scholarly journals Characteristics and impact of environmental shaking in the Taipei metropolitan area

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Kate Huihsuan Chen ◽  
Ting-Chen Yeh ◽  
Yaochieh Chen ◽  
Christopher W. Johnson ◽  
Cheng-Horng Lin ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Seismic Noise ◽  
Ground Vibration ◽  
Considerable Effect ◽  
Local Source ◽  
Large Area ◽  
High Rise ◽  
Building Array ◽  
Continuous Interaction ◽  
Atmospheric Perturbations

AbstractExamining continuous seismic data recorded by a dense broadband seismic network throughout Taipei shows for the first time, the nature of seismic noise in this highly populated metropolitan area. Using 140 broadband stations in a 50 km × 69 km area, three different recurring, strong noise signals characterized by dominant frequencies of 2–20 Hz, 0.25–1 Hz, and < 0.2 Hz are explored. At frequencies of 2–20 Hz, the seismic noise exhibits daily and weekly variations, and a quiescence during the Chinese New Year holidays. The largest amplitude occurred at a station located only 400 m from a traffic-roundabout, one of the busiest intersections in Taipei, suggesting a possible correlation between large amplitude and traffic flow. The median daily amplitude for the < 0.2 Hz and 0.2–1.0 Hz frequency bands is mostly synchronized with high similarity between stations, indicating that the sources are persistent oceanic or atmospheric perturbations across a large area. The daily amplitude for the > 2 Hz band, however, is low, indicating a local source that changes on shorter length scales. Human activities responsible for the 2–40 Hz energy in the city, we discovered, are able to produce amplitudes approximately 2 to 1500 times larger than natural sources. Using the building array deployed in TAIPEI 101, the tallest building in Taiwan, we found the small but repetitive ground vibration induced by traffic has considerable effect on the vibration behavior of the high-rise building. This finding urges further investigation not only on the dynamic and continuous interaction between vehicles, roads, and buildings, but also the role of soft sediment on such interaction.

scholarly journals Whispering of the city: Characteristics and origin of environmental shaking in the Taipei metropolitan area

2021 ◽  
Author(s):  
Kate Huihusan Chen ◽  
Ting-Chen Yeh ◽  
Christopher W. Johnson ◽  
Yaochieh Chen ◽  
Cheng-Horng Lin ◽  
...  
Keyword(s):  
Seismic Data ◽  
Seismic Noise ◽  
Local Source ◽  
High Similarity ◽  
Large Area ◽  
Natural Sources ◽  
Atmospheric Perturbations ◽  
First Time ◽  
The City ◽  
Dominant Frequencies

Abstract Examining continuous seismic data recorded by a dense broadband seismic network throughout Taipei shows for the first time, the nature of seismic noise in this highly populated metropolitan. Using 140 broadband stations in a 50 km x 69 km area, three different recurring, strong noise signals characterized by dominant frequencies of 2–20 Hz, 0.25-1 Hz, and < 0.2 Hz are explored. At frequencies of 2–20 Hz, the seismic noise exhibits daily and weekly variations, and a quiescence during the Chinese New Year holidays. The largest amplitude occurred at a station located only 400 m from a traffic-roundabout, one of the busiest intersections in Taipei, suggesting a possible correlation between large amplitude with traffic flow. The median daily amplitude for the < 0.2 Hz and 0.2-1.0 Hz frequency bands are mostly synchronized with high similarity between stations, indicating that the sources are persistent oceanic or atmospheric perturbations across a large area. The daily amplitude for the > 2 Hz band, however, is low, indicating a local source that changes on shorter length scales. Human activities responsible for the 2–40 Hz energy in the city, we discovered, are able to produce amplitudes approximately 2 to 1500 times larger than natural sources.

scholarly journals Monitoring the Impact of the Large Building Investments on the Neighborhood

2021 ◽  
Vol 11 (14) ◽  
pp. 6537
Author(s):  
Marian Łupieżowiec
Keyword(s):  
Groundwater Level ◽  
Soil Improvement ◽  
Deep Excavation ◽  
Large Area ◽  
Safety Measures ◽  
High Rise ◽  
The Impact ◽  
Large Building ◽  
Additional Safety ◽  
Made In

