首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
The secondary moment of prestressed concrete frame is different from that of continuous beam. In this paper,the principle and calculation method of equivalent load secondary moment and axial secondary moment are discussed,and the infection of secondary moment in moment modulation is analyzed,together with the suggestions of moment modulation for prestressed concrete frame with adopting the total control. The suggestions would be able to distinguish the advantageous and disadvantageous effect of secondary moment. Some helpful advises for moment modulation design are given in this paper.  相似文献   

2.
Based on the experimental study of two prestressed frames in redistribution of Internal force, it can be concluded that the dominating influence factors on moment modulation are the relative height of equivalent compression zone, the secondary moment, the ratio of beam rigidity to column and development of cracks in the top of columns.The secondary moment is very important in modulation of frames. Especially, the secondary moment will governing the modulation when the relative height of equivalent compression zone is large enough.  相似文献   

3.
In this paper, comparing the bending-twisting model with the tension-bending one, the critical moment of the thin-walled beams under unequal end moment is derived easily by the improved CDC (column deflection curve) method based on the increment interaction equations of beam-columns.A simplified formula is presented and the calculated results show a good agreement with the numerical ones.  相似文献   

4.
The moment modulation of prestressed concrete frame has some differences compared with that of continuous beam.Based on the analysis of ratio of column linear rigidity to beam one,form of load,second moment and plastic hinge in column,this paper is intended to get some helpful advise for moment modulation design.  相似文献   

5.
《保鲜与加工》2003,(11):117-120
Axial compress is produced by the tension of prestressing beam, which engenders the third moment of column. And the third moment is always ignored in design. The thesis analyses elementarily the third moment of column and finds that the third moment must be taken seriously in some condition, and it is not the same value as the manner of tensions is different . As a result, some helpful conclusion and suggestion are presented.  相似文献   

6.
Based on the information from China and overseas,a design suggestion for moment modulation of post-tensioned prestressed concrete continuous beams with bond has been put forth in this paper. The result calculated by the suggestion is consistent with the result of varying rigidity method.  相似文献   

7.
The energy-momentum tensor of electromagnetic field outside the neutron star with magnetic moment is cal-cuated based on the metric tensor and 4-dimmensioal potential outside the spherical symmetric mass with magnetic moment. The numerical calculation and the distributed curve indicate that the electromagnetic energy of the magnetic-dipole will be greater in curved space-time than in Minkowski space-time.  相似文献   

8.
9.
Adhesive anchors are widely used as post-installed fasteners in civil engineering. A typical steel-to-concrete connection includes multiple anchors which are commonly subjected to combined moment and shear loading. Based on the assumption that all anchors take up shear load, a revised method is developed for the design of ductile anchors, which considers that only the row of most stressed anchors in the tension zone are needed to meet the elliptical interaction of tension and shear capacity requirement during the design process of anchorage group under combined shear and moment loading. The ultimate strength of post-installed fastenings should be controlled by the strength of anchor steel for the purpose of connection safety and full utilization of anchor capacity. For the objective of ductile design in anchor group, the ratio of shear span could be used as an evaluation parameter in the process of strength prediction. According to the theoretical analysis and results comparison, the ductile failure of anchor steel in post-installed fastenings can be guaranteed when the ratio of shear span is greater than 0.6 and other anchorage requirement is met. In the end, design proposals and construction specification of anchor group are given for practice.  相似文献   

10.
The models,principle,deducing constitutive equation by means of variational method,and general solution are researched for bi moment in anisotropic spacial rod with opening thin walled seation.  相似文献   

11.
The stability behavior of shuttle-shaped steel lattice columns subject to combined axial force and bending moment was examined through elastic buckling analysis and geometrically and materially nonlinear analysis. Firstly, the concept of section stiffness variation ratio is proposed for shuttle-shaped lattice columns and the elastic buckling behavior is discussed. Then, the effect of bending moment on the stability behavior of lattice columns is investigated, with the emphasis on the development of axial stress, bending stress and shear stress. The influence of column component spacing and diaphragm thickness on the stability bearing capacity is also analyzed. It is shown that the elastic buckling mode of the lattice column is dependent on its section stiffness variation ratio; for lattice columns with C-shaped buckling mode, the reduction in stability bearing capacity caused by bending moment is smaller than that of columns with S-shaped buckling mode; the maximum stability bearing capacity of the lattice column can be achieved by adjusting the column component spacing, and the spacing corresponding to the maximum capacity is basically consistent with the critical spacing for transformation of C-shaped buckling mode and S-shaped mode; and it is more effective to increase the thickness of columns with S-shaped buckling mode to get larger bearing capacity.  相似文献   

