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22 June 1992, Volume 11 Issue 3 Previous Issue    Next Issue

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The Exact Solutions of Near Crack Line Field for a Mode III Crack in an Elastic Perfectly-Plastic Material Yi Zhijian 1992, 11(3): 1-7.  Abstract ( )   PDF (444KB) ( )   The quite new analysis of near crack line field for a Mode Ⅲ crack in an elastic perfectly-plastic material has been given in this paper.In the plastic region near the crack line,the particular solutions of the plastic stress and displacement fields have not been nsed to match with the elastic dominant fields (i.e.the elastic K-dominant fields),but the general solutions of the plastic fields have been taken to match with the exact elastic fields at the elastic-plastic boundary.The roughly qualitative assumptions of the small scale yielding theory have not been taken in this paper.No other qualitative assumptions have been attached.The solutions of this paper are sufficiently precise near the crack line. Related Articles | Metrics

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Highway Waste-Watering and Neotectonic Stress Field in Mountainous regions in Western Sichuan Lu Deshou, Bai Zipei, Chen Hongkai 1992, 11(3): 8-12.  Abstract ( )   PDF (343KB) ( )   In order to approach the relations between neotectonic stress field and highway waste-watering in mountainous regions in Western sichuan,this paper studies the neotectonic stress field with Scheidegger method,which shows that N10°W is the main geostress direction,and N35°W and N15°E are two groups of shear stress belts of the regions.Meanwhile,with the same method we discover that N40°W and N35°are the chiefly distributive orientations of highways in the regions,which are near to the shear stress belts.Therefore,we believe that there are intimate relalions between the neotectonie stress field and the highway waste-watering.generally,the neotectonic stress field controls the time and space evolutive rule of highway waste-watered,such as landslide,debris flow anb avalanche,etc. Related Articles | Metrics

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Fast Stability-Test Algorithms for Discrete-Time Linear Multivariable Systems with Multistep Lags Xu Maozeng 1992, 11(3): 13-20.  Abstract ( )   PDF (453KB) ( )   In this paper a set of finite recursive algarithms are set up in terms of thoughts of system identification to expose characteristic polynomials of discretetime linear multivariable systems with multistep lags.Based on these algorithms fastalgorithms for testing the stability of the systems under study are given.Illustrative examples are also given.It is shown that the obtained algorithms not noly have excellent properties in computation and programming,but also allow treating continuous-time linear systems without time delays and discrete-time linear systems with one or more step lags in a unified way. Related Articles | Metrics

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A Study of the Bending Cracks in Unbonded Prestressed Concrete Beam Zhou Zhixiang, Jiang Bingzhang 1992, 11(3): 21-27.  Abstract ( )   PDF (470KB) ( )   On the basis of our test data,this paper studies the influences of unbended tendon,prestressing degree,section shape and concrete strength on the development of flextural cracks of P.P.C.beams,and proposes a mathematic model for predicting the width of flextural cracks.Combined with the existing achievement and statistical analysis on the measured data,a simple and practical formula is put forward for reference. Related Articles | Metrics

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An Interaction Equation for Evaluating the Critical Moment of Steel Beams Li Kaixi, Cui Jia 1992, 11(3): 28-36.  Abstract ( )   PDF (560KB) ( )   According to the concept of critical bimoment,this paper proves two independent critical forces that affect the bearing capacity of a steel beam.The procedure is illustrated by several numerical examples.Corresponding to the numerical results of three load conditions,a practical interaction equation is proposed for evaluating the critical moment of steel beams. Related Articles | Metrics

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The Research on Evaluation Method of Load Carrying Capacity of Damaged Composite Structures Zhang Xixiang, Wu Zulie 1992, 11(3): 37-44.  Abstract ( )   PDF (521KB) ( )   The preliminary investigation on the evaluation of load carrying capacity of large composite structures in engineering from which the samples can't be taken for tests in the damaged state is carried out in the paper.Through the analyses and comparisons,an actual evaluation method fitting to beam structures which is based on the "replacing design" idea is developed,and a reference model of theoretical analysis and its being carried into practice,which is used in the preliminary evaluation of these types of structures when they are required for repair and reinforcement,is suggested. Related Articles | Metrics

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Extraneous Prestressed Technique and Its Application to Bridge Engineering Qiao Dun 1992, 11(3): 45-55.  Abstract ( )   PDF (675KB) ( )   The extraneous prestressed technique was invented in the 1920s.More Than ten extraneous prestressed concrete bridges had been constructed by the early 1050s.Because of the corrosion of steel cables and some other problems,its study and application was once put aside.In the recent years,with the problems gradually solved,the technique has regained attention and found wide application and development.This paper deals with the extraneous prestressed technique and its application to bridge engineering. Related Articles | Metrics

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The Experimental Research on Ultimate Shear Strength of Partially Prestressed Concrete Beams With Curved Unbonded Tendons Yang Limei, Jiang Bingzhang 1992, 11(3): 56-63.  Abstract ( )   PDF (501KB) ( )   In this Paper,We Study the Property of unbonded P.P.C.beams on the basis of the test that includes 17 straight tendon unbonded P.P.C.beams and 8 curved tendon beams.From the test and study,we give the distributing Pattern of the limit strength of the curved unbonded tendons and the calculating formula of shear strength of P.P.C.beams with curved tendons.The formula in this paper could be used to calculate shear strength of unbonded P.P.C.beams with both straight and curved tendons.In this paper,the revsults of test and calculation are compared and they all coincide very well with each other.The results of this paper could be used asa a basis of theoretical experiment and practical engineering design. Related Articles | Metrics

