| With the development of China’s economy and the enhancement of seismic safety awareness,the Code for Seismic Design of Buildings has been updated several times,putting forward stricter requirements on the seismic capability of industrial and civil buildings existing nationwide,especially the promulgation and implementation of the fifth-generation seismic parameter zoning map and the development of a new round of risk survey.The inadequacy of earthquake resistance of many existing buildings in China is becoming increasingly apparent.Since the 18th CPC National Congress,the work of earthquake prevention and disaster reduction has been attached great importance by the CPC Central Committee.The strengthening project of housing facilities in earthquakeprone areas has been listed as one of the nine key projects to improve China’s ability to prevent and control natural disasters.Seismic evaluation and reinforcement of existing buildings have been carried out to improve building safety performance,revitalize existing housing stock,and promote the transformation of cities to a low-carbon and sustainable development model.It has become a hot topic in the field of civil engineering.In this paper,the technical and economic comparison of seismic strengthening methods for existing frame structures in areas with increased fortification intensity is made,and the main research is as follows:(1)the research background,significance and purpose of this paper are described,and the research progress on seismic reinforcement technology,economic analysis of seismic reinforcement methods and carbon emission measurement for seismic reinforcement of existing RC frame structures at home and abroad is summarized.(2)a method for calculating the cost of seismic reinforcement engineering is put forward,and the information database of engineering cost including the unit price of daily wage,the unit price of materials and the unit price of construction machinery is established.A process-based carbon emission measurement method for building reinforcement is proposed,and a carbon emission coefficient database including energy consumption carbon emission coefficient,labor carbon emission coefficient,carbon emission coefficient of various transportation modes,carbon emission coefficient of materials carbon emission coefficient and energy consumption coefficient of machinery shift is established.The economic evaluation index system of reinforcement methods is established through research,the EWM method is proposed to determine the economic evaluation index weight of reinforcement technology,and the economic evaluation model of existing seismic reinforcement methods of RC frame structures is constructed based on EWM-TOPSIS method.(3)a typical RC frame structure model is designed based on PKPM software,and the basic seismic fortification intensity increases from 6 degrees(0.05g)to 7 degrees(0.10g),7 degrees(0.15g)and 8 degrees(0.20g).The variation rules of seismic reinforcement control parameters such as period ratio,shear weight ratio,axial compression ratio,interlayer displacement Angle and reinforcement amount of the example structure are calculated.The influence of the increase of seismic fortification intensity on the selection of seismic strengthening methods for existing RC frame structures is summarized.It is analyzed that the seismic bearing capacity and ductility of structural members cannot meet the requirements when the seismic fortification intensity is increased from 6 degrees(0.05g)to 7 degrees(0.10g)and 7 degrees(0.15g).The structural reinforcement methods such as pasting carbon fiber,pasting steel plate,and external steel are selected,and the overall reinforcement methods such as adding antiseismic wall and adding buckling constraint supports are used to strengthen the structure,so as to improve the stress status of the components and improve the seismic performance of the structure.When the seismic fortification intensity increases from 6 degrees(0.05g)to 8 degrees(0.20g),the seismic bearing capacity and ductility of the structural members do not meet the requirements,and the interstory displacement Angle of the structure under the action of earthquakes is beyond the limit.Overall reinforcement methods such as adding seismic wall and buckling constraint bracing are selected,and combined with component reinforcement methods,to improve the overall stiffness of the structure and improve the stress status of the members.(4)the seismic fortification intensity was increased from 6 degrees(0.05g)to 7 degrees(0.10g),7 degrees(0.15g)and 8 degrees(0.20g),and the typical examples were reinforced.The seismic performance of the reinforced structure was analyzed,and the results showed that the reinforced structure met the requirements of the seismic fortification target.The reinforcement cost,construction period and carbon emission of the reinforcement method were calculated,and the comprehensive economic analysis and evaluation of the seismic reinforcement method adopted were carried out based on EWMTOPSIS method.The analysis showed that when the seismic fortification intensity increased from 6 degrees(0.05g)to 7 degrees(0.10g),the economy of the reinforcement method of pasted steel plate and external steel was the best.The second method is pasting carbon fiber and adding buckling restraint support,adding seismic wall reinforcement method has the worst economy;When the seismic fortification intensity is increased from 6 degrees(0.05g)to 7 degrees(0.15g),the economy of the reinforcement method with pasted steel plate and external steel is the best,followed by the reinforcement method with the addition of seismic wall,and the economy of the reinforcement method with the addition of buckling constraint bracing is the worst.When the seismic fortification intensity increases from 6 degrees(0.05g)to 8 degrees(0.20g),the economy of the reinforcement method with buckling constraint bracing is better than that with the reinforcement of seismic wall. |
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