后张法简支箱梁预应力施工工艺（The prestress construction technology of the post-tensioned box girder）.doc

后张法简支箱梁预应力施工工艺（The prestress construction technology of the post-tensioned box girder） The prestress construction technology of the post-tensioned box girder China railway 19 bureau group fifth engineering co. LTD. Xinxiang girder field Keywords: three control, strength, elasto, age, control stress, tension, periodic calibration, periodic calibration, before use Abstract: after the construction of the prestress construction of the box girder with the latter, the required tensioning equipment includes oil pumps, jacks and 0.25 class anti-shock oil pressure meters. The raw materials are used in a 1 x 7-15.2-1860mpa type low relaxation steel strand. According to the process construction of prestressed construction process, pull rod, clear hole, steel strand processing and production, steel strand wire transfer and so on. The prestressing stress is performed in the three stages of pre-tensioning, the initial tension and the final tension, and the pre-tensioned three control: when the concrete reaches 35.5 MPa, the pre-tensioning can be carried out. When the strength meets the design requirements of 43.5 MPa, the initial tensioning can be carried out. According to the situation, the preliminary and early tensile can be carried out simultaneously, and the precast and the first tensioning can be carried out with the die tensioning. When the concrete strength reaches 53.5 MPa and the elastic modulus reaches 35.5 GPa, the age is greater than 10 days. During the tensioning process, the prestressed values are mainly based on the oil gauge reading, and the elongation value is supplemented, and the three concentric, two synchronization is achieved. Prestressed equipment to do: periodic verification (jack use more than 1 months or 200 times), regular calibration (hydraulic table by collision or oil leakage, oil pointer cannot be returned to the zero point) and before using the check (tensioning, determine if the hydraulic table and jack is properly matched; make jack empty 2-3 ti