Experimental Investigation of the Elastic Moduli of Existing Minangkabau Wooden Buildings using Non-Destructive Testing

Introduction The existing Minangkabau traditional wooden buildings that are more than 100 years old are commonly found in Tanah Datar Regency, West Sumatra Province, Indonesia. However, it is necessary to assess the residual strength of the wood to evaluate the main structural members, such as beams and main columns, which may have experienced a decrease in strength. The aim of this research is to carry out non-destructive testing to obtain the dynamic elastic moduli of the existing buildings. Methods Non-destructive testing was conducted using ultrasound technology specifically designed for wood. The members studied were the main columns and beams of the existing buildings. This study focused on the two existing Minangkabau wooden buildings located in Tanah Datar Regency. Results The test results for the first building yielded a dynamic elastic modulus (MoE d ) of 14,600.8 MPa, with a standard deviation of 1,803.1 MPa and a coefficient of variation of 12.35% (0.1235). In comparison, the second building showed a dynamic elastic modulus of 11,108.52 MPa, with a standard deviation of 1,720.14 MPa and a coefficient of variation of 15.48% (0.1548). Additionally, the elastic modulus for the first building was 10,282.25 MPa, while the second building had an elastic modulus of 7,822.90 MPa. Discussion The results from this study indicated that the elastic modulus of the first existing building showed a trend of no significant decrease in strength. These results matched with visual observation that the tested columns and beams did not experience damage. In contrast, the test results for the second building indicated that the tested main beams experienced a decrease in strength due to damage, which ranged from 28.23% to 35.18%. Conclusion The non-destructive testing of existing timber buildings offers benefits, including providing recommendations for repairs and assessing structural members that need to be replaced due to strength degradation using the same quality or the same species of timber. This study suggests a non-destructive testing method for evaluating existing timber buildings.