Calculation Method on Bearing Capacity of Anchor Bolt of Transmission Line Tower Foundation Considering Influence of Horizontal Force

2012 ◽  
Vol 170-173 ◽  
pp. 327-330
Author(s):  
Qiang Cui ◽  
Xian Long Lu
Keyword(s):  
Transmission Line ◽  
Bearing Capacity ◽  
Engineering Application ◽  
Theoretical Method ◽  
Horizontal Force ◽  
Transmission Tower ◽  
Strength Theory ◽  
Anchor Bolt ◽  
Uplift Force ◽  
The Third

Anchor bolt which is one of the most important component connecting foundation and transmission tower bears the force transmitted from superstructure. At present, in the conventional design method, uplift force is only included, however, the influence of horizontal force on bearing capacity of anchor bolt is neglected. Thus, a theoretical method on obtaining bearing capacity of anchor bolt is proposed for the first time based on the third strength theory in this paper, in which the influence of horizontal force is considered. According to the third strength theory, the calculation results of bearing capacity of anchor bolt under different force are obtained. It can be seen that the cross-section area of single anchor bolt shows linear increase with the increment of vertical uplift force, at the same time, the influence of horizontal force to bearing capacity of anchor bolt is more significant with the addition of the ratio of horizontal force to uplift force, which should be attached enough attention in engineering application. And the conclusion achieved in this work can provide valuable guidance for anchor bolt design of the transmission line project.

Axial Compression Performance Research of RPC Filled Steel Tube Columns Based on the Unified Strength Theory

2013 ◽  
Vol 351-352 ◽  
pp. 337-341
Author(s):  
Qian Zhu ◽  
Jun Hai Zhao ◽  
Yan Li ◽  
Peng Wu ◽  
Su Wang
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Engineering Application ◽  
Steel Tube ◽  
Strength Theory ◽  
Unified Strength Theory ◽  
Bond Slip ◽  
Compression Performance ◽  
Performance Research ◽  
Good Agreement

With consideration of the intermediate principal stress,the calculation formula of bearing capacity of RPC filled steel tube columns under axial compression is deduced based on the twin shear unified strength theory. Combining with the bond-slip theory,new ultimate bearing capacity formula is derived with the highest regard for bond stress. Compared with the theoretical result and the experimental data,good agreement can be found. The results show that unified strength theory and the bond-slip theory are versatile in theoretical analysis of the column. The analysis results can be provided for the optimum design of RPC filled steel tube and the solution has an important practical value for engineering application.

scholarly journals CONSIDERATIONS ON THE APPLICATION OF EUROCODES 2 AND 4 FOR CONCRETE BRIDGES

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Philippe Van Bogaert
Keyword(s):  
Bearing Capacity ◽  
Concrete Bridges ◽  
Logical Relation ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Uplift Force ◽  
The Third ◽  
Definition Of ◽  
Compression Resistance ◽  
Limiting Value

The application of certain parts of Eurocodes may result in surprising conclusions. Three independent examples of code requirements are presented. A first striking example is the fatigue compression resistance of RC or PC bridge girders and the prediction of the resulting lifetime, which may be excessively low. The second issue concerns the limiting value of slenderness of concrete arches, which shows no logical relation to the load bearing capacity. An alternative for the definition of slenderness is proposed. The third item is the necessity to consider an uplift force in the design of connectors, thus excluding virtually the use of block connections. In all three cases, alternatives are being proposed, needing further research or allowing a different approach to these issues. In addition, clarification of some code recommendations may overcome misunderstanding or erroneous application.

scholarly journals Influence of Double-Limb Double-Plate Connection on Stable Bearing Capacity of Quadrilateral Transmission Tower

2021 ◽  
Vol 11 (24) ◽  
pp. 12024
Author(s):  
Tengfei Zhao ◽  
Hong Yan ◽  
Panpan He ◽  
Lei Zhang ◽  
Zhiwen Lan ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Engineering Application ◽  
Elastic Stiffness ◽  
Scale Model ◽  
Connection Form ◽  
Axial Stiffness ◽  
Transmission Tower ◽  
Single Plate ◽  
Plate Connection

