A Simple Stilt Structure Technique for Earthquake Resistance of Wooden Vernacular Houses in Bima, Sumbawa Island, Indonesia

Abstract

The existence of local building structures in Bima vernacular architecture is the research object in this study. The condition of the Bima Regency, which is prone to tectonic and volcanic earthquakes, is the context that influences the structure of the wooden stilt houses. This vulnerability occurs because of two earthquake fault lines flanking the Sumbawa island and an active volcano, Mount Tambora. Identification of Bima vernacular houses' structures and their effectiveness in reducing deformation due to earthquakes become the aims of this study. Data collection uses field observation methods to identify local building structures and construction systems. It also uses digital simulation to determine diagonal bar elements' effectiveness on the stage structure in reducing deformation due to an earthquake. The results showed that the stilt structure consisting of post components with corbels to support the beams, double beams arranged in a cross, diagonal bars, and wooden pegs were structures that maintained their existence. The existence of this stilt structure technique is part of the local seismic culture of the Bima community. The simulation result shows that diagonal bars' presence reduces deformation in structural elements due to earthquake loads. The synergy between structural components occurs in the construction of the Bima vernacular house structure. Thus, the system, form, and material of the Bima stilt structure can reference the development of earthquake-resistant houses in Indonesia.