(a) template installation overview
The design of this project conforms to the relevant specification requirements of the Code for Design of Timber Structures. The section size of the wooden column is100 mm *100 mm; The diameter of log tail is not less than 70mm. The column spacing is 500mm.
(2) Template preparation before installation
1. Before the template is installed, the project technical director shall make a written safety technical disclosure to the operation team leader, and then the operation team leader shall conduct safety technical disclosure and safety education for the operators. Relevant construction operators should be familiar with the construction drawing and template engineering construction design.
2, the construction site set up reliable measurement control points, meet the needs of template installation and inspection.
3, the template used on site should be in good condition and clean.
4. When the pillars of beam and floor formwork are supported on the soil ground, the ground should be leveled and compacted in advance, and the bottom plate of the column should be prepared.
5. The bottom of vertical formwork installation shall be smooth and solid, and reliable positioning measures shall be taken.
(3) Template installation safety technical measures
1, template installation must be carried out in accordance with the template construction design, it is strictly prohibited to make any changes.
2. The bearing surface under the pillar and diagonal brace should be smooth and padded, and have enough stress area. The foundation formwork must be firmly supported to prevent deformation, and the bottom of the side formwork diagonal brace should be padded. The bottom of the column template should be leveled, and the lower end should be padded with the positioning datum prepared in advance. When the formwork is installed on the column, it should have reliable support points and correct its straightness.
3, the strength of the lower floor structure, when can bear the weight of the upper template, support and new concrete, before, otherwise the lower floor structure support system can't be dismantled, at the same time, the upper and lower pillars should be in the same vertical line.
4, template and its supporting system in the installation process, must set up temporary fixed facilities, to prevent capsizing, after all the columns are installed, should be timely set up in the horizontal and vertical direction bracing, and fixed firmly with the column, when the height of the column is less than 4 meters, should set up two horizontal bracing, between two horizontal bracing, between vertical and horizontal bracing, and then every 2 meters high to add a horizontal bracing, and also need to add a bracing between horizontal bracing, support rod connection.
5, template and its supporting system in the installation process, temporary fixed facilities must be set to prevent capsizing.
6. After the installation of all pillars, horizontal bracing and vertical bracing should be added in time along the horizontal and vertical directions, and fixed firmly with the pillars. Horizontal bracing should be set in the upper and lower directions, and between two horizontal bracing, bracing should be added in the vertical and horizontal directions.
7. The vertical pole of the support should be set vertically, and it is forbidden to pad bricks and other fragile items below. The vertical allowable deviation of 2M height is 15mm.
8, when the beam template support stud adopts a single stud, stud should be located in the center line of the beam template, the eccentricity is not more than 25 mm..
9. Set a longitudinal bracing between the four sides of the full-house template and every four rows of supporting poles in the middle, and connect them from bottom to top.
10, shuttering shall be carried out according to the construction technology, and the next working procedure shall not be carried out before the formwork is fixed.
1 1. When installing column formwork and beam formwork, the facility floor must be installed. Scaffolding should be laid strictly, and protective railings should be set on the outside. It is forbidden to walk on column formwork and beam formwork, and climb up and down with the support of tie rods.
12, when the floor formwork is installed in place, it must be firmly supported, and the horizontal stare blankly under the plate is firmly connected with the support.
13, strong wind of magnitude 5 or above, formwork installation must be stopped.
14, after the template is installed, concrete can be poured only after inspection and acceptance, and the contents of the acceptance certificate should be quantified.
(4) Safety technical measures for formwork removal
1. Before form removal, it is necessary to confirm that the concrete strength meets the requirements, and it can only be carried out after the application for form removal is approved. When the concrete strength report does not meet the requirements, it is forbidden to dismantle the form in advance.
2. Before dismantling the formwork, the safety technical disclosure shall be made to the operation team, and a safety warning line shall be set within the operation scope and warning signs shall be hung. When dismantling the formwork, there shall be a special person (guardian) to guard it.
3. Sequence and method of form removal: according to the principle of supporting first and then removing, remove the non-bearing part first and then the bearing part, from top to bottom.
4. When dismantling the formwork, there should be special personnel to command and practical safety measures, and a work area should be set at the corresponding position. Non-operators are strictly prohibited from entering the work area.