The article presents the concept of monitoring buildings and infrastructure elements located near large construction investments (the construction of high-rise buildings of the Oak Terraces housing estate in Katowice and the construction of a tunnel under the roundabout in Katowice along the intercity express road DTŚ). The impacts include deep excavation, lowering of the groundwater level over a large area, and dynamic influences related to the use of impact methods of soil improvement. The presented monitoring includes observation of the groundwater level with the use of piezometers, geodetic measurements of settlement and inclinations, as well as the measurement of vibration amplitudes generated during the works involving shocks and vibrations. It was also important to observe the development of cracks on the basis of a previously made inventory of damage. The results of the monitoring allow corrections to be made in the technology of works (e.g., reduction of vibration amplitudes, application of additional protections at excavations, etc.) or the use additional safety measures. Currently, there are also monitoring systems used during the operation of completed facilities.

scholarly journals Two-Step Seismic Noise Reduction Saused by COVID-19 Induced Reduction in Social Activity in Metropolitan Tokyo, Japan

2020 ◽  
Author(s):  
Suguru Yabe ◽  
Kazutoshi Imanishi ◽  
Kiwamu Nishida
Keyword(s):  
Noise Reduction ◽  
Frequency Band ◽  
Metropolitan Area ◽  
Seismic Noise ◽  
Social Activity ◽  
State Of Emergency ◽  
Tokyo Metropolitan ◽  
Tokyo Metropolitan Area ◽  
The World ◽  
40 Hz

Abstract The COVID-19 pandemic that started at the end of 2019 forced populations around the world to reduce social and economic activities; it is believed that this can prevent the spread of the disease. In this paper, we report a seismic noise analysis during such an induced social activity reduction taking the Tokyo Metropolitan area, Japan. Using seismic data obtained from 18 stations in the Metropolitan Seismic Observation Network (MeSO-net), a two-step seismic noise reduction in the frequency bands 1–20 Hz and 20–40 Hz was observed during the timeline of COVID-19 in Tokyo. The first noise reduction occurred at the beginning of March in the frequency band 20–40 Hz. This corresponded with the request of the Prime Minister of Japan for a nationwide shutdown of schools. Although social activity was not reduced significantly at this juncture, local reduction of seismic wave excitation in the high frequency band, 20–40 Hz, was recorded at some MeSO-net stations located in school properties. The second reduction of seismic noise occurred at the end of March to the beginning of April 2020 in the frequency band 1–20 Hz. This timing corresponds to when the Governors of the Tokyo Metropolitan area requested citizens to stay home and when the state of emergency was declared for the Tokyo Metropolitan area by the government, respectively. The estimated population at train stations abruptly dropped since this timing, which suggests that social activity was severely reduced. Such large-scale change in social activity affects the seismic noise level in the low frequency bands. The seismic noise level started to increase from the middle of May correlating with increase in population at the train stations. This suggests that social activity restarted even before the state of emergency was lifted at the end of May. The two-step seismic noise reduction observed in this study has not been reported in other cities around the world. Unexpected reduction of social activity due to COVID-19 provided us a rare opportunity to investigate the characteristics of seismic noise caused by human activities.

scholarly journals A Review on Seismic Issues and Remedies in High-Rise Structures

2021 ◽  
Author(s):  
Adarsh S ◽  
Sajeeb R
Keyword(s):  
Urban Areas ◽  
Seismic Vulnerability ◽  
Base Isolation ◽  
High Strength ◽  
Seismic Retrofitting ◽  
Limited Area ◽  
Large Area ◽  
Isolation System ◽  
Ground Shaking ◽  
High Rise

