The Beijing National Stadium, known as the Bird’s Nest, hosted the opening ceremony of the 2008 Olympic Games on 8 August 2008. Herzog & de Meuron designed it with the China Architecture Design & Research Group, Arup was structural engineer, and Beijing Urban Construction Group was general contractor. Groundbreaking was in December 2003.

Its outer structure is a steel lattice of about 42,000 t of twisted, non-repetitive box-section members, carried on 24 trussed columns of roughly 1,000 t each. Temporary supports carried the primary roof structure through assembly and closure, before its load was transferred into the permanent structure. The project paper describes unloading a roof of about 14,000 t; the 42,000 t figure covers the wider outer steel structure. Secondary top-surface steel was installed after the primary structure had been unloaded, so the erection scheme was as much a plan for taking the supports away as for putting them up.

42,000 t
Outer steel structure
14,000 t
Roof unloaded
78
Temporary supports
35
Unloading sub-steps
271 mm
Measured deflection
Phase 1 — The supports
78 supports in three rings
China Daily reported that 78 supporting structures stood under the roof: 24 along the outer circle, 24 in the middle circle and 30 in the inner circle. They carried the primary roof structure, about 14,000 t, through assembly and closure.
Phase 2 — The closure
A temperature gate before the load transfer
The 128 closure joints across four closure lines could only be welded once the whole structure sat within 19 °C ± 4 °C, and the work was done in three operations on 26, 29 and 31 August 2006. That constraint is the subject of Newsletter Issue 7.
Phase 3 — The unloading
Seven major steps, 35 sub-steps
In September 2006 the supports were removed in seven major steps and 35 sub-steps. Jacking pads 100 to 200 mm high were placed on top of the supports; the roof was lifted off synchronously, the welds were cut and it was lowered in stages. The engineering account counts 156 jacks, and Enerpac’s account of its hydraulic system lists 156 cylinders of 150 tons.
Phase 4 — The check
271 mm against 286 mm
The engineering account gives a calculated maximum deformation of 286 mm and a measured one of 271 mm, a difference of 5.2%. The structure was monitored at 232 stress and strain points on four main trusses and two truss columns, with the 156 jack reactions and 16 points on the inner ring of the roof tracked as well.
Four-phase schematic of the Beijing National Stadium primary roof structure: about 14,000 t held on 78 temporary supports in three rings; closure welding within a 19 plus or minus 4 degree Celsius temperature band on 26, 29 and 31 August 2006; synchronised unloading by 156 jacks in seven major steps and 35 sub-steps; and measured deflection of 271 millimetres against 286 calculated
From temporary supports to a self-supporting roof. Conceptual schematic, not to scale; support positions and roof geometry are not drawn from the project. The 42,000 t figure covers the wider outer steel structure; secondary top-surface steel, installed after unloading, is not shown.
Sources: Li et al., CIB W78 (2013); China Daily (18 September 2006); Enerpac (2007). Diagram: EE&HL Network, 2026.

The temporary works at the Bird’s Nest did not end with the last closure weld. They ended when 156 jacks had lowered the roof onto the permanent structure and the measurements matched the calculation.

This is the moment the de-propping pages describe in general terms: load leaves the temporary supports and the permanent structure takes it up, through intermediate states. At the Bird’s Nest those states were planned in 35 sub-steps and measured as they happened. The sources reviewed describe the sequence and the result; they do not describe how responsibility for the unloading was allocated between the parties.

For the general pattern, see What Is a De-Propping Sequence? and the insight Why Removing Temporary Works Can Be Riskier Than Installing Them. For other roofs released onto themselves, see the Singapore Sports Hub and SoFi Stadium Canopy case studies, and for the closure constraint, Newsletter Issue 7.

Related case studies: Singapore Sports Hub · SoFi Stadium Canopy · Grande Arche · Eiffel Tower · Gateway Arch

Core concepts: What is erection engineering? · What is heavy lift engineering?

The Beijing National Stadium at dusk during the 2008 Olympics, its interwoven steel facade lit red from inside and the Olympic cauldron burning on the roof
The Beijing National Stadium during the 2008 Summer Olympics, with the Olympic cauldron alight on the roof. Optimised for web display.
Photo: 东林 (Dong Lin), via Wikimedia Commons, CC BY 2.5 CN.

Sources: Li et al. — “National Stadium (Bird’s Nest) Digital Construction Technology”, CIB W78 2013 — steel tonnage, 78 supports, unloading steps, 286 mm and 271 mm, closure dates, monitoring points, general contractor; China Daily — 18 September 2006 — 24/24/30 distribution of the 78 supports, 35 mini-steps in seven phases, jacking pads; Manufacturing.net — “Beijing’s Bird’s Nest becomes permanent”, March 2007 — the 156 hydraulic cylinders and the lift, cut and lower procedure; The Structural Engineer — Fan, Z., “Design of large-span steel structure for the National Stadium, Beijing”, vol. 85, no. 22, 2007 — design context; Wikipedia — design team, groundbreaking and the 24 trussed columns. Steel tonnages quoted for the stadium differ between sources because they cover different scopes; the 42,000 t figure is the outer steel structure as given in the engineering account, which puts the roof unloaded from the 78 supports at about 14,000 t. The two Newsletter Issue 7 constraints (closure temperature and window) are covered there and are not repeated in full here.

Frequently Asked Questions

78, according to China Daily and the engineering account: 24 along the outer circle, 24 in the middle circle and 30 in the inner circle.

In seven major steps and 35 sub-steps, using hydraulic jacks. The primary roof structure, about 14,000 t, was lifted synchronously off its supports, the welds were cut and it was lowered in stages. The engineering account counts 156 jacks. Secondary top-surface steel was installed after unloading.

The calculated maximum deformation on unloading was 286 mm and the measured value was 271 mm, a difference of 5.2%.

The outer steel structure is reported at about 42,000 t. The roof carried on the 78 temporary supports and then unloaded is put at about 14,000 t in the project paper. Other totals quoted for the stadium cover different scopes, so a figure should be read together with what it includes.