In order to study the amount and effect of excess prestress loss, taking a pretensioned PC simply supported beam bridge of a certain line as the background, a group of (3) pretensioned beams under rapid construction were monitored for prestress, and a finite element model was established to analyze the degradation of the crack resistance of the beam under excess prestress loss.
The results show that the friction prestress loss accumulates along the longitudinal direction due to long-line tensioning, and the friction prestress loss exceeds 46 ~ 115mpa; Compared with natural curing, steam curing makes the prestress loss of steel strands exceed 50MPa on average; The elastic modulus of concrete during early age release is insufficient, resulting in an excess of 40MPa of elastic compression prestress loss; In the process of rapid construction, the cumulative prestress loss exceeded 153mpa, resulting in the cracking resistance of the beam body decreased by 11%.
Research on excess prestress loss caused by rapid construction of pretensioned PC Beams Yang Yongqing 1, sun Baolin 1, Li Xiaobin 1, 2, Yan Meng 1, 2, Wang Ruiji 2 (1.
School of civil engineering, southwestjiaotonguniversity, Chengdu, Sichuan 610031; 2.
It is suggested to optimize the construction process by changing the roller steering gear, adjusting the steam curing system and delaying the tensioning, so as to ensure the safety, applicability and durability of the structure while realizing the rapid construction…
Sichuan Jiaotong University Engineering Inspection and Consulting Co., Ltd., Chengdu, Sichuan 610031) Summary: pretensioned PC Beams realize rapid construction through long-term tensioning, steam curing, and early age tensioning, However, during this period, excessive prestress loss is accompanied, which significantly affects the crack resistance of the beam.
