Erection scheme of steel pipe protective frame in engineering project
1, load calculation (internal and external poles and diagonal braces are taken for calculation)
2. Self-weight of the frame: the distance between vertical poles 1.5m, and the distance between horizontal poles is 0.9m ..
1)QL 1 = 0. 166 kn/m2gk 1 = 1/2la×lo×qk 1 = 1/2× 1.5× 108×5×0.66 = 1. 12KN
2) Self-weight of support: each column should be set continuously;
Gk2=0.038××2=0. 18KN
3) The weight of federated eye network.
gk3 = 15× 1.8×5/ 1.86×0.06 = 0.08 kn
4) Self-weight of bamboo basketry board (* * * five layers)
GK4 outside =1/2× 0.14×1.5× 5 = 0.45kn.
Gk4 =1/2× 0.4×1.0×1.5× 3+1.5+0.15× 0.35 = within 0.47kn.
5) Frame surface construction load
QK = 1/2×2× 1.0× 1.5×2 = 3kn。
Within QK =1/2× 2×1.0×1.5× 2+1.5× 0.15× 2 = 3.9 kn.
6) Design value of axial force of scaffold column
Internal column: n1=/kloc-0 /× (within GK1+GK4)+1.4qk.
= 1.2×( 1. 12+0. 18+0.08+0.32)+ 1.4×3
Outer vertical pole: N2 = 1.2× (outer GK1+gk2+gk3+gk4)+1.4 qk.
= 1.2×( 1. 12+0. 18+0.08+0.32)+ 1.4×3
= 6.24 kilonewtons
According to the Code for Building Load, the design value of the load should be multiplied by a reduction factor of 0.9 due to the number of temporary scaffolding structures.
0.9ma = n 1ab/2h(Ha/2 =-0.6 kn . m
0.9 MB = n 1ab/2h(3-b/l)= 0.26 kn . m
3. Checking calculation
Strength: a = mmax/w = 202n/㎜ 2.
Deflection: f = n1B2/96et-(9a-2b) = 0.95mm.
Anchorage: it is made of φ 10 steel bar, the embedded concrete shall not be less than 100㎜, the anchorage length shall not be less than 250㎜, and the concentrated load of every two steel pipes for construction load shall be considered as1.5kn..
f 1 = 1.4×2× 1.2/ 1. 1 = 0.76 kna 2f 2 = 16KN
Sliding resistance of fasteners:
The axial force acting on the front end of the diagonal brace is used for rotation deduction.
S=8. 125KN
0.9S=7.3 1KNps=8.5KN
Stability of diagonal braces;
l0 = u . l = 1.5×/2 = 23 1.5cmλ= LC/2 = 146.5
Check the stability of the stud:
This project is located in the family area, and the wind load can be ignored.
lookup table
0.9N/4A = 55.8n/㎜2 < fc/VM = 144.4n/㎜2
Wall connecting rod
The short steel pipes embedded in the column are connected with scaffolding by steel pipes, and it is advisable to embed 200㎜ concrete at the height of steel pipes, and stagger one point up and down every three uprights on each floor.
HW = 1.45wk = 1.4×3×3× 1.5×0.29 = 5.48 kn
Considering the axial force caused by the out-of-plane deformation of the scaffold, an additional stress is added.
Ns=3KN
n = 0.9 NW+Ns = 0.9×5.48+3 = 7.93 kn < 9C = 8.5 kn
So it meets the requirements.
4, protective frame erection requirements
The technical requirements, allowable deviation and inspection methods of scaffold erection shall meet the following requirements:
1) foundation: the surface is solid and flat, without water accumulation, the cushion layer does not shake, and the foundation does not slide or sink. The mat is made of 50㎜*500㎜*2000㎜ boards.
