Metal steel frame scaffolding is a factory-produced, site-erected scaffold and is one of the most common scaffolds used internationally today. It can be used not only as external scaffolding, but also as internal scaffolding or full scaffolding. Due to its standardised geometry, reasonable structure, good stress performance, easy installation and dismantling during construction, safety and reliability, economy and practicality, the portal scaffold is widely used in construction, bridges, tunnels, subways and other projects.
The erection of h frame scaffolding is generally carried out in accordance with the load and erection regulations listed in the catalogue, without the need for further calculations. If the actual use differs from the regulations, the corresponding reinforcement measures should be applied or the calculations carried out. Usually the height of the a frame scaffolding is limited to 45m, but after taking certain measures it can reach about 80m. The construction load is generally taken as: 1.8kN/㎡, or a concentrated load of 2kN acting in the span of the scaffold.
Portal scaffolding is made of ordinary steel pipe material as a tooled standard part, which is combined at the construction site. The basic unit is made up of a pair of portal frames, two pairs of scissor braces, a horizontal beam frame and four connectors. A number of basic units are stacked vertically by means of connectors, fastened with arm buckles, to form a multi-layer frame. In the horizontal direction, reinforcement bars and horizontal beam frames are used to make the adjacent units integral, together with inclined ladders, balustrade posts and crossbars to form an external scaffold with upper and lower step connections.
Advantages.
(1) Standardised geometry of portal steel tube scaffolding.
(2) Reasonable structure, good stress performance, full use of steel strength, high load-bearing capacity.
(3) Easy to install and dismantle, high erection efficiency, labour and time saving, safe and reliable, economical and applicable.
Disadvantages.
(1) There is no flexibility in the size of the frame, any change in the size of the frame has to be replaced by another type of portal frame and its accessories.
(2) Cross bracing is prone to breakage at the centre hinge point.
(3) The heavy weight of the shaped scaffold.
(4) More expensive.
Adaptations.
(1) to construct shaped scaffolds
(2) as a support frame for sorghum and slab frameworks (to carry vertical loads)
(3) Construction of movable working platforms.
Post time: Apr-27-2022