Transportation infrastructure, its safety and reliability are one of the main factors determining the economic development of each country. The development of various industries is unthinkable without the development of road and bridge infrastructure and the safe use of existing structures. Increasing traffic flows, their intensity, weights and other parameters become a new challenge both in the design, operation and maintenance of transport infrastructure structures.
According to Vilnius Gediminas University of Technology (VILNIUS TECH) Department of Reinforced Concrete Structures and Geotechnics Prof. Dr. Darius Bačinskas, the service life of modern bridges reaches 100 years. and more. When designing bridges, the changes in operating loads and effects, environmental conditions, operational requirements, possible degradation of material properties and other factors determining the safety and reliability of bridges during the entire operational period must be evaluated. Practice shows that the age of bridges can often be significantly shorter. Examples in Lithuania are the Panemune Bridge in Kaunas or the Ferns Viaduct on the A1 Vilnius-Klaipėda road. The service life of these structures was just over 50 years.
“In modern bridge engineering, a double question often arises – do we have to think about the bridges of the future or the bridges in the future?” Both aspects are important. The first reflects the level of development of the region or the country, and the second – the ability to adapt knowledge and competence, properly plan financial resources for the maintenance of infrastructure structures and the use of timely intervention measures”, emphasizes the VILNIUS TECH innovator.
According to D. Bačinskas, the collapse of the bridge over Nevēži in Kėdainiai and the reconstructed bridge of A. Meškinis over the Neris River in Kaunas can be considered a kind of blickrygu, in the system of car road bridges operated in Lithuania. The number of bridge-related incidents in a few weeks is higher than in the last 10 years. bridge accidents that have occurred. In this case, the consequences of provoked incidents, which occurred due to the collision of vehicles, vandalism, etc., are not evaluated. The collapse of the overlay beam of the bridge over Nevėžis in Kėdainiai will go down in the history of the restored Independent Bridge Engineering of Lithuania as the first structure whose supporting element possibly collapsed not due to external mechanical effects, but due to significant physical wear of the structural element.
“All over the world, morally and physically aging infrastructure structures, their maintenance and the planning of timely intervention measures are one of the biggest problems for bridge engineers in recent decades. As recent events have shown, the bridges operated in Lithuania are not left behind. After the passions and critical interpretations after the incidents have subsided, it is possible to take a fresh look at the problems of bridge operation and the main causes, the analysis of which and the lessons learned will prevent accidents in the future”, the professor points out.
He argues that the first step is to identify the concept of bridge operation. The technical operation of bridges must include not only constant supervision, annual inspections, identification of damage and defects and monitoring of their change, but also activities of implementing intervention measures to remove damage and defects and prevent their change. Degradation of bridge structures does not begin instantaneously. It develops over a long period of time and it all starts with small things that do not require large investments to eliminate in the initial stages.
Studies carried out in foreign countries show that adapting the “Do nothing” strategy (English. Donothingstrategy), the lifespan of bridges is about 45-50 years. Life expectancy can be increased more than twice (on average to 100-120 years) by properly maintaining bridges and taking timely intervention measures.
“In Lithuania, the Lyduvėnai Bridge, the longest in Lithuania, should become an example and benchmark of good practice, with its three-span truss decks successfully operated for more than 100 years.” The operational experience of bridges shows that the operating costs of bridges that are repaired more often and properly are about 50% in their life cycle. smaller than bridges for which the inter-repair periods are twice as long. Unfortunately, this is already becoming a trend in Lithuania and as a result we have bridges in bad or even critical condition, the actual number of which may be much higher than declared in the public space”, says D. Bačinskas.
Another important aspect, according to the professor, relates to the timely identification of the real safety level of bridges in bad or critical condition. In a common case, when a bad or even emergency condition is identified during the technical inspection, it is limited to limiting the weight of the vehicles. Often, after analyzing the submitted reports or research documents, it remains unclear whether the further operation of the structure is generally safe.
“For bridges in bad and critical condition, it is not necessary to carry out an assessment of the technical condition, but a structural examination, which obliges the research contractor to carry out an assessment of the load-bearing capacity of the structure’s supporting structures (all or only the most worn ones) and safety for operational effects. Properly performed expertise of a specific structure would allow to adequately evaluate the response of the existing structure to external influences, its bearing capacity, safety level and critically assess the nature of possible intervention measures. Also – the recommended or mandatory deadlines for their implementation”, the VILNIUS TECH innovator shares his insights.
D. Bačinskas emphasizes that the collapsing bridges send a clear message – the accidents could have caused much sadder consequences and it seems to provide another free opportunity to change not only the attitude, but also the existing system. The latter is inefficient and does not sufficiently contribute to the overall safety growth of operational Lithuanian bridges. Concept bridges in the future in the recent period and in the coming decades should become a key aspect in the Lithuanian bridge engineering system. Real legislative, strategic planning, financial and other related measures must be taken immediately.
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Vilnius Gediminas Technical University (VILNIUS TECH) is an innovative higher education institution that educates creative and qualified specialists. VILNIUS TECH ensures modern, labor market-oriented studies and carries out many different scientific research and experimental development works – they are carried out in 13 institutes, 3 research centers, and 22 laboratories. The University has the most modern Civil Engineering Science Center in Eastern Europe. With more than 500 partners among foreign higher education institutions, VILNIUS TECH provides wide opportunities for international studies and internships.
