DEFLECTION CALCULATION OF PARTIALLY PRESTRESSED CONCRETE BEAMS UNDER HEAVY DUTY

To predict bridge deformation laws under existing traffic loads and identifies the main influencing factors of midspan deflection of the structure, this study performed static and fatigue tests on seven pieces of prestressed concrete scale model beams using the pre-tensioning method. The general variation laws and characteristics of deflection were studied, and the calculation method of deflection of partially prestressed concrete beams under heavy loads was discussed. Results demonstrate that the changes of concrete strain along the section height conform to the plane hypothesis. The deflection of prestressed concrete beams under heavy load basically conforms to the "quick-stable-quick" variation law, and the change rate is significantly higher than that under normal operating loads. The deflection after the fatigue cracking of prestressed concrete beams under heavy load can be calculated from the residual and load deflections. Based on the established formula of fitting deflection, the amplification coefficient of deflection during the fatigue steady state is approximately 20%-35%, and the amplification coefficient at critical failure is approximately 80%-100%. This study provides references for the fatigue performance assessment of prestressed concrete beams under heavy traffic loads and the selection of reinforcement time. Keywords: Heavy duty, Fatigue test, Partially prestressed concrete beams, Deflection calculation