The increase in population in urban areas have popularised high rise structures, as a means of accommodating more people in a limited area. The major concerns in the designing and construction of high-rise structures are the safety aspects against wind and earthquake forces, as the collapse of the structure can lead to a disaster. The seismic zoning map of India shows that a large area of India is prone to earthquakes. The growing use of high strength and lightweight materials in high-rise structures makes them more flexible and lightly damped, thereby making these structures more sensitive to dynamic excitations. Presence of irregularities, setbacks, open ground story, weak and soft storeys, also increases the seismic vulnerability of high-rise structures. Vertical ground shaking can be of significant concern in terms of amplification of acceleration along the height of the building, and also, achieving vertical isolation had been challenging as the gravitational load must be sustained by the isolation system. Quasi-Zero stiffness system was found to be effective in vertical isolation of structures. Installing damping devices at optimal locations, base isolation systems, and suitable seismic retrofitting strategies can enhance the seismic performance of structures. This paper reviews the various factors that lead to seismic issues in high-rise structures such as size, shape, configuration, structural aspects, and material properties. The appropriate remedies to address the seismic issues are also reviewed.

Shear wave velocity model of the ABANICO formation underlying The santiago City Metropolitan Area, chile, using ambient seismic noise tomography

2020 ◽  
Author(s):  
J Salomón ◽  
C Pastén ◽  
S Ruiz ◽  
F Leyton ◽  
M Sáez ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Metropolitan Area ◽  
Shear Wave Velocity ◽  
Seismic Noise ◽  
Velocity Model ◽  
Dispersion Curves ◽  
Ambient Seismic Noise ◽  
Travel Times ◽  
Abanico Formation

Summary The seismic response of the Santiago City, the capital of Chile with more than 5.5 million inhabitants, is controlled by the properties of the shallower quaternary deposits and the impedance contrast with the underlying Abanico formation, among other factors. In this study, we process continuous records of ambient seismic noise to perform an ambient seismic noise tomography with the aim of defining the shallower structure of the Abanico formation underneath the densely populated metropolitan area of Santiago, Chile. The seismic signals were recorded by a network consisting of 29 broadband seismological stations and 12 accelerograph stations, located in a 35 × 35 km2 quadrant. We used the average coherency of the vertical components to calculate dispersion curves from 0.1 to 5 Hz and Bootstrap resampling to estimate the variance of the travel times. The reliable frequency band of the dispersion curves was defined by an empirical method based on sign normalization of the coherency real part. The ambient noise tomography was solved on a domain discretized into 256 2 × 2 km2 cells. Using a regularized weighted least squares inversion, we inverted the observed travel-times between stations, assuming straight ray paths, in order to obtain 2D phase velocity maps from 0.2 Hz to 1.1 Hz, linearly spaced every 0.05 Hz, in 157 of the 256 square cells of the domain. In each square cell with information, dispersion curves were assembled and used to invert shear wave velocity profiles, which were interpolated using the ordinary Kriging method to obtain a 3D shear wave velocity model valid from 0.6 to 5 km depth. The 3D velocity model shows that the Abanico formation is stiffer in the south of the study area with larger velocity anomalies towards the shallower part of the model. The value of the shear wave velocity narrows with depth, reaching an average value of 3.5 km/s from 3 to 5 km depth.

scholarly journals Evaluation of the impact of wood combustion on benzo[<i>a</i>]pyrene (BaP) concentrations; ambient measurements and dispersion modeling in Helsinki, Finland

2017 ◽  
Vol 17 (5) ◽  
pp. 3475-3487 ◽  
Author(s):  
Heidi Hellén ◽  
Leena Kangas ◽  
Anu Kousa ◽  
Mika Vestenius ◽  
Kimmo Teinilä ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Ambient Air ◽  
Local Source ◽  
Small Scale ◽  
Dispersion Modeling ◽  
Wood Combustion ◽  
Annual Average ◽  
Target Value ◽  
Detached House ◽  
Helsinki Metropolitan Area

