scholarly journals Interface Separation Detection of Concrete-Filled Steel Tube Using a Distributed Temperature Measuring System

2018 ◽  
Vol 8 (9) ◽  
pp. 1653 ◽  
Author(s):  
Shengshan Pan ◽  
Yuxi Zhu ◽  
Dongsheng Li ◽  
Jian Mao
Keyword(s):  
Detection System ◽  
Steel Tube ◽  
Measuring System ◽  
Temperature Detection ◽  
Increase Rate ◽  
Structure Surface ◽  
Void Area ◽  
Core Concrete ◽  
Heating Direction ◽  
Solid Area

In recent years, concrete-filled steel tubular (CFST) bridges have been widely used in bridge construction. However, interface disengaging is one of the bridges’ most common defects. It affects not only the confinement of the steel tube to the core concrete, but also the bearing capacity and the structure durability. In order to solve the problem of disengaging at the interface of steel tube-confined concrete and ensure the integrity of the structure, a new method based on a distributed temperature detection system is proposed to identify disengaging at the interface between steel tube and concrete. Through the analysis of experiments and numerical simulation, it was found that when the structure surface was heated, the temperature of the void area was higher than that of the solid area. The temperature of the maximum void height was the highest, the temperature increase rate was the fastest, and the cooling rate was the slowest. The boundary of the void suffered from sudden changes in temperature. The more serious the void, the greater was the temperature difference between the void and the solid. After changing the heating direction, the temperature distribution could still be identified. This study achieved simplicity and efficiency with respect to the detection of interface separation.

Design and Realization of CNG Intelligent Monitoring System

2013 ◽  
Vol 380-384 ◽  
pp. 761-764
Author(s):  
Zhen Hua Wang ◽  
Ge Fei Yu
Keyword(s):  
Monitoring System ◽  
Detection System ◽  
Short Message ◽  
Danger Signal ◽  
Intelligent Monitoring ◽  
Alarm Signal ◽  
Filling Station ◽  
Temperature Detection ◽  
Arm Microprocessor ◽  
Monitoring Information

One CNG remote intelligent monitoring system is designed and realized in this article. The monitoring system can receive real time monitoring information and monitor environment of CNG filling station by using GSM short message platform , terminal PC and cell phone based on ARM microprocessor, PTM100GSM module, pressure and temperature detection system, when the pressure, temperature or consistence of gas storage well is over the threshold , the monitoring system will send the alarm signal. Its proved that the monitoring system works stably and reliably and can effectively monitor fatal public danger signal.

Study on Grain Moisture Detection System Based on the Theory of Dielectric Properties

2013 ◽  
Vol 333-335 ◽  
pp. 1558-1563
Author(s):  
Ling Bin Tan ◽  
Hai Yan Ji
Keyword(s):  
Dielectric Properties ◽  
Detection System ◽  
Capacitive Sensor ◽  
Extreme Environment ◽  
Single Chip ◽  
Display Module ◽  
Temperature Detection ◽  
Grain Moisture ◽  
Moisture Detection ◽  
The Relationship

After studying the relationship between the moisture content of crops and their relative permittivity, the principle of capacitive sensor and the research results of measuring micro-capacitance, this paper summarizes the theoretical basis of dielectric properties of grain, the dielectric properties of wheat, corn and rice, the relationship between the dielectric properties of these crops and their water content. With these theory analyses, the paper gives a full look on the grain moisture detection system by the means of dielectric properties, which consists of six parts, a cylindrical capacitor, signal conditioning circuits, single-chip control module with an A/D converter, temperature detection module, keyboard module and display module. The system is simple, and can adapt to extreme environment and accomplish the rapid detection in manufacturing. A description is given of the principle, its hardware circuit and software programming flow chart.

Experiment Study on Interfacial Normal Bond Strength of Concrete Filled Steel Tube

2012 ◽  
Vol 594-597 ◽  
pp. 947-954 ◽  
Author(s):  
Zhen Yu Liu
Keyword(s):  
Bond Strength ◽  
Temperature Change ◽  
Concrete Strength ◽  
Steel Tube ◽  
Test Method ◽  
Bending Test ◽  
Concrete Filled Steel Tube ◽  
Normal Bond ◽  
Core Concrete ◽  
Test Result

To study the debonding of concrete filled steel tube (CFST), pulling and bending methods were used to test the normal bond strength. Based on the test result, debonding due to temperature change and shrinkage of core concrete in CFST was analyzed. The test and analysis result shows that the bending method is a better test method; the concrete strength has little influence on bond strength while the surface condition of steel has much influence on it. The bond strength of steel which is rust is greater than that of the steel with smooth surface. According to the analysis on the bending test result, the normal bond strength of 0.86MPa was got and the debonding of CFST arch was analyzed, the analysis result shows that debonding will easily happen under the action of temperature change and shrinkage of core concrete. The test methods and results can provide a reference for engineering applications.

