Ultrasonic evaluation regarding the effects of biological corrosion of historical roof trusses

Wojciech Skowroński,Bohdan Stawiski,M Kaszynska

doi:10.1051/matecconf/201928407006

Wojciech Skowroński, Bohdan Stawiski + Show 1 more

Open Access

https://doi.org/10.1051/matecconf/201928407006

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Abstract

For many years work has been performed to obtain sufficiently accurate correlation between the results of ultrasonic tests and the results of strength tests for evaluation of the strength parameters of wood in a structure. It is also important to ensure the development of methods which will facilitate the work of construction mycologists; that is, non-invasive methods of determining the volume of missing materials caused by biological corrosion. The study presents the idea of the objective examination of the thickness of a corroded layer by measuring the velocity of ultrasonic pulse along the fibre length using for this spot heads with thin waveguides. Another testing method presented in the study is controlling the velocity of ultrasonic wave in the direction tangential to annual growth rings by conducting tests on the corner of the corroded beam.

Highlights

Use of the ultrasonic method to evaluate the technical condition of fresh wood, especially when not built-in, is easy
It is important to develop methods which will facilitate the work of construction mycologists aimed at discovering defects and missing parts of materials caused by biological corrosion
This concerns the work which can be performed without infringing the continuity and structure of the building

Summary

Introduction

Use of the ultrasonic method to evaluate the technical condition of fresh wood, especially when not built-in, is easy. If it is assumed that wood can be regarded as a homogenous matter and the elastic susceptibility tensor is described by Srs indices (r, s = 1, 2, 3, 4, 5, 6), based on the Hook’s law the following equation is formulated: This statement is obtained taking into account the identicality of coordinate indications x ≡ x1, y ≡ x2, z ≡ x3. The described object is a building located in the centre of Wrocław – a compact complex of gothic prison structures (pearl of the Middle Ages). This is one of the oldest public utility buildings surviving until now (it reaches the first half of the 14 century); it obtained its current shape in the second half of the 17th century.

Ultrasonic tests of old structures made of wood

Findings

Comments and conclusions