scholarly journals Discussion on Temperature Control Method of Cooling Water Pipe for Mass Concrete Construction

2020 ◽  
Vol 165 ◽  
pp. 04037
Author(s):  
Zhi-Gang Yang ◽  
Jin-Lan Song ◽  
Yan-Fang Hu ◽  
Kun-Fa Lee
Keyword(s):  
Temperature Stress ◽  
Control Method ◽  
Great Influence ◽  
Cooling Water ◽  
Element Model ◽  
Mass Concrete ◽  
Concrete Construction ◽  
Concrete Temperature ◽  
Short Time ◽  
Cooling Pipes

For studying the influence of cooling pipes on the mass concrete construction, the dam is taken an example to build the ANSYS finite element model. The model simulates dam concrete construction based on two projects, one without cooling pipes and the other with cooling water pipes provided. The data comparison and analyzing will be in three aspects: temperature, stress and displacement. The result shows that the cooling pipes not only can indeed reduce the concrete temperature in a short time, making the concrete reach the steady temperature more quickly, but also help to alleviate the concrete temperature stress. However, the reductions of temperature do not make a great influence on the displacement during the construction process.

scholarly journals Temperature Control Technology for Construction of Jinsha River Bridge

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Hui-Wu Jin ◽  
Guo-An Wang ◽  
Zhan-Ming Chen
Keyword(s):  
Temperature Control ◽  
Temperature Difference ◽  
Cooling Water ◽  
Good Health ◽  
Large Mass ◽  
Maximum Temperature ◽  
Mass Concrete ◽  
Jinsha River ◽  
Mixture Ratio ◽  
Concrete Temperature

The key problem of mass concrete temperature control is to effectively control the maximum temperature inside concrete, the temperature difference between inside and outside concrete, and the temperature difference between surface and environment. The size of the main tower cap of No. 3 Jinsha River Bridge is 37 m × 23.5 m × 5.5 m, and the cubic volume of concrete reaches 4782.3 m3, which is poured in two times. In order to ensure construction quality of mass concrete structure, prevent the large mass concrete temperature stress, through the numerical simulation of the temperature control and optimization scheme, by optimizing the mixture ratio design, reducing the temperature of concrete pouring into the mold, cooling water cycling, insulation keeping in good health and a series of measures to effectively achieve the control goal, and eliminating the temperature cracks. The measured data show that the maximum temperature inside concrete, the temperature difference between inside and outside, and the temperature difference between surface and environment are qualified, but the temperature difference control of cooling water inlet and outlet has hysteresis effect, and the temperature difference between inlet and outlet will be greater than 10°C, which should be noticed.

Study of the Influence of Hydration Coefficient on Concrete Temperature Stress

2011 ◽  
Vol 255-260 ◽  
pp. 3548-3552
Author(s):  
Pan Wu Li ◽  
Peng Dong Qu ◽  
Xian Zhe Zeng
Keyword(s):  
Temperature Stress ◽  
Construction Management ◽  
Influence Factor ◽  
Internal Heat ◽  
Mass Concrete ◽  
Temperature Stresses ◽  
Root Cause ◽  
Concrete Temperature ◽  
Influence Of Hydration ◽  
Main Influence

The hydration coefficient of cement is the main influence factor of the cumulating quatity of internal heat. It directly affects temperature-rise of the concrete and the variation in temperature stresses of mass concrete, to a certain degree, control occurring of the mass concrete cracks. So,it is the main content of construction management of mass concrete. According to the root cause which lends to mass concrete cracks occur, we have analyzed the influence of hydration coefficient on mass concrete temperature stress by the large finite analyzing software ANSYS, and drawn the corresponding conclusion.

Study on Crack Mechanism for Concrete Bedding Cushion on Rock

2010 ◽  
Vol 163-167 ◽  
pp. 1291-1295 ◽  
Author(s):  
Min Zhi Liu ◽  
Sheng Qiang ◽  
Zhen Yang Zhu
Keyword(s):  
Tensile Stress ◽  
Great Influence ◽  
Reference Value ◽  
Mass Concrete ◽  
Prevention Measures ◽  
Concrete Dam ◽  
Depth Study ◽  
Calculation Results ◽  
Cushion Layer ◽  
Cooling Pipes

Bedding cushion cracking in concrete dam is widespread, and has not been completely prevented [1,2]. There are many cracking causes of bedding cushion, including construction difficulty and structure requirements for concrete dam. Based on the method of FEM simulative calculation of temperature and stress fields of mass concrete using water cooling pipes, this paper makes relatively in-depth study on crack mechanism for concrete bedding cushion on rock. It is revealed that all three factors of uneven thickness of bedding cushion, thickness of new dam concrete placed on cushion after off period and foundation gallery upon bedding cushion have great influence on the tensile stress of bedding cushion and should be paid special attention during construction. The calculation results show that the tensile stress of thinner concrete cushion layer is much greater than the thicker one, and the thinner upon new concrete will also make greater tensile stress in cushion. As a result, both the thinner cushion layer and the cushion with thinner new concrete on it would have a bigger chance to crack than others. The mechanism is used to explain reasonably a dam crack in construction. Then some cracking prevention measures, which should have reference value for the construction of bedding cushion, are put forward in this paper.

