Seismic resilience assessment of corroded reinforced concrete structures designed to the Chinese codes

The natural landscape in China exposes many existing RC buildings to aggressive environments.Such exposure can lead to deterioration in structural performance with regard to resisting events such as earthquakes.Corrosion of embedded reinforcement is one of the most common mechanisms by which such structural degradation occurs.There has been increasing attention in recent years toward seismic resilience in communities and their constituent construction;however,to date,studies have neglected the effect of natural aging.This study aims to examine the effect of reinforcement corrosion on the seismic resilience of RC frames that are designed according to Chinese seismic design codes.A total of twenty RC frames are used to represent design and construction that is typical of coastal China,with consideration given to various seismic fortification levels and elevation arrangements.Seismic fragility relationships are developed for case frames under varying levels of reinforcement corrosion,i.e.,corrosion rates are increased from 5%to 15%.Subsequently,the seismic resilience levels of uncorroded and corroded RC frames are compared using a normalized loss factor.It was found that the loss of resilience of the corroded frames is greater than that of their uncorroded counterparts.At the Rare Earthquake hazard level,the corrosioninduced increase in loss of resilience can be more than 200%,showing the significant effect of reinforcement corrosion on structural resilience under the influence of earthquakes.

Seismic fragility assessment of RC frame structure designed according to modern Chinese code for seismic design of buildings

Following several damaging earthquakes in China, research has been devoted to find the causes of the collapse of reinforced concrete （RC） building sand studying the vulnerability of existing buildings. The Chinese Code for Seismic Design of Buildings （CCSDB） has evolved over time, however, there is still reported earthquake induced damage of newly designed RC buildings. Thus, to investigate modern Chinese seismic design code, three low-, mid- and high-rise RC frames were designed according to the 2010 CCSDB and the corresponding vulnerability curves were derived by computing a probabilistic seismic demand model （PSDM）.The PSDM was computed by carrying out nonlinear time history analysis using thirty ground motions obtained from the Pacific Earthquake Engineering Research Center. Finally, the PSDM was used to generate fragility curves for immediate occupancy, significant damage, and collapse prevention damage levels. Results of the vulnerability assessment indicate that the seismic demands on the three different frames designed according to the 2010 CCSDB meet the seismic requirements and are almost in the same safety level.

Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artifi cial and historic records

A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum （EPS）. Special attention is given to the definition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an efficient auto-regressive moving-average （ARMA） filtering technique is utilized to generate ensembles of non-stationary artificial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signals＇ response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass filtering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice.

Comparison of seismic actions and structural design requirements in Chinese Code GB 50011 and International Standard ISO 3010

This papcr presents a comparison between the Chinese Code GB50011-2001 and the International Standard ISO3010:2001(E),emphasizing the similarities and differences related to design requirements,seismic actions and analytical approaches.Similarities include:earthquake return period,conceptual design,site classification,structural strength and ductility requirements,deformation limits,response spectra,seismic analysis procedures,isolation and energy dissipation, and nonstructural elements.Differences exist in the following areas:seismic levels,earthquake loading,mode damping factors and structural control.

The law of oral traditional Chinese medicine for insomnia based on Chinese medical code

Objective:This study aimed to collect,sort out and excavate the literature on the diagnosis and treatment of insomnia in Chinese Medical Code,and to explore the law of internal administration of traditional Chinese medicine in the treatment of insomnia.Methods:We used"Chinese Medical Code"as the source of data retrieval,"insomnia","not sleepy","no sleeping"and"eye not sleeping"as the key words,and excluded temporary insomnia,physiological insomnia,insomnia caused by other diseases,and excluded other methods such as acupuncture and massage,the medical cases.Prescriptions of insomnia treated with traditional Chinese medicine were screened out.The database was established by using Microsoft excel 2010.Descriptive statistics were used to analyze the frequency,menstruation of nature,taste and efficacy of traditional Chinese medicine.We analyzed the association rules between drugs and mined the rules of prescriptions by the Apriori algorithm in SPSS Modeler 14.1.Results:A total of 147 prescriptions,138 traditional Chinese medicines,20 pairs of core drugs,57 common drug combinations and 3 core pharmaceuticals were included.The basic prescription is:Suan Zao Ren,Bai Zi Ren,Fu Shen,Fu Ling,Yuan Zhi,Dang Gui,Gan Cao(Zhi).Conclusion:In summary,according to the drug analysis above,the main disease of insomnia is in the heart,involving the liver,spleen and kidney.Because it involves different viscera and syndrome,the methods of treatment are also different.However,there is a basic pathogenesis,that’s the loss of mental nourishment.By excavating the law of the use of traditional Chinese medicine in the treatment of insomnia on the Chinese Medical Code,we expect that it can guide the treatment of insomnia.