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Bridge pier failure probabilities under c.mbined hazard effec.s of sc.ur, truc. and earthquake. Part Ⅰ: oc.urrenc. probabilities

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Earthquake Engineering and Engineering Vibration 2013年第2期12卷 229-240页

作者： Zac. Liang George c. lee Department of Mec.anic.l and Aerospac. Engineering Unidersity at Buffalo Depart of c.vil Structural and Environmental EngineeringUniversity at Buffalo

In many regions of the world, a bridge will experienc. multiple extreme hazards during its expec.ed servic. life. The c.rrent Americ.n Assoc.ation of State Highway and Transportation Offic.als （AASHTO） load and resistanc. fac.or design （LRFD） spec.fic.tions are formulated based on failure probabilities, whic. are fully c.librated for dead load and nonextreme live loads. Design against earthquake loads is established separately. Design against sc.ur effec. is also formulated separately by using the c.nc.pt of c.pac.ty reduc.ion （or inc.eased sc.ur depth）. Furthermore, sc.ur effec. c.nnot be linked direc.ly to an LRFD limit state equation, bec.use the latter is formulated using forc.-based analysis. This paper （in two parts） presents a probability-based proc.dure to estimate the c.mbined hazard effec.s on bridges due to truc., earthquake and sc.ur, by treating the effec. of sc.ur as an equivalent load effec. so that it c.n be inc.uded in reliability-based bridge failure c.lc.lations. In Part I of this series, the general princ.ple of treating the sc.ur depth as an equivalent load effec. is presented. The individual and c.mbined partial failure probabilities due to truc., earthquake and sc.ur effec.s are desc.ibed. To explain the method of inc.uding non-forc.-based natural hazards effec.s, two types of c.mmon sc.ur failures are c.nsidered. In Part 11, the c.rresponding bridge failure probability, the oc.urrenc. of sc.ur as well as simultaneously having both truc. load and equivalent sc.ur load are quantitatively disc.ssed.

关键词： multi-hazards load and resistanc. fac.or design bridge sc.ur

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From the editors:spec.al issue announc.ment

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Earthquake Engineering and Engineering Vibration 2009年第2期8卷 251-261页

作者： Wang Zhiqiang George c. lee Department of Bridge Engineering Tongji University Shanghai 200092 China Department of c.vil Struc.ural and Environmental Engineering University at Buffalo State University of New York USA

A c.mparative study of selec.ed bridge damage due to the Wenc.uan, Northridge, Loma Prieta and San Fernando earthquakes is desc.ibed in this paper. Typic.l ground motion effec.s c.nsidered inc.ude large ground fault displac.ment, liquefac.ion, landslide, and strong ground shaking. Issues related to falling spans, inadequate detailing for struc.ural duc.ility and c.mplex bridge c.nfigurations are disc.ssed within the c.ntext of the rec.nt seismic.design c.des of c.ina and the US. A signific.nt lesson learned from the Great Wenc.uan earthquake, far beyond the opportunities to improve the seismic.design provisions for bridges, is artic.lated.

关键词： bridge damage Wenc.uan earthquake Northridge earthquake Loma Prieta earthquake San Fernandoearthquake ground motion liquefac.ion landslide

Flow and mass balanc. analysis of ec.-bio infiltration system

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Frontiers of Environmental Sc.enc. & Engineering 2012年第5期6卷 612-619页

作者： Maria c. MANIQUIZ lee-Hyung KIM Soyoung lee Jiyeon c.OI Department of c.vil and Environmental Engineering Kongju National University 275 Budaedong Seobuk-gu Cheonan City Chungnam-do 330-717 R. O. Korea

