Vibration protection

Vibration protection impacts were assessed on the basis of the following viewpoints:

• Unpleasant vibration (limit values of the environmental vibration load).
• Emitted internal noise (excess of the limit value in indoor areas).
• Does the produced noise or vibration disturb the function of the devices installed in buildings (indoor noise and protection loads of technological nature).
• Building damages caused by vibrations loads.

Summarising the investigations performed according to such viewpoints, it can be concluded:

• In the buildings located along Metro alignment the vibrations are in compliance with the limit values of environmental vibration loads. In areas with lower surface traffic flow and the equivalent level of the Metro's travelling vibrations not exceeding 3.2 mm/s2 (70 dB), no complaints against noise and vibration are to be expected. If the same value reaches 10 mm/s2 (80 dB), however, complaints against noise and vibrations can be expected, and from 85 to 90 dB it is almost sure that any excess of noise or vibration limits within the apartements concerned occurs according to the new regulation.
• Since individual vibration levels can reach 70 to 80 dB at several sites along the Metro's alignment (even more near switches and rail points), installation of proper vibration insulation will be reasonable.
• There are especially sensitive objects along Metro line. That is why an alignment correction took place based on an earlier study near the Hungarian Radio, which correction has been considered in the plans. Near the acoustic laboratory of the Institute for Transport Sciences other actual measures were taken to diminish disturbing vibrations.
• A comparative assessment revealed that the modification of tram traffic in the area will have an actual result in vibration reduction, since trams on line 49 will have a frequency of about half of the existing one after the start of operation of the new Metro.
• The tram running on the Danube embankment to the Lgymnyosi bridge, on the Buda side, in front of the Technical University, is a vibration source which could produce minor disturbing effects in the university's buildings in the operation of extremely delicate instruments and installations, but this issue should be discussed in the authorization process of the tram line on the Danube embankment.
• Damages in building structures caused by any environmental vibration during operation are not expected
• The envisaged extension of the alignment does not represent any restrictions in terms of vibration protection that could rule out the existing alignment; limit values can be observed on the extended alignment by suitable measures.
• Tunnel driving in the period of construction is associated with no considerable vibration effect. In the construction phase such a technology should be selected that enables proper vibration protection. In case of technologies causing severe vibration loads it should be checked by test runs whether they are suitable for the operation concerned and damage the neighbouring buildings (e.g. test piling).
• Increased heavy vehicle traffic on the construction sites does not cause any vibration damage in case of traffic developing on base roads. On secondary roads a speed restriction of 20 km/h should be implied on transport vehicles, whenever necessary.