Study on the Method of Structural Seismic Performance Evaluation Based on the Damage Spectra

2010 ◽  
Vol 163-167 ◽  
pp. 4324-4330
Author(s):  
Jun Teng ◽  
Hu Bing Tu

Park-Ang seismic damage model is increasingly concerned due to it considers not only maximum elasto-plastic deformation, but also low cycle fatigue accumulated hysteretic energy, while research on the method of seismic performance evaluation based on the model is still rare. Therefore, a new evaluation method on the basis of damage spectra is proposed in this paper. Damage spectra of site I considering three kinds of ultimate deformation ductility factor are built firstly, and then transformation relationship between damage of MDOF and SDOF of frame structures is researched. Lastly, procedure of seismic damage evaluation on the structure is proposed. An example is used to confirm the validity of the spectra-based seismic performance evaluation method. The example analysis shows that: the method proposed here is reasonable to consider the impact of the cumulative hysteretic energy on the structural damage. The results from the method have good consistency with the time history analysis results. It can assess the extent of structural damage from the statistical viewpoint.

2014 ◽  
Vol 488-489 ◽  
pp. 398-402 ◽  
Author(s):  
Hai Qing Li ◽  
Yong Jun Ni ◽  
Xin Gang Liu ◽  
Jin Xing Yan

Seismic damage was the key reason which resulted in the serviceability degradation or collapse of the bridge. How to quantify the seismic damage and evaluate the seismic performance of the bridge under earthquakes through the damage analysis was the significant research direction in the performance based seismic design. In this paper the Park-Ang model (a well-known dual parameters model) and its modification version used for the damage evaluation of the concrete structure were compared. Furthermore, through the definition of the damage indices of the models based on the modified Park-Ang model and the descending slope of the IDA(incremental dynamic analysis) curve, the seismic damage levels of the typical bridge in the urban rail transit line under the designated earthquakes were analyzed, respectively. It was shown from the results that the calculated results from the two model was essentially consistent. The damage analysis based evaluation method was feasibly used for the seismic performance evaluation of the bridge.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Wilfried B. Krätzig ◽  
Yuri S. Petryna

This paper applies recent research on structural damage description to earthquake-resistant design concepts. Based on the primary design aim of life safety, this work adopts the necessity of additional protection aims for property, installation, and equipment. This requires the definition of damage indicators, which are able to quantify the arising structural damage. As in present design, it applies nonlinear quasistatic (pushover) concepts due to code provisions as simplified dynamic design tools. Substituting so nonlinear time-history analyses, seismic low-cycle fatigue of RC structures is approximated in similar manner. The treatment will be embedded into a finite element environment, and the tangential stiffness matrixKTin tangential subspaces then is identified as the most general entry for structural damage information. Its spectra of eigenvaluesλior natural frequenciesωiof the structure serve to derive damage indicatorsDi, applicable to quasistatic evaluation of seismic damage. Because detKT=0denotes structural failure, such damage indicators range from virgin situationDi=0to failureDi=1and thus correspond with Femaproposals on performance-based seismic design. Finally, the developed concept is checked by reanalyses of two experimentally investigated RC frames.


2015 ◽  
Vol 9 (1) ◽  
pp. 557-569 ◽  
Author(s):  
Hyo-Sang Park ◽  
Tae-Hyung Lee

Liquefied natural gas (LNG) terminals, one of the lifeline facilities, need to be protected by a proper seismic design against extreme earthquakes. An LNG terminal consists of a series of process facilities that are connected by pipelines of various sizes. Boil-off gas (BOG) compressor is one of the critical process facilities whose failure will cause the functional failure of the LNG terminal. Process facilities, including BOG compressor, other than LNG storage tanks and pipes, have not been a major concern in terms of the seismic performance evaluation. In this study, the seismic performance of a BOG compressor is evaluated and the seismic fragility functions are presented. An integrated system of a BOG compressor is modeled by a 3 dimensional finite element modeling scheme. A series of time history analyses are conducted to monitor the behavior of anchor bolts, one of the most critical elements in the BOG compressor. To develop fragility curves, a set of 20 ground motions are selected from a database of the historic earthquake accelerations. Fragility curves are developed based on the maximum likelihood estimation approach with respect to the strength limit states. When an earthquake load is applied to the BOG compressor, the main motor is likely to overturn and the flywheel is likely to slide, and, consequently, anchor bolts will be subjected to tension and shear force, respectively. It is concluded that the BOG compressor is safe against the design level earthquake


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