Post-cast strip is a deformation joint set to overcome harmful cracks caused by temperature and shrinkage during the construction of cast-in-place integral reinforced concrete structure. After a certain period of time, it is closed by post-pouring belt to form an integral structure. Because the structure is connected into a whole by post-pouring belt, the construction quality of post-pouring belt is closely related to the structure quality. Post-cast strip often has large cross section and dense steel bars, so it is difficult to support the formwork, especially debris and garbage are easy to fall into, so it is very difficult to clean up. If the cleaning is not thorough, it will affect the quality of the structure. This paper introduces the structural measures of post-pouring belt construction in a project. Lijing Garden is located in Qi Kui Road, Foshan City, with a total construction area of 63000m2, of which 1 1 storey reinforced concrete frame structure with a construction area of 5 1000m2, basement of about 12000m2 and flat roof structure. The basement floor of this project adopts C35 and P6 impervious concrete with a thickness of 60cm, the wallboard adopts C40 and P6 impervious concrete with a thickness of 30cm, and the basement roof adopts C35 and P6 impervious concrete with a thickness of 45cm. The plane shape is □, the longitudinal length is 143m, one post-poured strip is set in the longitudinal direction, the transverse width is 86m, and three post-poured strips are set in the transverse direction. The reinforcement of the bottom plate and the top plate is double-layered and bidirectional, with a steel mesh in the middle. The reinforced concrete in the post-pouring belt is dense, the overlapping length of reinforced concrete in the post-pouring belt is 950mm, and there is a water-stop steel plate with a thickness of 4mm, so the treatment of the post-pouring belt is more complicated. The design position of post-cast strip in this project is as shown on the right, and the basement floor, roof and wallboard are all poured with post-cast strip. First, the structural measures of post-cast strip of floor are 1. The thickness of the bottom plate of the post-cast strip is 0.6m The post-cast strip adopts 2 Ф 25 steel bars as the skeleton, and the steel mesh is set in the post-cast strip as the side formwork support and bound on the steel bar skeleton. Vertical stud adopts Ф 25 @ 250. In order to ensure the construction quality of the structure, the steel skeleton of post-cast strip shall not be welded on the bottom steel bar. Since the post-cast strip has a certain lateral pressure, the formwork can be fixed as shown in the following figure to resist the lateral pressure of concrete and ensure the accuracy of the formwork position and geometric size. 2. Temporary protection measures for floor post-cast strip During the period when the post-cast strip is vacant, in order to prevent sundries and sewage from entering, the following sealing measures can be taken: build a brick strip with a width of 120mm and a height of 60mm on the upper side of the floor post-cast strip. The corner between the brick belt and the bottom plate is painted into an arc with 1: 2 cement mortar, and the upper part is fully enclosed with plywood or woven cloth. (as shown in the figure below) 2. Structural treatment of concrete wall 1 post-poured strip. Protective measures before backfilling of post-cast strip. Due to the tight construction period of this project and the narrow construction space around the building, the post-construction can only be carried out after backfilling earthwork, leveling the site and hard bottom, so temporary protection measures should be taken for the post-pouring zone of the wall. Our construction plan is to use the brick retaining wall as shown in the figure below to close the post-pouring zone of the wall, and use the ring beam of 240-600 (reinforcement: 4 Ф10 Ф 6 @ 200) to form the facilities to protect the post-pouring zone of the concrete wall, and do a good job in edge safety protection and drainage measures. 2. The protection of the inner side of the wall post-cast strip is fully enclosed with plywood to prevent sundries from falling into it. Three. Structural measures of roof post-cast strip The roof of this project adopts a flat structure with a thickness of 450mm; Part of it is beam-slab structure, with the maximum section size of 250- 1000 and the thickness of120 mm. The structural measures of post-cast strip with flat roof floor are the same as those of post-cast strip at the bottom. Before the post-cast strip is closed, the roof formwork at the post-cast strip shall not be removed. Iv. Problems needing attention in the construction of post-cast strip a) Support scheme of post-cast strip Before the post-cast strip is closed, the beam slab formwork support at the post-cast strip shall not be removed, and other loads shall not be imposed within the span of post-cast strip, such as placing construction equipment and stacking construction materials, to ensure structural safety. B) Temporary protection measures for floor post-cast strip During the period when post-cast strip is vacant, plywood shall be closed to prevent sundries from entering. C) Quality requirements of post-cast strip: The concrete of post-cast strip adopts micro-expansive high-grade waterproof concrete. D) The curing method of post-cast strip concrete is water storage curing. V. Summary According to the construction treatment method of post-pouring belt, the construction period and construction quality are guaranteed. After one year's completion, there is no cracking and water leakage in the post-pouring belt, and the effect is good, which meets the requirements of design and construction acceptance specifications.
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