The automatic detection of faint quasars from CFHT grens plates

1986 ◽  
Vol 119 ◽  
pp. 55-56
Author(s):  
C.J. Keable ◽  
R.G. Clowes
Keyword(s):  
United Kingdom ◽  
Detection System ◽  
Automatic Detection ◽  
Measuring System ◽  
Schmidt Telescope ◽  
The United Kingdom

The automatic quasar detection system (AQD, see Clowes, 1984) has been used to successfully select quasars from prism plates taken by the United Kingdom Schmidt Telescope. Surveys compiled using this technique have a magnitude limit of B-19.5. We present work here which extends the possible survey limit to B-21. This is done by putting plates taken with the Canada-France-Hawaii Telescope's grens (see Richardson, 1984, for a description) through the AQD measuring system. We will follow this work with a comparable photometric survey of the same field.

Research on Concrete-Filled Rectangular Steel Tube Stiffeners and Axial Compression Bearing Capacity

2014 ◽  
Vol 1065-1069 ◽  
pp. 1092-1096 ◽  
Author(s):  
Gao Cheng ◽  
Yong Jian Liu ◽  
Lei Jiang
Keyword(s):  
Bearing Capacity ◽  
Mechanical Performance ◽  
Compressive Load ◽  
Steel Tube ◽  
Simple Construction ◽  
The Core ◽  
Steel Bar ◽  
Stiffening Ribs ◽  
Reinforcement Measures ◽  
Core Concrete

Concrete-filled rectangular steel tube four sides restraint effect on the core concrete was weaker than the corner, which made the effect not significant. The paper studied a new kind of stiffening rib –PBL stiffener to strengthen restraint effect of concrete-filled rectangular steel tube , and evaluated its advantages compared with other stiffening ribs. 9 PBL stiffened concrete-filled rectangular steel tube columns under axial compressive load were tested. It also collected the test with other stiffened rids, such as straight ribs, binding bars, knee brace, steel reinforcement cage, steel bar stiffeners, saw tooth shaped stiffeners, stitching straight stiffeners and no rib concrete filled rectangular steel tube to compare. It evaluated increasing coefficient of bearing capacity by stiffening ribs. The results showed that: the PBL stiffeners and binding bar of concrete-filled rectangular steel tube bearing capacity was greater than other reinforcement measures by more than 20%; PBL stiffener could be a new prominent type of stiffener because of its excellent mechanical performance and simple construction.

scholarly journals Theoretical Analysis on Mechanical Behavior of Axially Loaded Recycled Aggregate Concrete Filled Steel Tubes

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Yijie Huang ◽  
Yuedong Sun ◽  
Huangsheng Sun ◽  
Qing Wang
Keyword(s):  
Mechanical Behaviour ◽  
Mechanical Model ◽  
Confining Pressure ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Steel Tubes ◽  
Concrete Filled Steel Tubes ◽  
Numerical Program ◽  
Core Concrete

A new mechanical model for analysing the behaviour of axially loaded recycled aggregate concrete filled steel tubes (RACFSTs) stub columns is presented in this study. The model is derived from the typical elastoplasticity, the nonlinear elastic mechanics, and the properties of materials. Based on the mechanical model, a novel numerical program is developed. The mechanical model and the numerical program are adopted to study the effect of recycled coarse aggregate (RCA) replacement percentage on RACFST mechanical behaviour. The complete load-deformation relationship of specimens, the steel tube axial and circumferential stresses, and the performance of the confined core concrete and the variation of interaction are also investigated. The analytical results indicate that this model is able to capture the mechanical behaviour of RACFST. It is also found that the axial and circumferential stresses of steel tube change nonlinearly during the loading stages. It is concluded that the behaviour of the confined core concrete is significantly influenced by the confining pressure. The steel tube confinement could improve the mechanical behaviour of RAC effectively and the RCA replacement percentage slightly changes the response of core concrete. Finally, the relations between confined core concrete and confining pressure are analysed.

Field Test of a Leak Detection System: Planning, Execution and Results

2010 ◽  
Author(s):  
Daniel Sampaio da Silva ◽  
Si´lvio A. Melo Filho ◽  
Mauro Niehues de Farias ◽  
Anderson Pacheco
Keyword(s):  
Steady State ◽  
Field Test ◽  
Communication Systems ◽  
Detection System ◽  
Transient State ◽  
Leak Detection ◽  
Point Of View ◽  
Measuring System ◽  
Operational Parameters ◽  
Pump Station

