The core part of WDJ bowl buckle type multifunctional scaffold consists of upper bowl buckle, lower bowl buckle, cross bar joint and upper bowl buckle limit pin. A set of bowl buckle joints shall be set every 0.6m on the vertical and top poles of scaffold. The lower bowl buckle and the upper bowl buckle limit pin are directly welded on the vertical bar or the top bar. When the notch of the upper bowl buckle is aligned with the limit pin, the upper bowl buckle can slide upward along the rod. When connecting the crossbar, first insert the crossbar joint into the circular groove with teeth around the lower bowl buckle, slide the upper bowl buckle down along the limit pin and buckle the crossbar joint, rotate it clockwise and fasten it, then knock it with a hammer for several times to firmly lock it. The bowl buckle joint is connected with four cross bars at the same time, which can be perpendicular to each other or deflected by a certain angle.
2.3.2 basic components
1) Pole: it is the main force-bearing component of the scaffold, and a set of bowl buckle joint is installed on a certain length of φ 48 × 3.5mm2 Q235 steel pipe with each Φ / span > 0.6m.
2) Transverse bar: the transverse connecting bar of the frame is made of welded transverse bar joints at both ends of φ 48 × 3.5mm Q235 steel pipes of a certain length, with a length of 950mm 1550mm.
3) Diagonal bar: it is a series of components designed to enhance the stable strength of the scaffold. It is made by riveting diagonal bar joints at both ends of φ 48 × 2.2mm/span > Q235 steel pipe. The diagonal bar joints can rotate. The joint can be installed in the lower bowl buckle like the cross bar joint to form the joint inclination.
4) Base: it is a component installed at the root of the vertical pole to prevent it from sinking and transmit the upper load to the foundation.
5) Auxiliary components: such as right angle bracing, wall bracing, cantilever beam, cantilever frame cross bracing, etc.
2.3.3 performance characteristics of WDJ bowl button type multi-functional steel pipe frame
1) Multi function: according to the specific construction requirements, multi-functional construction equipment, such as scaffolds, support frames, material lifting frames, climbing scaffolds, can be composed of different size, shape and bearing capacity of the scaffolds, especially suitable for erecting curved scaffolds and heavy-duty support frames.
2) High efficiency: the longest of the common members of the scaffold is 3130mm, with a weight of 17.07kg. The whole assembling and disassembling speed is 3-5 times faster than the normal speed, and the assembling and disassembling is fast and labor-saving. Workers can complete all the operations with a hammer, completely avoiding many inconveniences caused by bolt operation.
3) Strong universality: the main components are steel pipes of ordinary fastener type steel pipe scaffold, which can be connected by ordinary steel pipes, with strong universality.
4) Large bearing capacity: the joint has reliable mechanical properties of shear resistance, bending resistance and torsion resistance, and the axis line of each member intersects at one point. The joint is stable and reliable in the frame plane, which is 0.5 times higher than the structural strength of other types of scaffolds with the same pipe material.
5) Safe and reliable: in the joint design, considering the screw friction and self gravity of the upper bowl buckle, the joint has a reliable self-locking ability; the load acting on the cross bar is transmitted to the vertical bar through the lower bowl buckle, and the lower bowl buckle has a strong shear resistance (maximum is 199kn). Even if the upper bowl buckle is not pressed, the cross bar joint will not come out and cause accidents; the whole frame is equipped with a relatively perfect Safe and reliable use of safety facilities;
6) Easy to process: the main component is made of Φ 48 × 3.5 〿 > Q235 welded steel pipe. The manufacturing process is simple and the cost is moderate. It can directly process and transform the existing fastener type steel pipe, and the renewal cost is greatly reduced.
7) Less maintenance: the bolt connection is eliminated, the components are bump resistant, not afraid of general corrosion, and the daily maintenance is simple.
8) Easy to manage and transport: the scaffold has no scattered and easy to lose fasteners, which is light, firm and compact and convenient for transport;
2.3.4 bearing capacity of bowl buckle scaffold
The ultimate axial shear strength of the lower bowl buckle is 170kN, and the ultimate eccentric tensile strength of the upper bowl buckle is / span > 43kn; the bending capacity of the cross bar joint: under the concentrated load of the cantilever end > 2Kn m, under the concentrated load of the middle span > 6 ~ 9kn M  step distance of 1.8m, the maximum bearing capacity of the vertical bar is > 25kn / piece
In order to improve the bearing capacity of the support frame, in addition to reducing the step distance of the cross bar, the diagonal bar, diagonal brace and diagonal brace can be added to enhance the stability of the support frame. When the support frame is set according to the structural requirements and the height width ratio is less than 100 million, the overall stability of the support frame may not be considered. The bearing capacity of each upright depends on the step distance of the cross bar.
2.3.5 the design requirements of the bowl button support frame
Generally, the step distance is 1.8m, and the span is 1.2-2.4m. All around the scaffold, diagonal bars are arranged at the full height of the partition frame, and scaffold boards are laid on the working floor. In order to reduce the amount of scaffold, some cross bars can be appropriately reduced in the middle. It can be divided into several unit frames according to the height and load layout. Each unit frame is composed of several spans, and its height width (narrowest side) ratio is less than 3 / span > 1. A layer of cross bar is set between the unit frames every 3-5 steps to connect them into a whole. For the full-scale red scaffold, because the vertical pole is equipped with cross bars in four directions (except for the scaffold vertical pole around), and the cross bar is in the plane of the frame, there is no eccentricity, so in the cross bar layer, the vertical pole is constrained by the limit position of the cross bar in the horizontal direction. When the height width ratio of the whole frame is less than 100 million, it can be considered that the bearing capacity of the whole frame is determined by the pole
Span lang = "EN-US" > 2.5 beam slab support mainly composed of slab (early dismantling system >
The local stability of the bar, i.e. the step distance of the horizontal cross bar, is limited to > 2.5, which is the schematic diagram of the support form of the bowl buckle frame beam plate formwork (mainly plate layout)
2.3.6 economic and technological analysis
For the general cast-in-place concrete formwork support frame, when accurate calculation is not needed, it can be estimated by experience that the amount of bowl buckled support frame for the general building floor formwork is the support volume per cubic meter (i.e. the net height of support multiplied by the support area) with bowl buckled line / span > 7kg; the amount of bridge formwork support frame is about 14kg per cubic meter of support volume with bowl buckled frame