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Internal Force Distribution in Steel-Concrete Composite Structure for Pylon of Cable-Stayed Bridge 被引量:5
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作者 蒲黔辉 白光亮 《Journal of Southwest Jiaotong University(English Edition)》 2009年第2期95-101,共7页
Adopting a steel-anchor beam and steel corbel composite structure in the anchor zone on pylon is one of the key techniques for the design of Jintang bridge, a cable-stayed bridge in Zhoushan, China. In order to ensure... Adopting a steel-anchor beam and steel corbel composite structure in the anchor zone on pylon is one of the key techniques for the design of Jintang bridge, a cable-stayed bridge in Zhoushan, China. In order to ensure the safety of the steel-concrete composite structure, a stud connector model for the joint section was put forward. Experiments were conducted to obtain the relation between load and slip of specimen, the failure pattern of stud connector, the yield bearing capacity and ultimate bearing capacity of a single stud, etc. The whole process of the structural behavior of the specimen was comprehensively analyzed. The features of the internal force distribution in the steel-concrete composite structure and the strain distribution of stud connector under different loads were emphatically studied. The test results show that the stud connector is applicable for the steel-concrete composite structure for pylon of Jintang bridge. The stud has a good ductility performance and a obvious yield process before its destruction. The stud connector basically works in a state of elasticity under a load less than the yield load. 展开更多
关键词 Stud connector Experimental research Steel-concrete composite structure Cable-stayed bridge internal force distribution
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Internal Force Analysis Due to the Supporting Translation in Statically (Indeterminate) Structures for Different Elastic Modulus 被引量:1
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作者 姚文娟 叶志明 《Journal of Shanghai University(English Edition)》 CAS 2004年第3期274-280,共7页
For statically indeterminate structure, the internal force will be changed with the translation of the supports, because the internal force is related to the absolute value of the stiffness EI. When the tension is dif... For statically indeterminate structure, the internal force will be changed with the translation of the supports, because the internal force is related to the absolute value of the stiffness EI. When the tension is different with the compression modulus, EI is the function of internal force and is not constant any more that is different from classic mechanics. In the other words, it is a nonlinear problem to calculate the internal force. The expression for neutral axis of the statically indeterminate structure was derived in the paper. The iterative program for nonlinear internal force was compiled. One case study was presented to illustrate the difference between the results using the different modulus theory and the single modulus theory as in classical mechanics. Finally, some reasonable suggestions were made for the different modulus structures. 展开更多
关键词 different moduli in tension and compression statically indeterminate structure translation of support nonlinear internal force iteration.
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Calculation and Analysis of Internal Force in Arch Structure of Frozen Soil
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作者 YUE Feng-tian ZHANG Yong SHI Rong-jian 《Journal of China University of Mining and Technology》 EI 2005年第4期279-282,共4页
Aimed at the frozen soil arch reinforcement form of upside shed used for the shield machine launching in tunneling the internal force of the structure was calculated with the aid of the structural mechanics theory. Co... Aimed at the frozen soil arch reinforcement form of upside shed used for the shield machine launching in tunneling the internal force of the structure was calculated with the aid of the structural mechanics theory. Considering the space characteristics of the structure, this calculating method is suitable for practical engineering. Moreover, the behavior of the freezing arch reinforcement structure was analyzed combined with an engineering case. 展开更多
关键词 shield machine launching freezing reinforcement arch structure internal force
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New Insights on the Deflection and Internal Forces of a Bending Nanobeam
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作者 De-Min Zhao Jian-Lin Liu 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第9期74-77,共4页
Nanowires, nanofibers and nanotubes have been widely used as the building blocks in micro/nano-electromechanical systems, energy harvesting or storage devices, and small-scaled measurement equipment. We report that th... Nanowires, nanofibers and nanotubes have been widely used as the building blocks in micro/nano-electromechanical systems, energy harvesting or storage devices, and small-scaled measurement equipment. We report that the sur- face effects of these nanobeams have a great impact on their deflection and internal forces. A simply supported nanobeam is taken as an example. For the displacement and shear force of the nanobeam, its dangerous sections are different from those predicted by the conventional beam theory, but for the bending moment, the dangerous section is the same. Moreover, the values of these three quantities for the nanobeam are all distinct from those calculated from the conventional beam model. These analyses shed new light on the stiffness and strength check of nanobeams, which are beneficial to engineer new-types of nano-materials and nano-devices. 展开更多
关键词 New Insights on the Deflection and internal forces of a Bending Nanobeam
