Ali Limam

Fire safety is a crucial issue for buildings, especially with the rise of modular construction, which demands materials that combine lightness with mechanical performance and stability. This study investigates a new concept for single-story modular constructions, made up of 3D cells assembled from thermally and acoustically pre-insulated concrete panels. These panels comprising four walls and two slabs forming the module, are stiffened, with thicknesses of only 5 cm for the walls and 7 cm for the slabs. Their constituent material is a self-compacting, high-volume steel-fiber concrete, containing 80 kg/m³ of steel fibers and 0.3 kg/m³ of polypropylene fibers. Experimental tests on a full-scale wall and slab revealed that adding 0.3 kg/m³ of polypropylene fibers effectively prevents concrete from splintering and achieves the necessary 30 min fire resistance. Standardized full-scale fire tests on walls and slabs confirmed that these thin structures meet fire resistance, insulation, and airtightness standards. The high volume of steel fibers provides ductility, maintaining structural integrity despite concrete spalling. The maximum spalling depth observed in some areas ranged 35 to 50 mm, without compromising structural performance. Overall, the modular system satisfies the fire safety requirements for structural stability (no collapse) and performance in single-story modular construction.

A new concept of a 3D volumetric module, made up of six plane stiffened self-compacting fiber-reinforced concrete (SFRC) panels, is here studied. Experimental campaigns are carried out on SFRC material and on the thin-slab structures used for this modular concept. The high volume of steel fibers (80 kg/m³) used in the formulation of this concrete allow a positive strain hardening to be obtained in the post-cracking regime observed on the bending characterization tests. The high mechanical material characteristics, obtained both in tension and compression, allow a significant decrease in the module slabs’ thickness. The tests carried out on the 7 cm thick slab demonstrate a high load-bearing capacity and ductility under bending loading; this is also the case for shear loading configuration, although without any shear reinforcements. Numerical simulations of the material mechanical tests were conducted using Abaqus code; the results corroborate the experimental findings. Then, simulations were also conducted at the structural level, mainly to evaluate the behavior and the bearing capacity of the thin 3D module stiffened slabs. Finally, knowing that the concrete module truck transport can be a weak point, the decelerations induced during transportation were characterized and the integrity of the largest 3D module was demonstrated.

Flexible protection barriers are often located on the mountainsides in order to decrease the risk of rockfall. In the present study, different scales of experimental tests are considered, to gauge the behaviour and to estimate the bearing capacity of a new type of cable-nets used for these flexible barriers in case of quasi-static loads. A large experimental campaign addressing cables characterization, as well as the behaviour of the constitutive cells of the net, which particular shape, a water drop shape instead of the classical rings, induces asymmetric loading transfer. Finally, the net behaviour itself is characterized through appropriate tests. These tests highlighted the non-linear behaviour perceived at different scales and permitted to evaluate the bearing capacity of the various components. Numerical simulations using the finite element code Abaqus were also conducted for the different components, a group of constitutive cells with rigid or fuse clip or the whole net, to reproduce the behaviour observed experimentally.

The rockfall hazard in areas such as mountainous regions, quarries and mines needs to be well managed. This is essential in order to avoid fatalities, damage to infrastructure and production losses. Preventing all rockfall events is almost impossible, but the installation of rockfall protection systems is a common and effective way to control the hazard. The installation of wire-meshed net anchored is a possible solution to prevent slippage of landslide of the surface layers. This paper will be focused on the study of numerical modeling, using finite element analysis software, ABAQUS, of double-twisted hexagonal wire-meshed net anchoraged which has been developed by the French-based company, GTS. The objective is to analyze several configurations and performances of wire-meshed nets, cables. As final result, we will comparing between the experiment and numerical modeling analysis.