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Parameter study of railway-induced structural vibrations using numerical and semi-analytical models

Rasmussen, Filip LU (2024) In TVSM-5000 VSMM01 20241
Structural Mechanics
Department of Construction Sciences
Abstract
As the importance of sustainability increases more weight is laid upon using both
greener building materials and efficient transportation systems. As more and more
buildings are being built with wood and other light weight materials, and ever more
slender constructions, the need to understand the impact of vibrations in these types of
structures increases. Furthermore the increasing urban density leads to more buildings
being built near railways, and there is apprehension within the industry to constructing
these potentially vibration sensitive building near railways. These vibration can have
an impact on both occupants’ health and the function of sensitive equipment within the
buildings. The solution has been to construct concrete... (More)
As the importance of sustainability increases more weight is laid upon using both
greener building materials and efficient transportation systems. As more and more
buildings are being built with wood and other light weight materials, and ever more
slender constructions, the need to understand the impact of vibrations in these types of
structures increases. Furthermore the increasing urban density leads to more buildings
being built near railways, and there is apprehension within the industry to constructing
these potentially vibration sensitive building near railways. These vibration can have
an impact on both occupants’ health and the function of sensitive equipment within the
buildings. The solution has been to construct concrete buildings as their heavier weight
and stiffer construction are assumed to counteract the impact of railway vibrations.
However, discounting the wooden buildings is often done without knowledge about if
these buildings actually are worse at handling vibrations than concrete buildings.
In this master’s dissertation, the behavior of wooden and concrete structures when
exposed to external vibrations is examined. Through the use of a new three dimensional semi-analytical soil model an extensive parameter study was conducted for both
a steady state stationary load and a realistic train load. The soil model was coupled
to a finite element structure and building, soil and train parameters were studied. By
examining comfort vibrations inside the building within a frequency spectrum of 1
to 80 Hz, the impact of each variable could be determined and comparisons between
similar concrete and wooden structures could be made.
The parameter studies showed that a correlation between the natural frequency of
the building and the large response frequency in the soil did not seem to cause any
additional resonance in the building. It was also discovered that increased structural
damping of a building can cause a large increase in vibrations within a building exposed
to an external vibration. A comparison between examining steady state conditions and
a realistic train load showed that while results of a steady state analysis may indicate
how the building will react to a train load, the effect of a parameter change in the steady
state analysis does not always correlate to the effect of that same parameter change
when considering a train load. When comparing the wooden and concrete buildings
to each other, it was found that while for most scenarios the concrete building has the
lowest vibration levels, there are some exceptions to that rule. Those exceptions were
when the building was placed on very elastic soil such as clay, when the structural
damping of the two buildings was similar, and when the building is placed within
approximately 20 meters of the railway (Less)
Popular Abstract
By using state-of-the-art computational methods, vibration levels in a concrete and wooden buildings exposed to railway vibrations can be compared in significantly less time than previous methods. When constructing buildings near railways, the choice of building materials is in part based on the assumption that heavy concrete buildings will have lower vibration levels than lighter wooden buildings. However, it was concluded in the study that a wooden building can experience significantly lower vibration levels in certain conditions. Furthermore, higher energy losses within the buildings can result in higher vibration levels overall.
Please use this url to cite or link to this publication:
author
Rasmussen, Filip LU
supervisor
organization
alternative title
Parameterstudie av järnvägsinducerade strukturella vibrationer genom numeriska och semianalytiska modeller
course
VSMM01 20241
year
type
M3 - Professional qualifications ( - 4 Years)
subject
keywords
Railway, Cross-laminated timber (CLT), Concrete, Structural dynamics, Vibration, Steady-state analysis, Soil
publication/series
TVSM-5000
report number
TVSM-5268
ISSN
0281-6679
language
English
id
9172560
alternative location
https://www.byggmek.lth.se/english/publications-old/tvsm-5000-present-2014/
date added to LUP
2024-08-28 08:46:09
date last changed
2024-08-28 08:46:09
@misc{9172560,
  abstract     = {{As the importance of sustainability increases more weight is laid upon using both
greener building materials and efficient transportation systems. As more and more
buildings are being built with wood and other light weight materials, and ever more
slender constructions, the need to understand the impact of vibrations in these types of
structures increases. Furthermore the increasing urban density leads to more buildings
being built near railways, and there is apprehension within the industry to constructing
these potentially vibration sensitive building near railways. These vibration can have
an impact on both occupants’ health and the function of sensitive equipment within the
buildings. The solution has been to construct concrete buildings as their heavier weight
and stiffer construction are assumed to counteract the impact of railway vibrations.
However, discounting the wooden buildings is often done without knowledge about if
these buildings actually are worse at handling vibrations than concrete buildings.
In this master’s dissertation, the behavior of wooden and concrete structures when
exposed to external vibrations is examined. Through the use of a new three dimensional semi-analytical soil model an extensive parameter study was conducted for both
a steady state stationary load and a realistic train load. The soil model was coupled
to a finite element structure and building, soil and train parameters were studied. By
examining comfort vibrations inside the building within a frequency spectrum of 1
to 80 Hz, the impact of each variable could be determined and comparisons between
similar concrete and wooden structures could be made.
The parameter studies showed that a correlation between the natural frequency of
the building and the large response frequency in the soil did not seem to cause any
additional resonance in the building. It was also discovered that increased structural
damping of a building can cause a large increase in vibrations within a building exposed
to an external vibration. A comparison between examining steady state conditions and
a realistic train load showed that while results of a steady state analysis may indicate
how the building will react to a train load, the effect of a parameter change in the steady
state analysis does not always correlate to the effect of that same parameter change
when considering a train load. When comparing the wooden and concrete buildings
to each other, it was found that while for most scenarios the concrete building has the
lowest vibration levels, there are some exceptions to that rule. Those exceptions were
when the building was placed on very elastic soil such as clay, when the structural
damping of the two buildings was similar, and when the building is placed within
approximately 20 meters of the railway}},
  author       = {{Rasmussen, Filip}},
  issn         = {{0281-6679}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{TVSM-5000}},
  title        = {{Parameter study of railway-induced structural vibrations using numerical and semi-analytical models}},
  year         = {{2024}},
}