Life Cycle Cost Of Base Isolated Frame Structure Considering Earthquake Damage Loss Based On The Concept Of Sustainable Development

With the development of economy and science and technology,the idea and theory of aseismic design and the form of aseismic structure in China are constantly updated and improved.Because of its simple construction technology,good shock absorption effect and mature theoretical method,the foundation isolation technology is increasingly prominent in many seismic techniques and means,and widely used in lifeline engineering,public buildings and other building structures with important social functions and special use functions.The safety of such buildings requires a higher degree of seismic performance indicators for quantitative evaluation.In addition,the understanding of economic,social and environmental benefits in the whole life cycle of isolated buildings is not deep enough,and the lack of unified evaluation index research directly restricts the popularization and application of the isolation technology on a larger scale.Therefore,based on the probability density evolution theory,this paper studies the seismic vulnerability analysis method of the base isolation structure,combined with the life-cycle assessment method,introduces a reasonable discount rate,the life-cycle cost assessment method of the base isolated building,and carries out a comparative analysis of safety and economy with the traditional structure.The main research contents and conclusions are as follows:1.Seismic vulnerability analysis method based on probability density evolution theory.Considering the total probability information of random earthquake excitation,taking the maximum inter-layer displacement angle of the structure as the performance quantitative index,the structural vulnerability solution method based on probability density evolution theory is derived based on the equivalent extreme value idea,and compared with the traditional vulnerability method.The results show that the structural response has greaterdiscreteness and randomness,and its equivalent extreme probability density function changes with time,which has the characteristics of evolution and multi-peak,which is very different from the normally assumed normal distribution.The proposed method does not cause a large amount of information loss phenomenon,which largely guarantees the origin of stochastic problems.2.Vulnerability analysis of base isolated structure.Based on the research on the basic isolation RC frame hospital building,considering the composite randomness of seismic excitation and structural material parameters,taking the maximum inter-story displacement angle of the superstructure and the maximum horizontal displacement of the isolation layer as the performance quantitative index,the maximum inter-layer displacement angle of the above part structure and the maximum horizontal displacement of the isolation layer as the performance quantification index,the vulnerability analysis of the isolation structure is completed and compared with the results of the seismic structure analysis.The results show that the multi-peak performance of the equivalent extreme value probability density curve of isolation structure is weakened,and the response mean,standard deviation and coefficient of variation are smaller,which can withstand the adverse effects of the randomness of earthquake excitation and structural material parameters.It has obvious energy consumption effect,higher safety performance reserve,and more able to meet the performance requirements of the owner.3.Life cycle cost assessment of building structure.Considering the cost of isolation layer,the initial cost of foundation isolation structure and traditional structure are calculated respectively.Combined with the results of structural vulnerability analysis and seismic hazard analysis,the loss expectation of the two structures is evaluated.Based on the cost of saving life in society,the monetization of casualty loss during structural earthquake damage is realized.Based on life cycle analysis method and the willingness to pay theory,the environmental cost of producing isolation support is studied,and theestimation of structural environmental cost is completed.Considering the time value of funds and introducing a reasonable discount rate,the total life-cycle cost assessment of building structure is realized and compared.It is found that the initial cost of isolation structure is 13.5% lower than that of the traditional structure,the expected loss of the structure is reduced by 78.8%,the loss of casualties is reduced by 92.7%,the environmental cost is reduced to a some extent,and the total cost of life-cycle is reduced by17.5%,which shows better economy,seismic performance,safety performance and environmental friendliness.Using the base isolation technology for reasonable structural design can get the isolation structure optimal life-cycle cost,so as to promote the popularization and application of the base isolation technology and the sustainable development of the construction industry...