Banwag Pharos is a bamboo structure located in the city of Parang, Maguindanao province of the Philippines. The structure serves as a gathering space for the local community, where they can organize various events and where their children can play. Summum Engineering provided structural engineering services for the structure, which includes global design calculations for the bamboo and steel elements.
The Banwag Pharos project was developed by design and build company Impossible Projects, in the Philippines. An initial design was checked by Summum Engineering, and revised based on our recommendations to improve its structural behaviour and feasibility.
Commissioned for the Pablo Sarmiento Group in close proximity to the expected new government centre of the Bangsamoro, it is a place for people to congregate and serves as a symbol of peace between the Muslims, Christians and Lumads of the region. The name ‘Banwag’ comes from the Visayan word for beacon or illumination. In fact, the structure is adaptable for multi-colored LED lighting, transforming it into a radiant beacon during nighttime and special events.
The bamboo structure is unique in its adoption of computational design and digital fabrication. It is 9 meters high and 16 meters in diameter, resembling a lamella dome shape. It is built primarily using blumeana bambusa bamboo species, locally referred to as kawayang tinik . Use of vernacular whole bamboo poles provides a warm and welcoming feel to the gathering space, thus encouraging different local communities to come together and interact within the space. It also aims to encourage the local community to embrace bamboo as a more conventional option for building safe, permanent structures.
The structure is covered in parts with a membrane fabric. The membrane is divided into three different layers to allow for a chimney effect for natural ventilation.
The design is evocative of decorative patterning in Islamic architecture and its dome shape reminds us of the vaulted domes of the early Mosques and Cathedrals. The bamboo framework forms a geometric pattern consisting of star shaped triangles. This triangulated grid of bamboo elements is connected using digitally fabricated, stainless steel nodes, behaving as a spatial frame.
The main structure comprising of bamboo elements, steel wire ropes and stainless steel pipes is checked against the high wind loads occurring in Philippines for hurricane-like situations.
The wind loads are applied on the membrane cover, which transmits the loads to the inner bamboo and steel structure. Since the geometry of the structure resembles both a dome as well as a cone, in order to determine the wind pressure coefficients, it is treated both as a dome according to the Philippine standard and as a cone according to a European standard for tent structures.
The strength of bamboo poles was checked using international standards for bamboo structures, based material properties derived from academic studies on this particular species of bamboo. The section sizes for bamboo elements are distributed along the height of the dome to meet strength requirements. Moreover, the diameters and thicknesses were chosen within the range of sizes that the client was able to procure, by coordinating closely with them during the design phase.