Bamboo Amphitheater Space Structure
The dome of the Amphitheater Prof. Junito Brandão in PUC-Rio is a mobile free-form bamboo space structure spanning 17 x 12m, in a total of 200m² of covered area.
The structure was designed on the foundation previously designed by the architect Carlos Pingarrilho. The structural design developed through a form-finding method, using physical scale models and computer models in interaction.
The dome employs a textile hybrid space structure formed by self-supporting treated bamboo bipods, tensile pantographic gridshells and self-stressed active bending beams, avoiding buckling of the structural members. Gridshell modules were disposed discontinuously in overlapping steps 0.5m apart, allowing air circulation and natural lighting. Active bending beams and pantographic gridshells were subjected to prescribed external loads in a process of elastic deformation during assembly. The hybrid space structure created resistant and naturally acoustic forms, applying concave surfaces that maintain and distribute the sound in the space. The roof employs pre-stressed acrylic membranes, protecting from the rain and sun in the tropical climate.
The design is inspired in the forms of nature. Textile flexible connections were developed, allowing the mobility and the deployability of the structural members during the assembly procedure in the inclined topography site, with low mechanical stresses applied in the members. The structure was assembled in 25 working days, using creative techniques and an engineering design for safety with low environmental impact. Prefabricated modules, pantographic systems, textile systems and a mobile lifting device were developed, without the use of cranes and heavy equipment.
Reinforced concrete anchors fix the dome to the ground and preserve the structure from the direct contact with the soil moisture.
Since it was inaugurated in 2014, the Amphitheater dome hosts events, shows and lectures. The Amphitheater space structure is also used by students and staff for leisure, rest and reading.
The space structure presents a proper weigh of 1.4 tons, ie 7 kgf/m², and is a sustainable ultra-lightweight mobile free-form space structure. Its lightness and strength is only comparable to modern composite structures of advanced polymers.
The project received the financial support from the Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, FAPERJ.
Photos: Juan Dias