Blog

8-4-1 Loose Support and Disassembly Plywood Formwork

The plywood used for concrete formwork is plywood formed concrete and plywood shuttering board. Plywood used as concrete formwork has the following advantages.

(1) The plywood shuttering sheets width is large, light weight, and the board surface is flat. Can reduce the installation workload, saving site labor costs, and can reduce the cost of decorating the exposed surface of the concrete and grinding away the joints.

(2) Large load-bearing capacity of black shuttering plywood, especially after surface treatment with good wear resistance, can be repeatedly used.

(3) Light material, 18mm thick wood plywood, the weight per unit area is 50kg, the transportation, stacking, use and management of the formwork are more convenient.

(4) Good insulation performance suraksha shuttering ply, can prevent temperature changes too fast, winter construction helps the concrete insulation.

(5) Convenient for sawing and cutting, easy to process into various shapes of formwork.

(6) Easy to bend and shape according to the needs of the project, used as curved formwork.

(7) Phenol film 12mm used for clear concrete formwork, the most ideal.

In 1981, plywood formwork was used for the first time in the construction of high-rise cast-in-place flat structure of Nanjing Jinling Hotel, and the superiority of best quality shuttering plywood was recognized for the first time. At present, in the construction of high-rise cast-in-place concrete structures in large and medium-sized cities all over the country,shuttering plywood sheets has been used in a considerable amount.

Request a quote ,free sample

8-4-1-1      Wooden plywood formwork

Wood plywood can be divided into softwood plywood (species of horsetail pine, yellow pine, larch, red pine, etc.) and hardwood plywood (species of wrought wood, birch, ash, poplar, paulownia, etc.) from the classification of species. From water resistance, plywood is divided into four categories.

1. class – with high water resistance, good boiling water resistance, the adhesive used is phenolic resin adhesive (PF), mainly used for outdoor.
   1. Class – water and moisture resistant plywood, the adhesive used is melamine modified pulse-formaldehyde resin adhesive (MUF), which can be used in high humidity conditions and outdoors.
      1. Class – moisture resistant plywood, the adhesive is pulse-formaldehyde resin adhesive for indoor use.
      1. Class – not resistant to water, not resistant to moisture, bonded with blood powder or soybean powder, which has been discontinued in recent years.

Concrete formwork with wood plywood is highly weather-resistant, water-resistant class I plywood, the adhesive is

Phenolic resin glue, mainly with clone, Abidon, Liouan, birch, horsetail pine, Yunnan pine, larch and other tree species processing.

1. Structure and specifications

(1) Structure of construction plywood sheets

The wood plywood for formwork is usually made of 5, 7, 9, 11 layers and other odd layers of veneer cured by hot pressing and glued together. The grain direction of adjacent layers is perpendicular to each other, and usually the grain direction of the outermost surface is parallel to the long direction of the plywood surface, so that the long direction of the whole plywood is strong, and the short direction is weak, which must be noted when using.

(2) Specifications of film faced birch plywood

China’s template with wood plywood size specifications, see Table 8-53.

Specification size of wood plywood for formwork Table 8-53

2. Gluing performance and load-bearing capacity

(1) Gluing performance

The adhesive of plywood for formwork is mainly phenolic resin. Such adhesives have high bonding strength, water resistance, heat resistance, corrosion resistance and other properties, and its outstanding boiling water resistance and durability. There is also the use of chemically modified phenolic resin adhesive.

There are two main indicators for evaluating the adhesive performance.

Gluing strength – for the initial gluing performance, refers to the veneer after gluing completely sticky, there is sufficient strength film coated plywood

Gluing durability – for long-term gluing performance, refers to a certain period of time, but still maintain a good gluing 18mm shuttering ply wickes.

The above two indicators can be determined by the glue strength test, boiling water impregnation test plywood formwork for concrete.

In the professional standard ZBB70006-88 “Plywood for concrete formwork”, the bonding strength of wood plywood for concrete formwork is specified in Table 8-54.

