Lessons learnt from 2011 Christchurch earthquakes

Author(s):  
Alessandro Palermo ◽  
Liam Wotherspoon ◽  
John Wood ◽  
Howard Chapman ◽  
Allan Scott ◽  
...  

On 22 February 2011 the Mw6.2 Christchurch earthquake occurred with an epicentre less than 10 km from the Christchurch Central Business District (CBD) on an unknown buried fault at the edge of the city. The majority of damage was a result of lateral spreading along the Avon and Heathcote Rivers, with few bridges damaged due to ground shaking only. The most significant damage was to bridges along the Avon River, coinciding with the areas of the most severe liquefaction, with less severe liquefaction damage developing along the Heathcote River. Most affected were bridge approaches, abutments and piers, with a range of damage levels identified across the bridge stock. In the days following the earthquake, teams from various organizations performed inspections on over 800 bridges throughout the affected Canterbury region. This paper details the preliminary findings based on visual inspections and some preliminary analyses of highway and road bridges. The paper comprises information supplied by consulting engineering firms which were also directly involved in the inspections soon after the earthquake.

Author(s):  
Misko Cubrinovski ◽  
Brendon Bradley ◽  
Liam Wotherspoon ◽  
Russell Green ◽  
Jonathan Bray ◽  
...  

The 22 February 2011, Mw6.2-6.3 Christchurch earthquake is the most costly earthquake to affect New Zealand, causing 181 fatalities and severely damaging thousands of residential and commercial buildings, and most of the city lifelines and infrastructure. This manuscript presents an overview of observed geotechnical aspects of this earthquake as well as some of the completed and on-going research investigations. A unique aspect, which is particularly emphasized, is the severity and spatial extent of liquefaction occurring in native soils. Overall, both the spatial extent and severity of liquefaction in the city was greater than in the preceding 4th September 2010 Darfield earthquake, including numerous areas that liquefied in both events. Liquefaction and lateral spreading, variable over both large and short spatial scales, affected commercial structures in the Central Business District (CBD) in a variety of ways including: total and differential settlements and tilting; punching settlements of structures with shallow foundations; differential movements of components of complex structures; and interaction of adjacent structures via common foundation soils. Liquefaction was most severe in residential areas located to the east of the CBD as a result of stronger ground shaking due to the proximity to the causative fault, a high water table approximately 1m from the surface, and soils with composition and states of high susceptibility and potential for liquefaction. Total and differential settlements, and lateral movements, due to liquefaction and lateral spreading is estimated to have severely compromised 15,000 residential structures, the majority of which otherwise sustained only minor to moderate damage directly due to inertial loading from ground shaking. Liquefaction also had a profound effect on lifelines and other infrastructure, particularly bridge structures, and underground services. Minor damage was also observed at flood stop banks to the north of the city, which were more severely impacted in the 4th September 2010 Darfield earthquake. Due to the large high-frequency ground motion in the Port hills numerous rock falls and landslides also occurred, resulting in several fatalities and rendering some residential areas uninhabitable.


2013 ◽  
Vol 40 (8) ◽  
pp. 759-776 ◽  
Author(s):  
Kenneth J. Elwood

At 12:51 pm local time on 22 February 2011, a M 6.2 aftershock of the 4 September 2010, Darfield earthquake shook the city of Christchurch, New Zealand. The aftershock occurred on an unmapped fault less than 10 km from the city centre resulting in significant damage, particularly in the Central Business District (CBD). The earthquake resulted in the collapse of two reinforced concrete office buildings, one parking garage, and numerous unreinforced masonry buildings, including many heritage structures, leading to 185 deaths. Liquefaction was wide spread in the CBD and the eastern suburbs, resulting in foundation movement for housing and office buildings alike. Many buildings in the CBD experienced severe damage, some requiring demolition, necessitating careful controlled access to the CBD in the months following the earthquake. This paper summarizes the recorded earthquake shaking and observed damage to concrete buildings in CBD, with a specific focus on identifying future research and possible changes for seismic design practice and codes in Canada to address the Christchurch observations.


