Techno Press
Techno Press

Computers and Concrete   Volume 20, Number 5, November 2017, pages 529-537
DOI: http://dx.doi.org/10.12989/cac.2017.20.5.529
 
Thermo-mechanical behavior of prestressed concrete box girder at hydration age
Gang Zhang, Meichun Zhu, Shuanhai He and Wei Hou

 
Abstract     [Full Text]
    Excessively elevated temperature can lead to cracks in prestressed concrete (PC) continuous bridge with box girder on the pier top at cement hydration age. This paper presents a case study for evaluating the behavior of PC box girder during the early hydration age using a two-stage computational model, in the form of computer program ANSYS, namely, 3-D temperature evaluation and determination of mechanical response in PC box girders. A numerical model considering time-dependent wind speed and ambient temperature in ANSYS for tracing the thermal and mechanical response of box girder is developed. The predicted results were compared to show good agreement with the measured data from the PC box girder of the Zhaoshi Bridge in China. Then, based on the validated numerical model three parameters were incorporated to analyze the evolution of the temperature and stress within box girder caused by cement hydration heat. The results of case study indicate that the wind speed can change the degradation history of temperature and stress and reduce peak value of them. The initial casting temperature of concrete is the most significant parameter which controls cracking of PC box girder on pier top at cement hydration age. Increasing the curing temperature is detrimental to prevent cracking.
 
Key Words
    prestressed concrete box girder; hydration heat; FEM; test; thermo-mechanical behavior; parametric analysis
 
Address
Gang Zhang, Shuanhai He and Wei Hou: School of Highway, Chang
 

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