Study on early-age thermal field of single-cell box girder concrete cured with electric heating furnaces

2021 ◽  
Author(s):  
Yong Zeng ◽  
Yutong Zeng ◽  
Dong Jiang ◽  
Shanhong Liu
Keyword(s):  
Single Cell ◽  
Thermal Field ◽  
Electric Heating ◽  
Early Age ◽  
Box Girder ◽  
Heating Furnaces

Design of the Murray and Wolverine River rail bridges

1984 ◽  
Vol 11 (4) ◽  
pp. 701-708 ◽  
Author(s):  
G. W. Taylor
Keyword(s):  
Single Cell ◽  
Key Words ◽  
Continuous Steel ◽  
Box Girder ◽  
Railway Bridges ◽  
Branch Line ◽  
Steel Box Girder ◽  
Deck Plate ◽  
Bridge Steel

This paper describes the design of the Murray and Wolverine River rail bridges, two of the largest river crossings on British Columbia's Tumbler Ridge branch line. These unique railway bridges feature a single-cell, continuous steel box girder superstructure supported by pairs of steel delta legs. The top flange of the box girder is an orthotropic deck plate that is a part of the ballast containment trough. Stability of the delta legs is provided by posttensioning of their bases to the concrete substructure. Key words: rail bridge, steel box girder, steel delta legs, orthotropic deck, posttensioning.

scholarly journals Study on the Mitigative Effect of Controlled Permeable Formwork (CPF) Liner on Early-Age Shrinkage of Box-Girder Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jianxiong Ye ◽  
Linwen Yu ◽  
Yong Chen
Keyword(s):  
Moisture Content ◽  
Concrete Surface ◽  
Early Age ◽  
Working Mechanism ◽  
Box Girder ◽  
Relative Moisture Content ◽  
Relative Moisture ◽  
Bridge Structures ◽  
Girder Bridge ◽  
Surface Covering

Because of its high binder content and severe construction environment, early-age cracking is one of the most important threats to concrete used in continuous box-girder bridge structures. In this study, controlled permeable formwork (CPF) liner was used to mitigate the early-age shrinkage and reduce the early-age cracking risk of box-girder concrete. Early-age shrinkage was measured by a noncontact method and started at 30 min after adding mix water until 7 d. Internal relative moisture content and pore distribution tests were also carried out to reveal the working mechanism of CPF liner. The results show that covering the concrete surface with CPF liner decreased early-age shrinkage significantly. Under the temperature of 20°C and the relative humidity of 60%, two-surface-covering and three-surface-covering CPF liner on concrete decreased the shrinkage by 44% and 48%, respectively, at 7 d compared with concrete without CPF liner covered on it. The main reason is that CPF liner enhanced the internal relative moisture content and resulted in better performance of the surface concrete.

scholarly journals ANALISIS STRUKTUR JEMBATAN BOX GIRDER DENGAN PENAMPANG KURVA PARABOLIK SINGLE CELL

2019 ◽  
Vol 2 (3) ◽  
pp. 255
Author(s):  
Jason Ongkosurya ◽  
FX Supartono
Keyword(s):  
Single Cell ◽  
Box Girder ◽  
Post Tension

Box Girder adalah salah satu kompenen penting dari sekian banyak komponen struktur dari pembuatan jembatan segmental box girder yang berperan dalam menyalurakan gaya yang diterima dari lapisan perkerasan ke pier (kolom). Bentuk dari box girder sangat mempengaruhi ketahanan dan kekuatan dari suatu jembatan, serta effisiensi dari jembatan. Merubah bentuk dari box girder akan mempengaruhi inersia, beban sendiri, perletakan tendon. Yang menjadi komponen utama dalam perancangan jembatan post – tension box girder. Dengan bantuan program MIDAS CIVIL 2019 akan dianalisa  gaya, berat sendiri. Lendutan dan jumlah tendon yang terjadi serta perubahannya akibat perubahan bentuk box girder.

scholarly journals The Dynamic Characteristics Research of Compact Heat Regenerator used in Regenerative Burners for Metallurgical Heating Furnaces

2014 ◽  
Vol 59 (2) ◽  
pp. 805-808
Author(s):  
M. Wnęk
Keyword(s):  
High Frequency ◽  
Thermal Field ◽  
Temperature Sensors ◽  
Flame Stabilization ◽  
Heat Transfer Intensification ◽  
Heating Furnaces ◽  
Starting State ◽  
Gas Fuel ◽  
Gas Burner ◽  
The Right

Abstract The gas burner is a device which the main aim is delivering the right number of gas fuel and oxidizing agent and it also has to ensure flame stabilization. The difficult controlling problem appears when the modern and compact high temperature regenerative burners are used. The controlling difficulties in those systems are related to the large number of burners and a periodic change (with high frequency) of temperature field which depends on such parameter as reversion time. The knowledge of the dynamic and static regenerator characteristics makes easier the programming of automatic control and regulation process and helps in creating the new regenerator filling construction in order to improve the heat transfer intensification and the furnaces efficiency. Based on research results the paper presents the selected data research dealing with the dynamic and static regenerator characteristic. The measurement of quick-changing fluctuating thermal field and the way of the temperature sensors selection have been indicated. The regenerator starting state and pseudo-steady state characteristics have also been presented. Finally the qualities of the regenerator and the economic income have been expressed.

Thermal Field Characteristics of Reinforced Concrete Box Girder during High-Temperature Asphalt Pavement Paving

2018 ◽  
Vol 2672 (41) ◽  
pp. 56-64 ◽  
Author(s):  
Dong Zheng ◽  
Zhen-dong Qian ◽  
De-xuan Liu ◽  
Xiang-fei Zhang ◽  
Yang Liu
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Thermal Field ◽  
Field Model ◽  
Asphalt Pavement ◽  
Structural Safety ◽  
Characteristic Analysis ◽  
Box Girder ◽  
Temperature Load ◽  
Concrete Box Girder

During high-temperature asphalt pavement paving, the bridge is subjected to significant temperature variations, and thereby the nonlinear thermal field distribution that occurs in the box girder might threaten the safety and serviceability of the bridge structures. Therefore, this study aims to investigate the thermal field characteristics of reinforced concrete box girder with steel fiber-reinforced concrete leveling layer during asphalt pavement paving. Firstly, a three-dimensional thermal field model of a reinforced concrete segmental box girder was developed and validated using the transient thermal field theory, and the dynamic paving process was simulated by the element deletion method. Secondly, the thermal field model was applied to analyze the vertical, transversal, and longitudinal temperature distribution during asphalt pavement paving. Thirdly, the effects of various sensitive factors on the thermal field of bridge components during asphalt pavement paving were evaluated. Finally, the extreme temperature load model was established through the statistical analysis method, in which the sensitive factors were introduced. Results demonstrate that the proposed numerical simulation method is feasible for thermal field characteristic analysis of reinforced concrete box girder during asphalt pavement paving. In addition, the research results can provide the theoretical foundation for temperature load selection and structural safety design of the concrete box girder during asphalt pavement paving.

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