The Den

A demountable timber theatre: a curved timber drum with a canopy ring suspended at its centre.

Role: Detailed structural design, buckling analysis and connection checks
Status: Built
Architect: Haworth Tompkins
Structural engineer: Expedition Engineering
Timber specialist: Xylotek
Photographs: Ronan Hunt

The timber drum inside the hall, with rope bracing and the canopy ring suspended at its centre — The timber drum inside the hall, with the canopy ring suspended at its centre.

The Den is a demountable timber theatre: a temporary audience space inside a curved timber drum. I did its detailed structural design at Expedition Engineering, working closely with the design team.

The dome is minimal and low-rise, so stability was the main question. I built analysis models to study how it could buckle, because its buckling load factor was low.

Rope ends, thimbles, shackles and turnbuckles meeting at a tension node — A rigging node: ropes, thimbles, shackles and turnbuckles.

Timber members joined with bolted steel plates at a column head, with rigging above — A column head: bolted timber connections and steel plates, seen from below.

The structure comes down to bolts, plates and rigging. I wrote connection design spreadsheets to Eurocode 5, so that each timber connection could be checked alongside the analysis of the whole structure.

The timber drum during assembly, with people working beside the suspended canopy ring — Assembly inside the hall. The canopy ring hangs below the upper timber members.

Inside the timber drum: the suspended canopy ring, rope bracing and a hand winch — Inside the drum during the lift: the canopy ring, bracing and winch.

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