Northwest Europe is a region in which damaging earthquakes exist. Assessing the risks of damages is useful, but this is not an easy work based on exact science.
Northwest Europe is a region in which damaging earthquakes exist. Assessing the risks of damages is useful, but this is not an easy work based on exact science.
A dynamic analysis model of a wind-train-bridge system is *** wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter *** p...
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A dynamic analysis model of a wind-train-bridge system is *** wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter *** proposed formulations are then applied to a long rail-cum-road suspension *** dynamic responses of the bridge and the train under wind action are *** results show that the lateral and rotational displacements of the bridge are dominated by wind,while the vertical by the gravity loading of the moving *** running safeties of the train vehicles are much affected by *** wind conditions of 30-40 m/s,the offioad factors,derail factors and overturn factors of the train vehicles exceed the safety allowances,to which great attention should be paid.
The production and construction conditions are composed of various elements, including building materials usable for construction and type of labor. The actual situations of them are clearly indicated by conventional ...
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A method based on entropy-based criteria is present to choose the optimal decomposition of Wavelet Packets Analysis (WPA) for damage detection in composite materials. The structural damage indexes constructed based on...
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A method based on entropy-based criteria is present to choose the optimal decomposition of Wavelet Packets Analysis (WPA) for damage detection in composite materials. The structural damage indexes constructed based on energy spectrum variation of the structural vibration responses decomposed using WPA before and after the occurrence of structural damage usually generate a complete binary tree to calculate its elements. Date mining is carried out in this paper by adoption entropy as the criteria to choose the optimal decomposition tree. In the decomposition process, only the sub-signals which contain main information of the original signal are decomposed to generate next level sub-signals. New damage index is constructed based on the optimal decomposition. Then the dimension of the damage index is reduced while still keeping its sensitive to damage. Whether Artificial Neural Network (ANN) or genetic algorithm (GA) is used in the further process of telling structural damage status from damage index, this reduction will make remarkable time saving.
Airfield road surface roughness is the major impact source of aircraft, discrete Fourier transform (DFT) is usually applied to analyze road surface roughness. However, DFT has serious limitations, especially it has no...
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ISBN:
(纸本)9780784409329
Airfield road surface roughness is the major impact source of aircraft, discrete Fourier transform (DFT) is usually applied to analyze road surface roughness. However, DFT has serious limitations, especially it has no time domain analysis function. To overcome this problem, wavelet transform for analyzing airfield road surface roughness and aircraft's dynamic response was proposed. Autoregressive moving average (ARMA) model (Gersch W. et al, 1976) was used to establish time series of road surface roughness. Asymmetrical mathematical model of aircraft was presented via Quarter Car Simulation (QCS). Time series of road surface roughness was input, and aircraft's vibration response corresponding to this roughness input was obtained. The results show that correlation between aircraft's dynamic response and road surface roughness is linear in a certain frequency range. Aircraft's vibration responses increase with road surface roughness excitation. Road surface roughness also can be deduced via aircraft's dynamic response. Wavelet analysis method can be applied to establish correlation between road surface roughness and aircraft's response. Copyright ASCE 2007.
Total heat exchanger model based on experimental results was incorporated in the entire building model with the stay and internal generation of heat and with window opening-closing schedule, and energy-saving effects ...
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ISBN:
(纸本)9784861630712
Total heat exchanger model based on experimental results was incorporated in the entire building model with the stay and internal generation of heat and with window opening-closing schedule, and energy-saving effects of total heat exchangers were evaluated including regional features in Japan. Regional differences were found in the effects, and it was found that the reduction rate of heating and cooling loads was in the range of about 2-15%, and the reduction amount of heating and cooling loads was in the range of about 0.1-11 GJ. Also, based on the fact that cooling load increases due to the installation of total heat exchanger in the regions under cold climatic conditions, the buildings in the regions with warm climate designed in the high air-tightness and high insulation specification. As a result, it was found that heating load was reduced by about 35%.
Purpose – Owing to limited space, reducing the waste going to landfills has become a pressing issue in Hong Kong. As most of the solid waste was generated from construction activity, the Hong Kong Government has inst...
