Non-Destructive Tests on Carpentry Steels

Abstract

Background: Industrial archaeology represents a modern branch of urbanism and architecture that studies, applying an interdisciplinary method, all the evidence inherent the process of industrialization from its origins to the actuality. Aim: Looking at the cities of our epoch, more and more are the testimonies of these historical artefacts, which in fact represent our cultural identity and are often intended to be recovered and converted into modern destinations of use. Methods: If the identification of constructive schemes is based on direct essays and surveys, the definition of material properties requires material testing and investigation. For metal structures, the standards involve destructive investigations only, with a sampling of specimens, which often conflict with the protection requirements of the artefact. This leads to the need to refine and make reliable non-destructive investigations using the Leeb method, by means of portable micro-durometers, for in-situ characterization of carpentry steels, so to suggest new regulatory guidelines for existing structures surveys. Results: In the paper, the classification of carpentry steels based on non-destructive hardness test was illustrated and discussed. Firstly, for the evaluation of the resistance class of a structural steel, it was recorded that the execution of tests required a careful cleaning of the surface of samples. Subsequently, analyzing the data obtained from the experimentation, it was clear that the best methodology of data conversion from micro-hardness (Leeb method) tests for the determination of the steel class was given by tables and formulations of the ASTM standard. In the case of a few values to be converted, the most effective method was the manual use of the tables, with an average error of 0.10%. Conclusion: In conclusion, it should be remarked that differently from the reinforced concrete structures, where the non-destructive tests are allowed by the current Italian technical code on, for metallic structures only, destructive tests are permitted, so that the use of non-destructive ones should be encouraged, especially when interventions on cultural heritage constructions are of concern.

Diagnostic of degraded reinforced concrete bridges explaining the environmental condition effect and reinforcement method

“…The combination of NDT tools and visual inspection helps to indicate the corrective or preventive maintenance actions (Esteves et al , 2018). At the international level, it can be observed that existing Italian regulations allow for the use of NDTs with a double number, replacing 50% of destructive tests, such as the rebound and ultrasonic, which are correlated to the compressive strength (Formisano et al , 2019).…”

“…The sclerometric test is applied by means of aluminum sclerometer and in a cabinet of laser measuring mark LM and referenced SKU: 490500, a professional standard concrete (Plate 7a). Usually, the rebound is used to assess the metal hardness, a measure of the surface resistance to permanent plastic deformations (Formisano et al , 2019). During this test, the tool is held perpendicular to the surface examined, and a slight pressure is applied without touching the side button until the shock mass is released.…”

“…, with average values of (Na Usually, the rebound is used to assess the metal hardness, a measure of the surface resistance to permanent plastic deformations (Formisano et al, 2019). During this test, the tool is held perpendicular to the surface examined, and a slight pressure is applied without touching the side button until the shock mass is released.…”

Modification of the Leeb Impact Device for Measuring Hardness by the Dynamic Instrumented Indentation Method

“…Despite these features, portable hardness testers are widely used for the inspection of welding joints in pipelines, building structures, etc. [7,8]. Currently, some of the most common types of portable hardness testers are dynamic Leeb hardness testers [9,10].…”

Portable Measurement Systems Based on Microcontrollers to Test Durability of Structures: Mini-Review

“…However, some researchers (Bossio et al, 2018) are working in a High-Performance Concrete (HPC) that could aid the structure to sustain stress and improve the structure ductility even in advanced corrosion levels. However, reasearchers (Formisano et al, 2018(Formisano et al, , 2019 discussed the use of non-destructive tests such as the leed hardness test to measure steel properties. These tests use a penetration device, which punctures a sample with a fixed force and measure the dent on the steel.…”