Some of the equipment in the Structures Laboratory for each of the sections already shown in the presentation section of the Laboratory is shown below.
Trio control system RT3–S
The RT3 controller consists of an embedded system managed by a software application developed in the Labview environment, which operates in real-time and interfaces via an Ethernet network link with a PC running Windows XP.
Electronic modules are integrated into the RT3 system to condition the transducers, drive the servo-valves and manage the hydraulic equipment according to the specific characteristics of the end application.
Displacement acquisition can take place using laser sensors and analogue position transducers.
For both, the acquisition system is provided by power cables that connect the transducers to the control system, with which data can be acquired by setting a predefined sampling rate.
The transmission of signals from the measuring sensors to the central unit is digital.
In this way, it is possible to guarantee the total absence of interference in data transmission and, therefore, the absence of errors in the measurement of experimentally measured quantities.
Acquisition of displacements
Luchsinger laser sensors of the optoNCDT 1302 series with 200 mm measuring range, max. linearity 40 µm, max. resolution 4 µm, 750 Hz measuring speed and scalable analogue output.
Balluff Micropulse BTL7-A/E501-M analogue position transducer, measuring range 0 to 500 mm.
Some of the equipment in the “Materials” section
One of the most significant pieces of equipment in the “Materials” section of the Laboratory is the 2000kN Rexroth actuator, which allows a series of static tests on structural components (beams, walls, columns, nodes, etc.) to qualify traditional and innovative technological solutions.
The actuator is a servo-hydraulic system that operates with force and displacement control. It features a maximum stroke of 10 cm and a joint that allows the correct load distribution on the specimen.
The actuator is attached to a contrasting frame, as shown in the following figure.
Rexroth 2000 kN actuator for structural component testing
The servo-hydraulic actuator drive system is provided by a hydraulic power unit consisting of: an oil tank with a capacity of 100 litres, block complete with servo valve, pressure regulating valve, μ 6 delivery filter, external gear pump with a capacity of 16 litres/min – operating pressure 250 bar, air heat exchanger, 10 kW electric motor, electric control panel including PLC programmed to the functions of the hydraulic actuators.
The servo-actuator is interfaced with the user via a PC connected to a control system equipped with RT3 software produced by TRIO Sistemi e Misure Srl, similar to that used in the “Components and full-scale structures” section of the same Laboratory.
The displacement acquisition system is also similar to that used in the Laboratory section described above.
There is also an additional acquisition system consisting of digital comparators with a resolution of 0.001 mm (ABSOLUTE Digimatic ID-S, model S43- 7908″) that send data via a wireless system consisting of a U-WAVE-T emitter and U-WAVE-R receiver.
3000 kN press, motorised with Servotronic
The machine enables tests to be carried out to determine the compressive strength of cubic and cylindrical specimens and determine the compressive secant modulus of elasticity.
It consists of a four-column frame, load plates and a hydraulic system.
The machine comes complete with a servo-driven control unit to make the test fully automatic in all its phases of acquisition, display, data processing, including adjusting the load gradient and software for printing the results.
Leveling grinding machine
Used for flattening and grinding cubic and cylindrical specimens of concrete, bricks, natural stone, etc. It consists of a steel structure supporting the abrasive head, the coolant collection and decantation tank with an electric pump and the splash protection casing.
The specimens are fixed employing appropriate brackets, which ensure the coupling and locking.
The descent of the sanding head is automatic, with adjustment for a minimum feed of 0.05 mm.
Tank for curing concrete specimens
The curing tank is used for curing specimens in an air-conditioned chamber with constant humidity and temperature.
The tank consists of a sheet steel structure subjected to anti-corrosion treatment employing total hot-dip galvanisation.
Complete with a grid at the base, it is equipped with a thermoregulator with an immersion heating element.
Vibrating table 800 x 400 mm
Used to compact concrete specimens in the Laboratory.
The table is made of a sturdy steel plate, equipped with an electric vibrator with 3000 vibrations/minute.
The vibrating intensity can be adjusted by acting on the eccentric masses.
The table has fixing brackets, a control panel and a footswitch.
Test bench for checking the flatness of concrete, brick and natural stone specimens, etc. The bench consists of a 632x400x73 mm block of black granite, with a lapped surface that guarantees high precision and gives excellent results in the sliding of cylindrical specimens.
The top has an accuracy of 00 according to DIN 876 and is made of granite, guarantees dimensional stability over time, thermal stability, hardness, wear-resistance and oxidation resistance.
The top rests on feet supported by a steel frame.
The feet are height-adjustable so that the top itself can be levelled.
100 litre vertical axis mixer
Used to prepare the mortar and concrete mixes.
As the mixer has a vertical axis, it incorporates less air during the mixing phase, takes less time and ensures perfect homogeneity even for mixtures with a low percentage of water concerning the cement used.
Frame for hydrostatic weighing
Used to determine the specific gravity of hardened concrete, aggregates and solid materials in general.
It consists of a jumper support frame with a hooked tie-rod, a movable platform on which a vertically adjustable tank rests employing a crank for weighing both in water and in air, a stainless steel basket and an electronic scale with a lower hook.
Automatic computerised tropicalized Vicat apparatus
The device determines the start and end-setting time of a hydraulic binder.
Manufactured with anti-corrosion and tropicalised components for use in humidity and temperature controlled environments as the Standards require.
It automatically performs the entire test, ensuring results of absolute precision and repeatability.
Le Chatelier moulds and trays
Le Chatelier moulds are used to determine cement specimens’ stability (expansion) in both cold and boiling water.
The Le Chatelier tray is used to heat Le Chatelier moulds immersed in water to boiling point.
The inner chamber is made of stainless steel and can accommodate up to 12 Le Chatelier moulds in the basket.