scholarly journals FEA of Effects Induced by Diurnal Temperature Variation on Downstream Surface of Xiaowan Arch Dam

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huanhuan Li ◽  
Shaojun Fu ◽  
Gang Li ◽  
Guofei Hu
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Temperature Stress ◽  
Air Temperature ◽  
Mesh Size ◽  
Element Model ◽  
Arch Dam ◽  
Mass Concrete ◽  
Finite Element Program ◽  
Field Simulation

In order to make clear the cracking reasons in arch dam of Xiaowan Hydropower Station during operation period, the approach to combine ANSYS with finite element program COCE-3D is adopted. Firstly, the influence by element type and mesh size for the temperature field simulation result is analyzed. Subsequently, the three typical dam segments cut from Xiaowan arch dam are selected and the relevant finite element model is established; the effect of the measured diurnal air temperature on temperature field and temperature stress of arch dam is analyzed thoroughly. The results indicate that the temperature gradient in mass concrete becomes lower, whereas the affecting depth becomes deeper when the mesh size is too large. Therefore, it is advisable to use smaller size mesh to study the influence of the measured diurnal air temperature on the surface temperature distribution in mass concrete. The temperature of downstream zone in arch dam is significantly affected by air temperature; the changing laws of temperature field and temperature stress with the air temperature are basically consistent, which is sensitive to lower temperature. When the temperature sharply decreased, the temperature stress in the downstream zone is mainly in tensile stress state. The calculated results are basically consistent with the measured results, and the temperature stress induced by the day-night temperature difference is the important reason for the horizontal cracks on the downstream surface. The submodel analysis method is an important alternative approach to study the changing laws of temperature field of arch dam. The research results not only provide an evidence for temperature control and crack prevention of Xiaowan arch dam but also provide a reference for temperature field simulation of similar projects.

Finite Element Analysis of Mass Concrete Temperature Crack Mechanism

2012 ◽  
Vol 594-597 ◽  
pp. 713-716
Author(s):  
Zhi Hua Xu ◽  
Da Wei Sun ◽  
Hai Xiao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Stress ◽  
Concrete Structure ◽  
Large Scale ◽  
Mass Concrete ◽  
Continuous Development ◽  
Element Analysis ◽  
Concrete Temperature ◽  
Temperature Crack

With the large-scale continuous development of economic, mass concrete structure plays an important role in the architecture construction field. This paper simulates the mechanism of temperature crack which is caused by temperature stress due to the change of temperature, introduces the generative principle of temperature crack simply and could provide references for control the temperature crack effectively.

The Design of Cooling Water Pipe and Cooling Analysis in Mass Concrete

2011 ◽  
Vol 255-260 ◽  
pp. 3510-3513
Author(s):  
Pan Wu Li ◽  
Qian Qian Si
Keyword(s):  
Heat Transfer Performance ◽  
Cooling Water ◽  
Mass Concrete ◽  
Water Cooling ◽  
Water Pipe ◽  
External Temperature ◽  
Concrete Cracking ◽  
Massive Concrete ◽  
Water Pipe Cooling ◽  
Cooling Pipes

Inconstruction process of mass concrete is apt to form excessive temperature stress and cause mass concrete cracking, because of its high inner temperature, big internal and external temperature difference. In order to prevent their cracking, in mass concrete of the internal Settings with cooling water pipe cooling is one of the commonly used massive concrete construction method. This paper presents a massive concrete design of cooling water cooling and calculation theory, based on the cooling pipes in concrete heat transfer performance, through the cooling water pipe and concrete heat exchange principle.

Experimental Study on Temperature Data of Mass Concrete Construction in Hot Weather Conditions

2012 ◽  
Vol 170-173 ◽  
pp. 3270-3273
Author(s):  
Jun Wang ◽  
Yu Zhang ◽  
Xin Long Zhu
Keyword(s):  
Concrete Strength ◽  
Time History ◽  
Weather Conditions ◽  
Temperature Data ◽  
Mass Concrete ◽  
Characteristic Parameters ◽  
Concrete Construction ◽  
Concrete Temperature ◽  
Hot Weather ◽  
Temperature Time

Through studying on temperature data of mass concrete poured completely after 20 days, the temperature time-history curves were plotted in different heights section of the raft foundation. Moreover, the characteristic parameters such as solid concrete temperature, temperature difference between inside and outside , also between surface and atmosphere, and its cooling rate were studied. Then by checking cracks of the mass concrete, the most likely period of temperature stress cracks appearing is pointed out. The useful experience data of the mass concrete construction in conditions of hot weather is accumulated, whose concrete strength standard is evaluated by 28d age.

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