Procedia Engineering最新文献

The city of Guwahati in north-east India falls under seismic zone V and is located in Assam gap of Himalaya. It has historically witnessed devastating earthquakes up to 8.7 on the Richter scale in 1897 and 1950. Unplanned rapid urbanization has increased its seismic vulnerability of life and property. This paper attempts to develop a ward-level hazard map of the city through systematic vulnerability analyses of the hazard by overlapping the ward map and the earthquake hazard microzonation map. Out of total 31 wards, five wards with highest density of population and taller buildings were taken as the most vulnerable areas and were selected for this study. These buildings have reinforced cement concrete framed structure but with various options of roof. A structured survey was carried out with Rapid Visual Screening (RVS) for existing building stock. Total100 buildings were randomly selected from the sample of residential, commercial, industrial, religious and mixed use buildings from municipal tax record. The buildings were categorized in terms of nine major vulnerability parameters based on Indian references. They were customized and graded as per US FEMA guideline which is more comprehensive in dealing with other building structures such as masonry or lightweight timber structures. Buildings under survey were scored and ranked based on their seismic vulnerability. Though the preliminary scoring passed (score>0.3) all buildings, but further refinement is needed to infer precisely. The result is helpful in formulating local level policy making to prioritize the building stock for appropriate remedial measures. The study also complements the earthquake resistant building codes and guidelinesof India developed for the new building construction.

In the history of Sri Lanka, the Indian Ocean Tsunami which occurred on 26^th December 2004 could be considered a major natural disaster with catastrophic consequences. The damage from Tsunami in Sri Lanka was so widespread unlike for many other countries. The main objective of the study is to investigate the current Tsunami resilience level and address the resilience gap by providing feasible recommendations thus building a resilient community to Tsunami. The study was carried out among hundred Tsunami affected families across five highly affected Grama Niladhari divisions in Panadura Divisional Secretariat division. These were selected based on convenience sampling technique. Data was collected from both primary and secondary information sources using a questionnaire survey with a scale of 0-5 where five represents "excellent" and zero is "condition absent". The data was quantitatively analyzed under a framework which combines eight significant resilience elements; governance, society and economy, resource management, land use and structural design, risk knowledge, warning and evacuation, emergency response and disaster recovery. The results highlighted that coastal community resilience to Tsunami was around medium level (2.5) in most dimensions. The highest (2.4) and lowest (1.3) scores were recorded by risk knowledge and society and economy respectively, out of all resilience elements. Further the current resilience level of the community was recognized as 40% and there exists a 60% gap to achieve the ideal condition. Therefore, this should be taken into consideration to improve resilience for all dimensions of the resilience framework by the relevant authorities of the government.

The durability assessment of a component or structure is often assessed using Finite Element Analysis (FEA)-based structural simulations. Fatigue is a progressive failure mode that is related to the stress cycle’s range in a power law such that the fatigue damage increases exponentially as the stress range increases.

When the frequency content of the loading gets closer to the natural frequencies of the structure, resonance effects are activated. In this case, the dynamic properties of the structure must be included in the analysis in order to better account for the increased stress response. A dynamic FEA produces therefore more realistic results compared to a static analysis, but requires knowledge of additional characteristics such as mass and damping. In a dynamic FEA, whether transient or steady state frequency response, the damping property governs indeed the magnitude of the dynamic stress response and hence the durability of the component.

Unfortunately a default damping value is sometimes erroneously assumed for all modes leading to errors in the stress response, which in turn leads to significant errors in the fatigue life estimates. The modal parameters – including damping ratios - for the structure’s modes of vibration can be extracted using experimental modal analysis techniques.

The purpose of this article is first, to explain the critical role that damping plays in fatigue damage; and second, to recommend best practices for determining modal damping experimentally.

