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2014 International Conference on Sensors Instrument and Information Technology, ICSIIT 2014

作者： Yu, Hao Lin Xu, Xue Yan Wang, Wei Li, Ming Xuan Key Lab of Structures Dynamic Behavior and Control Harbin Institute of Technology Ministry of Education Heilongjiang Harbin 150090 China School of Civil Engineering Harbin Institute of Technology Harbin 150090 China

ISBN: (纸本)9783038350392

Research work on the thermosiphon layout design of transmission line pile foundation in Geermu permafrost region was performed by finite element method and the influence of thermosiphon layout design on the temperature of soil around pile foundation was calculated and analyzed. The numerical calculation results indicated that the cooling effect of thermosiphon was obvious, but the coolling effect varied with the difference of thermosiphon layout design. The more thermosiphon bars were laid out aound pile foundation, the lower the temperature of soil around pile foundation. The cooling effect of thermosiphon on pile foundation and soil became weaker and weaker with the increment of the horizontal distance between soil and thermosiphon-pile. The layout design of 12 thermosiphon bars was the best for the transmission line pile foundation in permafrost region. © (2014) Trans Tech Publications, Switzerland.

关键词： Piles

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Node shift method for stiffness-based optimization of single-layer reticulated shells

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2014年第2期15卷 97-107页

作者： Chang-yu CUI Bao-shi JIANG You-bao WANG School of Civil Engineering Harbin Institute of Technology Harbin 150090 China Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education Harbin 150090 China

This paper presents a node shift method to find the optimal distribution of nodes in single-layer reticulated shells. The optimization process searches for the minimum strain energy configuration and this leads to reduced sensitivity in initial imper- fections. Strain energy sensitivity numbers are derived for free shift and restricted shift where nodes can move freely in the 3D space or have to move within a predefmed surface respectively. Numerical examples demonstrate the efficiency of the proposed approach. It was found that optimized structures achieve higher ultimate load and are less sensitive to imperfections than the initial structure. The configuration of the final structure is closely related to factors like the initial structural configuration, spatial conditions, etc. Based on different initial conditions, architects can be provided with diverse reasonable structures. Furthermore, by amending the defined shapes and nodal distributions, it is possible to improve the mechanical behavior of the structures.

关键词： Node shifts Strain energy sensitivity Structural optimization Static stability Imperfection sensitivity

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Research on deterioration of anchoring performance between anchorages to steel bars for prestressed concrete under fire

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Jianzhu Jiegou Xuebao/Journal of Building structures 2014年第3期35卷 110-118页

作者： Hou, Xiaomeng Zheng, Wenzhong Sun, Hongyu Key Laboratory of Structures Dynamic Behavior and Control of China Ministry of Education Harbin Institute of Technology Harbin 150090 China

In order to research the deterioration of anchoring performance between anchorages to steel bars for prestressed concrete under fire, 65 prestressed anchorage systems were tested under elevated temperatures. The typical tested prestressed anchorage system was specifically designed, which composed by JXM-clip anchorage, 7 steel bar for prestressed concrete (with a characteristic strength fptk=970 MPa) with surrounding concrete and a loading frame. A total of 29 unsealed prestressed anchorage systems and 18 prestressed anchorage systems with insulation were conducted as transient-state tests, while 18 prestressed anchorage systems were conducted as steady-state tests. The test variables included stress level (0.2~0.7), temperature (20~800°C), insulation (sealing anchorages by grouting, fire resistive coating and sealing anchorages by grouting and coating) and heating rate (10.0, 26.7°C/min). Transient-state test results from unsealed prestressed anchorage systems show that the failure mode of prestressed anchorage system is through slippage of anchorages. Lower the stress level, temperature and heating rate are, the higher will be the failure time in prestressed anchorage systems. In steady-state tests, failure mode of prestressed anchorage system is rupture of steel bar for prestressed concrete in temperature range of 20~400°C, while failure mode is through slippage of anchorages in temperature range of 400~800°C. Anchorages after elevated temperatures can not be applied in new structures. Test results from prestressed anchorage systems with insulation show that failure mode of anchorage systems is through slippage of anchorages, and insulations do not change the failure mode at elevated temperatures. As compared with unsealed prestressed anchorage systems, the failure time of prestressed anchorage systems with insulations is increased above 100%. It is not safe to apply the recommendation of fire resistive coating thickness for steel structures in GB 14907-2002 'Fir

关键词： Failure modes

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Parametric modeling and stability analysis of temporary grandstand

Parametric modeling and stability analysis of temporary gran...