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AN ANALYTICAL METHOD FOR SOLVING INTERNAL FORCES AND DEFORMATIONS OF BAR-SYSTEM STRUCTURE IN SPACE
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作者 袁发荣 陈雪峰 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1989年第7期623-630,共8页
In this paper, based on the idea of finite element method, the initial parametric method in bending, problem of a beam is extended to analyse the bar-system structure by employing Dirac function and llcavisidc step fu... In this paper, based on the idea of finite element method, the initial parametric method in bending, problem of a beam is extended to analyse the bar-system structure by employing Dirac function and llcavisidc step function.Then a new method for analysing the internal forces and deformations of bar-system structure in space is suggested by improving the mixed method in statically indeterminate structure.The inferred process and obtained answer will be more succinct and accurate when the problem of internal forces and deformations of bar-system structure is analysed by using the new method provided in this paper. 展开更多
关键词 AN ANALYTICAL METHOD FOR SOLVING internal forceS AND DEFORMATIONS OF BAR-SYSTEM STRUCTURE IN SPACE
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Hybrid method of limit equilibrium and finite element internal force for analysis of arch dam stability against sliding 被引量:6
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作者 BAO TengFei1,2,3,XU BaoSong1,2,3 & ZHENG XueQing1,2,3 1State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China 2National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety,Nanjing 210098,China 3College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第4期793-798,共6页
A hybrid method of limit equilibrium and finite element internal force for analysis of arch dam stability against sliding is presented.The finite element internal force method(FEIFM) is used to provide more accurate t... A hybrid method of limit equilibrium and finite element internal force for analysis of arch dam stability against sliding is presented.The finite element internal force method(FEIFM) is used to provide more accurate thrust forces acting on the faces of a slip body,and the limit equilibrium method(LEM) is employed to evaluate the factor of safety of the slip body.The method presented can deal with a slip body with large amount of geometrically complex slip faces.In addition,compared with the traditional LEM,it can meet the balance condition of the forces in the slip faces.An example shows that the factor of safety obtained by the method presented agrees well with the theoretical solution.A practical example is also presented to demonstrate the application of the method in the stability analysis of an arch dam project.The results from the examples show that the method is promising in analysis of arch dam stability against sliding. 展开更多
关键词 arch dam stability against sliding limit equilibrium method finite element internal force method
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An Estimation of Internal Soliton Forces on a Pile in the Ocean 被引量:13
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作者 DU Tao SUN Li +2 位作者 ZHANG Yijun BAO Xianwen FANG Xinhua 《Journal of Ocean University of China》 SCIE CAS 2007年第2期101-106,共6页
Internal soliton forces on oil-platform piles in the ocean are estimated with the Morison Formula. Different from sur- face wave forces, which change only in magnitude along a pile, internal soliton forces can be dist... Internal soliton forces on oil-platform piles in the ocean are estimated with the Morison Formula. Different from sur- face wave forces, which change only in magnitude along a pile, internal soliton forces can be distributed over the entire pile in the water and they change not only in magnitude but also in direction with depth. Our calculations show that the maximum total force caused by a soliton with its associated current of 2.1 m s-1 is nearly equal to the maximum total force exerted by a surface wave with a wavelength of 300 m and a wave-height of 18 m. The total internal soliton force is large enough to affect the operations of marine oil platforms and other facilities. Therefore, the influence of internal solitons should not be neglected in the design of oil platforms. 展开更多
关键词 oceanic internal wave internal soliton internal soliton force ocean oil platform
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Electro-elastic Fields of Piezoelectric Materials with An Elliptic Hole under Uniform Internal Shearing Forces 被引量:6
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作者 DU Yanliang LIU Shuhong +1 位作者 DUAN Shijie LI Yanqiang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第3期454-461,共8页
The existing investigations on piezoelectric materials containing an elliptic hole mainly focus on remote uniform tensile loads. In order to have a better understanding of the fracture behavior of piezoelectric materi... The existing investigations on piezoelectric materials containing an elliptic hole mainly focus on remote uniform tensile loads. In order to have a better understanding of the fracture behavior of piezoelectric materials under different loading conditions, theoretical and numerical solutions are presented for an elliptic hole in transversely isotropic piezoelectric materials subjected to uniform internal shearing forces based on the complex potential approach. By solving ten variable linear equations, the analytical solutions inside and outside the hole satisfying the permeable electric boundary conditions are obtained. Taking PZT-4 ceramic into consideration, numerical results of electro-elastic fields along the edge of the hole and axes, and the electric displacements in the hole are presented. Comparison with stresses in transverse isotropic elastic materials shows that the hoop stress at the ends of major axis in two kinds of material equals zero for the various ratios