Gluing strength index value of plywood for formwork Table 8-54

Construction units in the purchase of concrete formwork with plywood, the first thing to discern whether it belongs to Class I plywood, that is, to discern whether the batch of film faced plywood using phenolic resin glue or other adhesives with equivalent performance. If the test conditions, can not do the bonding strength test, you can use boiling water to boil small pieces of specimens quickly and simply discriminate. The method is from the plywood for construction saw cut off 20mm square small pieces, put in boiling water boiling 0.5 ~ 1h. The specimen with phenolic resin as adhesive black film faced plywood will not be decoupled after boiling, while the specimen with pulse-formaldehyde resin as adhesive will be decoupled after boiling.

(2) Load-bearing capacity

The load-bearing capacity of film faced plywood price is related to the thickness, static bending strength and elastic modulus of plywood. Table 8-55 shows the standard of “Plywood for concrete formwork” (ZBB70006-88) stipulated by the Ministry of Forestry of China.

Longitudinal bending strength and modulus of elasticity of plywood for formwork Table 8-55

Due to the production of phenolic film faced plywood species and origin vary, the mechanical properties of plywood is also unstable, the values in Table 8-55, only for the guidance of the production plant with, not for the use of units of plywood assessment indicators. The technical specification for Steel Framed Plywood Forms (JGJ96-95) specifies the main technical properties of concrete form plywood suppliers near me for concrete forms for reference (Table 8-56)

Request a quote ,free sample

Standard values of static flexural strength and modulus of elasticity N/mm2 of plywood ^Table 8-56

Note: 1. parallel to the direction of the fiber parallel to the plywood sheet; vertical to the direction of the fiber perpendicular to the plywood sheet.

• When the column or tie rod is directly supported on the plywood, the standard value of shear strength of plywood should be greater than 1.2N/mm2.

If the construction unit needs to be purchased concrete form plywood suppliers near me, to determine its static bending strength and modulus of elasticity, can be tested and calculated according to the following methods.

(1) from the test for the plate arbitrarily intercepted and the table board wood fiber parallel to the length of 25 times the thickness of the plate plus 50 mm and width of 75 mm test pieces 6 pieces. Specimens should be straight and smooth around.

2) Assemble the specimen according to the test device shown in Figure 8-231. The support distance L is 25 times the thickness of the specimen, but not less than 175mm. The indenter must coincide with the centerline of the specimen length. When the indenter touches the test piece on the force gauge disk load is zero, adjust the pointer of the percentage meter to zero.

Figure 8-231 static bending strength and modulus of elasticity testing device used shuttering ply for sale

1 – indenter; 2 – test piece; 3 – support; 4 – percentage table

3) Slowly and evenly add the load. Stop the test piece at least 5 times in sections before the test piece is damaged, record the pressure and corresponding deflection at 5 points, and record the damage pressure. The pressure value is accurate to 1N, and the deflection value is accurate to 0.01mm 18mm shuttering ply price.

(4) Draw the pressure – deflection curve. Determine the slope of the curve, according to the pressure and deflection value of the test, the pressure P (N) as the vertical coordinate, the deflection Y (mm) as the horizontal coordinate, record all the test points on the coordinate paper, and according to the proportional limit of each point (not less than 3 points) to make the slope line, find the slope value P / Y (N / mm) 9mm shuttering plywood.

(5) modulus of elasticity E is calculated according to the following formula.

Where plywood modulus of elasticity (N/mm2).

Support distance (mm).

Width of the specimen (mm).

Thickness of the specimen (mm).

Specimen slope value (N/mm).

The value of the modulus of elasticity is taken as the arithmetic mean of six specimens.

(6) static bending strength in best shuttering plywood. Calculated according to the following formula

Where plywood static bending strength value (N/mm2)

The test piece of plywood on frame boat building damage pressure (N)

Support distance (mm)

The thickness of shuttering plywood b&q the specimen (mm)

The width of the waterproof shuttering plywood price specimen (mm)

Static bending strength value to take the arithmetic mean of six specimens.

Request a quote ,free sample

Use precautions

1. must be used after the shuttering plywood near me surface treatment of plywood.

Without plate surface treatment of waterproof shuttering plywood, because of the concrete hardening process, plywood and concrete interface between the cement – wood bonding force, so that the plate surface and concrete bonding more firmly, easy to tear the plate surface wood fibers when demoulding, affecting the quality of the concrete surface. This phenomenon increases with the number of times the plywood is used and gradually aggravated.

