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Building environment

 

The environment impact study had also the task to investigate the impact of Metro construction and operation on various engineering structures (buildings and other facilities with special emphasis on those buildings, which are especially sensitive to Metro construction works (monument, substance, function) or its later operation. Subject of this investigation were all those buildings that are located within the range of influence.
Urban landscape and architectural values

The first section of Metro 4 will fully run under the surface, thus, it cannot directly influence surface landscape but by certain engineering structures and the planned depot in Kelenfld.

The exits of stations leading to the surface are usually connected to existing underpasses (Keleti pu., Kálvin tér etc.), and no special building is necessary to be implemented on the surface. However, in several stations, entirely or partly they need their own exit building, which may comprise escalators, elevators or other technical installations. An exclusive individual surface exit will be constructed in Kztrsasg tr, Rkczi tr and Kelenfld city centre, which do not need any material deterioration of the green surface or the urban landscape. It is reasonable to implement at such places some other functions, too (public toilets, phones etc.), but it is the local development plan which should decree in this respect.

Areas near the surface (underpasses) and any deep stations of the Metro, as well as its escalators and corridors may become parts of the city image, thus, their connection and aspect is an important duty of urban aesthetics nature and should be finalised not later than building authorisation.

However, Metro construction will have a positive impact on city image, since the value of buildings near Metro alignment will be upgraded, and especially at those locations where full renewals, renovations and other building possibilities will take place according to development plans. In this respect, an improvement can be expected in the environment of listed and protected, as well as of other valuable buildings, which is favourable in respect of the city image and, implicitly, the protected buildings themselves, as well.

However, city image does not comprise only built in environment, but also its mobile elements, like surface vehicle traffic, which has covered almost every inch both in big cities and Budapest, in the rate of motorization development. The public transport possibilities offered by Metro will enable to re-conquer of some of the surface to the population's benefit. This is the greatest and most essential advantage of all Metro lines, which should be managed to the benefit of the city image.

The depot in Kelenfld will be implemented on the area assigned for railway development, which is farther from residential areas. Thus, it will be fused with the track area of the Kelenfld railway station, so it will form no individual element in the urban landscape.

A further development of the Metro towards Rkospalota will be carried out at a low depth under the surface and, consequently, will have a landscape contribution similar to Phase I. The plans of the jpalota residential area are already comprising Metro line, this city image will only be completed accordingly. The section beyond Szentmihlyi t is now being an agricultural area, which does not belong to any urban landscape, and such an image will be formed just by the new developments envisaged.

Buildings and other facilities

In respect of the various buildings and other facilities, the range of influence includes a band defined by the so called depression of settlement.

Other structures in the range of influence by their function:

  • Buildings of general use (living and public houses, plants, railway stations, buildings of special function, monuments).
  • Utilities (water, sewage, gas, district heating pipes, electric and telecommunication cables).
  • Roads.
  • Bridges.

 

The survey and record of the actual technical conditions of the buildings and other facilities located along the Metro alignment assigned is defined as a task in the terms of reference titled Record of Buildings and Other Facilities on the Area Affected by Metro.

Buildings

From an architectural viewpoint, the Metro line starting from Kelenfld pu. will run under very heterogeneous areas. It will touch a residential quarter in Kelenfld, industrial and institutional areas, then family houses before arriving to Mricz Zsigmond krtr. Living estates built in the years 1920 to 1930 are characteristic to this square, with a school, market and medical center in the neighbourhood. Between this circular square and Szent Gellrt tr several "protected building units" and "protected buildings" are located. Bartk Bla t is formed by relatively uniform buildings of 70 to 100 years old in a closed and tall row. The station planned will affect some buildings (CH and K) of the Technical University of Budapest. Both buildings are part of the World Heritage.

The section under the Danube rill run south of Szabadsg bridge) then will be continued on the Pest side. The section between Fvm tr and Klvin tr also comprises buildings built at the turn of the 19th and 20th centuries. Monument, monumental environments and protected building groups can be found in this area. Just a few characteristic monuments can be cited, as an inn built in the 18th century under No. 9 Klvin tr, the Church in Klvin tr, a monument building of the Budapest University of Economy, as well as the big Market Hall.

In the next section, between Klvin tr and Jzsef krt, old palaces (OMIKK, Hungarian Radio, the building of College of Theater and Motion Picture, Pzmny Pter University) can be found, on the one hand, as well as living buildings with the origin in the 19th century and early in the 20th century, on the other hand. This is the area of the National Museum, too. The section between Jzsef krt and Baross tr is formed by 3-, 4- and 5-storey buildings from the second half of the 19th century, but also by old lodging houses. There are several one- and two-storey buildings, too. Its peculiarity is the load bearing wall structure supporting various types of slabs. The market hall on Rkczi tr is constructed in the 1890s, having an iron frame structure and brick perimeter wall. The main building of the Keleti railway station resting on wooden piles is originated in the 1880s. In the second half of the 20th century two big buildings were constructed in Kztrsasg tr, namely a metal structure tower building made with sliding formwork and a building of the Budapest Gas Supply Company.

Utilities, linear facilities, engineering structures

The Metro line will affect almost all the types of utility pipelines. Among them, rigid wall supply and sewage pipes are sensitive with respect to the motions to be expected in the network.

The Metro line to be constructed will cross railway tracks at two places and several tram lines, or will run in parallel to the latter. It will be connected with the existing metro lines and possibilities to change line will be available at junctions. Metro tunnels will also cross several public roads and will pass under several pedestrian underpasses. The band of Metro construction will comprise Szabadsg hd and the overpass between Fiumei t and Rottenbiller utca.