Author(s):  
Sean O'Sullivan ◽  
John Morrall

A quantifiable basis for developing design guidelines for pedestrian access to light-rail transit (LRT) stations is provided for planners based on observations in Calgary, Canada. Calgary's LRT system, which began operations in 1981, has been operating for long enough for walking patterns to and from its stations to become established. Interviews were conducted with 1,800 peak-hour LRT users about the origins and destinations of their LRT trips. Those who walked to or from a station were asked to point out on a map their approximate origins or destinations. The distances were then measured off the maps. Walking distance guidelines were developed for central business district (CBD), transfer and local stations. Catchment area maps were produced, and the relationship between reported walking time and measured walking distance was calculated. Also compared are the walking distances at LRT stations and the walking distances at bus stops. The research strongly indicates that people walk farther to reach an LRT station than a bus stop. Using bus walking standards would result in an underestimate of LRT walking distances by about half. For the city of Calgary the average walking distance to suburban stations is 649 m with a 75th-percentile distance of 840 m. At CBD stations the average walking distance is 326 m and the 75th-percentile distance is 419 m.


2018 ◽  
Vol 01 (02) ◽  
pp. 01-09
Author(s):  
Baig Farrukh ◽  
Sahito Noman ◽  
Bano Arsla ◽  

In developing countries, rapid urbanization has created an enormous pressure on land use, infrastructure and transportation. The fast growing ratio of motorized vehicles in urban areas is the main cause of environmental degradation. Almost 80% of the greenhouse gas emission is from vehicles in cities. In the city centers, on-street parking is considered the major cause of traffic congestion. The aim of this study was to evaluate the problems of on-street parking and disorderly parking at Central Business District (CBD) of Hyderabad city. The field survey methodology was adopted to perceive the current traffic problems in the city center and traffic count survey was carried out in both peak and off hours. The data was analyzed using descriptive statistics frequency analysis technique with the help of Statistical Package for the Social Sciences (SPSS). The findings revealed that increasing number of vehicles, on-street parking, improper parking, encroachment, inadequate parking space and poor condition of roads are the main causes of traffic congestion. The study bridges up the research gap of determining public views about on-street parking challenges in the context of Hyderabad, Pakistan and provides statistical results which may equally be adapted by policy makers and transportation planners in order to improve the traffic situation.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 470 ◽  
Author(s):  
Hassan Saeed Khan ◽  
Riccardo Paolini ◽  
Mattheos Santamouris ◽  
Peter Caccetta

There is no consensus regarding the change of magnitude of urban overheating during HW periods, and possible interactions between the two phenomena are still an open question, despite the increasing frequency and impacts of Heatwaves (HW). The purpose of this study is to explore the interactions between urban overheating and HWs in Sydney, which is under the influence of two synoptic circulation systems. For this purpose, a detailed analysis has been performed for the city of Sydney, while considering an urban (Observatory Hill), in the Central Business District (CBD), and a non-urban station in Western Sydney (Penrith Lakes). Summer 2017 was considered as a study period, and HW and Non-Heatwave (NHW) periods were identified to explore the interactions between urban overheating and HWs. A strong link was observed between urban overheating and HWs, and the difference between the peak average urban overheating magnitude during HWs and NHWs was around 8 °C. Additionally, the daytime urban overheating effect was more pronounced during the HWs when compared to nighttime. The advective flux was found as the most important interaction between urban overheating and HWs, in addition to the sensible and latent heat fluxes.


Author(s):  
Константин Аркадьевич Холодилин ◽  
Леонид Эдуардович Лимонов

The city center is at the core of urban and housing economics. Many models crucially depend on it. In a market economy, the location of urban amenities, especially eating establishments, closely correlates with that of the city center and, more generally, with the Central Business District (CBD). In a centrally planned economy, the spatial distribution of those amenities is determined by the central planner and can differ significantly from a market-based distribution. Using the case of St. Petersburg (Russia), we investigate changes in the spatial distribution of eating establishments resulting from the transition from a market economy to a centrally planned one and then again to a market economy. In addition, we explore the shifts of the city center between 1895 and 2017 using eating establishments as a proxy. The spatial distribution is analyzed using a 2-D kernel density estimation. We find evidence for a substantial reduction and dispersion of eating establishments during the Soviet period. We also establish that after the October 1917 Revolution the city center of St. Petersburg moved several kilometers to the north-east.


Author(s):  
Rangajeewa Ratnayake ◽  
Naduni Wickramaarachchi ◽  
Julie Rudner

Planning, development and design policies influence sense of safety of people touse the City centre or Central Business District (CBD) and therefore city centres can becomeactive and vibrant during the day and night. This paper reviews past and present planningpolicies relevant for feeling of personal safety in the context of housing, retail, amenities,street infrastructure, building design and transportation aspects. The past development trendsshow that insignificant attention has been paid to people's sense of safety when using publicspaces, particularly at night, a factor identified important in creating attractive city centressince 1960s. Local plans primarily refer to safety in relation to roads, accessibility andworkability. Local policies also show the dominance of CCTV since the 1990s has becomeubiquitous, but changes to sense of safety in urban spaces now may actually be a betterreflection of planning and design decisions made over the past 20 years.


