Assessment of the timber elements integrity using a resistograph

The resistograph is an instrument that registers the energy used to penetrate a thin drill, under constant velocity, on a timber element. Since there is a correlation between the penetration energy (the test output) and the timber density, the test allows estimating some of the material mechanical characteristics, but also detecting the presence of degradations, decays and internal voids inside a timber element. Therefore, the test assesses the conservation state of structural elements and helps estimating effective residual sections.
The test output (a graphic representing spent energy vs penetration length) is of simple and intuitive interpretation and provides qualitative and quantitative information of great interest. The fact that the drilling is almost imperceptible and has no influence on the mechanical strength of the element makes the test to be one of the most used instruments on the inspection of timber structures.

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