The collaboration and support of LEMSC to research on Earthquake Engineering started at around early-mid 2019, coinciding with the arrival of Prof. João Almeida.
The first big project was the experimental testing of two large-scale 2.8 m ´ 2.8 m reinforced concrete walls. In one, shape-memory NiTi alloy rebars were used as a replacement to steel rebars. The superelastic flag-shaped hysteretic response of the smart alloy in the wall boundary elements guaranteed a sizeable energy dissipation but most importantly a clear reduction of the residual displacements. The results open a promising avenue both for new construction and repair works in RC walls, since economic damage and repair costs due to earthquakes are critically connected with permanent residual structural displacements.
The test setup consisted of two independent steel frames fixed to the laboratory strong floor, one supporting the vertical actuators and the other serving as reaction frame for the horizontal actuator force. The two vertical actuators, each with a force capacity of 350 kN and a stroke of 250 mm, applied a total compressive load as well as a varying bending moment corresponding to a pre-defined shear span through the lever arm of these actuators. Their forces were coupled with the force on a third horizontal actuator, which applied a cyclic quasi-static displacement history to the top RC beam of each specimen.
Apart from the actuator load cell and internal displacement, several other LEMSC instrumentation was used per test: 12 strain gauges, 22 displacement transducers, 9 micrometers, 1 inclinometer, and 2 cameras for digital image correlation of the speckle pattern applied on each wall’s surface.
A time-lapse of the tests can be seen here. A complete description of the test setup and results is available in this 2020 scientific paper. The complete set of experimental data can be downloaded from the UCLouvain open data public repository Dataverse.
The project actively engaged most of the laboratory staff: for control programming and data acquisition, for all instrumentation-related aspects, for the material testing (concrete, steel, and shape-memory alloys), as well as welding and for the different aspects related with the assembly of the test setup and overall assistance.
The LEMSC is also supporting, with both equipment and instrumentation, a second ongoing test programme on eight specimens to study scaling effects in reinforced concrete specimens. The first results will be accessible as soon as possible.