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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第8期13卷 571-583页

作者： Mykolas DAUGEVIIUS Juozas VALIVONIS Gediminas MAR IUKAITIS department of reinforced concrete and Masonry structures Vilnius Gediminas Technical University

This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer(CFRP) layer under long-term load action that lasted for 330 *** describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of *** conducted experiments showed that the additional anchorage influences the slip of the external layer with respect to the strengthened ***,concrete and carbon fibre composite interface stiffness decreases with a long-term load ***,the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load.

关键词： Carbon fibre composite Beam strengthening Beam deflection Long-term load Bending stiffness concrete and carbon fibre composite interface stiffness Effective inertia moment

Development of damage probability matrices based on Greek earthquake damage data

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Earthquake Engineering and Engineering Vibration 2011年第1期10卷 129-141页

作者： Anastasia K. Eleftheriadou Athanasios I. Karabinis Laboratory of reinforced concrete Department of Civil EngineeringDemocritus University of ThraceGreece

A comprehensive study is presented for empirical seismic vulnerability assessment of typical structural types, representative of the building stock of Southern Europe, based on a large set of damage statistics. The observational database was obtained from post-earthquake surveys carried out in the area struck by the September 7, 1999 Athens earthquake. After analysis of the collected observational data, a unified damage database has been created which comprises 180,945 damaged buildings from/after the near-field area of the earthquake. The damaged buildings are classified in specific structural types, according to the materials, seismic codes and construction techniques in Southern Europe. The seismic demand is described in terms of both the regional macroseismic intensity and the ratio αg/ao, where αg is the maximum peak ground acceleration （PGA） of the earthquake event and ao is the unique value PGA that characterizes each municipality shown on the Greek hazard map. The relative and cumulative frequencies of the different damage states for each structural type and each intensity level are computed in terms of damage ratio. Damage probability matrices （DPMs） and vulnerability curves are obtained for specific structural types. A comparison analysis is fulfilled between the produced and the existing vulnerability models.

关键词： seismic vulnerability observational earthquake damage damage probability matrices (DPMs) vulnerability curves post-earthquake surveys Athens earthquake existing buildings

A new isolation device using shape memory alloy and its application for long-span structures

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Earthquake Engineering and Engineering Vibration 2011年第2期10卷 239-252页

作者： Ding Youliang Chen Xin Li Aiqun Zuo Xiaobao Key Laboratory of concrete and Prestressed concrete structure of Ministry of Education Southeast University Nanjing 210096 China department of Civil Engineering Nanjing University of Science ＆ Technology Nanjing 210094 China

The key points to consider in determining the effectiveness of using structural isolation with shape memory alloys （SMA） are the constitutive model, the SMA isolation device and the analysis method. In this paper, a simplified constitutive model based on the classic theory of plasticity is proposed to simulate the behavior of the superelasticity of the SMA, in which the martensite volume fraction is considered as one of the state variables. Comparisons between simulation results and experimental results are made and indicate that the proposed constitutive model yields stress-strain curves that are in good agreement with the experimental ones. Thus, the proposed model can correctly simulate the yield mechanism and energy dissipation capacity of the SMA. Next, in order to make full use of the superelasticity of SMA, a new SMA isolator composed of pre-tensioned SMA bars is presented. Then, a finite element analytical model is established to simulate the behavior of the SMA isolator according to its configuration and simplified constitutive model. Finally, a simplified design method for long-span structures installed with SMA isolators is proposed, which is further used to investigate the isolation effects of a space grid structure. Results show that the SMA isolator can reduce the seismic responses of the structure effectively, which indicates the effectiveness of the proposed SMA isolation method.

关键词： shape memory alloy super-elasticity constitutive model seismic response structural isolation space gridstructure

Bi-normalized response spectra and seismic intensity in Bucharest for 1986 and 1990 Vrancea seismic events

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Earthquake Engineering and Engineering Vibration 2014年第1期13卷 125-135页

作者： Florin Pavel Radu Vacareanu Cristian Neagu Andrei Pricopie department of reinforced concrete structures Technical University of Civil Engineering BucharestRomania department of Strength of Materials Bridges and TunnelsTechnical University of Civil Engineering BucharestRomania

The Vrancea subcrustal earthquakes of August 30,1986 and May 30,1990 are the two most recent seismic events that have occurred in Romania with moment magnitudes M W ≥ *** spectral analysis of the strong ground motions recorded in Bucharest reveals that despite small differences in magnitude between the 1986 and 1990 earthquakes,their frequency contents are very different,sometimes even *** main focus of this study is to conduct a comparative analysis of the response spectra in terms of the bi-normalized response spectra(BNRS) proposed by Xu and Xie(2004 and 2007) for strong ground motions recorded in Bucharest during these two seismic *** mean absolute acceleration and relative velocity response spectra for the two earthquakes are discussed and ***,the mean bi-normalized absolute acceleration and normalized relative velocity response spectra with respect to the control period T C are computed for the ground motions recorded in Bucharest in 1986 and *** predominant period T P is also used in this study for the normalization of the spectral period ***,the methodology proposed by Martinez-Perreira and Bommer(1998) is applied in order to estimate the seismic intensity of the two *** results are discussed and several conclusions regarding the possibility of using the bi-normalized response spectra(BNRS) are given.