Surface settlements and motions

Two main detrimental or harmful sources can be identified in this Metro construction. One of them is the building motion produced during construction, a so called settlement depression, on the one hand, and the vibration load caused by construction works and later by the operation, on the other hand.

Tunnel construction can result in stress redistribution, soil motions and, consequently, surface displacement. With a displacement of surface layers new surface formations develop due to the settlement depression. The appearance of such motions and, implicitly, the shape and extent of settlement depression depend on soil nature around the cavity, soil condition and compactness, strength and deformation of the soil, soil thickness, ground water condition, tunnel depth and size, the applied construciton method, walls of the tunnel to be constructed, grouting in the annular gap etc.

A study has been prepared on the forecast of surface motions and settlements delimiting impact areas and specifying settlements above Metro tunnels.

Main conclusions of this study:

  • The borderline of settlements can reach or exceed 100 m from tunnel axis only at a few locations.
  • The calculated settlements cannot reach in general the extent considered dangerous for buildings. A radius of surface curvature with potential harm to buildings can be expected at only a few locations, where proper measures should be taken depending on observations.
  • The completed calculations assume a technological discipline and continuous construction.
  • Before stating construction a measurement programme is required.

 

Surface motions
A deformation by soil grains occur at any change in surface shape where some other motion elements can be remarked in addition to the settlement. These motion elements are the following: angular rotation, curvature, sliding, strain. These elements can cause displacements of the surrounding buildings. These motions are associated with the appearance of some other forces, which can cause additional stresses in certain structures. The formation of additional stresses are influenced by the following factors:

  • Characteristics of the settlement depression (vertical or horizontal displacement, angular rotation, curvature etc.).
  • Floor plan dimensions, height and location of the building with respect to the settlement depression.
  • Rigidity of building.
  • Condition, age and size of the settlements already produced.
  • Structural system of the building foundation.

 

Damage caused by settlements

The condition existing during Metro construction can be considered as the most dangerous from the viewpoint of engineering structures. Surface displacement appeared during construction and these are settlements that may have a decisive role in this process. Technological parameters and observance of technological regulations in the course of construction, as well as the possibilities enabled by soil are the most decisive factors of settlements.

Due to the technology and dimensions of stations, considerable settlements exceeding surface displacements at running tunnels can be expected around the deep stations, constructed by mining method, combined of several sections. On the contrary, much inferior surface settlements can be forecast around the stations built up from the surface. Along the north-south Metro line surface settlements of not more than 30 mm could be identified during tunnel driving with an open front shield.

Magnitude and distribution of surface settlements above stations are influenced by building succession and the geometry of connected additional engineering structures.

The problems with utilities are mainly timed to the period of construction. Rigid wall utility piping, like water supply, sewage or district heating lines, are extremely sensitive to non-uniform displacements, especially at the junctions and connections. In case of drinking water supply pipes, usually there was no problem whatsoever above deep running Metro sections. The damage caused by settlements can be prevented with proper preventing measures (compensation grouting, soil stabilisation).

Damage and problems caused by vibrations

Vibrations caused by metro operation depend upon vertical alignment. In case of deep running lines the soil around the tunnels can function as an attenuating medium and considerably diminish the vibrations caused by metro cars.

The condition of tram tracks is varied, and important renovations have been carried out in recent years within a network renovation programme, which have favourable effects in respect of noise and vibration as well.

Condition in the course of metro construction

The freight traffic or traffic diversions reqired for the construction cannot have any significant harmful effect on the engineering structures concerned as far the transport route will be reasonable enough. The control of the motions of Szabadsg bridge and the overpass at Rottenbiller - Fiumei t is indispensable in the period of construction.

Condition following metro construction

In comparison with the existing situation, vibration effects caused by the traffic of heavy vehicles and trams become more important then settlements. The change of tram network will not be postponed too much, and up-to-date tracks will also diminish vibrations. The same result can be obtained by a possible repair of roads and the replacement of road pavements.

No damage can be expected because of building vibrations caused by Metro traffic. A possible form of protection against the harmful vibrations to functionality can be the application of modern vibration attenuating superstructures.

The future operation of the Metro will have no significant effect on public utilities.

The connection of Kelenfld railway station with the city centre will be totally different. By reducing frequency of Bus group 7 the roads can be released from a severe load caused by heavy vehicles. Tram traffic will be preserved between Mricz Zsigmond krtr and Gellrt tr on the Buda side, but with a lower frequency, preserving about half or one-third of the existing tram traffic.

Following Metro completion the load on Szabadsg bridge will be much lower than the current value.

Sensitivity, load-bearing capacity and risks of engineering structures

According to forecasts, primary source of risks for engineering structures in relation with Metro construction and operation is the settlement, and the loads produced by vibrations will play a much more significant role. Vibrations can be harmful in the course of operation mainly in respect of the function of certain buildings, e.g. Hungarian Radio (where a correction of alignment has been carried out for this reason) and building CH of the Technical University because of instruments and delicate technical installations. The surface traffic of trams or heavy vehicles could cause vibrations from time to time exceeding the one arising from Metro operation.

No building damage whatsoever can be forecast based on the surface settlements calculated and related to tunnel construction. Maximum surface settlement values above 25 mm cannot be forecast for any of the technologies. Higher values can only be expected in case of the mining technology used in station constructions. Building damage can be prevented or drastically diminished by strict compliance with technological discipline and preventing measures.

Prior to work commencement it is indispensable to check the vertical position of buildings by measurements, which could be a reference basis for investigating the displacements caused by metro construction.