Study On Cost Estimation Method Of Post-Earthquake Rehabilitation

Destructive earthquake have caused not only severe human casualties but also damage or even ruin to various engineering structures, which results in disorder in human activities and industrial production. For the governments, it is critically important to make scientific decisions except for emergency relief so that the restoration work can be efficiently undertaken. Meanwhile, an accurate and reasonable cost estimation of post-earthquake rehabilitation establishes an essential prerequisite for the restoration and reconstruction work. China is one of the countries with the worst earthquake disaster; it is necessary and urgent to study cost estimation method of post-earthquake rehabilitation.Based on a large number of relevant literatures, the cost estimation methods for houses, fundamental facilities and three industries which include agriculture, industry and service industry are demonstrated and presented. The main salient and innovative points can be outlined as:1. The key influencing factors of the cost for post-earthquake rehabilitation are summarized herein and categorized into the earthquake influence factor, original fundamental facility condition factor and politic-economy-human resource factor. The corresponding indices, the influence extents of which on the cost for restoration and reconstruction are analyzed using grey correlation theory, have been proposed and detailed.2. The BP neural-network estimation method of the cost for post-earthquake rehabilitation is proposed. Based on the data samples of macro-economy data, seismic damage conditions and cost for post-earthquake rehabilitation in the earthquake affected towns, total cost for engineering construction and the terms such as residential housing, education system, health system, culture system, welfare system etc. in another earthquakes can be estimated and predicted using the 13-10-1 or 9-7-1 BP neural-network estimation model. The method takes into account of both macro-economy and seismic damage in the earthquake affected areas. It is highly accurate method.3. The estimation method based on population index is proposed to estimate restoration and reconstruction cost and the cost as education system, health system, culture system, welfare system, local fundamental governments, transportation system, electric power system, communication system, public civil facilities and hydraulic engineering. The method needs small information such as affected population, intensity, and price fluctuation and can conveniently and fast predict the cost for post-earthquake rehabilitation.4. The proportion estimation method based on cost for post-earthquake rehabilitation of urban and rural houses is poprosed, which could estimate the cost for education system, health system, culture system, welfare system, local fundamental governments, transportation system, electric power system, communication system, public civil facilities and hydraulic engineering. The method considers such factors as damage of urban and rural houses, restoration conditions, seismic intensities, and regional difference.5. The proportion estimation method based on gross product is poprosed, which could estimate the cost for agriculture, industry and service industry. The method considers a few macro-economy features, seismic intensities, and regional industry distribution. It can help decision-makers fast determine capital distribution for restoration and reconstruction.6. The proportion estimation method based on direct economic losses is improved. The modifying coefficients of restoration and reconstruction cost estimation are statistically presented for urban and rural houses, transportation system, electric power system, communication system, electric power system, communication system, public civil facilities and hydraulic engineering, agriculture, industry and service industry. Results are partially adopted to Seismic Field Code"Preliminary cost estimation of post-earthquake rehabilitation of engineering structures(draft)". The method considers damage conditions in the affected areas and seismic intensities. It has the advantages of easy calculation and high accuracy.7. Referring methods of the consumption index of material and labor, the influence of change of material cost, labor cost and machine cost on the unit reconstructing cost of brick-concrete, frame and frame-shear structures has been analyzed by statistics of 35 typical engineering building data. The suggested values of change of unit reconstructing cost for brick-concrete, frame and frame-shear structures are also given. The unit reconstructing cost change for brick-concrete structures which are mainly built after event is 16%-22%, and 8%-12% for frame and frame-shear structures. The results can be used to improve estimation accuracy of reconstruction capital of houses in the future earthquakes.8. The distribution features of caulties, direct ecmomic losses and post-earthquake rehabilitation cost are analyzed. The model of casualty estimation, economy loss and post-earthquake rehabilitation cost has been proposed. Meanwhile, the feasibility and applicability of the model have been verified by the case of Yushu earthquake.