Assessment method for seismic performance design of engineering structures under effect of multi-magnitude earthquakes

Abstract

The invention belongs to the field of civil engineering, and relates to an assessment method for seismic design of engineering structures. The method includes the following steps that (1) the design intensity, a performance level, a performance objective and a structure scheme are determined, and bearing capacity design and section reinforcement and capability structure design under the effect of frequent earthquakes are conducted according to earthquake resistant codes; (2) the number of vibration modes is determined according to a vibration mode participation quality factor; (3) seismic oscillation at the performance level is determined on the basis of the performance level and an equivalent single-degree-of-freedom model of each vibration mode, and a seismic oscillation-seismic demand quantitative relation is established; (4) the seismic demand is obtained, and modal reactions are determined through a square and square root extraction combination or a complete secondary vibration mode combination; (5) after the vibration modes response to the combination, structural displacement is conducted, and whether the requirements of top displacement, inter-story displacement and the component performance objective are met or not is judged; and (6) the seismic oscillation level is predicted and assessed under multiple performance levels. The new method and new idea for assessment of the seismic performance design are provided.

Description

technical field [0001] The invention belongs to the field of civil engineering, and relates to an evaluation method for anti-seismic design of engineering structures. Background technique [0002] The purpose of seismic performance design evaluation is to control the losses caused by earthquakes on the basis of structural seismic safety design. This advanced design idea has been recognized by scholars from all over the world, and it is the development direction of seismic design codes in all countries in the world, and is widely used in the evaluation of engineering seismic design. [0003] Engineering seismic design evaluation allows designers to conduct corresponding seismic design evaluation on the basis of the minimum safety level of seismic codes. Therefore, it is necessary to establish a new method for engineering structure seismic performance design evaluation. [0004] The development of seismic performance design and evaluation ideas has roughly gone through two st...

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Problems solved by technology

Capability spectrum method is the core method of pushover analysis to determine performance points (FEMA 440.Improvement of nonlinear static seismic analysis procedures[R].Federal Emergency Management Agency,Washington,D.C.,2005; FEMA 273.NEHRP Guidelines for seismicrehabilitation of buildings[R].Federal Emergency Management Agency, Washington, D.C., 1997; FEMA 356. Prestandard and commentary for the seismicrehabilitation of buildings[R]. Federal Emergency Management Agency, Washington, D.C., 2000; ATC-40. Seismic evaluation and retrofit of existing concrete buildings[R]. Applied Technology Council, RedWood City, California, 1996), the nonlinear single-degree-of-freedom system can be equivalent to a series of elastic systems with high damping ratio and lower stiffness than the original structure, and the elastic response spectrum can be reduced according to the equivalent damping ratio as the demand curve, but iteration is required, iterations may not converge, and displacements of different types of structures may be underestimated or overestimated (FEMA440. Improvement of nonlinear static seismic analysis procedures[R]. Federal Emergency Management Agency, Washington, D.C., 2005; ChopraA K, Goel R K.Capacity-demand diagram methods based on inelastic designspectrum[J].Earthquake Spectra,1999,15(4):637-656; Miranada E, Akkar SD.Evaluation of iterative schemes in equivalent liner methods[R].Earthquake Engineering Research I nstitute, 2003), for this reason, FEMA440 (2005) fully revised the equivalent period, equivalent damping ratio and iteration format (FEMA 440.Improvement of nonlinear static seismic analysis procedures[R].Federal Emergency Management Agency,Washington,D.C.,2005 )

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