2021 ◽  
Vol 23 (1) ◽  
pp. 72-78
Author(s):  
Eka Arista Anggorowati ◽  
Anggun Mega Nurfadhilla ◽  
Ari Widi Wibowo ◽  
Enrico Pria Anggana

ABSTRACTThe growing population and the shifting of population movement from the suburbs to the city center will make the demand for rail transportation services to the city center increase. To deal with this problem, it is necessary to study the analysis related to potential demand, the need for the number of facilities and new operating patterns for the extension of railroad relations. The results of the research showed that the potential demand was obtained from the calculation of actual and potential demand, where the actual demand was obtained by carrying out a survey on train from 644 respondents, 85.5% agreed with the extension of the Lembah Anai Railway relation and as many as 88% were willing to choose the train mode. In the potential demand analysis, a stated preference survey was carried out in Pauh District, from 2636 respondents, 86.7% were willing to switch from private vehicles and public transportation to the railroad mode. Based on the analysis of the calculation of facility requirements according to the demand, 1 trainset is ready for operation to accommodate the community to carry out daily mobilization to the center of the Central Business District (CBD) in Padang City.Keywords: Demand, pattern of rail operations, Railway Travel Graph (RTG) ABSTRAK Berkembangnya jumlah penduduk dan semakin bergesernya pergerakan penduduk dari pinggiran kota menuju pusat kota akan membuat semakin meningkatnya jumlah permintaan akan jasa angkutan kereta api sampai menuju pusat kota. Untuk menunjang permasalahan tersebut perlu dikaji analisis terkait potensi demand, kebutuhan jumlah sarana dan pola operasi baru perpanjangan relasi kereta api. Hasil penelitian menunjukkan potensi demand didapatkan dari perhitungan demand aktual dan potensial, dimana demand aktual dilakukan survey on train dari 644 responden 85,5% setuju dengan adanya perpanjangan relasi Kereta Api Lembah Anai dan sebanyak 88% bersedia untuk memilih moda kereta api. Pada analisis demand secara potensial dilakukan survey stated preference di Kecamatan Pauh dari 2636 responden 86,7% bersedia untuk pindah dari moda kendaraan pribadi dan angkutan umum ke moda kereta api. Berdasarkan analisis perhitungan kebutuhan sarana sesuai dengan demand didapatkan 1 trainset Siap Operasi untuk mengakomodir masyarakat melakukan mobilisasi sehari-hari menuju pusat Central Business District (CBD) di Kota Padang.Kata kunci : Demand, kebutuhan sarana, pola operasi kereta api, Grafik Perjalanan Kereta Api (Gapeka)


Author(s):  
Emily Remus

The central business district, often referred to as the “downtown,” was the economic nucleus of the American city in the 19th and 20th centuries. It stood at the core of urban commercial life, if not always the geographic center of the metropolis. Here was where the greatest number of offices, banks, stores, and service institutions were concentrated—and where land values and building heights reached their peaks. The central business district was also the most easily accessible point in a city, the place where public transit lines intersected and brought together masses of commuters from outlying as well as nearby neighborhoods. In the downtown, laborers, capitalists, shoppers, and tourists mingled together on bustling streets and sidewalks. Not all occupants enjoyed equal influence in the central business district. Still, as historian Jon C. Teaford explained in his classic study of American cities, the downtown was “the one bit of turf common to all,” the space where “the diverse ethnic, economic, and social strains of urban life were bound together, working, spending, speculating, and investing.” The central business district was not a static place. Boundaries shifted, expanding and contracting as the city grew and the economy evolved. So too did the primary land uses. Initially a multifunctional space where retail, wholesale, manufacturing, and financial institutions crowded together, the central business district became increasingly segmented along commercial lines in the 19th century. By the early 20th century, rising real estate prices and traffic congestion drove most manufacturing and processing operations to the periphery. Remaining behind in the city center were the bulk of the nation’s offices, stores, and service institutions. As suburban growth accelerated in the mid-20th century, many of these businesses also vacated the downtown, following the flow of middle-class, white families. Competition with the suburbs drained the central business district of much of its commercial vitality in the second half of the 20th century. It also inspired a variety of downtown revitalization schemes that tended to reinforce inequalities of race and class.


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