of major to minor axis lengths; If the ratio is greater than 1, the hoop stress in piezoelectric materials is smaller than that in elastic materials, and if the ratio is smaller than 1, the hoop stress in piezoelectric materials is greater than that in elastic materials; When it is a circle hole, the shearing stress in two materials along axes is the same. The distribution of electric displacement components shows that the vertical electric displacement in the hole and along axes in the material is always zero though under the permeable electric boundary condition; The horizontal and vertical electric displacement components along the edge of the hole are symmetrical and antisymmetrical about horizontal axis, respectively. The stress and electric displacement distribution tends to zero at distances far from the elliptical hole, which conforms to the conclusion usually made on the basis of Saint-Venant’s principle. Unlike the existing work, uniform shearing forces acting on the edge of the hole, and the distribution of electro-elastic fields inside and outside the elliptic hole are considered. 展开更多
关键词 piezoelectric material elliptic hole permeable boundary condition electro-elastic fields internal shearing forces
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Analysis and Calibration of Internal Flow Force of EjectorPowered Engine Simulator System in Wind Tunnels
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作者 TANG Wei WU Chaojun HU Buyuan 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2019年第5期747-759,共13页
The ejector-powered engine simulator(EPES)system is an important piece of equipment in conducting an influence test of the intake and jet flow in low-speed wind tunnels.In this work,through the analysis of the structu... The ejector-powered engine simulator(EPES)system is an important piece of equipment in conducting an influence test of the intake and jet flow in low-speed wind tunnels.In this work,through the analysis of the structure and principle of EPES,three parts of the internal flow force were obtained,namely,the additional resistance before the inlet,the internal flow force in the inlet and the thrust produced by the ejector.On the assumption of one-dimensional isentropic adiabatic flow,the theoretical formulae for calculating the forces were derived according to the measured total pressure,static pressure and total temperature of the internal flow section.Subsequently,a calibration tank was used to calibrate the EPES system.On the basis of the characteristics of the EPES system,the process and method of its calibration were designed in detail,and the model installation interface of the calibration tank was reformed.By applying this method,the repeatability accuracy of the inlet flow rate calibration coefficient was less than0.05%,whereas that of the exhaust flow rate and velocity was less than 0.1%.Upon the application of the calibration coefficients to the correction of the wind tunnel experiment data,the results showed good agreement with the numerical simulation results in terms of regularity and magnitude before stall,which validates the reasonableness and feasibility of the calibration method.Analysis of the calibration data also demonstrated the consistency in the variation law and trend between the theoretical calculation and actual measurement of internal flow force,further reflecting the rationality and feasibility of the theoretical calculation.Nevertheless,the numerical difference was large and further widened with a higher ejection flow rate mainly because of the accuracy of flow measurement and the inhomogeneity of internal flow.The thrust deflection angle of EPES is an important factor in correcting this issue.In particular,the thrust deflection angle becomes larger with small ejection flow and becomes smaller with an increase in flow rate,essentially exhibiting a general change of less than 10°. 展开更多
关键词 low-speed wind tunnel ejectorpowered engine simulator calibration tank internal flow force INLET JET
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Study on the tunnel shape and soil-lining interaction influencing the lining behavior under seismic loading
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作者 Van Vi Pham Ngoc Anh Do +2 位作者 Piotr Osinski Ngoc Thai Do Daniel Dias 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第4期845-862,共18页
The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil properties.The individual behavior of circular,r... The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil properties.The individual behavior of circular,rectangular,and sub-rectangular tunnels subjected to seismic loadings has already been studied in the literature.In the present research,two case scenarios of circular,rectangular tunnels and four sub-rectangular shaped tunnels,with similar cross-section areas,were adopted to perform a comprehensive numerical investigation.The purpose of the study was to determine the mechanical behavior of tunnels of different shapes,depending upon seismic conditions.Analyses were performed by considering the influence of soil-lining interaction,soil parameters,and lining thickness,as well as lining rigidity.Computations were performed for no-slip and full-slip conditions.The results indicate that the tunnel shape design is of great importance when regarding the mechanical behavior of the surrounding soil.This concerns no-slip as well as full-slip soil-lining interaction,especially when the lining is subjected to seismic loading.Moreover,it is shown that changes in incremental bending moments for circular,rectangular and sub-rectangular tunnels that depend upon the soil-lining interaction conditions differ significantly. 展开更多
关键词 tunnel shape soil-lining interaction seismic loading internal forces numerical analysis
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Study on the Distribution Law of Horizontal Seismic Forces between Slab-Column and Shear Wall
