Prefabrication and erection construction method of prestressed post tensioned 45m T-beam
Content Introduction The Ouchi River Bridge constructed by our project department is a part of Nanxian Maocaojie Bridge on Hunan Provincial Highway 1831, with a total length of 634.48m, a span of 14 × 45m, a total of 14 × 6=84 T-beams, a single beam weighing about 140t, and a concrete grade of C50. 7 φ j15.24mm and 9 φ j15.24mm steel strands, Rby=1860Mpa, and the tension control stress is 0.75Rby, are used for prestressed steel strands in the beam. During the implementation, the key points of construction technology and measures to ensure quality were studied and formulated, namely: large formwork construction technology, early strength and delayed setting concrete pumping, two 90t gantry cranes and highway JQL160t/50m bridge erecting machine combined with beam erecting construction technology, which effectively guaranteed the construction quality and safety. 1. Features ⑴ The T-beam formwork adopts large combined steel formwork, and the formwork sections are located at the diaphragm. The whole T-beam has no joints, which greatly improves the appearance of the T-beam. ⑵ The use of early strength retarding concrete pumping process can reduce one small gantry crane equipment, simplify the concrete transportation process and facilitate the operation. ⑶ The two 90t gantry cranes are used together with the highway JQL160t/50m bridge erecting machine, which can give full play to their advantages and ensure the normal construction even if there is no beam storage site. 2. The scope of application is applicable to 30-50m long span T-beams; The subgrade behind the abutment has been filled or not, but at least two or more T-beams can be set with gantry hangers, and the bridge deck can be used as the assembly site of the bridge erector; Applicable with or without beam storage yard