Supervision disclosure of a highway bridge deck system in Shanghai
1、 Preparation stage of concrete bridge deck pavement construction: 1. Check the installation of bearings to prevent void, deflection, shear deformation, etc. If similar conditions are found, rectify them as soon as possible, and prepare for the construction of bridge deck pavement. If the installation of bearings is unqualified, the construction of bridge deck system is not allowed. 2. Check the installation of beam and slab to prevent the width of expansion joint, the difference between the top surfaces of adjacent beams (slabs), and the height of beam top from exceeding the specification requirements. The construction of bridge deck system is not allowed if the beam and slab installation is not inspected and qualified. 3. Raw materials such as cement, sand, stone, admixtures, reinforcement, mesh reinforcement, etc. shall be inspected and qualified, and their stacking shall meet the specification requirements Construction stage: 1. Clean the bridge deck: thoroughly clean all sundries and loose objects on the surface of the beam and slab, including loose concrete on the surface of the beam top, mortar left over from construction hinge joints or wet joints, etc., and then use high-pressure water gun to wash or forest fire extinguisher to blow off any floating dust. (Note: when cleaning the bridge deck, the surface of the beam top should also be inspected, and if there is any defect, it should be repaired and reinforced in time) 2. The continuous structure of the bridge deck should be set up: first clean up the debris left in the expansion joint, then fill the expansion joint with plastic foam according to the design requirements, lay polyethylene rubber plates, and then lay continuous structure reinforcement bars 2、 Construction preparation stage of concrete guardrail: 1. Get familiar with the design of construction drawings, understand the design intent (including the embedding of pipelines and junction boxes, and the reservation of drainage holes on the bridge deck), and put forward questions about the design at the design disclosure meeting; 2. Application for inspection of reinforcement raw materials, submission of welding test pieces, concrete mix ratio verification test; 3. Surveying and setting out: the measuring points in the curve section shall be densified to ensure the roundness of the line and the width of the bridge deck; 4. The end of the flange plate of the edge beam shall be fully roughened, and loose concrete and sundries shall be removed; 5. Technical disclosure shall be made to the construction team, safety education shall be given to the mobilized personnel, and pre job training shall be given to the workers; 6. Application of construction scheme and commencement report; 7. Formwork inspection and trial assembly. Construction stage: 1. Rebar welding, binding and forming: ① the quality of vertical welding should be guaranteed; ② CO2 gas shielded welding should also take test weldments, and wind prevention measures should be taken on site; ③ the overlapping length of longitudinal rebars should be ≥ 25d, Grade II reinforcement ≥ 35d ④ Welding rod shall be protected from moisture, 422 welding rod is not allowed to be used ⑤ The thickness of protective layer shall be ensured, no exposed reinforcement is allowed, and it shall not be too large ⑥ It is not allowed to stack too many reinforcement on the bridge deck, and it shall be covered with rain proof ⑦ Welding slag at the welding head shall be cleaned before application for inspection ⑦ Hanging basket shall be made for the installation of external reinforcement, and workers shall wear safety belt during operation 2800 words