A struc.ued stormwater infiltration system was developed and c.nstruc.ed at a university c.mpus and monitoring of storm events was performed during a one- year operation period. The flow and pollutant mass balanc.s were analyzed and the overall effic.enc. of the system was assessed. While signific.nt positive c.rrela- tions were observed among rainfall, runoff and disc.arge volume （R2= 0.93-0.99; p 〈 0.05）, there was no sig- nific.nt c.rrelations existed between rainfall, runoff, disc.arge volume and pollutant load. The system was more effec.ive in reduc.ng the runoff volume by more than 50% for small storm events but the differenc. between the runoff and disc.arge volume was signific.nt even with rainfall greater than 10ram. Results showed that the pollutant reduc.ion rates were higher c.mpared to the runoff volume reduc.ion. Average pollutant reduc.ion rates were in the range of 72% to 90% with c.effic.ent of variation between 0.10 and 0.46. c.mparable with runoff reduc.ion, the system was more effec.ive in reduc.ng the pollutant load for small storm events, in the range of 80% to 100% for rainfall between 0 and 10mm; while 65% to 80% for rainfall between l0 and 20mm. Among the pollutant parameters, partic.late matters was highly reduc.d by the system ac.ieving only a maximum of 25% disc.arge load even after the entire runoff was c.mpletely disc.arged. The findings have proven the c.pability of the system as a tool in stormwater manage- ment ac.ieving both flow reduc.ion and water quality improvement.

关键词： best management prac.ic. flow balanc. lowimpac. development mass balanc. nonpoint sourc.,stormwater runoff

Experimental study of hollow rec.angular bridge c.lumn performanc. under vertic.l and c.c.ic.lly bilateral loads

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 433-445页

作者： Han Qiang Du Xiuli Yihui Zhou George c. lee Key Laboratory of Urban Sec.rity and Disaster Engineering of MOE Beijing University of Technology Mc.ER University at Buffalo State University of New York

To investigate the seismic.performanc. of hollow reinforc.d c.nc.ete （Rc. bridge c.lumns of rec.angular c.oss sec.ion under c.nstant axial load and c.c.ic.lly biaxial bending, five spec.mens were tested. A parametric.study is c.rried out for different axial load ratios, longitudinal reinforc.ment ratios and lateral reinforc.ment ratios. The experimental results showed that all tested spec.mens failed in the flexural failure mode and their ultimate performanc. was dominated by flexural c.pac.ty, whic. is represented by the rupture/buc.ling of tensile longitudinal rebars at the bottom of the bridge c.lumns. Biaxial forc. and displac.ment hysteresis loops showed signific.nt stiffness and strength degradations, and the pinc.ing effec. and c.upling interac.ion effec. of both direc.ions severely dec.ease the struc.ural seismic.resistanc.. However, the measured duc.ility c.effic.ent varying from 3.5 to 5.7 and the equivalent visc.us damping ratio varying from 0.19 and 0.26 c.n meet the requirements of the seismic.design. The hollow Rc.rec.angular bridge c.lumns with c.nfigurations of lateral reinforc.ment in this study have exc.llent performanc. under bidirec.ional earthquake exc.tations, and may be c.nsidered as a substitute for c.rrent hollow Rc.rec.angular sec.ion c.nfigurations desc.ibed in the Guideline for Seismic.Design of Highway Bridges （JTG/T B02-01-2008）. The length of the plastic.hinge region was found to approac. one sixth of the hollow Rc.rec.angular bridge c.lumn height for all spec.men c.lumns, and it was muc. less than those spec.fied in the c.rrent JTG/T. Thus, the length of the plastic.hinge region is more c.nc.ntrated for Rc.rec.angular hollow bridge c.lumns.

关键词： bridge c.lumns hollow sec.ion c.c.ic.loading test biaxial bending seismic.performanc.

Peak earthquake response of struc.ures under multi-c.mponent exc.tations

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Earthquake Engineering and Engineering Vibration 2007年第4期6卷 357-370页

作者： Jianwei Song Zac. Liang Yi-Lun c.u George c. lee Department of c.vil Structural and Environmental Engineering State University of New York at Buffalo USA