The plywood treated by the film cover, increased the durability of the board surface, mold release performance, smooth appearance, the most suitable for special requirements, the external surface of concrete without final decoration treatment of clear concrete projects, such as concrete piers, overpasses, silos, chimneys and towers.

2. without plate surface treatment of plywood (also known as white bad plate or plain plate), in use before the plate surface should be processed. The method of treatment is cold paint, the paint cured at room temperature glue painted on the surface of the plywood, forming a protective film shutter ply board.

3. by the surface treatment of plywood, construction site use, should generally pay attention to the following issues.

(1) immediately after demoulding to clean the board surface floating pulp, stacked neatly.

(2) template removal, throwing is strictly prohibited, so as not to damage the plate surface treatment layer.

(3) the plywood corners should be coated with sealing glue, so the cement paste should be removed in time. In order to protect the edge sealant of the template, it is best to paste waterproof tape or cement paper bag at the template joints when supporting the mold to protect it from leakage.

(4) Plywood board phenolic film surface as far as possible without drilling holes. In case of reserved holes, ordinary wooden boards can be used for patching.

5）The site should be equipped with repair materials, so that the damage to the panel in time to repair.

(6) Must be coated with release agent before use.

8-4-1-2 birch plywood template

China’s shuttering plywood 12mm resources are abundant, and construction plywood has the characteristics of fast growth and short production cycle (generally 2~3 years into timber). In addition, the general tensile strength of bamboo is 2.5 times that of pine and 1.5 times that of red pine; the cross-grain compressive strength is 6~8N/mm2, which is 1.5 times ^that of fir and 2.5 times that of red pine; the static bending strength is 15~16N/mm2. Therefore, in the case of shortage of wood resources in China, 12mm shuttering ply for making concrete formwork is a new type of construction formwork with a promising development because of its small shrinkage rate, low expansion rate and water absorption rate, and large load-bearing capacity.

1. Composition and structure

Concrete formwork with film faced shuttering plywood, its panel and core board materials used both different, but also the same. Different material is the core board will be split into poplar strips, 3 ~ 5mm thick, in the softening pool for high-temperature softening treatment, for baking green, baked yellow, to bamboo clothing and drying and other further processing. The weaving of birch plywood curtain can be done manually or by weaving machine. The panel is usually woven mat veneer, the practice is to split the pine plywood into pieces of contempt, woven into hardwood plywood mat by the weaver. The surface board is made of thin wood plywood. This can make use of bamboo resources, and also have the surface flatness of wood plywood.

In addition, there is also the use of shuttering plywood 18mm mat for the panel, the surface flatness of this plate is poor, and the amount of adhesive is more. construction grade plywood cross-sectional structure, see Figure 8-232.

Request a quote ,free sample

Figure 8-232 poplar construction grade plywood cross-sectional schematic

1 – concrete form plywood mat or thin wood sheet panel; 2 – bamboo curtain core board; 3 – adhesive

In order to improve the water resistance, abrasion resistance and alkali resistance of 9mm shuttering ply, it is proved that the surface of 12mm shuttering ply wickes with epoxy resin coating has better alkali resistance, and the enamel coating has the best comprehensive effect.

2. Specification and performance

(1) Specification

China’s national standards (bamboo plywood) (GB13123-91) bamboo plywood specifications are provided in Table 8-57, Table 8-58.

Greenply shuttering plywood length and width specifications table 8-57

Shuttering ply thickness and the number of layers correspond to the table 8-58

The thickness of suraksha shuttering ply for concrete formwork is often 9mm, 12mm and 15mm.

(2) Performance

Because of the different materials of bamboo produced in different places, and also with the adhesive glue species, glue layer thickness, glue coating uniformity and heat curing pressure and other production processes, therefore, the physical and mechanical properties of shuttering ply board price vary greatly, and its elastic modulus varies from 2 to 10×103N/mm². It is generally believed that the corresponding static bending strength and modulus of elasticity values are also high for denser bamboo plywood. Table 8-59 shows the physical and mechanical properties of film faced18mm shuttering ply b&q produced in Zhejiang, Sichuan and Hunan.

