Bending Performance of Tube Gusset Joint in Steel Tubular Tower for Extra High Voltage Transmission Line

This paper explored bending performance of tube gusset joint primarily according to experiment and finite element model. The method which is used to determine ultimate strength of the joint was proposed on the base of three joint types including /4 circle ribbed, half circle ribbed and circle ribbed stiffeners. Compared with the Japanese electricity transmitting steel tubular tower manufacture norm, a conclusion has been drawn that the ultimate strength has relationship with several different parameters. The result shows that the ultimate strength of the joint is related not only to the wall thickness t, diameter D, length of gusset plate B and the yield deflection δ at the top of the relevant section under the current status of the region, but also to the ribbed plate. The formula about ultimate strength has important application value for engineering design.     

Effects of Spherical Joint Stiffness on Seismic Response of Single-Layer Cylindrical Reticulated Shell Changing with Peak Ground Acceleration

The previous studies find that the hollow spherical joint stiffness has a certain influence on seismic response of single-layer cylindrical reticulated shell. In order to analyze the rule of this influence with PGA (peak ground acceleration) changing, two types of finite element models are built. The two types of models have the same size except the spherical joint. The first type is a fine model built by shell element and its spherical joints and tubes are built by considering the real size; the other type is the common model which is built by beam element, and the spherical joints are neglected. Comparing with the seismic response of the two types of models when PGA changes, the results show the difference between the two types of model in node displacement-time curves is increased as PGA increases; when the PGA is larger than the collapse acceleration of structure, the influence of increasing joint wall thickness on improving the structural capacity of anti-stability is decreased as PGA increases.     

Model Test and Mechanical Behavior Analysis of Steel-concrete Joint of Hybrid Girder

To study the bearing behavior, failure mode and mechanical behavior of different structural forms of steel-concrete joint of hybrid girder, based on the hybrid girder of Jiujiang Yangtze River Highway Bridge with 818-metre main 8pan, select a pressure-resistant shear-transferred steel-concrete joint, redesign a shear-transferred only joint for contrast, carry out two scale 1:2 model specimens bearing behavior experiment, measure the strain and relative slip of steel and concrete. The results show that:the bearing capacity of the pressure-resistant shear-transferred specimen is twice than the other;the bearing plate carries about 62.5% of the axial load, the force transmission of the bearing plate reduces the steel stress、steel-concrete relative slip and the force transmission ratio of connectors, makes the load transferred more effectively.     

Experimental Analysis of Rotational Behavior of Timber Beam-column Connection of Ancient Tibetan Architecture

Static experiment was carried out to study rotation behavior of timber beam-column connection. The influence of length of Gongmu and position of dowel on the initial rotational stiffness of the joint was analyzed. Rules of stiffness degradation under cyclic loading were studied as well. The results show that: the moment-rotation curve of typical timber beam-column connection can be simplified as bilinear model; the initial rotational stiffness of the joint is enhanced with the increase of the length of Gongmu, and it is decreased with the inward movement of dowel; under the same conditions, the influence of the inward movement of Gongmu-beam dowel on the initial rotational stiffness of the joint is smaller than that of Dianmu-Gongmu dowel; and stiffness degrades under cyclic loading and there exists obvious transition phenomenon.     

Elastoplastic Analysis of Discrete Jointin Rockmass Loaded by Compress_shear

In this paper the elastoplastic stress fields near joint line in rockmass loaded by compress- shear are analyesd by the line field method in fracture mechanics with Mokr- Coulomb criterion. Through the matching conditions of the elastoplastic fields on their boundary, the relations between the length of plastic zone on the joint line and the compress- shear loads are found, and the fracture criterion of the discrete joint is also obtained     

Seismic performance of first floor corner joints of high-rise reinforced concrete frame structure

Crushing risk of corner column will increase substantially due to first floor corner joint shear failure of high-rise reinforced concrete frame structure under bi-directional loading and high axial compressive load caused by earthquake action. Therefore,     

Rock classification method for tunnel boring machine

In order to study the geological factors which impact penetrating rate of tunnel boring machine (TBM), this paper uses three-dimensional discrete element model 3DEC to build simulated models on rock fragment by TBM cutter. It analyzes the influence of different geological conditions on TBM penetrating rate and classified the surrounding rock in west route of south-to-north transfer project according to the drill ability of TBM in surrounding rock. The results show that the penetrating rate of TBM is closely related to the mechanical properties of rock and joint conditions in rock mass. In certain extent, TBM penetrating rate will be increased with the decrease of rock strength or closely distributed joints. TBM penetrating rate will be decreased with the increase of rock strength or rarely distributed joint. Another result is that the surrounding rock by TBM penetrating can be divided into three classes based on the drill ability of TBM in surrounding rock, which can guide the TBM penetrating.     

