What Are Scaffolding Planks?

The scaffolding construction plan is a code of conduct for building construction practitioners and a guarantee for the safety and health of construction workers during the construction process. Scaffolding construction materials are mainly scaffolding and safety nets.

Scaffolding construction scheme

"Building Construction Calculation Manual"

Building construction site is located in the west

The project takes into account the construction period, quality and safety requirements, so when selecting a plan, the following points should be fully considered:

1. The structural design of the frame is to ensure that the structure is safe and reliable, and the cost is reasonable.

2. It can fully meet the expected safety and durability under the specified conditions and the specified period of use.

3. When choosing materials, strive to be common, reusable, and easy to maintain.

4. When selecting the structure, make sure that the force is clear, the structural measures are in place, and the lifting is easy to dismantle, which is convenient for inspection and acceptance;

5. To sum up the above points, the installation of scaffolding must also meet the requirements of JCJ59-2011 inspection standards, and must comply with the relevant standards of Jiangxi Province civilized chemical industry land.

6. Combining the above scaffold design principles and the actual situation of the project, considering the previous construction experience, it was decided to use the following scaffolding scheme: ordinary cantilever

Cantilever

l, steel pipe floor scaffolding, choose an outer diameter of 48mm, wall thickness of 3.20mm, steel strength grade Q235-A, the surface of the steel pipe should be straight and smooth, no cracks, delamination, indentation, ruling and hard bending, new The steel pipe must have a factory certificate. Before the construction of the scaffolding, the steel pipes entering the site must be sampled and sent to the relevant nationally qualified test unit for mechanical tests such as bending and tensile testing of steel pipes. The test results can meet the design requirements before they can be used in construction.

2. The use of malleable casting fasteners for the installation of steel pipe scaffolds in this project shall meet the requirements of the Ministry of Construction's Standard for Steel Pipe Scaffolding Fasteners JGJ22-85, and shall be provided by the manufacturer with a production license for fasteners. , Shrinkage, trachoma and other forging defects, the specifications of the fasteners should match the steel pipe, the surface should be dry and clean, the moving parts are flexible, the minimum distance of the opening when clamping the steel pipe is not less than 5mm. Steel tube bolts must not be damaged when the tightening torque reaches 70N.m. If the old fastener is used, the fastener must be sampled and sent to the relevant nationally qualified test unit for the anti-slip test of the fastener. The test results meet the design requirements before being used in construction.

3. Maintenance should be carried out before setting up the shelf, derusting and uniform coloring, and the color strives for beautiful environment. Scaffolding poles, protective railings, and kickboards are uniformly painted yellow, and shear braces are uniformly painted orange-red. The bottom row of poles and sweeping poles are painted red and white.

4. Scaffolding and scaffolding are used to meet relevant requirements.

5, safety net adoption

According to Article 5.2.4 of the "Safety Technical Specification for Fastener Steel Pipe Scaffolding" (JGJ130-2001), the large cross bar is calculated according to the strength and deflection of the three-span continuous beam. Calculate the maximum bending moment and deformation of the large cross bar using the scaffolding weight and construction live load on the large cross bar as the uniform load.

According to Article 5.2.4 of JGJ130-2001, the small cross bar is calculated according to the strength and deflection of the simply supported beam, and the large cross bar is above the small cross bar. The calculated value of the maximum reaction force of the large crossbar support is used as the concentrated load of the small crossbar, and the maximum bending moment and deformation of the small crossbar are calculated under the most unfavorable load arrangement.

According to the specification table 5.1.7, the bearing capacity of the right-angle, rotating single fastener is 8.00kN, and according to the anti-skid bearing capacity coefficient of the fastener of 0.80, the actual rotating single fastener bearing capacity of this project is 6.40kN.

