Concrete-as-circus-strongman emerges as the theme of the latest issue of Concrete Quarterly, produced by my company Wordmule for the Concrete Centre. At One World Trade Center in New York, a super-strength concrete backbone is at the core of what its developers intend to be the most robust tower in the world. In Beirut, most of Zaha Hadid’s concrete Issam Fares Institute hangs from an astonishing 21m cantilever over a concrete campus, while at the Rambert Ballet’s new HQ on the south bank of the Thames, witness dazzling structural gymnastics as a light-but-incredibly-strong structure supports an 18m column-free span to replicate the stage at Saddler’s Wells. And in our Final Frame back cover slot, there’s Christian de Portzamparc’s Cidade Das Artes in Rio – an entire city under a mighty 46,000m2 slab roof. Take your pick from the classic magazine version in PDF form or the more tablet-friendly interactive edition.