Transmission tower connection joint is an important connection component of the tower leg member and diagonal member. Its axial stiffness directly affects the stable bearing capacity of a transmission tower. The axial stiffness of the joint is mainly related to the connection form of joint. This paper takes the double-limb double-plate connection joint as the research object. Through the comparative study with the single-limb single-plate connection joint, the influence law of single-limb single-plate and double-limb double-plate joint on stable bearing capacity of quadrilateral transmission tower is studied from three aspects of model test, theoretical analysis and numerical simulation. Through the scale model test, it is found that the elastic stiffness of the double-limb double-plate joint is 3.12 times that of the single-limb single-plate joint, which can increase the bearing capacity of the joint by 26.1%. Through the energy method, the theoretical calculation expression of the stable bearing capacity of the quadrilateral tower considering the influence of the axial stiffness of the joint is derived. Compared with the effect of the single-limb single-plate connection joint, the double-limb double-plate joint can improve the stable bearing capacity of the quadrilateral tower by 15.6%. Considering the influence of geometric nonlinearity of tower and connecting joint, it is found that the double-limb double-plate connecting joint can improve the nonlinear stability bearing capacity of a transmission tower by 14.9%. The results show that the double-limb double-plate connection joint can not only improve the bearing capacity of the joint, but also greatly improve the stable bearing capacity of the tower. The research results can provide reference for the engineering application and design of double-limb double-plate connection joints.

scholarly journals A Vibration-Based Structural Health Monitoring System for Transmission Line Towers

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 515 ◽  
Author(s):  
Long Zhao ◽  
Xinbo Huang ◽  
Ye Zhang ◽  
Yi Tian ◽  
Yu Zhao
Keyword(s):  
Structural Health Monitoring ◽  
Transmission Line ◽  
Natural Frequency ◽  
Health Monitoring ◽  
Structural Changes ◽  
Natural Frequencies ◽  
Transmission Tower ◽  
Health Monitoring System ◽  
Wind Speeds ◽  
Before And After

In this paper, we present a vibration-based transmission tower structural health monitoring system consisting of two parts that identifies structural changes in towers. An accelerometer group realizes vibration response acquisition at different positions and reduces the risk of data loss by data compression technology. A solar cell provides the power supply. An analyser receives the data from the acceleration sensor group and calculates the transmission tower natural frequencies, and the change in the structure is determined based on natural frequencies. Then, the data are sent to the monitoring center. Furthermore, analysis of the vibration signal and the calculation method of natural frequencies are proposed. The response and natural frequencies of vibration at different wind speeds are analysed by time-domain signal, power spectral density (PSD), root mean square (RMS) and short-time Fouier transform (STFT). The natural frequency identification of the overall structure by the stochastic subspace identification (SSI) method reveals that the number of natural frequencies that can be calculated at different wind speeds is different, but the 2nd, 3rd and 4th natural frequencies can be excited. Finally, the system was tested on a 110 kV experimental transmission line. After 18 h of experimentation, the natural frequency of the overall structure of the transmission tower was determined before and after the tower leg was lifted. The results show that before and after the tower leg is lifted, the natural frequencies of each order exhibit obvious changes, and the differences in the average values can be used as the basis for judging the structural changes of the tower.

scholarly journals Research on Failure Characteristics of Concrete Three-Point Bending Beams with Preexisting Cracks in Different Positions Based on Numerical Simulation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Liuqun Zhao ◽  
Li Zheng ◽  
Hui Qin ◽  
Tiesuo Geng ◽  
Yonggang Tan ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Failure Process ◽  
Engineering Application ◽  
Tensile Failure ◽  
Engineering Structures ◽  
Failure Characteristics ◽  
Three Point Bending ◽  
Wide Range

