How do box-type steel structures perform in high-rise buildings?

2025-03-26 16:13:39

In today's race for ultra-high-rise buildings to break through the 600-meter skyline, box-type Steel Structure has become the core technical solution to support skyscrapers by virtue of its unique mechanical properties and industrialized construction advantages. From the giant frame of Shanghai Center Tower to the reinforced layer system of Dubai Burj Khalifa, box section steel structure shows revolutionary breakthroughs in lateral stiffness resistance, construction efficiency, space utilization and other aspects.

I. Significant advantage of lateral stiffness

The closed cross-section characteristics of box-type steel structure make its unit mass lateral stiffness 3-5 times that of H-beam. Shenzhen Ping An Financial Center (599m) adopts 1.8m×2.4m box section steel columns, with double-layer steel plate-concrete combined section, which controls the structural displacement angle at the apex of the structure to be within 1/600, which is better than 1/400 required by FEMA 356 specification, and the local stability coefficient is raised to 2.8 when its cross-section width/thickness ratio is optimized to be 18:1 to effectively avoid flexural damage under high intensity earthquakes.

Excellent torsional performance

The torsional moment of inertia of box-type steel structure section is 10-15 times that of H-type steel of the same size. The triangular core of Shanghai Center Tower (632m) adopts box-type steel column system, and the top torsion angle is only 0.0015rad under the working condition of Grade 12 typhoon, which meets the highest requirement of ISO 3010 standard. The built-in viscous damper system works in concert with the box-type steel frame to reduce the wind vibration acceleration to 0.15m/s², which significantly improves comfort.

Efficient Load Carrying System

Vertical Load Transfer

Through the four-way uniform force transfer mechanism, the box section steel members increase the axial compressive load bearing capacity to 1.3-1.5 times of the same cross-section H-beam steel. Wuhan Greenland Center (475m) adopts 1.5m×2.0m box section steel columns, with a maximum designed axial force of 120,000kN for a single column, which reduces the cross-section area by 35% compared with the concrete solution.

Advantage of node connection

The diaphragm through node increases the node domain shear bearing capacity of box steel frame by 40%. An 8-degree seismic area of 300 meters of super high-rise project measurements show that the plastic angle of the box steel node in rare earthquakes is only 0.015rad, much lower than the normative limit of 0.03rad.

Fourth, industrialized construction breakthrough

Modular construction

The prefabrication rate of box-type steel components can reach 95%. CITIC Tower (528m) in Beijing adopts three-dimensional box-type steel modules, and the lifting speed reaches 800 tons in a single day, which shortens the construction period by 25% compared with the traditional construction. Laser tracking measurement technology controls the installation error at ±2mm/30m.

Intelligent Welding Technology

Narrow-gap gas-shielded welding process improves the welding efficiency of 60mm-thick steel plate by 3 times, and the pass rate of one-time ultrasonic testing of weld seam is 99.5%. The Guangzhou East Tower (530m) project applies a robot welding system to complete the precision construction of 120km weld seams.

V. Space efficiency revolution

Cross-section optimization design

The box-type steel structure realizes efficient utilization of materials through variable cross-section technology. Suzhou International Finance Center (450m) adopts tapering box-type steel columns (1.8m×2.4m at the bottom → 1.2m×1.6m at the top), which saves 2,800 tons of steel and reduces direct costs by 15%.

Pipeline integration innovation

The box section steel cavity integrates electromechanical pipeline system. Shenzhen China Resources Building (392m) increases the net height of the standard floor by 0.8m through the built-in intelligent control system of 0.9m×1.2m box section steel beams, which increases the leasing value by 20%.