Obsidian Rain Pavilion

The 17th International Architecture Exhibition was opened to the public on May 22nd and deals with the theme "How will we live together?" crossing transversal and multidisciplinary collaborations.

Ergodomus engineered the “Obsidian Rain” pavilion, which is one of the main attractions since it is located at the entrance to the Biennale Gardens. Our scope of work was: structural analysis, production drawings, assembly drawings, suppliers and site management. We were not alone, we worked together side by side with the companies Holz snc (assembly) and Bozza Legnami (wood manufacturing).

The pavilion designed by cave_bureau (Kenya) represents a part of the Mbai cave which is part of the cave complex of the Anthropocene Museum. Inside the installation, the ceiling of the cave is created by 1686 Obsidian stones hung on steel ropes with different lengths. All those ropes are hung on a 18×18 cm net made by steel wires. The scope is to recreate the entrance of the cave that was laser scanned.

The first challenge was to keep the right shape of the cave’s entrance considering the deformation of the steel net. This was possible by calculating in advance the global deformation due to the weight of the stones, in order to get the real lengths of the wires.

At this stage, the interoperability between the structural analysis software (RFEM) and the algorithmic modeling software (Rhino + Grasshopper) was crucial. This synergy allowed the efficient management of a large amount of data through an algorithm that updated the FEM model during the various modifications and made it possible to extract the lengths (all different) of the 1686 cables sorted by rows.

To keep the structural elements as small, light and stable as possible we decided to go for Kerto and create the 10.5m tall columns as empty boxes. Then a steel octagon (with the steel net) is connected to the columns with bolts.
During the construction stage, in addition to the usual assembly drawings, it was also used an augmented reality app to speed up the assembly of the structure and avoid assembly mistakes. Once installed on the smartphone, the app gave the assemblers the possibility to virtually see the elements of the structure along with their label.

The final phase of the construction site was a challenge against time due to delays in the delivery of timber and the production of the ropes. Despite the very limited time, a great teamwork between all the companies and professionals involved allowed us to be able to hang the last stone at 3:00 am, just in time to allow another team to clean everything and paint the floor. The Biennale was therefore opened at 10 am as per the program.

Cave_Bureau Bio

Arch. Stella Mutegi
Arch. Kabage Karanja

Cave_bureau is a Nairobi-based bureau of architects and researchers charting explorations into architecture and urbanism within nature. Our work addresses and works to decode both anthropological and geological contexts of the postcolonial African city, explored through drawing, storytelling, construction, and the curation of performative events of resistance. The bureau is driven to develop systems and structures that improve the human condition, without negatively impacting the natural environment and social fabric of communities. By conducting playful and intensive research studies into caves within and around Nairobi, we aim to navigate a return to the limitless curiosity of our early ancestors while confronting the challenges of contemporary rural and urban living.


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