Calculation example of the hottest fastener type s

2022-10-24
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Calculation example of fastener type steel pipe scaffold

a project is a 6-story frame structure, with a parapet top height of 27.9m. The main body and decoration construction adopts the floor type double row steel pipe scaffold, which is only used as a maintenance frame during the main body construction. The basic wind pressure at the project site is ω 0=0.6kN/m2。 Try to design and calculate the decoration scaffold

I. design scheme

1 The number of layers of the proposed operation layer n1=2; The number of flooring layers is to lay a full layer of scaffold board every 10m, a total of n2=3 layers

2. The proposed scaffold structure size: the vertical distance of the pole la=1.5m, the horizontal distance of the pole lb=0.8m, the step distance h=1.8m, and the wall connecting parts are set in two steps and three spans

3. The scaffold board is made of stamped steel plate, with the standard value of self weight g k1=0.3kn/m2. A 20cm scaffold board is laid near the outer end of the building. A toe board is set outside the operation layer, G k5=0.11kn/M

4. Railings: due to the need of fixed safety, the number of railings added per step is n3=2, and the standard value of self weight of railings and their connecting fasteners g k3=0.0384+0.0132/1.5=0.0472kn/m (where 0.0132 is the weight of each right angle fastener)

5. Safety: no less than 2000 objects per 100cm2 shall be used for safety. It shall be closed along the full height of the frame, and its standard value of self weight is gq40.005kn/m2

6. All members adopt ф forty-eight × 3.5mm steel pipe (0.384kn/m)

II. Design calculation

1 Calculation of longitudinal horizontal bar

see Figure 1 for the support and calculation of longitudinal horizontal bar. The standard value of uniformly distributed live load for decoration construction qqk1=2kn/m2

(1) load calculation

the standard value of dead load acting on longitudinal horizontal bar PGK is pgk=0.3 × zero point seven five × 0.8÷2+0.11 × 0.75+0.384 (0.8 ÷ 2+0.1) =0.192kn

the standard value of live load acting on longitudinal horizontal bar pqK is pqk=2 × zero point seven five × 0.8 ÷ 2=0.6kn

(0.3 is the dead weight of the square meter of the stamped steel scaffold board; 0.75 is the spacing of the small cross bars; 0.8 is the row spacing of the double row scaffold)

(2) internal force calculation

the longitudinal horizontal bar is calculated as a three span continuous beam, considering the adverse combination of live load and static load, and the adverse combination of load, check the structural static calculation manual, at this time, the mid span bending is the maximum

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Figure 1 calculation diagram of longitudinal horizontal bar

(3) bending strength checking calculation

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(4) deflection calculation

deflection calculation adopts standard load for combination calculation, the most unfavorable live load arrangement is shown in Figure 2, and the maximum deflection in side span is

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2. calculation of horizontal pole (omitted)

3. Calculation of the erection height of the outer pole

it is known that the height to be erected is 30.6m

(1) load calculation

1) standard value of structural self weight borne by each m of the pole G: check the code Gk=0.1248kn/m

2) axial ng2k generated by the standard value of self weight of components and fittings in table A-1 of appendix a

a) axial force generated by the self weight of pavement structure ng2k

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b) axial force generated by fully enclosed safety and its accessories ng2k2

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3) axial force generated by construction load

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4) calculate the bending moment generated by wind load mwk

according to the basic wind pressure ω 0=0.6kN/m2; Wind pressure height coefficient μ Z check the wind load specification. When h=5m, the wind pressure height variation coefficient (class B area) μ Z=0.8, wind pressure shape coefficient μ S is taken as 1.3 according to the specification φ

generated by open scaffold φ It is 0.089

according to table A-3 of the specification, the wind proof area of open scaffold is:

1.8 × 1.5 when the preload P is 1.0kn × 0.089=0.2403m2

generated by safety φ Taking 0.5, the comprehensive wind-proof area of the scaffold is:

(1.8 × 1.. 2403) × 0.5+0.2403=1.47015 m2

its comprehensive wind-proof coefficient φ= 1.47015/(1.8 × 1. The State Post Office, the national development and Reform Commission, the Ministry of science and technology, the Ministry of industry and information technology, the Ministry of environmental protection, the Ministry of housing and urban rural development, the Ministry of Commerce, the General Administration of quality supervision, inspection and quarantine, the national certification and Accreditation Administration Commission, and the National Standardization Administration jointly issued the "guidance on promoting green packaging in the express industry in a coordinated manner" 5) =0.545

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5) calculate the stability coefficient of the pole ф

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check Appendix C of the specification ф= 0.185

(2) the experimental method is also relatively simple. 1. Calculate the erection height of scaffold

combined wind load

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according to 5.3.7 of the specification, the double row single pipe scaffold should not exceed 50m, and the erection height of the scaffold needs to be adjusted:

[h]=hs/(1+0.001 HS) =60.2/(1+0.001) × 60.2) =56.78m>30.6m the stability of the upright meets the design requirements

4. Calculation of wall connecting parts

wall connecting parts adopt the rigid connection method as shown in Figure 3

(1) design value of axial force of wall connecting parts n1

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(2) stability checking calculation of wall connecting parts

calculation length of wall connecting parts l0=lb=800mm

slenderness ratio λ= L0/i=80/1.58=50.6, check the table in Appendix C of the specification φ= 0.851

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Figure 2 Schematic diagram of wall fasteners 740) this.width=740" border=undefined>

(3) check calculation of anti sliding bearing capacity of wall fasteners

each wall fastener is connected by two right angle fasteners, then

n1=14.6 (KN) safety

5 Calculation of bearing capacity of pole foundation

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the bottom of the pole adopts 50 thick wood potential plate, the length of the base plate is a=3.9m, the width is b=0.25m, each base plate supports three poles, and the support area of the base plate of each pole is

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the bearing capacity of the foundation meets the design requirements

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