Comparison Analysis On Seismic Fragility Of Frame Structures Designed By New Codes And Old Codes

Earthquakes often occur in our country, which makes it necessary to carry out theearthquake resistance protection covering about60%land area of our country. Theframe structure can be widely used in our country. Master the seismic vulnerability ofthe frame structure play an important role in analysising earthquake disasters. In2010,China has issued the new seismic design standard, the frame structure is adjusted on thebasis of damage summary in the wenchuan earthquake. These adjustments impact onthe seismic performance of the frame structure to be studied. To this end, the papercarried out the following work:①Analysis the situation and development trend of fragility research in the world,summarize the method of the seismic fragility analysis, which details the theoreticalanalysis method, gives the analysis steps.②Take the contrast between the new and old Code and finds out the improvementand the main revised contents, especially the content of reinforced concrete framestructure.④Analysis the seismic fragility of the RC frame structure (with10calculationmodels), which own different fortification intensity and different height and designed inthe new Code and the old Code, with the method of incremental dynamic analysis, andthen by statistical analysis and data fitting on the structural response get the seismicfragility curve, finally assess and analysis the structural seismic fragility performance,and compare the seismic performance of the structures.Based on the above research, the main conclusions are as follows:①Both in the01Code and the10Code, the minimum section size of the framecolumn is controlled by axial compression ratio in the region of6and7intensity; andthe minimum section size of the frame column in case of2nd aseismic grades in8Seismic Subarea is controlled by elastic interstory drift angle, the minimum section sizeof the frame column in case of1st aseismic grades in8and9Seismic Subarea iscontrolled by shear minimum cross-section of node. Compared to01Code, axialcompression ratio and the maximum longitudinal reinforcement ratio becomes the morerigorous control condition for column section in10Code.②Give the seismic fragility curve of the typical frame structure in theGB50011-2001and the GB50011-2010, and fragility curves are derived to assess earthquake disaster.③Overall, the seismic performance of the structures designed by the new Code isgreater than that by the old Code, but for the frame structurethe of different intensityarea, different height, the influence degree is different. Specifically, In6degree area,the seismic performance of low floor frame structure designed by the new Code isslightly more than that by the old Code, while in multi-storey and high-rise framestructure the difference is not much; In7degree area, the seismic performance of lowand multi-storey frame structure designed by the new Code is significantly more thanthat by the old Code, while in high-rise frame structure the difference is not much; in8degree area, according to the new standard design of low-rise and high-rise framestructure seismic performance is slightly more than that by the old design of the framestructure, while in multi-storey frame structure the difference is not much; In9degreearea, the seismic performance of low floor frame structure designed by the new Code isslightly more than that by the old Code.