Bridges in the highway network and the building of new bridges

The condition of highway bridges 2021

There are approximately 15,000 bridges in the highway network, approximately 2,500 of which are located in the arterial road network. There are approximately 800 bridges in poor condition, of which around 80 are located in the arterial road network.

The number and surface area of bridges in satisfactory condition has increased significantly and the number of bridges in poor condition will continue to increase going forward. Bridges built in the 1960s and 1970s have accumulated a repair backlog. In addition to this, bridges built in the 1980s and early 1990s will need to be renovated soon.

Bridges are critical to the road network. The condition of bridges is causing an increasing number of challenges for trade and industry transport, especially heavy special transport and other conveyance in bulk. Shortcomings in load capacity will often lead to having to renew a bridge instead of renovating it, leading to exponential costs. Delays and other functional shortcomings should be repaired at the same time.

Large, critical bridge projects on highways

Below is a list of the large, critical bridges on highways that are at risk of receiving capacity limits in the period under review in 2021–2032.

Their location in the road network would cause a significant challenge, especially to trade and industry transport. Sites where a critical bridge must be replaced. The cost estimate for an individual bridge is more than EUR 20 million. There are plans to renew critical bridges in connection with a larger road project, with which they are connected. The implementation will not be possible as part of basic route maintenance; instead, the project will require development funding.

The large critical bridges Kirjalansalmen silta bridge (EUR 100 million) and Hessundinsalmen silta bridge (EUR 30 million) received implementation decisions in the government’s third supplementary budget proposal for 2021 (2021 III LTA). The actual construction work is estimated to start in 2023 and last for approximately three years.

Small and medium-sized bridges on highways

Load limitation = the load capacity of the bridge is insufficient for loads in accordance with the vehicle regulation.

Funding for basic route maintenance can be used to implement approximately ten small and medium-sized bridges critical in terms of the carrying capacity in the main road network. The total annual costs will be approximately EUR 30 million in 2021–2032.

In addition to these, the main road network has roughly 10 medium-sized critical bridges with a risk of requiring a load limitation in the period under review in 2021–2032. The location of the sites in the road network would pose a significant challenge to trade and industry transport of normal mass. The cost estimate for individual bridges is approx. EUR 5–15 million, approximately EUR 100 million in total. Implementing these sites using the funding for basic route maintenance is very challenging.

Condition = the bridge needs to be renovated to ensure traffic safety or bridge lifespan.

Approximately one hundred bridge renovations can be implemented with the basic route maintenance funding. The total annual costs will be approximately EUR 200 million in 2021–2032. Basic route maintenance funds will also be used to repair approximately 70 smaller bridges each year. The costs will amount to roughly EUR 60 million annually.

In addition to these, the main road network has two and the rest of the road network has around ten medium-sized bridges that need to be renovated in the period under review in 2021–2032. The costs of the sites on the main road network are approximately EUR 25 million in total and the costs for the rest of the sites are approximately EUR 70 million. Implementing these sites using the funding for basic route maintenance is very challenging.

Replacing short ferry routes with bridges

In 2019, the Finnish Transport Infrastructure Agency drafted a project assessment on replacing short ferry routes with (nine) bridges. The volume of traffic in the sites under review is small. Average daily traffic is 650 vehicles per day in Skåldö (KVL), 420 vehicles in Hanhivirta and less than 300 vehicles on other sites. The share of heavy transport of the total volume of traffic is also minor.

Currently, the annual costs of ferry traffic vary between EUR 0.43–1.0 million by site. The most important impact of the projects is the removal of ferry traffic service agreement costs.

The most significant impact in terms of transport is the shortening of travel time by 6–11 minutes on average, depending on the site.

The projects will eliminate the disadvantages to heavy transport posed by the carrying capacity restrictions on the ferries. Transport emissions will decrease slightly, but bridges may cause drawbacks in terms of the landscape and other disadvantages. Bridges will not inconvenience commercial waterborne transport, but the tallest sailboats may have to seek alternative routes.

Based on the project assessment, the sites under review would be profitable in terms of socio-economic efficiency with the exception of the Tappuvirran silta bridge (Savonlinna/Varkaus). The total costs of bridge construction sites (eight bridges) deemed profitable in the project assessment are approximately EUR 110 million.

The projects with a good preparedness for planning can be implemented first: Kivimo (Parainen) and Hätinvirta (Puumala).

Other projects require funding for general planning, the implementation of the environmental impact assessment (EIA) procedure and final engineering in 2021–2025. The following projects could be implemented after 2026: Saverkeit (Parainen), Mossala (Parainen), Skåldö (Raasepori), Kyläniemi (Ruokolahti), Kuparonvirta (Mikkeli) and Hanhivirta (Enonkoski). Of the projects requiring general planning, the Skåldön silta bridge (Raasepori) has the best socio-economic efficiency based on the project assessment (benefit-cost ratio of 2.3).