Zdeněk Kaláb
Influence of vibrations on structures
Číslo: 3/2018
Periodikum: Acta Montanistica Slovaca
Klíčová slova: seismic load, seismic standard, Eurocode 8, earthquake, technical seismicity
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Anotace:
One type of occasional structural load is a seismic load. Earthquakes and blasts are typical sources of vibrations, but vibration
generated during urban tunnel construction can represent a significant problem. Evaluation of the harmful impact of vibrations transmitted
through rock massif into buildings is solved using experimental measurements, detailed analyses of measured signals, knowledge of
geological pattern and constructional analysis.
Seismic load of structures due to earthquakes is solved using the EUROCODE 8 standard. The earthquake movements at a certain
location on the surface are determined by an elastic response spectrum to the ground acceleration. Eurocode 8 puts emphasis especially on
the robust foundations and simplicity of construction systems. It is also mentioned vibration effect on historical buildings and effect under
the surface, for example, in mine spaces. Historical structures are usually even more prone to vibration damage than, for example, typical
wood-frame homes. The greater concerns over historic structures arise from the design, structure age, building materials and building
methods used. The peak values of vibration generated by earthquake decrease with depth; the decrease is faster in shallow layers compared
with the deeper part. Technical vibrations differ from natural earthquakes, for a comparable value of maximum vibration amplitudes,
especially in the frequency range of the signal and mostly its duration. Evaluation of technical seismicity is more complicated because there
are usually used national standards.
To document some common information about vibration effects on structures, some experimental measurements are presented.
Examples of real wave patterns document common shapes and also signals with significant resonant vibrations. Very interesting is
an example of resonant vibration that was generated as the influence of basin structures on the shape of wave patterns due to quarry blasts.
To obtain complete information, measurement system has to keep sufficient parameters, especially the frequency range of the whole seismic
channel, sampling frequency, and proper anchoring of the sensor. The basic methodology for evaluation of vibration on structures is
outlined.
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generated during urban tunnel construction can represent a significant problem. Evaluation of the harmful impact of vibrations transmitted
through rock massif into buildings is solved using experimental measurements, detailed analyses of measured signals, knowledge of
geological pattern and constructional analysis.
Seismic load of structures due to earthquakes is solved using the EUROCODE 8 standard. The earthquake movements at a certain
location on the surface are determined by an elastic response spectrum to the ground acceleration. Eurocode 8 puts emphasis especially on
the robust foundations and simplicity of construction systems. It is also mentioned vibration effect on historical buildings and effect under
the surface, for example, in mine spaces. Historical structures are usually even more prone to vibration damage than, for example, typical
wood-frame homes. The greater concerns over historic structures arise from the design, structure age, building materials and building
methods used. The peak values of vibration generated by earthquake decrease with depth; the decrease is faster in shallow layers compared
with the deeper part. Technical vibrations differ from natural earthquakes, for a comparable value of maximum vibration amplitudes,
especially in the frequency range of the signal and mostly its duration. Evaluation of technical seismicity is more complicated because there
are usually used national standards.
To document some common information about vibration effects on structures, some experimental measurements are presented.
Examples of real wave patterns document common shapes and also signals with significant resonant vibrations. Very interesting is
an example of resonant vibration that was generated as the influence of basin structures on the shape of wave patterns due to quarry blasts.
To obtain complete information, measurement system has to keep sufficient parameters, especially the frequency range of the whole seismic
channel, sampling frequency, and proper anchoring of the sensor. The basic methodology for evaluation of vibration on structures is
outlined.