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4th International Conference on Civil Engineering, Architecture and Building Materials, CEABM 2014

作者： He, Lin Liu, Cong Wu, Zhen Yu Key Lab of Structures Dynamic Behavior and Control Harbin Institute of Technology Ministry of Education Heilongjiang Harbin 150090 China School of Civil Engineering Harbin Institute of Technology Heilongjiang Harbin 150090 China

ISBN: (纸本)9783038351641

Temporary grandstands bear crowd load, which is created when spectators jumping on the structure. The simplified loads applied to temporary grandstand have been obtained based on experiment data of human body jumping forces. By the ABAQUS software, the parametric and automatic modeling of three-dimensional (3D) temporary grandstand structures has been realized with Python scripting. The linear buckling analysis and nonlinear buckling analysis of the structure have been carried out. The ultimate bearing capacity and the structural deformation under crowd load have been acquired. Results show that the nonlinear effect of the structure under crowd load is very obvious;the linear buckling analysis cannot get the ultimate bearing capacity of the structure and the first order buckling mode cannot simulate the final deformation of the structure either. The research of this paper greatly improve the efficiency of the construction and automation design of temporary structures and reveal the mechanical behavior of such structure to a certain degree. © (2014) Trans Tech Publications, Switzerland.

关键词： Python

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FEA on mechanical behavior of axially restrained concrete-filled steel tubular columns subjected to fire

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Jianzhu Jiegou Xuebao/Journal of Building structures 2015年 36卷 310-317页

作者： Liu, Faqi Pan, Yanchong Yang, Hua Key Lab of Structures Dynamic Behavior and Control of China Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China Tianjin Fire Research Institute of the Ministry of Public Security Tianjin300381 China

The internal force and the deformation of the column exposed to fire in structure change due to the restraint provided by adjacent members, which may affect the fire resistance. However, most of previous studies focused on the fire performance of individual concrete-filled steel tubular (CFST) column, without considering the structural interactions between the column and its adjacent members. A finite element model of axially restrained circular CFST column was developed with ABAQUS to analyze the influence of axial restraint on the axial force, axial displacement and fire resistance. It is found that axial restraint has significant influence on the axial force, which intensifies the axial force during the expansion period and relieves the axial force during the contraction period. The axial displacement decreases correspondingly, which enhances the fire resistance. The influences of parameters on the fire resistance of axially restrained columns were studied, including cross-sectional dimension, load ratio, slenderness ratio and load eccentricity ratio. The results show that the fire resistance can be increased by 10% to 40% for columns with the axial restraint stiffness ratio of 0.02 and slenderness ratio less than 30, and the beneficial effect on the fire resistance can be considered. The higher fire resistance can be attained with larger cross-sectional dimension, smaller load ratio and smaller slenderness ratio for both axially restrained and unrestrained columns. Different from members without axial restraint, the load eccentricity ratio has noticeable influence on the fire resistance of restrained columns. ©, 2015, Science Press. All right reserved.

关键词： Finite element method

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Strategic positioning of FRP anchors in frpstrengthened slabs 7

Strategic positioning of FRP anchors in frpstrengthened slab...

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7th International Conference on FRP Composites in Civil Engineering, CICE 2014

作者： Zhang, Huawen Smith, Scott T. Wang, Zhenyu Southern Cross University Australia Department of Engineering Southern Cross University Australia Key Lab of Structures Dynamic Behavior and Control Ministry of Education China School of Civil Engineering Harbin Institute of Technology Heilongjiang Harbin150090 China

ISBN: (纸本)9781771363082

A common problem associated with the strengthening of reinforced concrete (RC) structures with externally bonded fibre-reinforced polymer (FRP) composites is the ability of the FRP to prematurely debond. The installation of anchorage devices is an intuitive and logical means with which to enhance the debonding resistance of such strengthening systems, however, there are limited comprehensive experimental studies to date. Anchors may also enhance the ductility of the strengthened member although experimental studies are particularly limited that investigate this phenomenon. This paper reports the results of seven reinforced concrete (RC) slab tests of which six slabs were strengthened in flexure with FRP plates. Five of the strengthened slabs were anchored with FRP anchors of different positioning and geometry. Depending on their position of installation, anchors are shown to enhance either the strength alone or both the strength and ductility of the FRP-strengthened slabs.

关键词： Anchors

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Establishment of frost resistance model for autoclaved fly ash bricks

Establishment of frost resistance model for autoclaved fly a...

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The 2014 IMSS International Conference on Future Manufacturing Engineering(ICFME 2014)

作者： Shuang Lu Zheng Wang Key Laboratory of Structures Dynamic Behavior and Control Ministry of EducationHarbin Institute of Technology

In cold area,the freeze-thaw cycling durability of building materials is one of the primary influence *** paper studied on the loss ratio of the relative dynamic elastic modulus of the autoclaved fly ash bricks,which is according to the ultrasonic speed after suffering different freeze-thaw *** that,the corresponding numerical model has been established *** results indicate that the calculated results by the model can fit with the experimental data very ***,the model can be applied to predict the service life by using environment parameters as the factors in the model.