5, thinking should be concentrated at work, to prevent nail feet and sliding template cuts.
6, in case of more than six winds, suspend outdoor high homework.
7, dismantle the template to use a long crowbar, it is forbidden for operators to stand on the template being demolished.
8. There are reserved holes in the floor slab and stair floor slab. After the formwork is removed, do a good job of safety protection railings at the corresponding parts at any time, or cover the holes with cover plates.
9, ripping clearance, will have activities such as template, tie rod, support fixed firmly, beware of sudden fall, collapse cuts.
10. When dismantling the foundation template, first check the foundation template. When unsafe factors such as soft and cracking are found in the earth wall, measures must be taken before people can work. Dismantled formwork and supporting pieces shall not be stacked in the range of 1m at the top of the trough, and shall be transported with the dismantling.
1 1, when dismantling the formwork of plates, beams and columns, attention should be paid to:
(1) When dismantling the formwork more than 2m, scaffolding or operation platform shall be erected, and the scaffolding shall be spread all over, and protective railings shall be set.
(2) It is forbidden to operate on the same vertical plane.
(3) Dismantle them one by one, and do not break them into pieces, pry them off or pull them down.
(4) When the bottom formwork of beam balcony floor is dismantled, temporary support shall be set to prevent the big formwork from falling.
(5) It is forbidden to stand on the cantilever structure and knock off the balcony bottom die.
12, everyone should have enough working faces, and when several people operate at the same time, they should clearly divide their work, unify their signals and proceed.
(5) Calculation
1, beam template basic parameters
Beam section width B = 250.0mm,
Beam section height H=600.0mm,
Beam formwork adopts wood square with cross section of 80×80×80mm,
Beam template section at the bottom of the wood square distance of 500.0mm, beam template section side wood square distance of 400.0 mm. ..
Beam bottom formwork panel thickness h= 18.0mm, elastic modulus E= 10000.0N/mm2, bending strength [f]= 17.0N/mm2.
Beam side formwork panel thickness h= 18.0mm, elastic modulus E= 10000.0N/mm2, bending strength [f]= 17.0N/mm2.
Beam-wood formwork and supporting profile
2, beam template load standard value calculation
Template weight = 0.34kn/m2;
Self-weight of reinforcement =1.50kn/m3;
Concrete weight = 24.00kn/m3;
Standard value of construction load =2.50kN/m2.
The lateral pressure of newly poured concrete and the design value of load generated when pouring concrete should be considered in strength checking calculation; Deflection checking only considers the standard value of load generated by the lateral pressure of newly poured concrete.
The formula for calculating the lateral pressure of fresh concrete is the smaller of the following formulas:
In which, c refers to the gravity density of concrete, 24.000kn/m3; ;
T-initial setting time of fresh concrete, when it is 0 (indicating no data), take 200/(T+ 15) and 5.714h; ;
T -- concrete into the mold temperature, take 20.000℃;
V- concrete pouring speed, 2.500m/h;
H-the total height from the calculation position of concrete lateral pressure to the top surface of newly poured concrete, 0.80m；;
1- additive influence correction coefficient, taking1.000;
2- Correction coefficient of concrete slump, taking 1.000.
In actual calculation, the standard value of lateral pressure of fresh concrete is F 1=28.80kN/m2.
When pouring concrete, the standard load value F2=4.0kN/m2.
3, beam template bottom die calculation
In this example, the moment of inertia I and sectional resistance moment W of the section are:
w=30.00× 1.80^2/6= 16.200cm3；
i=30.00× 1.80^3/ 12= 14.580cm4；
Beam bottom formwork panel is calculated as a three-span continuous beam, and the calculation diagram is as follows
Calculation diagram of beam bottom formwork panel
(1). Calculation of bending strength
The formula for calculating bending strength requires: f = m/w.
F-beam bottom template bending strength calculation value (n/was);
M- calculated maximum bending moment (kn. m)；
Q—— uniformly distributed load acting on the bottom formwork of beam (kn/m);
q = 1.2×(0.34×0.30+24.00×0.30×0.80+ 1.50×0.30×0.80)+ 1.4×2.50×0.30 = 8.5 16kN/m
The maximum bending moment calculation formula is as follows:
m=-0. 1×8.5 16×0.50^2=-0.2 13kn.m
f=0.2 13× 10^6/ 16200.0= 13. 143n/mm2
The calculated bending strength of formwork panel at beam bottom 13. 143 is less than 17.0 N/mm 2, which meets the requirements.