A simple example of an automotive component will be used to illustrate the importance of using experimental modal analysis to adjust the properties of a FE-based dynamic structural analysis. An experimental modal test followed by a modal analysis will be described. The mode shapes obtained experimentally and analytically will be compared to validate the mass, stiffness and boundary conditions used in the modelling. Then, it will be shown that using realistic values for the damping ratios will help to obtain stress results that correlate with the measured stress.

Finally, this example will illustrate the very high sensitivity of the fatigue life estimate to the damping ratios.

After Indian Ocean tsunami of 26 December 2004, Government, NGO and private organizations provided various types of post-disaster permanent housing. This study focuses on Relocate houses in Namkem community, Phangnga after residents live long-term in this post-disaster house. Aims to analyze resident’s satisfaction to Housing after lived more than a decade in the post-tsunami houses and analyze the development to physical of house regard to reconstruction, functions, or size. The relocation effect to the house adaptation and residents life style as a result shown that even self-built house that residents have participate in design and construction process themselves also need the individual renovation, according to that many of residents have change their job or need to travel in longer distance for work, The car park was one of the popular choice for space extension follow after the adding more bedrooms as number of family member increase. Residents who individually renovated and extend the house have gain more satisfy with their house so provided land-plot for self-extension may important more for recovery housing.

The task of reducing disaster risks poses enormous challenges for international and local non-governmental organizations despite the immense assistance offered in reducing disaster risks and cushioning the effect of disasters. Among other issues responsible for the setback experienced is that of institutional constraints. ‘Institutions’ act as a fulcrum for achieving social norms that shape behaviour and actions within society via rules, professional ethics, standards, policies, regulations etc. Government establishments in the same organizational field - particularly those recognized to deliver public goods and services for disaster risk reduction often experience institutional constraints such as lack of clear policies and mandates to guide government institutions, lack of coordination between institutions, inadequacy in the required human capacity in public sector etc. These constraints often contribute to increased societal risk conditions. Where institutions are elements of governance, framing them also becomes a simultaneous attempt to manage risks to society. An overwhelming body of existing organizational behaviour literature affirms that organizations adopt practices or behave in a certain manner to gain access to resources and legitimacy for survival including under uncertain or complex circumstances when subjected to institutional pressures. Such pressures influence operational and strategic arrangements and has been discussed from a private sector organizations perspective. Against this background, little attention has been given to influence of institutional pressures on public sector organizations and scarcely from a disaster risk reduction perspective. The aim of this paper is to investigate the role of governance and influences of institutional pressures on public sector organizations from a disaster risk reduction perspective. This is achieved through reviewing literature on institutional theory to provide an understanding on the concept of institutional isomorphism and its effect on key issues such as goal ambiguity, professionalism and structuration as well as technical uncertainty. The implication for practitioners is that it offers background knowledge required for key players and professionals to design appropriate response strategies to isomorphic pressures to support institutional sustainability, encourage homogeneity for effective DRR delivery and fills the knowledge gap presented for further research.

With more and more natural gas has been transported by pipelines, the possibility of natural gas jet fire caused by inner or outer factors is increased gradually. That will result in casualties and domino effect to make further disaster and serious loss of property. It is imperative to study jet fire and prevent jet fire happening. This paper investigates the temperature profile for square and rectangular fuel nozzle (long side sets along transverse) horizontal jet fires. The numerical simulation code was carried out to simulate jet fires with different jet velocity varied from 27.5 m/s to 205.8 m/s. The fuel leak area for square and rectangular was same (400 mm²), but the aspect ratio (width / length, W/L) were 1:1 and 1:4, respectively. Results show that the temperature increase with the jet velocity, and the relationship between maximum temperature along centreline and jet velocity is closed to line which slope is 1.82. The simple function for this connection was established. The maximum temperature of vertical direction locates at 1m from centreline, and the maximum temperature increase with jet velocity. The temperature along centreline for rectangular flame is less than square flame at same point and the high temperature area along horizontal direction is less. It is deduced the rectangular nozzle results in flame shorter and more width due to larger relative surface area and air entrainment. The high temperature area in transverse direction for rectangular nozzle is greater than square.