The physical and mechanical properties of concrete form plywood suppliers Table 8-59

8-4-1-3 Construction process

1. The preparation method and requirements of plywood formwork

1) Directly prepare the template according to the size of the design drawing

For simple structural members, the template specification and quantity can be prepared according to the size listed in the structural construction drawings. The thickness of the formwork, the cross section and spacing of the fluting, and the configuration of the supporting system can be selected by calculation according to the supporting requirements.

2）Formwork shuttering ply 12mm price preparation by enlargement method

For complex structural members, such as staircase, circular pool, etc., the actual sample of the structural members can be drawn on the flat floor according to the size of the structural drawing, and the exact size of each part of the template can be measured or the sample plate can be set, and the node structure of the template and its installation can be determined and the template can be made.

3）Formwork phenol film 12mm preparation by calculation method

It is not easy to use the method of enlargement sample for the complex shape, but for the members with certain geometric shape pattern, the calculation method combined with the method of enlargement sample can be used to prepare the formwork.

4) the use of structural surface expansion method of 12mm film faced plywood

Some of the complex shapes and different shapes composed of a variety of complex body type structural components, such as equipment foundation. Its formwork can be prepared by drawing the formwork plan and expansion diagram first, and then carrying out formwork design and formwork production.

plywood template preparation requirements should be used directly as a whole, to minimize the random sawing, resulting in plywood waste.The common thickness of wood plywood is 12 or 18mm, and the common thickness of bamboo plywood is 12mm. The spacing of inner and outer flutes can be adjusted by design calculation with the thickness of plywood.Support system can choose steel pipe footing, but also can use wood. When using wood support, shall not choose brittle, severely twisted and easily deformed by moisture wood.The nail length should be 1.5~2.5 times of the thickness of the plywood, and at least 2 nails should be nailed at each plywood and wood flute stack. The nails of the second board should be nailed diagonally in the direction of the first template, so that the spacing is tight.(5) The prepared template should be numbered on the reverse side and the specifications should be written, and they should be stacked and kept separately to avoid misuse.

2. Wall and floor formwork 12mm film faced plywood

The use of plywood as the formwork of cast-in-place concrete walls and slabs is a commonly used formwork technology, which can reduce the joints on the exposed surface of concrete and meet the requirements of clear concrete than using the combined formwork.

(1) Straight wall formwork best quality shuttering plywood

Conventional support method is: plywood panel outside of the vertical file with 50 × 100 square wood, horizontal file (also known as drafting bar) available φ48 × 3.5 hand steel pipe or square wood (generally 100 square wood), both sides of the plywood formwork with through the wall

Bolt tie (Figure 8-233). Request a quote

Figure 8-233 wall formwork with plywood panels

1 – plywood; 2 – vertical file; 3 – horizontal file; 4 – diagonal brace; 5 – brace head; 6 – through the wall bolts

(1) When installing wall formwork shuttering plywood sheets, set up one side of the formwork first according to the side line, temporarily hold it up with support, correct the vertical of the formwork with line hammer, then fix the drawbar, and then fix it with diagonal brace. When assembling large side modules, the upper and lower vertical joints should be staggered with each other, and the two ends should be erected first, then the middle part.

After the reinforcement is tied, install the formwork and diagonal bracing on the other side according to the same method construction plywood sheets.

(2) in order to ensure the correct thickness of the wall, between the two sides of the formwork available small square wood props (small square wood length equal to the thickness of the wall), waterproof concrete walls to add a water stop plate props. Small square wood should be taken out one by one as the concrete is poured. In order to prevent the pouring of concrete wall bulge, available 8 ~ 10 lead wire or diameter 12 ~ 16mm bolts tie both sides of the formwork, the spacing is not greater than 1m. Bolts should be arranged longitudinally and horizontally, and often rotate before the concrete sets so that it can be taken out after it sets. If the wall is not high and the thickness is not large, it can also be nailed on the top of the cheap shuttering ply formwork on both sides with a lapwood.

