Construction safety knowledge points for the registered safety engineer examination – formwork installation and removal

The template construction and installation should comply with the following regulations:

(1) The formwork installation should be assembled in the order of the design and construction instructions. Support columns such as wooden poles, steel pipes, and door frames must not be mixed.

(2) When the vertical formwork and support column support parts are installed on the base soil,backing plates should be added The backing plate should have sufficient strength and supporting area, and should be centrally loaded. The base soil should be solid and there should be drainage measures. Waterproofing measures should be taken for collapsible loess; for particularly important structural projects, concrete, piling and other measures can be used to prevent the support columns from sinking. Measures should be taken to prevent frost-heaving soil from freezing and thawing.

(3) During the installation process of the template and its bracket, effective prevention must be set Overturned temporary fixtures.

(4) For cast-in-place reinforced concrete beams and slabs, when the span is greater than 4m, the formwork should Arching; When there are no specific requirements in the design, the arching height should be 1/ 1000~3/ 1000 of the full span length.

(5) For cast-in-situ multi-story or high-rise houses and structures, the installation of upper formwork and its brackets should comply with the following regulations: Lower floor slab It should be able to withstand the construction load of the upper layer.load capacity, otherwise support brackets should be added;The upper bracket columns should be aligned with the lower bracket columns, and pads should be laid at the bottom of the columns; When the cantilever hanging formwork and truss formwork methods are used, the support structure The load-bearing capacity and stiffness must meet the design and construction requirements. (6) When the inter-story height> 5m, truss formwork or steel pipe column formwork should be used. When the inter-layer height ≤ 5m, wooden columns can be used to support formwork.

When assembling vertical formwork with a height of more than 2m, you are not allowed to stand on the lower formwork Assemble the upper template. Temporary fixed facilities should be set up during installation.

The structure and installation of bracket columns supporting beams and plates should comply with the following regulations: (1) The vertical and horizontal columns of beams and plates should be The spacing should be equal or multiple. (2) Wooden posts should be set with pads at the bottom and support heads at the top. The steel pipe columns should be provided with pads and bases at the bottom, and adjustable supports should be provided at the top. The screw rod shall not protrude from the top of the steel pipe by more than 200mm. (3) At a height of 200mm from the bottom of the column to the ground, sweep poles should be installed in the vertical, horizontal and horizontal directions according to the vertical and horizontal procedures.

When the floor height is 8~20m, at the top step strong>A horizontal pull shouldbe added between the two horizontal tie rodsRods; When the floor heightis greater than 20m, a horizontal tie rod should be added between the top two steps of the horizontal tie rods.

The removal period of the formwork should comply with the following regulations:

① The non-load-bearing side formwork should be used only when the strength of the concrete can ensure that its surface and edges will not be damaged by removing the formwork. Dismantling, the dismantling time should be 12 hours later.

②The load-bearing formwork can only be removed after the concrete strength meets the requirements in the table below.

(2) In addition to meeting the concrete strength requirements, the form removal time for large-volume concrete should also ensure that the temperature difference between the inside and outside of the concrete drops below 25°C. Otherwise, effective measures should be taken to prevent temperature cracks from occurring.

(3) Before removing the mold, check that the tools used are effective and reliable. Wrenches and other tools must be put into tool bags or systems. Hang it on your body and check the safety measures within the mold removal site.

(4) The dismantling work of the formwork should be directed by a dedicated person. The work area should be fenced, no other types of work should be allowed within it, and a dedicated person should be assigned to monitor it. It is strictly prohibited to throw the removed templates and spare parts.

(5) The order and method of formwork removal should be carried out according to the design regulations of the formwork. When there is no provision in the design, the first support can be removed first, and the rear support can be removed first. Non-load-bearing formwork should be dismantled from top to bottom. The removed formwork should not be thrown away and should be stacked in designated locations.

(6) When dismantling formwork at high places, regulations on high-altitude operations should be followed. It is strictly prohibited to use sledgehammers and crowbars. The temporarily removed formwork on the operating level should not be stacked more than 3 layers. .

(7) The structure where the formwork has been removed can bear all the design load only after the concrete strength reaches the design strength value. If it is necessary to add construction load to the structure before the design strength is reached. , should be calculated separately, and if the strength is insufficient, temporary supports should be added.