Sclerometric Tests Research Articles

Experimental identification of a multi-span masonry bridge: The Tanaro Bridge

The Tanaro Bridge, an 18 span masonry bridge built in 1866, has been investigated both in service conditions and at different stages of its demolition. A comparative characterization of the brickwork was performed by means of compressive tests on cylinders, flat jacks, sonic and sclerometer tests, while the natural frequencies and mode shapes of the bridge and the brickwork damping have been identified by dynamic tests on the bridge. Data from material testing were used to set up FEM models, so that the reliability of the material characterization procedures is demonstrated by comparison between the dynamic tests and FEM results. A rational comparative analysis of the results showed that: (i) a large part of the bridge needs to be monitored if the mode shapes are to be identified through dynamic tests; (ii) elastic FEM models can provide some information on the bridge response under service loads provided the mechanical parameters are adequately identified. Besides, some information has been deduced on the effectiveness, in service conditions, of some retrofitting technique: (i) transversal tie bars through the arch thickness have been proved almost ineffective; (ii) internal spandrels were found to be quite efficient in connecting adjacent spans.

Micromechanical properties of Co-W alloys electrodeposited under pulse conditions

Results of the investigation of pulse current frequency influence (rectangular unipolar pulses, i m = 3 A/dm2, relative pulse duration 3, frequency 0.67–333 Hz, Q = 3600 C/dm2) on the properties of Co-W alloys at electrochemical deposition—deposition rate, current efficiency, structure of obtained coatings, and their microhardness (microindentation and sclerometric ones)—are presented. The correlation between the microhardness determined by quasi-static indentation and the “organic” phase content in the alloy is shown (the microhardness decreases as the total content of carbon and oxygen in the deposited layer increases). Sclerometric tests have shown that microhardness increases with an increasing tungsten concentration in the deposited layer.

Evaluation of measurement uncertainties for a scratching tester

The present study intends to evaluate the measurement uncertainty for a scratching tester, which was developed in the Mechanical Engineering Department of the Federal University of Santa Catarina. This tester furnishes the scratching hardness and the energy required to displace an unitary volume from material surface. The test basically consists in scratching a sample surface, knowing the scratching conditions and morphology. The uncertainties considered are associated to the stylus geometry, the scratch width and the load application system. Results suggested a preferential use to the equipment in materials with high performance in sclerometric tests, where the uncertainties are less than 10% of the base value.

Critical reflections on non-destructive testing of concrete

Sclerometer tests, the ultrasonic pulse velocity method, the acoustic emission technique and combined non-destructive methods for testing concrete properties are discussed. Examples and test results obtained by investigations with rigid and flexible loading plantens show the efficiency of additional non-destructive testing. Finally, the NDT methods under consideration as independent testing tools are critically analysed under several aspects.