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Purpose – Owing to limited space, reducing the waste going to landfills has become a pressing issue in Hong Kong. As most of the solid waste was generated from construction activity, the Hong Kong Government has instituted a number of measures aimed at reducing waste from this source. However, it appears that the application of these measures has been of limited effectiveness. Therefore, the purpose of this paper is to examine the effectiveness of implementing regulatory measures for reducing construction waste in Hong Kong. Design/methodology/approach – The data used for the analysis are from a survey to construction professionals in the local industry by means of questionnaire, interview discussions and case studies. The survey examined the commitments and responsibilities imposed on project participants for implementing seven major regulatory waste management controlling measures: legislative controls;controlling public filling facilities;controlling landfill areas;providing on-site sorting facilities;implantation of a environmental management system;implementation of a waste management framework plan;and implementing recycling scheme. Findings – The results of the investigation illustrate that legal commitments have been mainly allocated to contractors. Insufficient commitments and responsibilities are allocated to other project participants such as project clients, designers and consultants. The study has also found that existing waste control ordinances allow for skewed distribution of commitments and responsibilities of controlling construction waste among project stakeholders. The results demonstrate that there is need for a balanced allocation of responsibilities and commitments among all project stakeholders. Originality/value – Revision and further development of legal measures are necessary to ensure that all project stakeholders play an active role and share commitments in waste control and reduction. This research provides references for studying const
Soil nailing, developed from the New Austrian Tunnelling Method, has been widely used in many countries and regions in the world since the 1970's. This technique is used to stabilize in situ soil mass by installin...
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Soil nailing, developed from the New Austrian Tunnelling Method, has been widely used in many countries and regions in the world since the 1970's. This technique is used to stabilize in situ soil mass by installing a large number of closely spaced unstressed inclusions into the soil mass to increase its strength and stability. Since the mid 1970's, several design methods have been proposed based on laboratory and field tests. Among the design criteria in these methods, the pull-out resistance of a soil nail is a key parameter that controls the stability assessment of soil nail structure. In the previous investigations, the soil dilatancy was found to be an important factor that influences the soil nail pull-out resistance especially for drill-and-grout soil nails. In order to study the influence of soil dilatancy on soil nail pull-out resistance, laboratory pull-out tests and numerical parametric studies have been carried out for soil nails in Completely Decomposed Granite (CDG) fill. The results show that the soil dilatancy has a significant influence on the soil nail pull-out resistance.
With the development of living level, people pay much attention to thermal environment. The Predicted Mean Vote (PMV) is the famous index to evaluate the thermal environment, which has been widely used in practice. Ai...
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With the development of living level, people pay much attention to thermal environment. The Predicted Mean Vote (PMV) is the famous index to evaluate the thermal environment, which has been widely used in practice. Air temperature, radiant temperature, humidity and air movement is the four basic environmental parameters. In this paper, it is purposed to look into the actual conditions of indoor thermal environment in summer on residential buildings in Jiaozuo area of Henan Province. Based on the testing data of the four basic environmental parameters about model buildings in summer of 2005, the paper deduces the PMV-PPD and analyses the indoor thermal environment of residential buildings in Jiaozuo. Furthermore, it puts forward some measures to improve the quality of indoor thermal environment. The results can be summarized as follows: (1) With the trend of global warming and urban heat island, the summer climate of Jiaozuo is very hot though it is located at the heating section. Most families low the indoor temperature by air conditioners. The usage of them in dwelling houses is raised.;(2) The high PPD index shows that the dweller is not satisfied with indoor thermal comfort in summer, especially on the noon and at night;(3) Humidity can make strongly affection to predict thermal environment;(4) To improve the indoor thermal environment, some measures can be taken, such as by natural ventilation, shading devices and virescence etc.
The main challenge in designing ground source heat pump (GSHP) systems is finding the optimum size of the ground heat exchangers (GHEs). This paper presents a simulation model to investigate the effect of various desi...
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The main challenge in designing ground source heat pump (GSHP) systems is finding the optimum size of the ground heat exchangers (GHEs). This paper presents a simulation model to investigate the effect of various design alternatives for the optimal sizing of GHEs. The influences of certain critical parameters on the performance of GHEs are analysed and discussed for various design cases. The analysis shows that GHE size can be reduced to a certain extent by using grout and soil with a higher thermal conductivity, and also by increasing the borehole spacing and shank space, which may reduce drilling costs. This paper demonstrates the usefulness of the simulation model and attendant software as a tool for designing optimal GSHP systems.
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