček, Head of the Department of Steel and Wood Structures at the Faculty of Construction of the Czech Technical University.

He added that according to today’s standards, in the case of a new structure, the framework of the pillar itself should be more robust and the related protection more durable.

According to him, the supporting structure of the bridge was not designed badly. In the event of the collapse of one dominant pillar of such a large bridge of a similar arrangement, the supporting structure of other types would also collapse. To protect bridge piers against ship impact, for example, ship barriers, earth bodies and various protective walls are used, which aim to absorb the energy of the vessel’s impact and reduce or eliminate the force on the pier. According to Ryjáček, such protection exists, for example, at the Stonecutters bridge in Hong Kong, which, however, has a newer and more modern construction with a significantly larger span.

According to Jiří Kolísk, an expert in the diagnosis and evaluation of constructions, one of the possibilities of the collapse of the bridge could also be a horizontal shift of the lattice structure, i.e. the rod system of the bridge. But you can’t tell from the video, and according to him, damage to the pillar was primarily to blame. According to him, similar types of steel truss bridges are commonly built around the world.

For example, the lattice structures of the Výton bridge in Prague, and the arched bridge across the bay in Sydney abroad are well-known. But these are older bridges, according to structural engineer Václav Losík, lattice bridge structures are not very common in modern construction.

According to Ryjáček, the probability that an event similar to the one in Baltimore would also happen in the Czech Republic is much smaller. Ships the size of the one that hit the bridge in Baltimore do not exist in the Czech Republic. The underpass height of Czech bridges on the waterway is a maximum of 5.25 meters, and work is currently underway to increase it to seven meters. However, according to Ryjáček, the ship in the video is several times larger than a vessel that could be seen on the Elbe or Vltava.

In inland navigation in the Czech Republic, according to the director of the Prague branch of the State Navigation Administration Hynk Beneš, a ship hits a bridge very rarely, approximately once every five years. In the overwhelming majority, the cause of the accident is an incorrect maneuver with the vessel, i.e. the behavior of its helmsman. Due to the size of inland vessels, in the event of a collision between a ship and a bridge, as a rule, the vessel is damaged, not the bridge.