When the vertical or horizontal horizontal bar is connected with the vertical bar, the anti-sliding bearing capacity of the fastener is calculated according to the following formula (specification 5.2.5):

R Rc

Where Rc-design value of anti-sliding bearing capacity of the fastener, take 6.40 kN;

R-the design value of the vertical force transmitted from the horizontal or vertical horizontal rod to the vertical rod;

Standard value of dead weight of large cross bar: P1 = 0.035 × 1.500 × 2/2 = 0.053 kN;

Standard weight of small cross bar: P2 = 0.035 × 1.000 = 0.035 kN;

Standard weight of scaffolding board: P3 = 0.300 × 1.000 × 1.500 / 2 = 0.225 kN;

Standard value of live load: Q = 2.000 × 1.000 × 1.500 / 2 = 1.500 kN;

Design value of load: R = 1.2 × (0.035 + 0.225) + 1.4 × 1.500 = 2.412 kN;

R <6.40 kN, the design calculation of the anti-slip bearing capacity of the single fastener meets the requirements!

The loads acting on the scaffolding include static, live and wind loads. Standard static load values include the following:

(1) The standard value of structural dead weight (kN) per meter of pole is 0.1248

NG1 = [0.1248+ (1.50 × 2/2 + 1.50 × 2) × 0.035 / 1.80] × 15.00 = 3.200;

(2) Standard value of self-weight of scaffolding board (kN / m); bamboo scaffolding scaffolding board, standard value is 0.30

NG2 = 0.300 × 5 × 1.500 × (1.000 + 0.3) / 2 = 1.463 kN;

(3) Standard value of self-weight of railings and footboards (kN / m); using railings and bamboo board scaffolding boards, standard value is 0.15

NG3 = 0.150 × 5 × 1.500 / 2 = 0.563 kN;

(4) Hanging safety facility load, including safety net (kN / m); 0.005

NG4 = 0.005 × 1.500 × 15.000 = 0.112 kN;

After calculation, the standard value of static load

NG = NG1 + NG2 + NG3 + NG4 = 5.337 kN;

The live load is the sum of the axial forces generated by the standard value of the construction load, and the inner and outer poles are taken as 1/2 of the sum of the construction load within a longitudinal distance.

After calculation, the standard value of live load

NQ = 2.000 × 1.000 × 1.500 × 2/2 = 3.000 kN;

The wind load standard value is calculated according to the following formula

Where Wo-basic wind pressure (kN / m), in accordance with the "Building Structure Load Code" (GB50009-2001):

Wo = 0.600 kN / m;

Uz-coefficient of change in wind load height:

Uz = 0.740;

Us-wind load carrier type coefficient: value is 0.649;

After calculation, the standard value of wind load

Wk = 0.7 × 0.600 × 0.740 × 0.649 = 0.202 kN / m;

Calculation formula for design value of axial pressure of vertical pole without considering wind load

N = 1.2NG + 1.4NQ = 1.2 × 5.337 + 1.4 × 3.000 = 10.604 kN;

When considering the wind load, the design value of the axial pressure of the pole is

N = 1.2 NG + 0.85 × 1.4NQ = 1.2 × 5.337 + 0.85 × 1.4 × 3.000 = 9.974 kN

The bending moment MW of the vertical pole segment resulting from the design value of the wind load is

Mw = 0.85 × 1.4 WkLah / 10 = 0.850 × 1.4 × 0.202 × 1.500 ×

1.800 / 10 = 0.117 kN.m;

When the wind load is not combined, the stability calculation formula of the pole is:

Design value of axial pressure of vertical rod: N = 10.604 kN;

Calculating the Pole's

The design value of the axial force of the connecting piece should be calculated according to the following formula:

Nl = Nlw + N0

Wind load standard value Wk = 0.202 kN / m;

Windward area Aw = 16.200 m outside the scaffolding within the coverage area of each wall piece;

Axial force (kN) generated by constraining out-of-plane deformation of scaffolding with wall parts according to Article 5.4.1 of the Code, N0 = 5.000 kN;

The design value (kN) of the axial force of the connected wall component caused by wind load is calculated according to the following formula:

Nlw = 1.4 × Wk × Aw = 4.575 kN;

The design value of the axial force of the connecting piece Nl = Nlw + N0 = 9.575 kN;

The design value of the bearing capacity of the wall piece is calculated as follows:

Nf = · A · [f]

Where -the stability factor of the axially compressed pole;

From the result look-up table of slenderness ratio l0 / i = 300.000 / 15.900, = 0.949, l is the length of the inner shelf from the wall;

Again: A = 4.50 cm; [f] = 205.00 N / mm;

The design value of the axial bearing capacity of the connecting piece is Nf = 0.949 × 4.500 × 10 × 205.000 × 10 = 87.545 kN;

Nl = 9.575 <Nf = 87.545, the design calculation of the wall fittings meets the requirements!