Abstract. Even though emission inventories indicate that wood combustion is a major source of polycyclic aromatic hydrocarbons (PAHs), estimating its impacts on PAH concentration in ambient air remains challenging. In this study the effect of local small-scale wood combustion on the benzo[a]pyrene (BaP) concentrations in ambient air in the Helsinki metropolitan area in Finland is evaluated, using ambient air measurements, emission estimates, and dispersion modeling. The measurements were conducted at 12 different locations during the period from 2007 to 2015. The spatial distributions of annual average BaP concentrations originating from wood combustion were predicted for four of those years: 2008, 2011, 2013, and 2014. According to both the measurements and the dispersion modeling, the European Union target value for the annual average BaP concentrations (1 ng m−3) was clearly exceeded in certain suburban detached-house areas. However, in most of the other urban areas, including the center of Helsinki, the concentrations were below the target value. The measured BaP concentrations highly correlated with the measured levoglucosan concentrations in the suburban detached-house areas. In street canyons, the measured concentrations of BaP were at the same level as those in the urban background, clearly lower than those in suburban detached-house areas. The predicted annual average concentrations matched with the measured concentrations fairly well. Both the measurements and the modeling clearly indicated that wood combustion was the main local source of ambient air BaP in the Helsinki metropolitan area.

scholarly journals The Relationship Between Spatial Configuration and Social Interaction in High-Rise Flats: A Case Study On The Jatinegara Barat in Jakarta.

2018 ◽  
Vol 41 ◽  
pp. 07003
Author(s):  
Rifan Ridwana ◽  
Budi Prayitno ◽  
Adi Utomo Hatmoko
Keyword(s):  
Social Interaction ◽  
Open Space ◽  
Spatial Configuration ◽  
Space Use ◽  
Large Area ◽  
Large Space ◽  
High Rise ◽  
Shared Space ◽  
Use Behavior ◽  
The Relationship

The construction of high-rise flats to minimize urban slum areas in Indonesia still create space use behavior problems for its residents due to the changes of space configuration between high-rise landed housing. Conventional high-rise flats cannot well accommodate the needs of social interactions happened in landed housing because of its spatial limitation that leads to uncertainty of space use behavior settings. This study aims to understand the relationship between spatial configuration on high-rise flats and social interaction levels of its residents. The object of study is Jatinegara Barat high-rise flats built to relocate slums community from the landed housing in Kampong Pulo. This study applies mix method research using space syntax method to analyze spatial configuration by looking at connectivity and space integration values, and then comparing it with social interaction data from place centered observation to find out the level of interaction and spaces tendency used interaction place. The results of this study indicate that: (1) the relationship of spatial configuration to social interaction level in Jatinegara Barat flats can be positive or negative. (2) Positive relationships are found on the1st and 2ndfloor areas. High configuration values with high interaction levels are found in shared spaces on the 1st and 2nd floors with characteristics such as open space, large space, and availability of interaction supporting elements, while low configuration values with low interaction levels are found in more confined spaces such as private spaces and narrow corridors. (3) Negative relationships are found in the corridor and shared space in front of the elevator on each typical floors. Shared space in front of the elevator that has high spatial configuration value with large area show a low level of social interaction. While corridor with lower configuration value with the narrow area but have supporting elements such as chairs, mats, and shops have a higher level of social interaction. (4) This study shows that in the case of the relationship between spatial configuration and social interaction, availability of interaction supporting elements has greater influence rather than any other spatial factors.

scholarly journals Two-step Seismic Noise Reduction caused by COVID-19 Induced Reduction in Social Activity in metropolitan Tokyo, Japan

2021 ◽  
Author(s):  
Suguru Yabe ◽  
Kazutoshi Imanishi ◽  
Kiwamu Nishida
Keyword(s):  
Noise Reduction ◽  
Frequency Band ◽  
Metropolitan Area ◽  
Noise Level ◽  
Seismic Noise ◽  
Social Activity ◽  
State Of Emergency ◽  
Tokyo Metropolitan ◽  
Tokyo Metropolitan Area ◽  
The World