Experimental Research on the Behavior of Direct Anchoring Beam-wider-than-wall Joint

Based on the elastic finite element analysis of the RC beam-wider-than-wall joint, two large-scale specimens of the direct anchoring beam-wider-than-wall joint are designed to test the joint behavior. The stresses and slips of longitudinal bars in the beam, load-bearing capacity and destruction form are observed and analyzed. The analysis and test results show that: The wide beam should be extended through into the wall for some length to make the flexural stress uniform along beam section width, thus the beam's bearing capacity can be achieved. The anchorage condition of the upper longitudinal bar in the beam outside the wall's width is poor, thus the anchorage length prescribed in the current CODE is not enough to ensure the bearing capacity and ductility of joints. The beam stirrups are very important to the anchorage of the upper longitudinal bar in the beam outside the wall's width. If the quantity of the beam stirrups is not enough, the wide beam in the joint area would have more cracks which decrease the bearing capacity and ductility of joints. Finally, a novel spatial truss mechanism model for the beam-wider-than-wall joint is put forward.     

Study on the Application of Large-span Prestressed Concrete Frame in Added Floor and Rebuilding

Around the reconstruction design of the Popular Science Image Building of the Southwest Hospital, the advantage of prestressed concrete frame used in the rebuilding was approved. At the same time, the problem in the prestressed frame design was pointed out. In the end, the method to decrease the moment in the column had been put forward.     

New Monitoring and Assessment Method for the Joints of Steel and Concrete Connection in Large span Bridge

The joints of steel and concrete (JSC) is the key substructure to composite bridge, the method of condition monitoring and safety assessment were carried out for JSC with perfobond shear connectors (PBL) and local prestressed tendon in large span bridge. According to the damage mechanism of JSC, new monitoring parameters were proposed. The sensor location layout and the assessment thresholds of PBL were addressed with the consideration of the disadvantage influences of environment, load and concrete creep to local prestressed loss assessment and validated by the static load experiment. Compared the experimental results with field monitoring data, it was found that the new monitoring parameters and new assessment method were feasible and can be used as reference to the same type connectors in large span bridges.     

Application of Joint Element in the Stability Analysis of Rock Mass

According to the strongpoint and shortcoming of all kinds of plane joint elements and theirs applicable range, the basic theories of plane joint elements were introduced in brief. An example which utilized different plane joint elements to simulate the different sorts of discontinuity interface in rock mass was given, and the analysis result indicates that if only the constitutive model of a material is confirmed ,and some special element types are adopted,with the basic principle and approach of the finite element to simulate rock materials, a more satisfactory result can be obtained.     

发展我国冷链物流的对策研究

在我国的食品生产与流通消费过程中,落后的冷链物流体系不仅造成了巨大的经济损失,还对食品安全构成了威胁。分析了我国冷链物流的发展现状及其存在的主要问题,并提出相应的发展对策。     

Numerical simulation of remodeling in mandible under orthopedic loads

The research on the remodeling in mandible under the action of orthopedic loads is important for the determination of orthopedic scheme. a three-dimensional finite element model of mandible and temporomandibular joint is established. Using Cowin Remodeling Law, the finite element simulation of the remodeling in mandible during the orthopedics under the action of orthopedic loads is carried out. Comparing the numerical results after remodeling with those before remodeling, it is demonstrated that the normal remodeling greatly affects the distribution of strain and strain gradient on the surface, therefore the effect cannot be ignored in the determination of the orthopedic scheme.     

Innovating Method of Mechanism Configuration Project Based on Kinematic Chain

The structure design is the most crucial and innovative one in the process of mechanism system design, and attention is constantly given to them. Although the various methods of structural synthesis are presented, more study due to faultiness of them are essential. All of available configurations of the single joint kinematic chain are gotten by replacing its pairs. On the basis of symbolization of pairs, the authors put forward the mathematic approach of permutation and combination by which all of configurations of the kinematic chain can be obtained, structure graph is used to judge the type of same fabric of the kinematic chain. Finally their application examples in engineering are given.     

Mechanical Characteristics of Earthquake-Resistant Reinforced Concrete Frame Joints

On the basis of analysis and induction of experimental results on earthquake-resistant frame joint both at home and abroad, it is clearly pointed out that the mechanical characteristics of the joint in which shear failure may occur after yielding of longitudinal rebars at the beam end or at the column end are classified into three types, i. e ., diagonal tension, diagonal compression and a combination of diagonal tension and diagonal compression. A region of these three types of mechanical characteristics in the coordinates composed of relative shear force and relative ratio of transverse reinforcement is given, and the variation law and the corresponding reasons for the mechanical behaviors with the relative transverse reinforcement are analysed.     

On Joint Incentive Contracts Under Horizontal Monitor

According to the problem that the independent incentive contracts relying on one's own output,which is given out by classical principalagent theory,only can realize the second best efforts,this paper analyzes the optimal contract under horizontal monitor by which independent agents can monitor each other,and comes to the conclusion that the joint incentive contracts relying on one's own output and others' can realize the first best efforts under horizontal monitor.The independent agents can sign implicit side contracts among them by the horizontal monitor and the dynamic joint incentive contracts,in which strict team incentive compatibility contracts are taken at the first stage and individual incentive compatibility contracts are taken at the second stage,make the retaliation mechanism regulated by implicit side contracts among agents feasible and credible,and hence can realize optimal incentives.