2) Poling: Scaffolding must be provided with vertical and horizontal sweeping poles. Longitudinal rod sweeps the floor with right-angle fastener fixed on the vertical rod not more than 200㎜ away from the basic epithelium. The horizontal sweeping bar should also be fixed on the vertical bar next to the vertical sweeping bar with right-angle fasteners. Butt fasteners on vertical poles should be staggered: the joints of two adjacent vertical poles should not be set synchronously, and the distance between two separated joints of the same vertical pole should not be less than 500mm； in the height direction; The distance from the center of each joint to the main node should not be greater than 1/3 step. The top of the stud is higher than the parapet epithelium 1m, and the verticality of the stud is H/200 of the maximum erection height Hmax≤20m and not more than 100 ㎜. Spacing: step distance is 900㎜, deviation is 20 ㎜, span is 1600㎜, deviation is 50 ㎜, and distance from building is 1 100㎜.
3) Horizontal pole: the longitudinal horizontal pole is set inside the vertical pole, and the length should not be less than 3 spans. Extension pieces should be connected by butt fasteners, and the installation of material hoists should overlap. Butt fasteners of longitudinal horizontal bars shall be staggered. The joints of two adjacent longitudinal horizontal bars shall not be set in synchronization or within the same span. The horizontal staggered distance between two adjacent joints with unsynchronized or different spans shall not be less than 500mm. The distance from the center of each joint to the nearest master node should not be greater than 1/3 of the longitudinal distance. When longitudinal horizontal bars are overlapped, the overlapping length should not be less than 1. The three steering fasteners should be fixed at equal intervals, and the edge of the cover plate of the end fastener should be fixed at the end of the overlapping longitudinal horizontal bar.
The structure of the horizontal bar shall meet the following requirements: the horizontal bar must be set at the main node and fastened with right-angle fasteners, and it is strictly forbidden to be removed. The center distance between the two right-angle fasteners at the main node should not be greater than 150㎜.
Height difference of longitudinal horizontal pole: 20mm at both ends of the same pole, height difference of longitudinal horizontal pole of the same span 10mm.
4) Wall-connected poles: Wall-connected poles must be reliably connected with buildings. The first, third, fifth and sixth floors are provided with wall connecting pieces, four corner columns of each floor are rigidly connected with steel pipes, and other connection points are set every other column from the corner columns. Even the wall rod is set close to the master node, and the distance from the master node should not be greater than 300㎜. It should be arranged from the first step of the longitudinal horizontal bar at the bottom, and the rhombic arrangement is preferred, and the square and rectangular arrangement can also be adopted. Even the wall columns should be set horizontally. When it cannot be set horizontally, the end connected with the scaffold should be connected obliquely downward, not obliquely upward.
5) Scissors: A pair of scissors must be set at both ends of the scaffold facade, continuously from bottom to top, and the clear distance between the middle scissors should not be greater than 15m. The width of each bracing should not be less than 4 spans, and should not be less than 6m, and the inclination angle between the diagonal and the ground is between 450 and 600. The extension of diagonal braces shall be overlapped, with the overlapping length not less than 1m and not less than 2 steering fasteners. Braces should be fixed with steering fasteners on the protruding ends or columns of the horizontal bars intersecting with them, and the distance from the center line of the steering fasteners to the main node should not be greater than 150㎜.
6) Fastener installation: the height difference between two adjacent butted fasteners on the synchronous column is ≤50㎜, the distance between the butted fasteners on the column and the main node is ≤h/3, the distance between the butted fasteners on the longitudinal horizontal bar and the column point is ≤L/3, and the fastener bolts are tightened.
7) Scaffold board: when laid with bamboo frame board, it should be set on three horizontal poles, and the outrigger length of scaffold board is "A":100 mm.
5, inspection and acceptance
After the erection of protective frame is completed, the project department shall organize acceptance to check whether the protective frame is erected according to the specification requirements. After being qualified, it shall be reported to the Safety Production Section of the Branch for acceptance. After the acceptance is completed, check the tightening torque of the fastening bolts with a torque wrench, and the sampling method shall be randomly selected. If it is unqualified, it must be re-tightened or replaced, and it can only be used after it is approved by the Safety Production Section.
