Q. Guo, China, Z. Li, Prof., China, L. Duan, Sr. Bridge Eng., USA
The prestress tensioning process is very important to prestressed concrete and is a complicated non-linear process of force distribution and transfer. Predictability of the resultant of tension force is a principal requirement to ensure structural serviceability and capacity.
Once the control of prestress tensioning is lost, cracks or over-stressing may occur in the concrete that could lead to corrosion of the prestressing reinforcement. Accidents caused by losing control of tensioning, and which result in the collapse of the prestressed structure or even fatalities, take place frequently. The paper presents the concept and development of an automatic post tensioning system. The comparisons between calculated and measured values of prestress losses in an actual project are discussed. Application in a prestressed concrete structure shows that automatic post-tensioning technology can control prestress tensioning with high accuracy and efficiency.
