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Interior view of Chapel of Sound ©Zaiyestudio; Interior view of Chapel of Sound ©Zaiyestudio;

Chapel of Sound, Chengde

A reimagination and recreation of an instrument of sound

The Chapel of Sound is a boulder-shaped concert hall which sits in a rocky valley at the foot of Jinshanling Great Wall on Beijing’s northern border. Inside the rocky outcropping is a semi-outdoor amphitheater, an outdoor stage, viewing platforms and supporting spaces.

Suggestive of a strange and prehistoric fallen landform, the concrete structure is a ‘container’ to achieve the architect’s various visions – the outlook, the acoustic performance and how it echoes the natural surroundings.

As the structural and MEP engineer, Arup worked with OPEN Architecture to develop a purely integrated solution – the engineered structure without any decoration makes the hall with the perfect acoustic performance.

Project Summary

790 total GFA


24×36mtop plate outstretched from a small base

Unique geometry

The structure is 12m tall and greatly over-stretches – with a small base of 12m x 14m and a top plate of 24m x 36m – offering a total GFA of 790m2. This unique shape creates large over-turning moment. To tackle this, tie walls were added at critical positions between inner and outer shells to make a spatial structural system. Our structural engineers also adopted topology optimisation to fine-tune the curvature of the concrete shell.

© 2021 Jonathan Leijonhufvud

Pleasure for the ear

The semi-outdoor amphitheater and out-door stage posed great challenges to acoustic design. The steps and profile of the internal shell were set out through several iterations with the acoustic engineer to provide the best acoustic performance. The direct use of exposed concrete also eliminates the usage of additional decoration/acoustic materials.

Chapel of Sound (c) 2021 Jonathan Leijonhufvud Chapel of Sound (c) 2021 Jonathan Leijonhufvud

A comfortable amphitheater

A computational fluid dynamic (CFD) analysis was carried out to evaluate the comfort level inside the structure as it is mostly dependent on natural ventilation. The openings at the roof and elevation were afterwards added or adjusted based on the results.

Exterior view of Chapel of Sound © Zaiye Studio Exterior view of Chapel of Sound © Zaiye Studio

Cutting through the complexity

Due to the complex geometry, all coordination of architecture and engineering was carried out in Rhinoceros software, from which we produced the structure and MEP drawings and 3D models for the contractor.

We developed 3D set-out geometry and 2D layout drawings of all rebars (a total of 10,000!) to the contractor from the parametric model – which eased the contractor’s work a lot.

The construction was the ultimate challenge – thousands of small pieces of timber plates, shaped differently, fit together like a jigsaw. Not to mention the 10,000 rebars, all different, were bended and fixed into the position.


The project was designed to create a local landmark with minimal material consumption. Exposed concrete forms all the space and satisfies all functions through digital design. Crushed local, mineral-rich rocks were used as aggregates in the concrete mix to create the special dark tone of the concrete surface, and the wood strips of the formwork were all recycled.

More than a tourist draw, the hall will serve as a catalyst for the revitalisation of the area.