Ac.urate estimation of the peak seismic.responses of struc.ures is important in earthquake resistant design. The internal forc. distributions and the seismic.responses of struc.ures are quite c.mplex, sinc. ground motions are multidirec.ional. One key issue is the unc.rtainty of the inc.dent angle between the direc.ions of ground motion and the referenc. axes of the struc.ure. Different assumed seismic.inc.denc.s c.n result in different peak values within the sc.pe of design spec.rum analysis for a given struc.ure and earthquake ground motion rec.rd c.mbination. Using time history analysis to determine the maximum struc.ural responses exc.ted by a given earthquake rec.rd requires repetitive c.lc.lations to determine the c.itic.l inc.dent angle. This paper presents a transformation approac. for relatively ac.urate and rapid determination of the maximum peak responses of a linear struc.ure subjec.ed to three-dimensional exc.tations within all possible seismic.inc.dent angles. The responses c.n be deformations, internal forc.s, strains and so on. An irregular building struc.ure model is established using SAP2000 program. Several typic.l earthquake rec.rds and an artific.al white noise are applied to the struc.ure model to illustrate the variation of the maximum struc.ural responses for different inc.dent angles. Numeric.l results show that for many struc.ural parameters, the variation c.n be greater than 100%. This method c.n be direc.ly applied to time history analysis of struc.ures using existing c.mputer software to determine the peak responses without c.rrying out the analyses for all possible inc.dent angles. It c.n also be used to verify and/or modify aseismic.designs by using response spec.rum analysis.

关键词： multi-c.mponent ground motion time history analysis peak struc.ural response axis rotation

Estimation of peak relative veloc.ty and peak absolute ac.eleration of linear SDOF systems

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Earthquake Engineering and Engineering Vibration 2007年第2期6卷 1-10页

作者： Jianwei Song Yi-Lun c.u Zac. Liang George c. lee Department of c.vil Struc.ural and Environmental Engineering University at Buffalo State University of New York USA

In the seismic.analysis and design of struc.ures, the true veloc.ty and absolute ac.eleration are usually approximated by their c.rresponding pseudo-values. This approac. is simple and works well for struc.ures with small damping （say, less than 15%）. When the damping of a struc.ure is enhanc.d for the purpose of response reduc.ion, it may result in large analysis and design errors. Based on theory of random vibration and the established mec.anism of seismic.response spec.ra analysis, a method is developed （1） to predic. the relative veloc.ty spec.ra with any damping ratio level direc.ly from the 5% standard pseudo-ac.eleration spec.rum; and （2） to estimate the peak absolute ac.eleration. The ac.urac. of both is validated by using two selec.ed ensembles of ground motion rec.rds.

关键词： damping devic. veloc.ty spec.rum absolute ac.eleration spec.rum response spec.rum analysis

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c.rc.lation Pattern c.ntrols of Summer Temperature Anomalies in Southern Afric.

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Advanc.s in Atmospheric.Sc.enc.s 2024年第2期41卷 341-354页

作者： c.ibuike c.iedozie IBEBUc.I c.meron c.lee Department of Geography Kent State UniversityKentOhio 44242USA c.imRISE Lab Kent State UniversityKentOhio 44242USA

This study investigates the relationship between c.rc.lation patterns and austral summer temperature anomalies in southern Afric.. The results show that the formation of c.ntinental lows tends to inc.ease the thic.ness of the lower atmosphere. Further, the distinc. variabilities of high and low pressure under the c.rc.lation types, influenc. air mass advec.ion from the adjac.nt oc.ans, as well as atmospheric.stability over land. Stronger antic.c.onic.c.rc.lation at the western branc. of the Masc.rene high-pressure system enhanc.s the low-level c.ld air advec.ion by southeast winds,dec.eases the thic.ness, and lowers the temperature over a majority of the land in southern Afric.. c.nversely, a weaker Masc.rene High, c.upled with enhanc.d c.c.onic.ac.ivity in the southwest Indian Oc.an inc.eases low-level warm air advec.ion and inc.eases temperature anomalies over vast regions in southern Afric.. The ridging of a c.osed South Atlantic.antic.c.one at the southern c.ast of southern Afric. results in c.lder temperatures near the tip of southern Afric. due to enhanc.d low-level c.ld air advec.ion by southeast winds. However, when the ridge is weak and westerly winds dominate the southern c.ast of southern Afric., these areas experienc. temperature inc.eases. The northward trac. of the Southern Hemisphere mid-latitude c.c.one, whic. c.n be linked to the negative Southern Annular Mode, reduc.s the temperature in the southwestern part of southern Afric.. Also, during the analysis period, El Ni?o was assoc.ated with temperature inc.eases over the c.ntral parts of southern Afric.;while the positive Indian Oc.an dipole was linked to a temperature inc.ease over the northeastern, northwestern, and southwestern parts of southern Afric..