(2) adjustable curve wall formwork tego film plywood

1）Structure specrite film faced plywood

Adjustable curve formwork plywood for sale is mainly composed of four parts, such as panel, back flute, tight extender and side rib plate, etc. The structure is simple. The size of the standard slab is 4880×3660mm standard slab, concrete side pressure is designed according to 60kN/㎡, the panel is made of 18mm shuttering ply wickes plywood, the vertical rib is made of No.10 12mm shuttering plywood price, the flange card is made of 3mm thick steel plate rolled, the double channel steel of the horizontal rib and the flange card become a whole through effective structural combination, which enhances the stiffness and plays four aspects at the same time (1) the stiffness and integrity of the double-slotted steel horizontal ribs are improved; (2) the shuttering plywood jewson vertical ribs are fixed to the horizontal ribs by the flange card, which itself is one with the horizontal ribs, so that the integrity of the horizontal ribs and vertical ribs is enhanced; (3) the through-wall ties are fixed by the black faced plywood horizontal ribs, so that the wooden vertical ribs are tightly attached to the panel and fully play the role of the whole back flute; (4) the curvature adjuster is used to connect all the double-slotted steel molded ribs at the same level, so that the independent horizontal The curvature adjuster is used to connect all the double-slotted steel ribs at the same level, so that the independent horizontal ribs become a whole, and at the same time the curved formwork of any radius can be adjusted.

Figure 8-234 is the curved wall internal mold waterproof plywood for shuttering, arc length 2.34m; Figure 8-235 is the curved wall external mold, arc length 2.44m, internal and external wall mold matching use; Figure 8-236 is the arc wall mold. The principle of the above three kinds of formwork forming arc is to adjust the radius of the arc by adjusting the bolts to achieve different concrete plywood price radius of the arc wall formwork support. This kind of formwork is developed by Beijing Yiweier Formwork Co., Ltd. and has been used in the S-shaped curved wall of Beijing National Grand Theatre Drama Theatre and other projects.

Figure 8-234 adjustable circular arc film faced ply inner mold

1-Hook; 2-Adjustment support; 3-Short channel steel backing flute; 4-Adjustment bolt; 5-Panel; 6-Woodworking beam

Fig. 8-235 Adjustable circular arc plywood for construction outer formwork

1-Hook; 2-Adjustment support; 3-Short channel steel backing flute; 4-Adjustment bolt; 5-Panel; 6-Woodworking beam

Request a quote

Figure 8-236 adjustable curved black film faced plywood

Adjustable curve formwork construction points.

①Process

a. Assembling: set up the assembling operation frame → lay the main back flute steel pieces → main back flute long-way splicing → connect the adjuster between adjacent main back flute

1→Place surface wood plywood→Fix 18mm shuttering ply price and main back flute with screws→Install side rib angle with holes→Connect regulator 2 between main back flute and side rib angle→Drill holes for wall bolts→Adjust curvature of template by back regulator→Test curvature of template with special gauge→Install hook→No. of template→Save it in storage rack after qualified.

b. Installation: measure and place the line → use the hitch to lift the corresponding numbered template to the design position on one side of the wall → insert 9mm shuttering plywood and place the through-wall bolts and plastic sleeve → adjust the lower opening of the template in place according to the control line of the wall → lift the template on the other side of the concrete shuttering plywood → adjust the position of the template → tighten the through-wall bolts initially → silk tighten the connection → add wall diagonal bracing and diagonal wire rope → strengthen the processing at the horizontal splice of the main back flute of the template → adjust the verticality of the template → acceptance.

c. Disassembly: loosen the support → pull out the through best shuttering plywood → remove the lateral splicing screws of the formwork → the tower crane will lift the whole piece of formwork away → clean and level the formwork surface.

② Operation precautions phenolic film plywood

a. When the main back flute steel parts are spliced vertically, the joint position is staggered.

b. The direction of the adjuster installation is unified, so as to operate in the same direction when adjusting the curvature and avoid confusion plywood on frame boat building.

c. When adjusting the curvature, different positions of the adjuster should be rotated 2~3 buckles at a time to synchronize the process shuttering plywood b&q.

d. Formwork logo for plywood shop horizontal splicing screws are arranged at a spacing of not more than 300mm, while the regulator connected with the side ribs should be ensured to be in a tightened state.

e. As the formwork century plywood logo has only vertical back flute, horizontal square timber is added at its horizontal splice, and then steel pipe and through-wall bolts are used to tighten the square timber with the main back flute of the formwork.

③Floor slab formwork

There are several plywood company logo methods of supporting floor formwork as follows.

