Construction Challenges Arising from High Floor Heights
Conventional aluminum formwork support systems are well-established in projects with floor heights below 3.3m, achieving stability through standard independent supports. However, with a floor height of 3.7m, support stability and formwork deformation control become core challenges. This project implemented three key optimizations to the support system, representing the most significant difference from conventional projects:
Support Uprights: From "Standard" to "Customized"
Conventional projects often use independent steel supports consisting of a 1.7m sleeve + a 1.7m insert (sleeve outer diameter 60mm; insert outer diameter 48mm), resulting in a total height of only 3.4m, insufficient for a 3.7m floor height. This project welded and extended the 1.7m insert to 2.3m, combining it with the original 1.7m sleeve to form a support combination with a suitable total height. Simultaneously, the upright spacing was strictly controlled: the spacing between beam and slab bottom supports was ≤1.3m, and for large-span beams and large open areas, the spacing was increased to 0.9m to ensure uniform vertical load distribution.
Horizontal Tie Rods: Adding a "Critical Link to Stability" When the floor height is ≤3.3m, horizontal rods are unnecessary; diagonal bracing alone is sufficient for stability. However, at a floor height of 3.7m, horizontal loads (such as wind loads and construction vibrations) have a significant impact. In this project, a Ф48×3.0mm ordinary steel pipe tie rod is installed 1.5~1.6m from the structural surface, running both horizontally and vertically. This rod is securely locked to the uprights using "60-to-48 variable cross-section couplers." Simultaneously, the horizontal tie rod is connected to the frame columns and shear walls, forming a "spatial stability net" to limit lateral displacement of the uprights.
Diagonal Bracing + Shear Bracing: Double Insurance Against Overturning
To further enhance lateral displacement resistance: each column has one diagonal brace on all four sides, and shear walls have two diagonal braces (the first brace has a steel back rib at the bottom, and the second brace has the 4th to 6th steel back ribs at the top). The angle between the diagonal brace and the ground is strictly controlled between 45° and 60°. Every four spans between the uprights, a horizontal and vertical shear brace (made of ordinary steel pipe) is installed, forming a diamond structure with the uprights, connecting the scattered supports into a whole.
Aluminum Formwork + PC: From Precise Construction to Accelerated Cross-Construction
After solving the problem of supporting high-rise buildings, the project optimized the connection design between the aluminum formwork process and the PC panels, and combined this with zoned cross-construction to achieve a double guarantee of "efficiency + quality." This is also the core logic of 10 days/floor:
01-Aluminum Formwork Process: The project uses 6061 aluminum alloy formwork, which can withstand the lateral pressure of high-rise concrete pouring while ensuring the quality of the finished product. For wall and column formwork, a 2500mm standard board + adjusting board is used for height adjustment, with staggered joints and horizontal back bracing to prevent formwork displacement. For the curved beams at the hotel's four corners, custom-made curved aluminum formwork is used for on-site assembly, avoiding the grout leakage and misalignment problems associated with traditional wooden formwork.
02-PC Board Connection: As a prefabricated project, the connection between PC composite panels and aluminum formwork follows the sequence of "aluminum formwork first, PC follow," while ensuring load stability: Aluminum formwork installation prioritizes the wall/column and beam formwork (with quick-release heads at the bottom of the beams) to form a stable support frame before laying the top slab aluminum formwork. Independent steel supports for the aluminum formwork bear the upper load (including the PC board's self-weight and construction load), preventing PC board deflection. For joint treatment, a 15mm wide, 3mm thick sponge strip is applied to the top slab aluminum formwork before hoisting. After hoisting, the aluminum formwork elevation is corrected again to prevent grout leakage at the joints.
Significant Overall Benefits
When using conventional wooden formwork construction, each floor of a project with the same area and high ceiling requires 15-20 days. This project, through a combination of optimized support system, aluminum formwork + PC synergy, and zoned cross-construction, not only achieved a 50% acceleration in construction time but also yielded significant results in quality and green construction:
Quality: Concrete surface flatness error ≤2mm, verticality error ≤5mm, no honeycomb pitting, aesthetically pleasing curved beams, and excellent concrete appearance.
Safety: The reinforced aluminum formwork support system showed no deformation or instability during concrete pouring, ensuring construction safety. Because of the use of the aluminum formwork construction system, there was no need for an external cantilevered unloading platform, fundamentally avoiding this construction hazard.
Civilized Appearance: The absence of an unloading platform ensured the continuity and integrity of the standardized steel mesh facade used in the scaffolding, preventing damage to the steel mesh caused by the disassembly and assembly of the unloading platform, significantly improving the aesthetics of the building facade.
From a green perspective: Compared to traditional wooden formwork, aluminum formwork can be reused more times, reducing the consumption of formwork and timber, which aligns with the concept of green construction.