How to install the steel formwork of Hubei bridge

1. Bottom form of bridge steel formwork: erect 10×10cm square wood longitudinally on the distribution beam of the support and nail it firmly , Nail a large piece of bamboo glue board of 2440×1220×16mm on the square timber. The template must be close to the square timber. The longitudinal slope and height of the bottom of the beam are accurately set by adjusting the square timber. Hubei Wangke Formwork Co., Ltd. To ensure that the formwork is clean before concrete pouring, 0.3m*0.3m holes are reserved on both sides of the end as cleaning ports. After the template is cleaned before pouring, plug it.

2. The outer template and flange template of the bridge steel template: The outer template adopts a large piece of smooth bamboo plywood. The outer lining of the double-row steel pipe back-to-back is equipped with 3 rows of tie rods, which are drawn opposite to the inner mold with Φ20 tie rods. The longitudinal spacing of the tie bars is 0.9m, and the vertical spacing is 0.6m.

3. Head template and flange end template: The end template also uses bamboo plywood nailed square wood as The template is cut according to the section size due to the steel and prestressed pipe holes. The holes must be accurately positioned and cut according to the positions of the steel bars and prestressed pipes. The size and position of the notch template of the prestressed tension end shall be accurate.

4. Bridge steel formwork inner mold: Carry out the box after the construction of the bottom, web reinforcement and prestressed tunnel is completed The beam inner mold is installed, and the inner mold is made of 16mm bamboo plywood. The inner form of the box girder is supported by φ48×3.5 scaffold pipes, and the columns are supported on the channel steel on the top of the reinforced bench ribs on the top surface of the bottom form. The scaffold pipes are arranged in a row along the bridge at a distance of 0.9 meters, with 7 per row. And each row needs to be equipped with scissor braces and vertical and horizontal horizontal braces to increase the overall stability of the bracket and prevent the inner mold from expanding; the inner mold is equipped with 3 rows of tie rods, and the Φ20 tie rods are used to pull it against the outer mold, and the ribs are longitudinally stretched. The spacing is 0.9m, and the vertical spacing is 0.6m. Columns cannot be directly supported on the top of the bottom mold, and concrete pads must be placed between the two to isolate them.

5, bracket pre-compression

Pre-compress the bracket after the bottom mold and the outer mold are assembled

1.1. The purpose of bracket pre-compression is to check the overall stability of the bracket and to verify whether the strength and rigidity of the bracket meet the requirements , To ensure the safety of construction; eliminate the influence of inelastic deformation of the foundation and support, and determine the elastic deformation of the support at the same time.

1.2, the pre-compression load is 120% of the beam's own weight. This scheme adopts sandbag heavy pressing method for pre-pressing. The designed beam volume is 1458.66m3, and the weight of the reinforced concrete is calculated at 2.6t/m3, that is, the weight of the beam is 3792.52t. When preloading, consider preloading by multiplying the weight of the beam by a safety factor of 1.2.

1.3. The order of sand bag loading should imitate the order of beam construction as much as possible. Load the bottom plate first, then the belly Plate, stacking top plate and wing plate. The stacking is carried out by grading. Since most of the weight is located on the bottom web, the load of the bottom, web and the middle part of the top is considered to be evenly distributed on the bottom.

1.4. After the loading is completed, the load should be observed for 24 hours, once every 4 hours, and make a record, When the support is stable (the deformation of the support for 24 hours is less than or equal to 2mm), it is unloaded and carried out in order according to the loading reverse procedure.