The connecting piece is connected to the wall with double fasteners.

From the above calculation, Nl = 9.575 is less than the slip resistance of the double fastener 16.0 kN, which meets the requirements!

Schematic diagram of connecting wall fasteners

The horizontal steel beam of the cantilever scaffold is calculated as a continuous beam with cantilever.

The cantilever part is affected by the load N of the scaffolding, the inner end B is the anchor point with the floor, and A is the wall fulcrum.

In this solution, the scaffolding row distance is 1000mm, the inner row scaffolding is 300mm away from the wall, and the fulcrum of the supporting inclined bar is 1200mm away from the wall.

The horizontal steel beam uses 16a channel steel, and the calculation formula is as follows

Where b-the overall stability factor of a bending member that is uniformly bent, calculated according to the following formula:

b = 570 × 10.0 × 63.0 × 235 / (1200.0 × 160.0 × 235.0) = 1.87

As b is greater than 0.6, check the appendix B of the "Code for Design of Steel Structures" (GB50017-2003) and get a value of b of 0.919.

After calculation, the maximum stress = 1.651 × 10 / (0.919 × 108300.00) = 16.582 N / mm;

The stability calculation of the horizontal steel beam = 16.582 is less than [f] = 215.000 N / mm, which meets the requirements!

The axial force RAH of the horizontal steel beam and the axial force RUi of the rope are calculated as follows

RUicosi is the axial pressure generated by the tensile force of the steel rope on the horizontal rod.

Supporting force of each fulcrum RCI = RUisini

According to the above formula, the rope tensions from left to right are:

RU1 = 19.491 kN;

1. If the pressure points of the horizontal steel beam and the floor are reinforced, the strength of the ring is calculated as follows:

The tension of the tension ring at the pressure point between the horizontal steel beam and the floor is R = 0.124 kN;

The formula for calculating the strength of the pull ring at the pressure point between the horizontal steel beam and the floor is:

Where [f] is the tensile strength of the ring reinforcement, in accordance with Article 10.9.8 of the "Code for Design of Concrete Structures" [f] = 50N / mm;

The minimum diameter of the pull ring required for the horizontal steel beam and floor pressure point D = [123.680 × 4 / (3.142 × 50 × 2)] 1/2 = 1.255 mm;

The pull ring of the pressure point between the horizontal steel beam and the floor must be pressed under the reinforcing bar under the floor, and the overlap length of 30cm on both sides must be guaranteed.

2. If bolts are used for the horizontal steel beam and floor pressure points, the bolt anchor strength is calculated as follows:

Anchor depth calculation formula:

Where N-anchoring force, that is, the axial tensile force acting on the floor bolt, N = 0.124kN;

d-diameter of floor bolts, d = 20.000mm

[fb]-Allowable bonding strength between floor bolts and concrete, 1.270N / mm is used in calculation;

h-anchorage depth of floor bolts in the concrete floor.

123.680 / (3.142 × 20.000 × 1.270) = 1.550mm.

3. If the pressure point of the horizontal steel beam and the floor is bolted, the local bearing pressure of the concrete is calculated as follows:

The tension of the bolts under local pressure of the concrete should satisfy the formula:

Where N-anchoring force, that is, the axial pressure acting on the floor bolts, N = 8.274kN;

d-diameter of floor bolts, d = 20.000mm;

b-side length of bolt and anchor plate in the floor, b = 5 × d = 100.000mm;

fcc-design value of local compressive strength of concrete, 0.950fc = 11.900N / mm in calculation;

After calculation, the right side of the formula is equal to 115.26 kN, which is greater than the anchoring force N = 8.27 kN. The local pressure calculation of the floor concrete meets the requirements!