The OLAPA pipeline (Oleoduto Arauca´ria–Paranagua´) is a 12in diameter pipeline and, with its 97,6 km in length, crosses a mountain region called “Serra do Mar” attaining elevations of about 900m in a dense forest region. Besides that, this pipeline crosses cities, farms, rivers, including a short submerse stretch in the Paranagua´’s bay. An incident in this pipeline could result in severe consequences, especially under the environmental point of view. Therefore, this pipeline was chosen to test the performance of a new leak detector system in Transpetro. The test consists in comparing the theoretical results with practical values of alarm times obtained from a controlled removal of product in an adequate point, in the middle of the pipeline, simulating a real leak. The system chosen to be tested was the LeakWarn system, which is a computational system that uses the mass balance principle with line pack change to analyze the pipeline operational parameters in order to alert when there is a risk of product leak. This test had the objective to evaluate the LDS and help Transpetro’s management team to analyze and decide whether or not to replace its current leak management system, since this new one showed the expected results and was compatible with the excellence level already achieved in the company. The field test was performed in July 7th 2009, through a vent valve far from the ends of the pipeline and it was made in three different conditions: 1) A big leak in the steady state of operation; 2) A small leak also in the steady state of operation; and 3) A big leak in the transient state of operation (immediately after the pump station start up). In order to proceed this test, a multidisciplinary team was assigned and several resources were used such as: Two tank trucks, a specially designed leakage line with control valves, measuring system, flexible hoses, communication systems and emergency equipments. The complete operation was monitored from the Control Center in Transpetro’s Headquarter, Rio de Janeiro. This paper describes the way the tests were performed and presents the results in order to contribute with useful information to be used in any field test for any other leak detection system. It shows how planning were done in order to insure that all operations would be performed according to strict procedures and in a safe way. It also describes the milestones and the work of each team involved in the activity, as well as their constraints and difficulties that had to be overcome during the planning and execution phases, that lasted approximately one year.

scholarly journals Experimental Studies on the Effect of Properties and Micro-Structure on the Creep of Concrete-Filled Steel Tubes

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1046 ◽  
Author(s):  
Rongling Zhang ◽  
Lina Ma ◽  
Qicai Wang ◽  
Jia Li ◽  
Yu Wang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Steel Tube ◽  
Creep Tests ◽  
Steel Tubes ◽  
Concrete Filled Steel Tube ◽  
Steel Ratio ◽  
Air Content ◽  
Lateral Restraint ◽  
Concrete Filled Steel Tubes ◽  
Core Concrete

To study different lateral restraints, different constituents of expansion agents, the influence of different steel ratios, and concrete creep properties, we carried out experiments with lateral restraint and without lateral restraint conditions separately on 12 specimens with the expansion agent content accounting for 4%, 8%, and 12% respectively. In addition, the creep tests were performed on specimens with different steel ratios of 0.0%, 3.8%, 6.6%, and 9.2%. The test results show that the lateral restraint improves the strength of the system (concrete-filled steel tubes) which resists further load after the concrete ultimate strength is surpassed and reduces the creep. The creep degree of the concrete-filled steel tube with lateral restraint is about 0.09–0.30 times smaller than that of the tube without lateral restraints. The creep degree of the concrete-filled steel tube increases as the steel ratio decreases. Creep tests with different amounts of expansion agent indicate that the creep degree of the concrete structure increases as expansion agent content decreases. To study the internal mechanism of the creep of concrete-filled steel tubes with different lateral restraints and different expansion agent concentrations, a microscopic pore structure test on the steel core concrete was conducted using the RapidAir457 pore structure instrument. Microscopic studies show that the air content and the length of the bubble chord of the laterally restrained core concrete are lower than those without lateral restraint core concrete. The amount of air content and the length of the bubble chord of core concrete specimens increase as the expansion agent content in the core concrete specimens decreases from 12% to 4%. Under the same external loading conditions, as steel ratio increases, the lateral restraint causes a further reduction of creep. The results of this study suggest that the creep of concrete can be reduced by selecting appropriate lateral restraint conditions and an optimal amount of expansion agent in the mix design of concrete for concrete-filled steel tubes.

Experimental Study on Circular Hybrid SCCC Columns under Axial Compressive Load

2011 ◽  
Vol 368-373 ◽  
pp. 369-372
Author(s):  
Zhu Yan Li ◽  
Yong Jun Liu ◽  
Dong Wang
Keyword(s):  
Bearing Capacity ◽  
Test Specimen ◽  
Compressive Load ◽  
Strain Curve ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Compressive Performance ◽  
Core Concrete

The tests are order to investigate the axial compressive performance of the new circular hybrid Steel-Concrete- CFRP-Concrete column (simply called SCCC column).SCCC column is composed of steel tube, annular concrete, CFRP tube and core concrete. Axial ultimate bearing capacity test was performed on 3 SCCC columns, from which we gains the law of affecting SCCC columns, the load-strain curve and load-displacement curve of SCCC columns, and compare the test results of the test specimen with different annular concrete thicknesses, from which we finds that after the relationship curve of test specimen with small annular concrete thickness reaches yield load, the bearing capacity starts to decline, and then continues to rise till the ultimate load is reached and the test specimen is damaged. The result shows that the smaller the annular concrete thickness is, the greater the axial ultimate bearing capacity of SCCC column is, and also indicates that CFRP tube plays a role of binding and constraining to the core concrete in later period of loading the test specimens.

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