The time of formwork removal in construction stipulates the general requirements for formwork removaRelease Time : 2022-07-13 View Count : 次
The strength of concrete during formwork removal shall meet the design requirements; When there are no requirements in the design, the following provisions shall be met:
The non load bearing side formwork, including the side formwork of beams, columns and walls, can be removed as long as the concrete can ensure that its surface and edges and corners will not be damaged due to the removal of the formwork.
The bearing formwork, including the bottom formwork of horizontal structural members such as beams and slabs, can be removed only after the strength of the test block cured under the same conditions as the structure reaches the provisions in the table below.
In the process of formwork removal, if it is found that the actual concrete strength does not meet the requirements, and there are quality problems affecting the safety of the structure, the formwork removal should be suspended. After proper treatment, the actual strength can be continued after meeting the requirements.
The concrete structure with the formwork and its support removed shall not be allowed to bear all the designed service loads until the concrete strength reaches the designed standard value of concrete strength. When the effect of bearing the construction load is more unfavorable than the use load, it must be calculated and added with temporary support.
The core formwork or the internal formwork of the reserved hole can be removed only when the concrete strength can ensure that there is no collapse and crack. Before formwork removal, there must be a formwork removal application, and the technical director can approve formwork removal only when the strength record of the curing test block under the same conditions meets the requirements.
The formwork and support frame of the post cast strip cannot be removed without the approval of the technical director. The post cast strip area shall not be removed when the span is reserved. If it is removed without permission, it will be punished at 20000 yuan per span. The formwork and support frame at the lifting opening and cantilever end shall not be removed without permission.
For mass concrete, in addition to meeting the concrete strength requirements, thermal insulation measures should also be considered. After formwork removal, ensure that the temperature difference inside and outside the concrete does not exceed 200C, so as to avoid temperature difference cracks.
When the formwork is removed, the strength of the concrete must meet certain requirements. If the concrete does not meet the specified strength and the formwork needs to be removed in advance, it must be removed after calculation (leave more concrete test blocks, and the concrete test blocks have been tested before formwork removal) to confirm that its strength can be removed.
The sequence and method of formwork removal shall be carried out in accordance with the provisions of the formwork support design document, or the method of first supporting and then removing, the latter supporting and then removing, the non load-bearing formwork first, and then the load-bearing formwork, and the principle of top-down shall be strictly followed.
The removed formwork must be cleaned up as soon as it is removed, and the removed square timber and wood plywood must be stacked in bundles as soon as it is removed, so as to prevent the steel pipe from being damaged.