关键词： response spectra bi-normalized response spectra dynamic amplifi cation factor control period damage potential parameters

Compressive performance of a foam-filled fiber-reinforced grid beetle elytron plate

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Science China(Technological Sciences) 2023年第3期66卷 830-840页

作者： HAO Ning SONG YiHeng CHEN JinXiang HE ChaoChao LI YinSheng Key Laboratory of concrete and Prestressed concrete structures of the Ministry of Education Southeast UniversityNanjing 211189China

The compressive mechanical properties,failure modes and foam filler strengthening mechanism and effect of a short basalt fiber-reinforced epoxy resin composite grid beetle elytron plate with a polyvinyl chloride(PVC)foam-filled core(GBEPfc)are investigated via compression experiments and the finite element *** results are compared with those of a grid plate(GPfc)with the same wall thickness as the ***,a fully integrated preparation method and process are developed for the GBEPfc,with a material composition that is close to the structure and composition of the *** of more than 20%in the specific compressive strength and specific energy absorption of the GBEPfcrelative to the GPfcare *** foam provides a constraining force for the fiber composite structure;consequently,the trabeculae and honeycomb walls of the core transition from a lower-order deformation that easily occurs to a higher-order deformation that occurs less *** interaction between the core composite structure and PVC foam is *** GBEPfcdeveloped in this paper is simple in structure and easy to prepare,and the material composition is close to biological prototypes and materials used in practical engineerings,which lays a foundation for the application of beetle elytron plates.

关键词： beetle elytron beetle elytron plate foam-filled sandwich plate basalt fiber-reinforced polymer(BFRP) compressive properties

A numerical study on fire endurance of wood beams exposed to three-side fire

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第7期13卷 491-505页

作者： Jin ZHANG 1, Qing-feng XU2, Yi-xiang XU3, Bin WANG1, Jing-xiang SHANG1 (1Key Laboratory of concrete and Prestressed concrete structures of the Ministry of Education, Southeast University, Nanjing 210096, China) (2Shanghai Key Laboratory of New Technology Research on Engineering structure, Shanghai Research Institute of Building Sciences, Shanghai 200032, China) (3department of Civil Engineering, Strathclyde University, Glasgow G12 8QQ, UK) Key Laboratory of concrete and Prestressed concrete structures of the Ministry of Education Southeast University Nanjing China Shanghai Key Laboratory of New Technology Research on Engineering structure Shanghai Research Institute of Building Sciences Shanghai China department of Civil Engineering Strathclyde University Glasgow UK

To investigate the fire endurance of wood beams exposed to three-side fire, we conducted bearing capacity tests of two wood beams and experiments of five wood beams exposed to three-side fire. The finite element software ANSYS was also used to predict the fire endurance of those beams with the indirect order coupling method. It was found that the fire endurance decreases as the load level increases, and the reduction ratio tends to decrease. In the case of a certain load level, the fire endurance is improved if the section size is increased or covered by the fire protection coating. The central deformation increases as the fire duration increases, and the ratio of increase tends to rise. On another note, an increase in the density of wood leads to a rise in the fire endurance of a given beam. From the finite element method (FEM) calculation results, the fire endurance decreases as the load level increases, and the reduction ratio tends to decrease. When the load level is greater than 0.5, the fire endurance is significantly reduced, and it does not change significantly when the load level changes. Lastly, for a load level magnitude below 0.5, the fire endurance and load level are proportional to one another.

关键词： Three-side fire Fire endurance Load level Fire prevention measures Finite element analysis Density of wood

Numerical study on flexural behaviors of steel reinforced engineered cementitious composite(ECC) and ECC/concrete composite beams

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Science China(Technological Sciences) 2014年第3期57卷 637-645页

作者： YUAN Fang PAN JinLong WU YuFei Key Laboratory of concrete and Prestressed concrete structures of Ministry of Education Southeast University department of Civil and Architectural Engineering City University of Hong Kong

Engineered cementitious composite(ECC)is a class of high performance cementitious composites with pseudo strain-hardening behavior and excellent crack control *** of concrete with ECC can largely reduce the cracking and durability problems associated with brittleness of *** this paper,a simplified constitutive model of the ECC material was applied to simulate the flexural behaviors of the steel reinforced ECC and ECC/concrete composite beams with finite element *** simulation results are found to be in good agreement with test results,indicating that the finite element model is reasonably accurate in simulating the flexural behaviors of the steel reinforced ECC flexural *** effects of the ECC modulus,ECC tensile ductility,ECC thickness and ECC position on flexural behaviors in terms of ultimate moment,deflection and the maximum crack width of the steel reinforced ECC or ECC/concrete composite beam are hence evaluated.