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Moment Distribution Method on Skew Structures Xia Gan 1992, 11(3): 64-74.  Abstract ( )   PDF (668KB) ( )   In this paper,the moment distribution method is proposed first for the analysis of skew structures,and the corresponding formulas are developed.The method,used to analyse tne skew continuous beam bridges and the skew frames and so on,is similar to the bending-moment distribution method to the right-angle structures,so this is a simple and convenient method which has the characteristic of the clearcut concept.Finally,two examples are given,and the influence of skew angles on internal forces,reactions and displacements are discussed. Related Articles | Metrics

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The Reliability Design of Curving Section Shear-Bearing on Non-Stirrup Reinforced Concrete Slabs Huang Xiangcai, Li Qingfu, Wan Juan 1992, 11(3): 75-83.  Abstract ( )   PDF (584KB) ( )   From the mechanics model of curving section shear strength on reinforced concrete slabs,this thesis analyzes the existing indefinable and solving method in projects.The reliability analysis of different models has been done.At the last,based on reliability theory,the practical expression of partial coefficient has been derived.The results provide scientific basis for defining the formulas of curving section shear-bearing capacity on non-stirrup reinforced concrete slabs.The method is applicable to other similar cases. Related Articles | Metrics

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Research on Impedance Function of Urban Streets Wang Wei, Zhang Guihong 1992, 11(3): 84-92.  Abstract ( )   PDF (550KB) ( )   A semi-theoretical and semi-experimental impedance function is presented on the basis of the characteristic of mixed traffic in our country.In this impedance function,the theoretical model of relationship between ruuning speed and vehichlar traffic load is established by means of the relationship of three parameters in traffic flow theory,and this model is modified according to the influences of discontinuation of traffic flow,interference of bicycles,interference of pedestrians and width of lanes.The influence of discontinuation of traffic flow is emphatically discussed,the five running models of discontinuous flow and the calculation methods of occurrence probability,average running speed are presented. Related Articles | Metrics

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The Boundary Element Method Applied to Multi-Layered Elastic System of Flexible Pavement Huang Xiaoming 1992, 11(3): 93-99.  Abstract ( )   PDF (423KB) ( )   The theory of multi-layered elastic system was presented by Burmister in 1945.In this paper,the characteristics of boundary element method is analyzed.Based on Stokes's law,the mathematical expressions of singularity integrity of kernel function is obtained and the infinite boundary element is used to analyze infinite boundary conditions.The results show that the accuracy computed by BEMLAY program which is developed by the auther is better than Chevron's program which is based on multi-layered theory.A new method to analyze multi-layered system is presented. Related Articles | Metrics

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A Dynamical Analysis of Floating Pier Impacted By Barge Chen Jiaqin 1992, 11(3): 100-110.  Abstract ( )   PDF (599KB) ( )   A new dynamical analysis is given in this paper,which deals with floating pier with stay-bar system that is impacted by a berthing barge.First,suppose that a barge,floating pier and stay piers are combined into a compound system,a stiffness matrix of the system is inferred and the damping is counted.Then,according to the imitial velocity of the system impacted by barge,the impact force,the stress of stay-bars and the motive dip of pontoon are calculated by means of vibration analysis of the system.This supplies engineering analysis with a reasonable calculation method. Related Articles | Metrics

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The F.E.M.Regeneration Analysis of Reinforced Concrete Member Li Yazhe 1992, 11(3): 111-119.  Abstract ( )   PDF (546KB) ( )   In this paper,the new method of F.E.M.is studied.The method can be used to trace the propagation of concrete cracking automatically,and at the same time,the position and the width of crack can be calculated.This method has all the advantages of discrete cracking method and smeared cracking method.The method in this paper can be used for the nonlinear analysis of reinforced concrete structure. Related Articles | Metrics

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Some Technical Problems In River Disposal Pipe Project of Pollutants Sun Zhihao 1992, 11(3): 120-130.  Abstract ( )   PDF (707KB) ( )   It is very important that polluted water in modern life and industry should be disposed well.The total flow of the polluted water discharged into the Qiantang River after the first disposal in Hangzhou Sibao Disposal of Sewerage Factory is 7.5m3/s.A method of discharging it under the river is adopted.This method needs a tremendous amount of work and is rather difficult in the technique.In order to finish this project,a series of experiments on physical and mathematical model has been done based on the analysis of the current hydrology and landforms.Moreover,a meticulous design and construction have also been made.In this article we introduce the survey of the project and explain some cruxes of the project.The arrangement of pipes,the number of spray nozzles,the diameter of pipes,the attitude of discharging flow of the structure of spray nozzles and so forth are discussed. Related Articles | Metrics

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An Algorithm for an Optimal Assignment Problem of Trees with Only One Cross Point (Ⅰ) Lin Ying 1992, 11(3): 131-137.  Abstract ( )   PDF (435KB) ( )   In this paper the following problem is considered.There are n crewmen.They are formed into trees with only one cross point according to their experiences.Now we divide them into several groups with K+l persons in each group in which only one is appointed captain and the others are members.The experience of the captain should be superior to those of other members in the group.Every person p is given two numbers f (P):g (P).When p is a captain his contribution is f (P).When p is a member,his contribution is g (P).Now we want to find an algorithm in order that the whole crew can make their greatest contribution.In this article we have solved the first part of the problem. Related Articles | Metrics