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作者 GUO Nan GUO Yihong YANG Yingwei 《沈阳建筑大学学报(自然科学版)》 CAS 北大核心 2012年第3期443-448,共6页
In slab column-shear wall structures,both the whole structure′s seismic behavior and failure mode are greatly influenced by the distribution of horizontal seismic forces between slab-column and shear wall.In this pap... In slab column-shear wall structures,both the whole structure′s seismic behavior and failure mode are greatly influenced by the distribution of horizontal seismic forces between slab-column and shear wall.In this paper,a pushover analysis of topical slab column-shear wall structure was carried out,the seismic shear force that the slab-column and shear wall should undertake was worked out,the influences of plastic internal force redistribution and structure stiffness characteristic value on horizontal seismic distribution were studied and the calculation formula was given.The analysis results showed that with the yield of the shear walls,the story shear force was undertaken by slab-columns correspondingly increased while with the decrease of characteristic value of stiffness of a structure,and the horizontal seismic force was undertaken by slab-columns correspondingly decreased.According to the code,the design of horizontal force distribution may be cause insecurity problems,so it is necessary to give the distribution law of horizontal seismic forces in slab-column shear wall structures as the supplement to the corresponding regulation of the Code. 展开更多
关键词 slab column-shear wall structure horizontal seismic force pushover analysis plastic internal force redistribution characteristic value of stiffness of structure
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DALAI'S VISIT TO TAIWAN:Further Proof That He Is the Tool Of International Anti-China Forces
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作者 BIENGYI 《China's Tibet》 1997年第3期5-9,共5页
关键词 DALAI’S VISIT TO TAIWAN:Further Proof That He Is the Tool Of International Anti-China forces
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Effects of connection types and elevated temperature on the impact behaviour of restrained beam in portal steel frame
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作者 Yu-Xu Guo Feng Xi +2 位作者 Ying-Hua Tan Feng Liu Ya-Chao Hu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第7期174-191,共18页
Based on the background of structural protection and Disaster Reduction Engineering, the dynamic behaviour and failure mechanism of restrained beams in portal steel frames in localised fire are investigated via experi... Based on the background of structural protection and Disaster Reduction Engineering, the dynamic behaviour and failure mechanism of restrained beams in portal steel frames in localised fire are investigated via experimental measurement and numerical simulation techniques. Comprehensive parametric studies are carried out to discuss the influence of end connection types, temperature, impact velocity,impact mass and span-to-depth ratio(SDR) on the dynamic response of the beams. The characteristics of deformation, internal force and energy distribution about the restrained beams and its joints are investigated. A temperature dependent criterion for evaluating the frame joint performance is proposed to measure the degree of performance degradation and impact resistance of the joint. The dynamic displacement amplification factor in different temperature environments are proposed for the different beam end constraint types and SDRs. Results of the experimental and numerical analysis show that the welded connection(WC) of three typical joint types is the strongest, and the extended endplate connection(EEC) is the weakest in terms of the impact resistance performance. With regard to the failure mode of the joint, the failure positions of the WC and the welded-bolted connection are located in the inner web of the column. Meanwhile, the EEC is located in the connection position between the beam and the endplate. Three different internal force stages and two obvious critical temperature boundaries of the restrained beams emerge with the increase in temperature, and they have significant characteristics in terms of deformation trend, internal force transfer and energy distribution. During the impact, a phenomenon known as “compression arch action” develops into “catenary action” with the increase in deflection in the frame beam mechanism. 展开更多
关键词 Restrained beam CONNECTION Temperature Impact Failure modes internal force mechanism
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Driving Force to Socialize the International Norms of Human Rights
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作者 LIU BO,a researcher at the Foreign Affairs Institute of the Beijing Academy of Social Sciences 《The Journal of Human Rights》 2011年第6期24-28,共5页
Human rights, as a great term and lofty goal, have unquestionably become a topic of mainstream talk in the present-day world.2 Such mainstream talk has been internal- ized into part of the social structure. The curren... Human rights, as a great term and lofty goal, have unquestionably become a topic of mainstream talk in the present-day world.2 Such mainstream talk has been internal- ized into part of the social structure. The current international society is experiencing a profound reorganization and transition in values. All kinds of new interactions under the context of globalization have resulted in the development of the current norms of international human rights, which are constructed on the basis of law and ethics. Therefore, analyzing the dynamic factors of socialization that support the operation of human rights norms in international society has become increasingly important in today's mutually dependent society. 展开更多
关键词 Driving force to Socialize the International Norms of Human Rights