关键词： fly ash brick freeze-thaw cycling model dynamic elastic modulus durability

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Hysteretic phase transition sequence in 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3 single crystal driven by electric field and temperature

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Physical Review B 2015年第18期91卷 184105-184105页

作者： Limei Zheng Xiaoyan Lu Hengshan Shang Zengzhe Xi Ruixue Wang Junjun Wang Peng Zheng Wenwu Cao Condensed Matter Science and Technology Institute Harbin Institute of Technology Harbin 150080 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin 150001 China Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices School of Materials and Chemical Engineering Xi'an Technological University Xi'an 710032 China College of Electronics and Information Hangzhou Dianzi University Hangzhou 310018 China Department of Mathematics and Materials Research Institute Pennsylvania State University University Park Pennsylvania 16802 USA

Domain pattern variations with temperature were studied by polarizing light microscopy for the morphotropic phase boundary composition 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3 (PMN-0.33PT) single crystal. At room temperature, the monoclinic MA phase is the dominant phase in the unpoled crystal, which coexists with a small fraction of the tetragonal (T) phase. The orientation of spontaneous polarization was calculated to be ∼4.8∘ away from the pseudocubic 〈111〉C in the {001}C plane family. Under an electric field of 6 kV/cm along [011]C, a single domain orthorhombic (O) phase was induced but partially switched back to MA a few hours after the removal of the E field. It was found that the temperature induced phase transition sequence of the [011]C poled PMN-0.33PT single crystal is strongly hysteretic. On heating, the phase transition sequence is as follows: coexistence of O phase and MA→rhombohedral→monoclinicMC→cubic(C). On cooling, the phase transition sequence is given by C→T→MA. The complete set of dielectric, piezoelectric, and elastic constants for the [011]C poled PMN-0.33PT single crystal was measured, which showed the strong feature of the single domain O phase with high shear (d15=2321pC/N,d24=1941pC/N) and low longitudinal piezoelectric coefficients (d33=165pC/N).

关键词： SINGLE crystals ELECTRIC fields TEMPERATURE POLARIZATION (Electricity) PIEZOELECTRIC devices

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Analysis on dynamic response of quadrangular pyramid grid structure with supporting columns

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Tumu Gongcheng Xuebao/China Civil Engineering Journal 2014年第12期47卷 9-15页

作者： Sun, Menghan Fan, Feng Zhi, Xudong Kong, Dewen Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

In recent years, destructive earthquakes, such as the Wenchuan earthquake and the Lushan earthquake, have caused buckling of supporting members in large space grid structures and certain damages of bracing members, which attracted intense attentions of scholars to its failure mechanism. As a result, the conventional analyzing method, which only considers the characteristics of upper structure, and ignores the coupling effect between the supporting members and the upper structure, is reviewed. In this study, the grid structures with supporting columns are analyzed. With the regularly and obliquely placed quadrangular pyramid grid structures taken as the example, the seismic performances of grid structures with supporting columns of different stiffness are compared. In addition, the influence of site type on this kind of grid structure is evaluated. Consequently, the specific influence ranges from the varied stiffness on the grid structure under the impact of horizontal and vertical response spectrum are provided. Furthermore, the preliminary aseismic design methods are proposed for the two common types of grid structures.

关键词： Stiffness

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Probabilistic Seismic Safety Assessment of Chinese RC Frame structures Using Fragility Curves 2

Probabilistic Seismic Safety Assessment of Chinese RC Frame ...

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2nd International Conference on Vulnerability and Risk Analysis and Management, ICVRAM 2014 and the 6th International Symposium on Uncertainty Modeling and Analysis, ISUMA 2014

作者： Yu, Xiaohui Lu, Dagang Key Lab of Structures Dynamic Behavior and Control Harbin Institute of Technology Ministry of Education P.O. Box 2546 Harbin150090 China School of Civil Engineering Harbin Institute of Technology P.O. Box 2546 Harbin150090 China

ISBN: (纸本)9780784413609

A simulation-based procedure was adopted to generate fragility curves for five Chinese code-conforming reinforced concrete (RC) frame structures with increasing design-based earthquake (DBE) intensities. Two important elements, namely probabilistic seismic demand analysis (PSDA) and probabilistic seismic capacity analysis (PSCA), were involved in the procedure. In PSDA, 100 real ground motion records were selected to perform nonlinear time history analyses for representing the influence of earthquake uncertainties on structural demands. In PSCA, a group of ten structural parameters were considered as random, and then the conventional (deterministic) pushover analysis was extended by introducing 100 building samples according to the principle of the Latin hypercube sampling technique. From the derived pushover curves, the thresholds corresponding to the limit states -namely, "slight damage", "moderate damage", "extensive damage" and "complete damage" -were obtained for statistics. Finally, fragility curves were generated through combining the results of PSDA and PSCA, and the exceeding probabilities of the example frames conditioned on the three mostly concerned earthquake levels, i.e. frequent earthquake (FE), DBE and maximum considered earthquake (MCE), were consequently calculated. The results show that the increase of fortification earthquake intensity cannot correspondingly promote the probabilistic safety level. © 2014 American Society of Civil Engineers.

关键词： Uncertainty analysis

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