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22 April 1991, Volume 10 Issue 2 Previous Issue    Next Issue

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Anti-Cracking Capacity of Inclined Section of Partially Prestressed Concrete Beams with Unbonded Tendons Zhou Zhixiang, Jiang Bingzhang 1991, 10(2): 1-5.  Abstract ( )   PDF (360KB) ( )   Oa the basis of the test results of 25 P. P. C, beams with. unbonded tendons, this paper investigates the influence of the degree of prestress, shear span-depth ratio and unbonded tendons on the anti-cracking capacity of inclined section of beams. A formula is put forward by the analysis of the theory and the study of the test. The formula coincides well with the test results. Related Articles | Metrics

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Some Notes of the Efficiency of Two-Stage Estimate Yang Hu 1991, 10(2): 6-9.  Abstract ( )   PDF (232KB) ( )   In this paper, we improve the results of[2] easily by a transformation and give lower limits which are more concise and stricter. The method is commonly practical, and the bounds of this paper can't be further improved in essence. Related Articles | Metrics

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Dynamic Analysis of Bridge-Vehicle System of Continuous Horizontally Curved Bridge Shan Chenglin, Wang Xiangjian 1991, 10(2): 10-18.  Abstract ( )   PDF (594KB) ( )   This paper presents a method to aralyzc the coupled vibrfticn of the bridge-vehicle system of continvous horizontaily curved bridges under the action of moving vehicles.The horizontally curved bridge is considered a multidegree-of-freedom system, using the element of horizontally curved beam and lumped-mass and taking into acecurt the effect of Rayleigh viscous-damping.The vehicle is modelled by two-deg ree-of-freedcm sprirg-mass system of twe-axle springing load, and the load- deformation relationship is represented by a bilinear diagram.This dynamic response of continuous horizontally curved bridges under the action of moving vehicles is studied with the method of numerical analysis.The effect of some varying parameters on the dynamic increment of deflection and moment of horizontally curved bridges is investigated.These parameters are vehicle speed,curvature radius,rigidity ratio,road surface roughness and frequency ratio.A computer program in Fortran has been written.The results of numerical computations conincide with those of single-span horizontally curved bridges of infinite degrees of freedom. Related Articles | Metrics

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Calculation of the Lateral Stability of Ribbed Arches with Transverse Bars Xiang Zhongfu, Gu Anbang 1991, 10(2): 19-24.  Abstract ( )   PDF (363KB) ( )   In this paper, an approximate analytical solution for lateral stability of ribbed arches is developed. The method is based on the energy approach. The effect of transverse bars is studied Related Articles | Metrics

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Viscoelastic Constitutive Equations of Damaged Fiber-Reinforced Plastics Tang Yu, Tang Guodong, Meng Yun 1991, 10(2): 25-32.  Abstract ( )   PDF (523KB) ( )   Based on the five-parameter model of the viscoclasticity of the matrix, the vis-coelastic constitutive equations of the damaged fiber-reinforced plastics are derived in this paper with the introduction of the interfacial damage variable. The effects of matrix viscoelasticity, fiber volume fraction and the interfacial bonding condition on the viscoelastic behavior of the composite are included in the above constitutive equations, by which the theoretical prediction to the creep behavior of the composite is presented. Comparison between the calculation values of the formula and the test results gives a good agreement. Related Articles | Metrics

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The Explicit Scheme of Newmark's integration Method for Large Structural Dynamic Analyses Zhai Wanming 1991, 10(2): 33-41.  Abstract ( )   PDF (606KB) ( )   Based on the Newmark's implicit integration algorithm which is well known and widely used in the domain of structural dynamic analyses,an explicit scheme, called the Newmark's Explicit Scheme, is constructed in this paper. Unlike existing explicit algorithms, the integration process of this scheme is extremely simple. No matter what form the damping matrix is, this scheme no longer need to solve high order algebraic linear equations in each integration step as long as the mass matrix is diagonal. Therefore, it is very convenient for this explicit method to analyse large nonlinear dynamic systems discretized by finite element methods. The computer-time efficiency will be much more enhanced.In this paper, the numerical stability and accuracy of the new scheme is discussed. Some linear and nonlinear numerical examples are used to compare this scheme with currently popular methods. Two problems of railway engineering are analysed at the end of the paper. Related Articles | Metrics

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Experimental Research on Prestressed Lapping Concrete Continuous Slabs Huang Jiawei, Jiang Debin 1991, 10(2): 42-50.  Abstract ( )   PDF (650KB) ( )   By means of comprehensive analysis of 15 test specimens of lapping concrete continuous slabs, this paper demonstrates that the strength, stiffness and anti-cra-king capability of those slabs meet the requirements of design and application. With its bonding course artificially caved and structurally reinforced, the slab with a width of 500mm has been used in high-rise dwelling buildings. It is recommended that the prestressed lapping concrete continuous slab be worth extending to use because of its good result. Related Articles | Metrics

