(1) Before concrete pouring of box girder, the first procedure is steel bar binding, and before that, support erection, preloading and acceptance are carried out.
(2) The bridge crosses the international road and vehicles need to pass. Full-house support is adopted, and the selection is improper. Bailey beam with steel pipe column or steel support shall be adopted.
(3) Full-house support is too general, and the only steel pipe support suitable for box girder pouring is the buckle support, but it is not suitable due to the traffic restriction of national highway. Other portal steel pipe supports, fastener-type steel pipe supports and bowl-type steel pipe supports belong to the backward technology eliminated by the transportation industry and shall not be used for cast-in-place box girder construction.
Before box girder concrete pouring, safety supervision mainly includes:
(1) Before the full-house support site hardens, check whether the foundation bearing capacity meets the requirements of the special construction scheme and whether the surrounding drainage facilities are unobstructed.
(2) Check whether the hardened thickness and concrete strength of the site meet the requirements of the special construction scheme.
(3) Before the erection of full-house support, check the qualification and safety training of scaffolder and other special operators.
(4) Check whether the model, diameter, wall thickness and scaffold template of Mantang scaffold steel pipe meet the requirements of special construction scheme. Check whether the vertical and horizontal erection spacing, vertical poles, horizontal poles, sweeping poles, shear braces and diagonal braces of the full-house support meet the requirements.
(5) Check whether the support deformation and foundation settlement meet the requirements after preloading.
(6) Check the implementation of the emergency plan.
(7) In accordance with the Measures for the Administration of Safe Site Construction of Highway and Waterway Projects, check the safe production conditions of the sub-projects with greater risks before construction, and report the verification results to the construction unit for confirmation.
Check whether other safety protection measures conform to the provisions of the special construction plan.