Step 6 destroy
1) comprehensively check whether the fastener connection, wall parts and support system of scaffolding meet the safety requirements. According to the inspection results, the demolition sequence in the construction organization design is supplemented and improved, and can be implemented only after it is approved by the production department.
2) The builder and the full-time safety officer of the project department shall disclose the safety technical measures for demolition one by one.
3) Remove sundries and ground obstacles on the scaffold.
4) Demolition sequence should be carried out step by step from top to bottom, and it is forbidden to work at the same time.
5) All wall parts shall be removed step by step with the scaffold. It is forbidden to dismantle the whole or several layers of wall pieces before dismantling the scaffold. Demolition by sections, the height difference should not be greater than 2 steps. If the height difference is more than 2 steps, the connected walls should be strengthened.
6) When the scaffold is removed to the last long steel pipe (about 6.5m high) at the lower part, temporary supports shall be erected at appropriate positions for reinforcement, and then the wall pieces shall be removed.
7) When the scaffold height is 6m or higher, it shall be dismantled by sections and facets. For both ends of the scaffold that will not be dismantled, wall connecting pieces and transverse supports should be set up according to the structural requirements for reinforcement.
8) All components and accessories must be transported to the ground in time, and it is forbidden to throw them.
9) Components and parts transported to the ground shall be inspected, renovated and maintained in time as required, packed neatly according to varieties and specifications, and placed in a dry and ventilated place to prevent corrosion.
7, scaffolding engineering safety measures and regulations:
1) scaffolder must be trained, hold relevant certificates and have a physical examination once a year. Anyone suffering from hypertension, disease, anemia or other diseases that are not suitable for high-altitude shelf work is strictly prohibited. Crazy people, mental patients and people with unstable emotions are not allowed to work on the shelves, and those who wear hard-soled shoes or slippers and open-cuff pants are not allowed to work on the shelves.
2) When scaffolding is erected (dismantled) at high altitude, the operators must wear safety belts and helmets, and all kinds of tools and materials should be packed or properly placed to prevent people from falling.
3) When operating on the scaffold, it is forbidden to gather people, play and jump on the scaffold to form impact load.
4) The erection of all kinds of shelves must be carried out in strict accordance with the erection scheme and safety technical disclosure, and the erection scheme and safety technical disclosure requirements shall not be changed at will.
5) All kinds of shelves can be used only after they are installed and accepted by the project leader.
6) Without the consent of the construction director, the scaffold shall not be dismantled at will.
7) Demolition can only be carried out after the signature of the person in charge of the construction site and special technical disclosure.
8) Dismantle scaffolding. Fences or warning signs should be set around, and designated personnel should be assigned to prevent personnel from entering. Demolition should be carried out from top to bottom in sequence, step by step, and it is not allowed to work at the same time. Dismantled scaffolding and steel pipes should be handed down or tied with ropes and hung down. The removed fasteners should be hung in the box, and it is forbidden to throw any material down.
9) "Four don't let go" when disassembling the pole: standing unsteadily, you can't see the bottom clearly, and if someone doesn't let go, he won't let go when shouting.
10) Remove the middle fastener first, then the fasteners at both ends, and the middle operator will get off the pole.
1 1) During the use of scaffolding, it is forbidden to dismantle all the bars at will.
12) It is strictly forbidden to dig in the scaffold foundation and its vicinity at will, otherwise safety measures should be taken. When dismantling scaffolding, fences and warning signs should be set on the ground, and special personnel should be assigned to guard it. Non-operators are strictly prohibited from entering.
13) Scaffolding operations should be stopped in strong winds of magnitude 5 and above and in foggy, rainy and snowy days. After the rain and snow, anti-skid measures should be taken to shelve the operation, and the snow should be cleared first. Full-time security officer is responsible for the regular inspection and warranty of scaffolding.
14) The construction load of the operation floor meets the design requirements and shall not be overloaded. Template support and cable wind rope shall not be fixed on the scaffold, and it is forbidden to hang lifting equipment.
The above are collected and sorted by Zhong Da Consulting Company.
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