Check the verticality again before concrete pouring; After the installation of roof and beam formwork, the elevation, levelness, height difference of adjacent slab surfaces and the cross-section size of beam formwork shall be measured; During the structural construction, the general contractor and the supervision unit shall strictly control the elevation and camber of the floor formwork and beam bottom formwork, and check the elevation of the slab floor and beam bottom with a level gauge before binding the reinforcement.
Formwork acceptance – common problems Part5 formwork engineering quality I.
The columns of upper and lower supports shall be aligned and base plates shall be laid; There shall be no mortar leakage at the joint of formwork.
When removing the column under the beam with large span, it shall be removed from the middle of the span to both ends.
When applying release agent, the joint of reinforcement and concrete shall not be stained; Before pouring concrete, the garbage in the formwork shall be cleaned up; For fair faced concrete walls and decorative concrete walls, formwork that achieves the expected design effect shall be used; The embedded parts, reserved holes and reserved holes fixed on the formwork shall not be omitted, and shall be installed firmly.
axis displacement 1 Phenomenon: when removing the formwork after concrete pouring, it is found that the actual position of the column and wall is offset from the axis position of the building; 2.
At the same time, the technicians, quality inspectors and supervision engineers of the general contractor are required to inspect the formwork support system to ensure that the formwork support system is stable and reliable; In the process of concrete pouring, the general contractor shall assign formworks to track and observe the formwork.
The floor formwork support system shall be carried out in the following order: horizontal cross bar – supporting vertical bar – square timber joist – platform formwork – finishing and oiling – stacking as required.
Part4 formwork acceptance during formwork installation, the general contractor and the supervision unit shall inspect in strict accordance with the installation and reinforcement system and quality control requirements of each node of the formwork project, formulate inspection and acceptance records, directly represent the inspection records in the plan (participate in the small sample drawing of formwork acceptance), and timely feed back the problems to the construction team for rectification, The next procedure can be carried out only after the rectification is qualified; After the wall column formwork is installed, the perpendicularity and position of the wall column formwork shall be measured.
The removal of side formwork shall be carried out from top to bottom; Removal of multi-storey floor formwork pillars: when the upper formwork is pouring concrete, the pillars of the next floor slab shall not be removed, and only part of the pillars of the next floor slab can be removed.
Requirements for formwork removal: generally, the formwork shall be removed after it is supported first, and the latter shall be removed first.
The formwork columns of the next floor can be removed only when the floor concrete reaches the design strength.
The supervision unit shall also check the verticality of the formwork and the levelness of the roof during the pouring process.
The installation of window openings shall be controlled.
Cause analysis: the turnover is not serious or the technical disclosure is not clear, and the assembly is not in place as required during formwork assembly; Deviation of axis measurement and setting out; The infinite measures or limit at the bottom and top of the wall and column are not firm, and the deviation is not corrected in time, resulting in cumulative error; During formwork erection, horizontal and vertical through lines are not drawn, and there are no vertical control measures; The rigidity of the formwork is poor, the horizontal tie rod is not set or the spacing between the tie rods is too large; During the concrete pouring process, the blanking is not uniform, or the side pressure is too high due to one-time pouring, which squeezes the formwork; The axis deviation is caused by improper or loose use of pull screw, top support and wooden wedge..
Construction supervision; real-time understanding of construction industry information and more in-depth good articles; sources of concern: pingda consulting, Douding construction General regulations and requirements of Part1 formwork project of Rizhao construction supervision Association part2 support system erection and construction requirements process flow materials selection of control line elevation of setting out axis of formwork matching project beam bottom reinforcement wall beam joint column formwork frame shear wall formwork roof formwork slab joint treatment, exterior wall joint treatment, formwork joint treatment Definition of high formwork and high formwork in kitchen and bathroom regulations for high formwork part3 formwork installation and removal during formwork installation, the formwork and support shall be observed and maintained.
Therefore, during concrete pouring, the formwork removal test block cured under the same conditions must be reserved, and can be removed only when the strength of the test block reaches the formwork removal strength; Order and requirements of formwork removal: the formwork removal shall be carried out according to the principle of supporting first and then removing.
Floor type window openings shall be constructed according to the original construction method, and other window openings must be installed with stereotyped formwork; Doors and windows openings and openings more than 1500mm wide adopt 15mm thick multi-layer plates and 50 × 100 wood square, L160 for external corner × one hundred and sixty × The angle steel of 10 is fixed with the wood formwork, and the internal angle is L75 × seventy-five × 10 angle steel, through φ 16 screw is fixed with external angle steel and drilled on the side of door and window opening formwork more than 1500mm wide φ 15 holes, where an exhaust hole is formed.
If any abnormality is found, it shall be handled according to the construction scheme; When installing the upper formwork and support of cast-in-situ structure, the lower floor slab shall have the bearing capacity to bear the upper load, or add support.
It shall be carried out again before the initial setting after pouring is completed, and the verticality and roof levelness of wall column formwork shall be rechecked with infrared level.
The non load-bearing parts shall be removed first, and then the load-bearing parts shall be removed, so as not to damage the components or formwork; For ribbed floor, the column formwork shall be removed first, then the slab bottom formwork and beam side formwork, and finally the beam bottom formwork.
Add additional reinforcement on the wall reinforcement around the opening, spot weld steel support on the additional reinforcement, use steel support to support the opening formwork, and set diagonal bracing on the opening formwork to prevent the deviation of the opening formwork; Control of formwork removal time: the formwork can be removed above the cantilever beam with a strength of more than 2 meters, and the formwork can be removed above the beam and slab with a concrete strength of 75%.
Before pouring concrete, the formwork shall be cleaned, and the wooden formwork shall be watered and wetted, but there shall be no ponding in the formwork; The contact surface between formwork and concrete shall be cleaned and coated with release agent, but the release agent that affects the structural performance and hinders the later decoration construction shall not be used.
For beams with a span of 4m and more than 4m, columns shall be reserved, and the spacing shall not be greater than 3m.
If deformation and slurry leakage are found, measures must be taken in time.