关键词： engineered cementitious composite(ECC) constitutive model flexural behavior finite element

Experimental study on mechanical behaviors of pseudo-ductile cementitious composites under biaxial compression

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Science China(Technological Sciences) 2013年第4期56卷 963-969页

作者： ZHOU JiaJia PAN JinLong LEUNG Christopher Kin Ying LI ZongJin Key Laboratory of concrete and Prestressed concrete structures of Ministry of Education Southeast University department of Civil and Environmental Engineering Hong Kong University of Science and Technology

Experimental investigation was conducted to characterize the responses of pseudo-ductile cementitious composites (PDCCs) when subjected to uniaxial and biaxial *** PDCCs is a class of fiber reinforced cementitious composites with ultra-high ductility by using a low volume fraction (2%) of polyvinyl alcohol (PVA) *** different strength grades of PDCC were examined with cubic specimen size of 100 mm in the *** specimens were loaded with a servo-hydraulic jack at different stress *** principle stresses and strains of the specimens were recorded,and the failure modes with various stress states were *** test results indicated that the ultimate strength of PDCCs increased due to the lateral confinement in the other principal stress direction,and the maximum ultimate strength occurred at the biaxial stress ratio of 0.25,which was very different from common concrete *** the PDCC specimens,the biaxial strength may be lower than the uniaxial strength when subjected to biaxial compression with the stress ratio of 1.0,and the failure mode showed a shear-type failure because of the bridging effect of ***,a failure criterion was proposed for PDCCs under biaxial compression.

关键词： PDCC biaxial strength stress-strain curve failure mode failure criterion

An experimental and numerical study on the charring rate of timber beams exposed to three-side fire

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Science China(Technological Sciences) 2012年第12期55卷 3434-3444页

作者： ZHANG Jin LIU ZengHui XU YiXiang MA ShuWei XU QingFeng Key Laboratory of concrete and Prestressed concrete structures of Ministry of Education Southeast UniversityNanjing 210096China department of Civil Engineering Strathclyde UniversityGlasgow G128QQUnited Kingdom Shanghai Key Laboratory of New Technology Research on Engineering structure SRIBSShanghai 200032China

To investigate the charring rate of timber beams exposed to three-side fire, a total of fifteen new and used Douglas-Fir timber beams in four groups exposed to three-side fire were experimentally studied, together with the finite element analyses of the temperature distribution in the beam section. The durations of fire exposure were 0 (on a test piece), 10, 15, 20 and 30 min, according to the ISO 834 standard fire curve. The charring depth of each timber beam was calculated by averaging the values at one-third and two-thirds along each cross section to give the charring rate of timber beams. It was found that the timber beam's charring rate reduces as the duration of fire exposure increases and the vertical charring rate is slightly higher than the horizontal one. The areas of beam sections reduce due to charring and the strength and stiffness of the pyrolysis layer near the charring edge decrease owing to the high-temperature. The average horizontal and vertical charring rates are 0.98 and 1.08 mm/min, respectively. To take into account the difference between the test furnace temperature curve and the ISO 834 stand- ard fire curve, some corrections were made for these data to yield the solution for charring rate. With the help of the finite element software ANSYS, the temperature distribution of the wood's cross-section was analyzed. The longer the exposure time is, the greater the effect of density will impose on the distribution of temperature, but the moisture content has no effect.

关键词： timber beam charring rate exposed to three-sides fire charring layer pyrolysis layer

Current State of High 120 m concrete Dam Bratsk Hydroelectric Power Plant

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Journal of Civil Engineering and Architecture 2017年第3期11卷 222-231页

作者： Mark A. Sadovich Tatyana F. Shlyakhtina Sofia M. Ginzburg Alexander M. Yudelevich department of Civil Engineering Bratsk State University Bratsk 665709 Russia department of concrete and reinforced concrete structure Vedeneev VNIIG St.Petersburg 195220 Russia

The research object was high 120 m concrete gravity dam of the Angara Bratsk hydroelectric power plant. The state of the concrete dam is estimated based on the results of continuous supervision performed by site personnel as well as periodic monitoring. According to the classification of the interrelations in the system ＂concrete-environment＂, there were selected some important parts of dams and a comprehensive analysis of concrete was executed on these parts. Concerning the complex research of concrete, a combination of full-scale tests with core-sampling has been proposed. Core samples tests had an object to study the deep concrete layers and to determine the specific indicators such as strength, density, porosity, comparative diameter of capillary pores, CaO content in cement stone and others. Obtained findings and recommended criteria can be applied when selecting technologies for constructing dams that guarantee their durability in the north.

关键词： concrete gravity dam hydroelectric power plant monitoring.