12.
13.
在工程实践中,直墙拱应用较多。由于拱脚位移的存在,合理假设拱脚约束为转角约束、竖向约束和水平弹性约束,应用力法推导出了在弯矩、剪力和轴力共同作用下直墙拱沿弧长的弯矩公式。研究了竖向均布荷载、竖向三角形荷载和竖向集中力荷载作用下,直墙拱沿弧长的弯矩分布及反弯点形成的规律;发现在3种荷载作用下,使得拱脚弯矩为零时的圆心角依次减小。取弹簧支座刚度为等效的下端固支、上端允许水平位移的直墙的抗推刚度,得出了随着直墙高度增加,圆弧拱拱顶弯矩增大而拱脚弯矩减小的变化规律。在直墙拱的设计中,建议选取合适的直墙高度和使得圆弧拱拱脚弯矩为零的圆心角大小,从而有利于提高结构抗弯承载力及拱脚抗剪承载力。  相似文献   

14.
This paper presents a hybrid method of the Finite-Difference Time-Domain(FDTD) and the method of moment(MoM) to compute the radiation from the aperture.The FDTD is a commonly used electromagnetic simulation way.It can solve the question with complex dielectric,but it is difficult(even cannot) for FDTD to calculate the far field because of large compute time and computer memory.So the authors can make use of the FDTD to get a large number of near electric field intensity,and then use the MoM,which based on electric field integral equation to compute the far field.Using this procedure,the authors solve the radiation of the box with apertures on one or more sides and reduced the compute time and the computer memory.  相似文献   

15.
Most real power systems are not radial networks and evaluation of the stability often needs to establish electromagnetic transient simulation models. So the network equivalent is required first and foremost. The adjacent two-node equivalent method, which considers the coupling impedance between equivalent nodes, is used to realize the simplification and modeling to complex power grid. The analysis and simulation on both the HVDC system from Deyang to Baoji and a real extra-high voltage AC transmission system in South China shows that the static performance of the simulated system by using the adjacent two-node equivalent method is completely equivalent to the original one, as well as the performance of dynamic equivalent is in a satisfied level. Thus the transient system model simplified can be well established to support research of power grid’s security and stability.  相似文献   

16.
Through the analysis in this paper,the optimum relation of the discharging current peak interval t m ,the discharging loop equivalent inductance L and equivalent resistance R is obtained.This paper analyze the original discharging loop equivalent inductance L ,which provides an effective method for adjustment and selection of inductance L to realize the optimization energy saving design of the welding machine.  相似文献   

17.
In this paper,a new method with general purpose ispresented for balancing the shaking moment of articulated multi-barlinkage.The concept of this method is clear.The moment equation oflinkages is easy to establish and solve.Furthermore its pattern structuremakes it convenient to be programmed.  相似文献   

18.
Based on the actual situation that there is shortage of water,existence of many dry ditches,over-use of the underground water and the water pollution in the downtown of Jiaozuo city,in this paper,with comprehensive application of the multi-eco technologies such as comprehensive water-handlings and artificial wetland water purifications,the preservative strategies for the surface water and underground water together are put forward to optimize the water cycling,which can on the one hand reduce the contradictories in the water surroundings of the downtown,and on the other hand improve the landscape of dry ditches and sunk areas.  相似文献   

19.
In the minimum electromagnetism coupling model of interaction between photon and electron(antielectron),Feynman convergence integral method is often used to deal with the finite quantity of one-loop correction scheme.After analyzing,discussing and researching the method,a new method is found.That is the great moment integral limitation method.Through the method,the relative result is obtained.  相似文献   

20.
By using the Lorentz invariable coupling model of interaction between neutral meson and nucleon (antinucleon), Feynman convergence integral method is often used to deal with the finite quantity of one-loop correction scheme. On the basis of analyzing, discussing and researching the method, a new method is found. That is the large momentum integral limitation method. With the effective method, we obtain the integral convergence formulation for the finite quantity, by deducting-dimensionally calculating the finite quantity gained after renormalizing the meson loop propagator.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号