Modeling the effect of temperature on strength development for cast-in-place box girder

Abstract

In this paper, winter construction of cast-in-place box girder of Rongwu Expressway Project is taken as the research object. By analyzing the internal temperature field development data of box girder concrete structure and using MIDAS FEA finite element software, the simulation results are similar to those in the field. The development of concrete internal temperature field at ambient temperature 0°C and -10°C is calculated. The strength prediction of cast-in-place box girder concrete structure at lower internal temperature was carried out by using the maturity model established in laboratory test. With the decrease of ambient temperature, the internal temperature of cast-in-place box girder concrete structure decreases. The lower temperature of concrete in box girder is the edge part of the two flank plates, the windward side and the combined part of old and new concrete. Based on the maturity theory established earlier, the 5d tensile strength of different parts was calculated. Under 0°C and -10°C conditions, the minimum strength of the edge of cast-in-place box girder concrete wing plate is 47 MPa and 41.2 MPa, the minimum strength of the junction of new and old concrete is 50.5 MPa and 50.3 MPa and the minimum strength of the windward side is -52.2MPa and 51.2MPa respectively. The edge of the wing plate and the interface of new and old concrete should pay special attention to the protective insulation measures.