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A case study on behaviors of composite soil nailed wall with bored piles in a deep excavation 被引量:7
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作者 ZHU Feng-bin MIAO Lin-chang +1 位作者 GU Huan-da CHENG Yue-hong 《Journal of Central South University》 SCIE EI CAS 2013年第7期2017-2024,共8页
A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed w... A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the constitutive relationship of the soil in the numerical simulation. Results from the numerical analysis are fitted well with the field data, which indicate that the research approach used is reliable. Based on the field data and numerical results of the deep excavation supported by four different patterns of the composite soil nailed wall, the significant corner effect is founded in the 3D deep excavation. If bored piles or soil anchors are considered in the composite soil nailed wall, they are beneficial to decreasing deformations and internal forces of bored piles, cement mixing piles, soil anchors, soil nailings and soil around the deep excavation. Besides, the effects due to bored piles are more significant than those deduced from soil anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation. 展开更多
关键词 deep excavation 3D non-linear finite element bored pile composite soil nailed wall corner effect DEFORMATION internal force
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Safety analysis of optimal outriggers location in high-rise building structures 被引量:3
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作者 ZHANG Jiet ZHANG Zhong-xian +2 位作者 ZHAO Wen-guang ZHU Hong-ping ZHOU Chun-sheng 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第2期264-269,共6页
This paper presents the restraining moments of outriggers acting on the core wall and the equation of the horizontal top deflection based on a simplified outrigger model. The deformation compatibility conditions betwe... This paper presents the restraining moments of outriggers acting on the core wall and the equation of the horizontal top deflection based on a simplified outrigger model. The deformation compatibility conditions between outriggers and core wall as well as the finite rigidities of outriggers are also considered. One case study was carried out to analyze the horizontal top deflection and the mutation of the restraining moments caused by the variation of outrigger location. The results showed that the method adopted in the paper is simple and reasonable. Some conclusions are valuable to the safety design of high-rise building structures. 展开更多
关键词 High-rise building Frame-core structure OUTRIGGER internal force mutation Horizontal top deflection Safety
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Study on Structure of Arched Longitudinal Beams of Deep-Water Wharf 被引量:3
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作者 翟秋 鲁子爱 张淑华 《China Ocean Engineering》 SCIE EI 2008年第4期705-711,共7页
High-pile and beam-slab quays have been widely used after several years development. They are mature enough to be one of the most important structural types of wharves in China coastal areas. In order to accommodate l... High-pile and beam-slab quays have been widely used after several years development. They are mature enough to be one of the most important structural types of wharves in China coastal areas. In order to accommodate large tonnage vessels, wharves should be eorrstructed in deep water gradually. However, conventional high-pile and beam-slab structares are hard to meet the requirements of large deep-water wharf. According to arch' s stress characteristics, a new type of wharf with catenary arched longitudinal beams is presented in this paper. The new wharf structure can make full use of arch's overhead crossing and reinforced concrete compression resistance, improve the interval between transverse bents greatly, and decrease underwater construction quantity. Thus, the construction cost cab be reduced. Take the third phase project of the Yangshan Deep-water Port for example, comparative analysis on catenary arched longitudinal beams and conventional longitudinal beams has been made. The result shows that with the same wharf length and width, the same loads and same longitudinal beam moment, catenary arch structure can improve the interval between bents up to 28 m, decrease the nmnber of piles and underwater construction quantity. 展开更多
关键词 WHARF structural type cateriary arch internal force COST
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Self-contained Capsubot Propulsion Mechanism 被引量:1
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作者 M.Nazmul Huda Samuel Oliver Wane 《International Journal of Automation and computing》 EI 2011年第3期348-356,共9页
In this paper, a self contained capsubot (capsule robot) propulsion mechanism is investigated. The proposed capsubot works on the principle of internal force-static friction. A modified linear DC motor is used to dr... In this paper, a self contained capsubot (capsule robot) propulsion mechanism is investigated. The proposed capsubot works on the principle of internal force-static friction. A modified linear DC motor is used to drive the capsubot. A novel acceleration profile is proposed for the moving part (linear cylinder) based on the principle. A significant feature of the proposed capsubot is that it is legless, wheelless, and trackless. The developed capsubot with a proposed propulsion mechanism demonstrates a very good average velocity. The propulsion mechanism has the potential to be used for the propulsion of a wireless-controlled self-propelling capsule endoscope. Simulation and experimental results demonstrate the performance of the self-contained capsubot with the proposed acceleration profile. 展开更多
关键词 Capsubot internal force and static friction linear DC motor PROPULSION capsule endoscopy.
