Study on the bearing characteristics of PCCP under temperature effects

Prestressed concrete cylinder pipe (PCCP) is composed of concrete, steel cylinder, mortar and prestressed steel wire, which has been widely used in water conveyance and diversion projects. PCCP employs high-strength concrete, which undergoes a series of temperature responses due to hydration and external temperature variations, consequently affecting its bearing capacity. This study takes a DN3200 embedded prestressed concrete cylinder pipe (PCCPE) as the research object, and a hydration degree calculation model that considers both temperature and concrete age is proposed. The influence of the construction season is taken into account, and a full lifecycle simulation – from production and storage to buried operation – is conducted to investigate the bearing characteristics under temperature effects. The results show that: (1) through the overload failure analysis of PCCP under ideal conditions (without considering temperature effects), it is found that the safest way to determine the bearing capacity of PCCP is by analyzing the stress variation at the inner side of the concrete core invert at the mid-section of the pipeline. (2) After considering the effects of construction-season ambient temperatures, it is found that the higher the construction temperature, the lower the prestress in the concrete core and the greater the stress difference between the inner and outer sides, which has a more adverse impact on the pipeline’s bearing capacity. (3) Under the influence of construction temperatures in different seasons, the bearing capacity of the PCCP concrete core is significantly lower than that under ideal conditions. This study can provide a valuable reference for engineering design and construction.