Abstract The COVID-19 pandemic that started at the end of 2019 forced populations around the world to reduce social and economic activities; it is believed that this can prevent the spread of the disease. In this paper, we report an analysis of the seismic noise during such an induced social activity reduction in the Tokyo metropolitan area, Japan. Using seismic data obtained from 18 stations in the Metropolitan Seismic Observation Network (MeSO-net), a two-step seismic noise reduction was observed during the timeline of COVID-19 in Tokyo. The first noise reduction occurred at the beginning of March 2020 in the frequency band of 20–40 Hz. This corresponded with the request by the Prime Minister of Japan for a nationwide shutdown of schools. Although social activity was not reduced significantly at this juncture, local reduction of seismic wave excitation in the high frequency band, 20–40 Hz, was recorded at some MeSO-net stations located in school properties. The second reduction of seismic noise occurred at the end of March to the beginning of April 2020 in a wider frequency band including lower frequency bands of 1–20 Hz. This timing corresponds to when the Governors of the Tokyo metropolitan area requested citizens to stay home and when the state of emergency was declared for the Tokyo metropolitan area by the government, respectively. Since then, the estimated population at train stations abruptly dropped, which suggests that social activity was severely reduced. Such large-scale changes in social activity affect the seismic noise level in low frequency bands. The seismic noise level started to increase from the middle of May correlating with increase in population at the train stations. This suggests that social activity restarted even before the state of emergency was lifted at the end of May. The two-step seismic noise reduction observed in this study has not been reported in other cities around the world. Unexpected reduction of social activity due to COVID-19 provided a rare opportunity to investigate the characteristics of seismic noise caused by human activities.

scholarly journals FIRE SAFETY ASPECTS OF REFUGE FLOORS IN SUPERTALL BUILDINGS WITH COMPUTATIONAL FLUID DYNAMICS

2009 ◽  
Vol 15 (3) ◽  
pp. 225-236 ◽  
Author(s):  
Cheuk Lun Chow ◽  
Wan Ki Chow
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fire Safety ◽  
Emergency Services ◽  
Far East ◽  
Large Area ◽  
Water Curtain ◽  
High Rise ◽  
The Far East ◽  
Fire Codes

High-rise buildings in many big cities in the Far East, including Hong Kong, call for refuge floors as a matter of both practicality and compliance with regulations. Even though many countries’ fire codes are not clear in spelling out the necessity for refuge floors, it is accepted within construction that such floors are essential in resisting fire, allowing users a means of escape and allowing emergency services a means of access to stricken buildings. This paper discusses the reasons behind providing refuge floors, while also considering related fire safety provisions, such as their enclosure behind fire‐resistant construction or the protection of their openings behind a water curtain. Our discussion takes a tall building with balconies as a test example of refuge floors, running a hazard assessment based on Computational Fluid Dynamics assuming a fire of the broadly accepted level of 2 MW. The paper concludes that the design of the building's façade finally determines whether or not a refuge floor and associated fire safety provisions, such as a water curtain, can be waived. As the flat modelled used to store a high amount of combustibles up to 1135 MJm−2, the breaking of large area of glass window could lead to a major conflagration. The consequences of a scenario with a fire of 25 MW are also discussed. Santrauka Daugelio Tolimųjų Rytų didžiųjų miestų aukštuminiuose pastatuose, taip pat ir Honkongo, reikalingi saugos aukštai, paisant praktiškumo ir atitikimo reikalavimus. Netgi jei daugelio šalių gaisrinės saugos normos aiškiai nereglamentuoja būtinybės įrengti saugos aukštų, konstrukciniu požiūriu tokie aukštai yra būtini gaisrinei saugai, užtikrinant pastato naudotojams evakuacijos galimybę ir avarinėms tarnyboms patekimą į pastatą. Straipsnyje aptariamos saugos aukštų įrengimo priežastys, taip pat įvertinamos susijusios tokios gaisrinės saugos priemonės, kaip atsparių ugniai konstrukcijų įrengimas arba angų apsauga vandens užuolaida. Nagrinėjamas aukštuminis pastatas su balkonais, kaip eksperimentinis saugos aukštų pavyzdys, įvertinant pavojų. Tai daroma naudojant skysčių dinamikos modeliavimą ir plačiai pripažintą 2 MW galios gaisrą. Straipsnyje daromos išvados, kad pastato fasado projektiniai sprendiniai daro įtaką, ar saugos aukštai ir susijusios tokios gaisrinės saugos priemonės, kaip vandens užuolaida, gali būti nenumatomi. Jei pastate numatoma saugoti daug degiųjų medžiagų viršijant 1135 MJm–2 gaisro apkrovą, didelio ploto langų išdužimas gali veikti visuminį užsidegimą. Aptariami ir 25 MW galios gaisro scenarijaus padariniai.

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