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Seismic response of the long-span steel truss arch bridge with the thrust under multidimensional excitation 被引量:1
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作者 Yongliang Zhang Jibei Ma +1 位作者 Xingchong Chen Yun Wang 《Railway Sciences》 2022年第1期40-55,共16页
Purpose–Under different ground motion excitation modes,the spatial coupling effect of seismic response for the arch bridge with thrust,seismic weak parts and the internal force components of the control section of ma... Purpose–Under different ground motion excitation modes,the spatial coupling effect of seismic response for the arch bridge with thrust,seismic weak parts and the internal force components of the control section of main arch ribs are analyzed.Design/methodology/approach–Taking a 490 m deck type railway steel truss arch bridge as the background,the dynamic calculation model of the whole bridge was established by SAP2000 software.The seismic response analyses under one-,two-and three-dimension(1D,2D and 3D)uniform ground motion excitations were carried out.Findings–For the steel truss arch bridge composed of multiple arch ribs,any single direction ground motion excitation will cause large axial force in the chord of arch rib.The axial force caused by transverse and vertical ground motion excitation in the chord of arch crown area is 1.4–3.6 times of the corresponding axial force under longitudinal seismic excitation.The in-plane bending moment caused by the lower chord at the vault is 4.2–5.5 times of the corresponding bending moment under the longitudinal seismic excitation.For the bottom chord of arch rib,the arch foot is the weak part of earthquake resistance,but for the upper chord of arch rib,the arch foot,arch crown and the intersection of column and upper chord can all be the potential earthquake-resistant weak parts.The normal stress of the bottom chord of the arch rib under multidimensional excitation is mainly caused by the axial force,but the normal stress of the upper chord of the arch rib is caused by the axial force,in-plane and out of plane bending moment.Originality/value–The research provides specific suggestions for ground motion excitation mode and also provides reference information for the earthquake-resistant weak part and seismic design of long-span deck type railway steel truss arch bridges. 展开更多
关键词 Railway steel truss arch bridge Seismic response Multidimensional excitation Spatial coupling effect internal force component
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Quantifying the contribution of natural variability to September Arctic sea ice decline 被引量:1
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作者 SONG Mirong WEI Lixin WANG Zhenzhan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第5期49-53,共5页
Arctic sea ice extent has been declining in recent decades. There is ongoing debate on the contribution of natural internal variability to recent and future Arctic sea ice changes. In this study, we contrast the trend... Arctic sea ice extent has been declining in recent decades. There is ongoing debate on the contribution of natural internal variability to recent and future Arctic sea ice changes. In this study, we contrast the trends in the forced and unforced simulations of carefully selected global climate models with the extended observed Arctic sea ice records. The results suggest that the natural variability explains no more than 42.3% of the observed September sea ice extent trend during 35 a(1979–2013) satellite observations, which is comparable to the results of the observed sea ice record extended back to 1953(61 a, less than 48.5% natural variability). This reinforces the evidence that anthropogenic forcing plays a substantial role in the observed decline of September Arctic sea ice in recent decades. The magnitude of both positive and negative trends induced by the natural variability in the unforced simulations is slightly enlarged in the context of increasing greenhouse gases in the 21st century.However, the ratio between the realizations of positive and negative trends change has remained steady, which enforces the standpoint that external forcing will remain the principal determiner of the decreasing Arctic sea ice extent trend in the future. 展开更多
关键词 internal variability sea ice decline external forcing
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