The Beijing National Stadium was designed by Herzog & de Meuron with Arup as structural engineer, for the 2008 Summer Olympics. It seats 91,000 people. Its steel lattice — an interlacing of twisted box sections in which, of thousands of members, only two are identical — is one of the most recognised structures on Earth.
The stadium's primary structural system is 24 trussed columns, each weighing approximately 1,000 tonnes. When construction of the outer shell began in 2005, no crane on site was capable of lifting those columns into position as complete units. They were shipped to Beijing in sections and assembled in situ, piece by piece, at height. Not placed. Built where they stood.
The connecting lattice — 42,000 tonnes of curved, twisted box sections — was hoisted in sections and welded into position, using Q460 high-strength structural steel, employed at this scale in China for the first time. Installation ran for nearly eight months, from initial erection to final closure.
That closure became the programme's most tightly constrained operation. The lattice's 128 closure joints, across four closure lines, could only be welded once the whole steel structure — not just the local joint — sat within a design temperature band of 19°C ± 4°C. Get the temperature wrong and the closure gap itself would be the wrong size: the 42,000-tonne frame expanded and contracted with heat across its full span. Engineers monitored structure temperature in real time through 60 sensors and planned each closure operation against the weather forecast.
The closure welding itself required at least 14 hours to complete. On an August day in Beijing, the daily period in which the whole structure was within the design range was under 3 hours. The lattice could not be locked into a single load-bearing whole within a single day's qualifying temperature window. The constraint forced the closure into scheduled overnight sessions, timed and monitored against real-time data, spread across three separate operations: 26, 29, and 31 August 2006.
Over 100 skilled welders worked those closures, using some 2,000 kilograms of welding rod to complete the 128 joints — the final and most consequential fraction of a reported 320 kilometres of weld seam across the full erection programme.
The stadium hosted the Olympic opening ceremony on 8 August 2008. Final cost: $423 million.