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Kuhn-Tucker Sufficient Conditions for Nondifferentiable Programming Yang Xinmin 1991, 10(2): 51-58.  Abstract ( )   PDF (447KB) ( )   Concepts of generalized strict pseudoconvexity, generalized quasiconvexity and generalized weak quasiconvexity are introduced; Properties and relations between these generalized convex functions are investigated, and Kuhn-Tucker sufficient conditions are proven for nondifferentiable programming under some weaker conditions. Related Articles | Metrics

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A Convex Structure of Abstract Metric Spaces and Its Fixed Points Zheng Quan, Ding Zuohua 1991, 10(2): 59-62.  Abstract ( )   PDF (276KB) ( )   Our purpose is to introduce the concept of a convex structure of abstract metric spaces, by virtue of which we prove the following fixed point theorem for nonex-pansive mappings.Theorem. Let (X,r) be a complete convex abstract metric spaces. Let K⊂X be a bounded closed star shaped set, xa be its center, satisfying r((WA(x,x0),(WA,(y,x0))≤AR(x,y),∀x,y∈K.where WA is the convex structure of X, and A, which satisfies some conditions, is a mapping in a partially ordered space. Suppose further that mapping f:K-K is (WA, x0) convex, m is a positive integral number such that fm is compact on {WA(x,x0;x∈f(K)) and r(fx,fy)≤r(x,y) for x,y∈K. Then f has a fixed point in K. Related Articles | Metrics

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An Effective Parallel Algorithm of Structural Eigenvalue Problem Hu Ning 1991, 10(2): 63-68.  Abstract ( )   PDF (424KB) ( )   In this paper, a parallel algorithm of structural natural frequencies and vibrating modes is presented by using the polynomial secant iterative method and inverse power method. The method first utilizes the polynomial secant iterative method to determine the approximate value of every eigenvalue and introduces the parallel step. Then these eigenvalues are classified into N regions(N is the number of CPU). The shift parameters are taken as the central values of these regions. Finally, the inverse power method is used to get the exact eigenvalues and eigenvectors in the neighborhood of shift parameters concurrently in every CPU by introducing every shift parameter. The program of these algorithm has been realized on the ELXSI-6400 parallel computer of Xian Jiaotong University. The computational results show the CPU times can be saved effectively, and the algorithm is effective in the dynamic analysis of larg-scale engineering structures. Related Articles | Metrics

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Back-Calculating Elastic Moduli of Multilayer Pavement by Measured Displacements with Damped Least Square Method Wang Kai, Fan Jianhua 1991, 10(2): 69-78.  Abstract ( )   PDF (648KB) ( )   This paper selves the problem of back-calculatirg the elastic modulus of every layer of multilayer pavement by meastred displacements with damped least square method winch is are cf morlinear numeal analystis methcds and the corresponding program is worked out in Fortran 77. Related Articles | Metrics

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Study on Impulsive Pressure Properties of Wave on Water-Proof Slope Surface Huang Bishan 1991, 10(2): 84-93.  Abstract ( )   PDF (601KB) ( )   Based on data of laboratory tests, this paper states impulsive case of wave on the condition of different wave smoothness 10≤L/H≤20and different slope (2≤m≤5), and approaches the influence of wave smoothness and slope on impulse pressure of water. Experimental results are compared with those of CHHI Ⅱ-57-76 and IIIa-HKuH.The water depth of maximum inpulsive pressure located in, the range of maximum impulsive pressure exerted, and an experimental formula of maximum of impulsive pressure are proposed. Related Articles | Metrics

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Risk, Risk Value and Risk Cost Shen Qiming 1991, 10(2): 94-99.  Abstract ( )   PDF (373KB) ( )   To appraise and select risk type decision alternative, we should consider the possible amount of risk. In this paper, we propose a method of appraisal and selection alternative by calculating and comparing the risk value and risk cost of the alternative. Related Articles | Metrics

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Development and Management of the Mass Transport in Chongqing Wang Jian, Ding Chun 1991, 10(2): 100-105.  Abstract ( )   PDF (470KB) ( )   Chengqing is the largest mountain city in the southwest of China.Two rivers converging here divide the urban areas into three parts (the Central District, the North and South Banks). The built-up areas is 84.5 sqaure kilometres and with a population of over 1.65 million. The buses and trolley-buses have dominated in urban transit system which have transported 2.56 million passengers every day, and the passenger vloume has increased by 4.269b per year over the last few years. The increase of the motor vehicle has made urban highways and streets more congestd, and it is difficult to build or reform the highways and streets because of the limitation of geographical factor here. However, the way for dealing with the urban transport problem will develop the new mass transpoot system. The rail transit system is under planning.As the city municipality can't offer sufficient capital investment and the technology to this project, and the urban transport authority lacks the experiences of management in mass transport system, how to finance and manage the new system will be the critical factor for ensuring the most effective use of the avialable re-soures. The city welcomes various ways of cooperation with industrialised and developing countries in the project of mass transport system, by the project financing gained from capitals, technologies and experiences,and a cooperation organization should be set up to plan, construct, operate and maintain the new mass transport system. Related Articles | Metrics