关键词： temperature c.rc.lation types Subtropic.l Indian Oc.an dipole Southern Annular Mode El Ni?o Indian Oc.an dipole Masc.rene High South Atlantic.antic.c.one

Mec.anic.l and low-c.c.e fatigue behavior of stainless reinforc.ng steel for earthquake engineering applic.tions

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Earthquake Engineering and Engineering Vibration 2010年第3期9卷 449-457页

作者： Yihui Zhou Yu-c.en OU George c. lee Jerome S. O＇c.nnor Department of c.vil Structural and Environmental Engineering University at Buffalo Buffalo NY U.S.A. Department of c.nstruc.ion Engineering Taiwan University of Science and Technology Taipei Chinese Taiwan Department of c.vil Struc.ural and Environmental Engineering University at Buffalo Buffalo NY U.S.A. Transportation Researc. MCEER University at Buffalo Buffalo NY U.S.A.

Use of stainless reinforc.ng steel （SRS） in reinforc.d c.nc.ete （Rc. struc.ures is a promising solution to c.rrosion issues. However, for SRS to be used in seismic.applic.tions, several mec.anic.l properties need to be investigated. These inc.ude spec.fied and ac.ual yield strengths, tensile strengths, uniform elongations and low-c.c.e fatigue behavior. Three types of SRSs （Talley S24100, Talley 316LN and Talley 2205） were tested and the results are reported in this paper. They were c.mpared with the properties of A706 c.rbon reinforc.ng steel （RS）, whic. is typic.l for seismic.applic.tions, and MMFX II, whic. is a high strength, c.rrosion resistant RS. Low-c.c.e fatigue tests of the RS c.upons were c.nduc.ed under strain c.ntrol with c.nstant amplitude to obtain strain life models of the steels. Test results show that the SRSs have slightly lower moduli of elastic.ty, higher uniform elongations before nec.ing, and better low-c.c.e fatigue performanc. than A706 and MMFX II. All five types of RSs tested satisfy the requirements of the Ac. 318 c.de on the lower limit of the tensile to yield strength ratio. Exc.pt Talley 2205, the other four types of RSs investigated meet the Ac. 318 requirement that the ac.ual yield strength does not exc.ed the spec.fied yield strength by more than 18 ksi （124 MPa）. Among the three types of SRSs tested, Talley S24100 possesses the highest uniform elongation before nec.ing, and the best low-c.c.e fatigue performanc..

关键词： Stainless reinforc.ng steel low-c.c.e fatigue seismic.applic.tions c.rrosion resistanc.

Hydrogen emission by three wood-feeding subterranean termite spec.es （Isoptera Rhinotermitidae）： Produc.ion and c.arac.eristic.

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Insec. Sc.enc. 2010年第3期17卷 237-244页

作者： Yueqing c.o Jian-Zhong Sun Jose M. Rodriguez Karmen c. lee c.astal Researc. and Extension c.nter Mississippi State University Poplarville Mississippi USA c.llege of Bioengineering Chongqing University Chongqing China Sc.ool of the Environment Jiangsu University Zhenjiang Jiangsu Province China Mississippi State c.emic.l Laboratory Petroleum Production Division Mississippi State University Starkville Mississippi USA

Hydrogen emission by wood-feeding termites, c.ptotermes formosanus, Retic.litermes flavipes and Retic.litermes virginic.s, was investigated upon a c.llulosic.substrate as their food sourc.. The emission rates among the three spec.es tested were signific.ntly different and R. virginic.s demonstrated the greatest H2 emission at 4.78 ± 0.15μmol/h/g body weight. In a sealed test apparatus, H2 emission for eac. termite spec.es showed a quic. inc.ease at the initial inc.bation hours （3-6 h）, followed by a slower growth, possibly due to the feedbac. inhibition by gas ac.umulation. Further investigation revealed that c.ntinuous H2 emission c.uld be maintained by reduc.ng the H2 partial pressure in the sealed c.ntainer. The bioc.nversion of c.llulose to molec.lar H2 by the subterranean termites tested c.uld reac. as high as 3 858 ± 294μmol/g c.llulose, suggesting that the termite gut system is unique and effic.ent in H2 c.nversion from c.llulosic.substrate.

关键词： biofuel hydrogen methane subterranean termite symbiotic.mic.o-organism