Concrete three-point bending beams with preexisting cracks are widely used to study the growth process of I-II mixed mode cracks. Studying the failure characteristics of preexisting cracks at different locations on concrete three-point bending beams not only has important scientific significance but also has a wide range of engineering application backgrounds in the safety assessment of engineering structures. In this paper, through several numerical experiments, the influence of preexisting cracks at different positions on the failure characteristics of concrete three-point bending beams is studied, and three typical failure modes are obtained. The failure process of the specimens with three typical failure modes is discussed in detail, and it is pointed out that the crack failure mode is tensile failure. The change trends of bearing capacity, acoustic emission quantity, and acoustic emission energy of three typical failure modes are analyzed. The maximum bearing capacity, the maximum acoustic emission quantity, and energy of three failure modes of concrete three-point bending beams generally show an increasing trend.

Practical Calculation Method for the Bearing Capacity at High Temperature of Concrete Filled Steel Tubular Columns Subjected to Fire

2014 ◽  
Vol 1065-1069 ◽  
pp. 1358-1362
Author(s):  
Jin Sheng Han ◽  
Hao Ran Liu ◽  
Shu Ping Cong
Keyword(s):  
High Temperature ◽  
Bearing Capacity ◽  
Fire Resistance ◽  
Calculation Method ◽  
Engineering Application ◽  
Practical Calculation ◽  
Tubular Columns ◽  
Calculation Results ◽  
Simplified Calculation ◽  
Simplified Calculation Method

The fire resistance of concrete filled steel tubular column is usually obtained by the numerical analysis method, which is difficult to operate and not convenient in the actual civil engineering. So it is necessary to study the simplified calculation method. A large number of numerical simulation results of the temperature distribution of the section and the bearing capacity at high temperature of the concrete filled steel tubular columns are analyzed. The influences of secondary parameters are simplified. The simplified calculation method at 150 min and 180 min for the bearing capacity at high temperature of concrete filled steel tubular columns subjected to axial compression and fire is presented on the basis of comprehensive analysis of the numerical calculation results. The calculation results can be used as the basis to judge the fire resistance. It is shown by the comparison with the experimental results that the precision of the simplified calculation method can meet the requirements of engineering application.

scholarly journals A monocular-based navigation approach for unmanned aerial vehicle safe and autonomous transmission-line inspection

2019 ◽  
Vol 16 (1) ◽  
pp. 172988141982994 ◽  
Author(s):  
Xiaolong Hui ◽  
Jiang Bian ◽  
Xiaoguang Zhao ◽  
Min Tan
Keyword(s):  
Transmission Line ◽  
Unmanned Aerial Vehicle ◽  
Transmission Lines ◽  
Spatial Distance ◽  
Vanishing Point ◽  
Transmission Tower ◽  
Flight Direction ◽  
Field Environment ◽  
Smooth Tracking ◽  
Aerial Vehicle

This article presents a monocular-based navigation approach for unmanned aerial vehicle safe and continuous inspection along one side of transmission lines. To this end, a navigation model based on the transmission tower and the transmission-line vanishing point was proposed, and the following three key issues were addressed. First, a deep-learning-based object detection and a fast and smooth tracking algorithm based on the kernelized correlation filter were combined to locate transmission tower timely and reliably. Second, the vanishing point of transmission lines was computed and optimized to provide unmanned aerial vehicle with a robust and precise flight direction. Third, to keep a stable safe distance from transmission lines, the transmission lines were first rectified by optimizing a homography matrix to eliminate the parallel distortion, and then their interval variation was estimated for reflecting the spatial distance variation. Finally, the real distance from transmission tower was measured by the triangulation across multiple views. The proposed navigation approach and the designed UAV platform were tested in a field environment, which achieved an encouraging result. To the best of authors’ knowledge, this article marks the first time that a safe and continuous navigation approach along one side of transmission lines is put forward and implemented.

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