Seismic Vulnerability Assessment In Vernacular Houses: The Rapid Visual Screening Procedure for Non Engineered Building with Application to Java Indonesia

ABSTRACT: Vernacular houses or known as non-engineered houses in fact are still the most inhabited buildings in this world, especially in developing countries. Many developments have been done, mostly by the occupants themselves, in various ways in order to follow the needs along to the capability of the people. Unfortunately, not all developments were relied on the real necessities, and some even lead to danger the user. In the other hand, least attention had been made by scholars, professionals, or even the authorities since the subject is vernacular, by mean can be devolved upon the people and considered as less important issue. This miss conception had been paid when it becomes a disaster, such as from an earthquake; when the houses are fail to give protection, instead its give a threat because of its deficiencies particularly in those countries that are allocated in high seismic zone such as Java Island. Under seismic hazards, vernacular houses have various behaviors from most to least capability of resisting such hazard, which is related to architectural and structural system. Many methods for examining seismic vulnerabilities for building have been proposed through the structural analysis procedures which could be only done by competent engineers, other simpler survey procedures were also developed by the rapid visual screening for investigating building probabilities from the risk. However, almost all of these evaluations were intended for well defined-engineered buildings in structural point of view. None of them was applicable for form-typology-related evaluation such as vernacular buildings which are very different in many aspects. This research deals with the assessment of vernacular house development by the influence of natural disaster of earthquake. The aim of this research is to examine the seismic vulnerability level of the houses by developing a specific-applicable simple procedure, to be applied for Javanese vernacular houses. A method based on FEMA 154, Rapid Visual Procedure had been adapted for Javanese vernacular house circumstances. To achieve this, a quantitative study based on computer simulation had been done for various types the houses, and a full performance comparison has been utilized. Post quake field finding were used to support the examination. Field applications were also taken in order to confirm the procedure and to discover the level of vulnerability. The result shows that the level of seismic risk in vernacular houses can be assessed by a certain method adopted from available well-defined procedure. Proper adaptation regarding the local seismicity and building practices turned the procedure become applicable for Javanese vernacular houses. Unfortunately, the vulnerability level of those houses, especially the new houses after the May 27th 2006 earthquake, is not as ideal as expected before, and this can be associated to the mixed technique in building practice between old and new. In other side, some original traditional (unmodified) houses were proved to have better performance under the earthquake Hazard. These findings on vulnerability trigger a new thinking for the more suitable alternative of the future of Javanese houses. Keywords: Javanese vernacular houses, reconstruction of Javanese houses, seismic risk assessment, rapid visual screening procedure. ……………………………………………………………………………………………………………………………………………………………………………………………………………………