(2) Shear calculation
The formula for calculating the maximum shear force is as follows:
Q=0.6ql
The shear strength of the section must meet the following requirements:
t = 3Q/2bh & lt； [T]
The maximum shear force q = 0.6× 0.50× 8.516 = 2.555kn.
Calculated shear strength of section T = 3× 2554.920/(2× 300.000×18.00) = 0.710n/mm2.
Design value of section shear strength [T]= 1.20N/mm2
The calculated shear strength of beam bottom formwork panel is less than 0.7 10 1.2n/mm 2, which meets the requirements.
(3) Deflection calculation
The maximum deflection calculation formula is as follows:
Where q = 0.34× 0.30+24.00× 0.30× 0.80+1.5× 0.30× 0.80 = 6.222 Newton/mm.
Maximum deflection of three-span continuous beam under uniform load
v=0.667×6.222×500.00^4/( 100× 10000.00× 145800.000)= 1.779mm
The deflection of beam bottom formwork is 1.779 less than 2.0mm, which meets the requirements.
4, beam template side form calculation
The beam side formwork is calculated as a three-span continuous beam, and the calculation diagram is as follows
Fig. Schematic diagram of beam side formwork calculation
(1). Calculation of bending strength
The formula for calculating bending strength requires: f = m/w.
F-beam side template bending strength calculation value (n/was);
M- calculated maximum bending moment (kn. m)；
Q—— uniformly distributed load acting on the beam side formwork (n/mm);
q =( 1.2×28.80+ 1.4×4.00)×0.80 = 32. 128n/mm
The maximum bending moment calculation formula is as follows:
m=-0. 1×32. 128×0.40^2=-0.5 1kn.m
f=0.5 14× 10^6/43200.000= 1 1.899n/mm2
The calculated bending strength of beam side formwork panel 1 1.899 is less than 17.0 N/mm 2, which meets the requirements.
(2) Shear calculation
The formula for calculating the maximum shear force is as follows:
Q=0.6ql
The shear strength of the section must meet the following requirements:
t = 3Q/2bh & lt； [T]
The maximum shear force q = 0.6× 0.40× 32.128 = 7.711kn.
Calculated shear strength of section t = 3× 7710.720/(2× 800.00×18.00) = 0.803 n/mm2.
Design value of section shear strength [T]= 1.20N/mm2
The calculated shear strength of beam side formwork panel is less than 0.803 1.2n/mm 2, which meets the requirements.
(3) Deflection calculation
The maximum deflection calculation formula is as follows:
Where q = 28.80×0.80 = 23.040 N/mm.
Maximum deflection of three-span continuous beam under uniform load
v=0.667×23.040×400.00^4/( 100× 10000.00×388800.000)= 1.0 12mm
The deflection of beam side formwork is less than 1.0 12, which meets the requirements.
5, the calculation of beam bottom template wood top bracing
The stability calculation formula of beam bottom formwork top bracing is
Where n- the load force acting on the top support of beam bottom formwork,
n = 1.2×[0.34×(0.30+2×0.80)+24.00×0.30×0.80+ 1.50×0.30×0.80]×0.50+ 1.4×2.50×0.30×0.50 = 4.585 kn；
I-rotation radius of top bracing, I = 0.289×100.00 = 28.900 mm;
L- calculation length of top bracing, l = 3600.00mm；;
—— The stability coefficient of shaft jacking is determined by slenderness ratio l/i= 124.567;
=0. 193
-top bracing stud compressive strength calculation value; Calculated = 4584.600/(0.193×10000.000) = 2.372n/mm2;
[f]- jacking
Compressive strength design value of vertical pole, [f] =13.00n/mm2;
The calculation of jacking stability is less than 2.372 13.0 N/mm 2, which meets the requirements.
In order to strengthen the stability of the column, Galla plate should be installed at the middle height of the column to reduce the free length.
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