(1) the use of scaffolding plywood logo pipe to set up a row of frame laying floor formwork

Often used logo plywood to support the mold method is: φ48 × 3.5 scaffold steel pipe set up a row of frame, in the row of frame laid 50 × 100 square wood, spacing of about 400mm, as the panel of the shelf (flute wood), on which plywood panels are laid (Figure 8-237).

Figure 8-237 floor slab formwork using scaffold steel pipe (or steel pillar) row support types of plywood used in construction

For the erection of steel pipe support, see “5 Scaffolding and vertical transportation facilities” in this manual.

(2) Using wooden roof support to support the floor slab formwork shuttering ply waterproof

①Floor slab bunnings film faced plywood is laid on the joist. Both ends of the joist are placed on the joist, and the joist is generally made of square wood with section of 50mm×100mm and spacing of 400~500mm. When the span of the joist is large, the long drawbar should be laid under the joist again to reduce the span of the joist. The cross-sectional requirements of the drawbar are the same as the top support column, and the following must be padded with wooden wedges and pads. Generally use 50~75mm×150mm square wood. The floor template should be nailed perpendicular to the direction of the shelf, see Figure 8-238.

Request a quote

Figure 8-238 ribbed floor cover formwork smooth phenolic plywood

1 – floor formwork; 2 – beam side formwork; 3 – joist; 4 – cross-file (to wood); 5 – drawbar; 6 – clip wood; 7 – short support wood; 8 – drawbar support; 9 – pillar (lute support)

② plywood phenolic film floor template installation, first in the second beam template on both sides of the outside of the board to play the horizontal line, the horizontal line elevation should be the floor bottom elevation minus the thickness of the floor template and the height of the joist, and then nailed on the horizontal line of the joist, the upper mouth of the joist and the horizontal line flush. Then put the joist next to the beam mold first, equal to the joist spacing, the middle part of the joist. Finally, anti slip phenolic plywood nail the floor formwork on the joist. In order to facilitate the demolition of the mold, only in the end of the template or the joint nail firm, the middle as little as possible nail. If the middle is equipped with drawbar support and drawbar, the drawbar support should be erected before placing the joists, and the drawbar should be laid flat.

See Figure 8-239 for the construction of the wooden top brace.

Figure 8-239 Wooden top bracing ply board for shuttering

(3) the use of early demolition system to support the floor slab formwork

The typical plan layout is shown in Fig. 8-240, and the supporting structure is shown in Table 8-60 and Table 8-61.

Request a quote

Figure 8-240 frameless types of plywood for construction building slab formwork combination schematic diagram

1 – ply board shuttering; 2 – early demolition column head plate; 3 – the main beam; 4 – secondary beam

Table 8-60

Notes. L and B are the same as Table 8-22.

Table 8-61: Performance of various support lattices concrete shuttering ply

①Molding process ply formwork

Set up adjustable support column and demolish the column head early → install the main beam of the formwork → install horizontal support → install diagonal support → level the top surface of the support → install the secondary beam of the formwork → lay the wood (bamboo) plywood formwork → panel joints gluing tape → brush release agent → formwork pre-inspection → carry out the next process.

②Demoulding process brown film faced plywood

Drop the column head pallets, lower the main beam of the price of shutter ply board → remove the diagonal bracing and upper horizontal support → remove the main and secondary beams of the formwork → remove the panel → remove the lower horizontal support → clean up and remove the support parts → transport to the next flowing section → when the floor (roof) slab reaches the design strength, remove the column (the cast-in-place top slab can retain the column of 1~2 layers according to the growth of strength).

8-4-2 Plywood formwork reference

Timber joist allowable load reference table (N/m) Table 8-62 ply shuttering concrete

Allowable load reference table for draft bar wood (N/m) Table 8-63 formwork plywood price

Reference table for allowable load of wooden pillar (N/root) Table 8-64 cost of shuttering ply

Note:construction shuttering plywood 1. Table 8-62~Table 8-64 wood is calculated by the permissible stress of red pine, considering the increase factor of construction load and the discount factor of wet wood, calculated by [σa] = _[σw] = 11.7N/mm2. If Northeast larch is used, the allowable load can be increased by 20%.

2. Round concrete form ply is calculated by fir, also considering the above situation, calculated by [σa] = [σw] = 10.5N/mm2.

3. The draft waterproof shuttering plywood 12mm bar system is calculated with a concentrated load.

Request a quote