In a new construction of a seventeen-storey building, it is necessary to remove a prop on the second floor, which has made it possible to complete the structure of the building. In the drafting of the executive project, no security measures were described, because it was understood that they were not necessary. In the construction phase, the need to monitor the process was raised, and to be able to stop it, or reverse it if necessary. It is a reinforced concrete structure, with metal elements and composite elements, with a torsional behavior of the cores making the slabs serve as horizontal diaphragms, so the final behavior could be different from what was expected. To make this process possible, two pairs of four metallic cantilevers were introduced into which four Hydraulic pistons were inserted. Before starting the process, they were loaded to be sure that they would not fail. Strain gauges were also placed to control the stresses and how the situation changed during the unshoring process. The process of cutting the provisional pillar was a success, obtaining less deformations than expected, having a complementary safety.

The degradation of the natural fibers in the hydraulic binder alkaline matrix is widely known. This study investigates the effect of two fiber treatments, namely immersion in sodium hydroxide (NaOH) solution and hornification, in two types of alkaline environmental ordinary Portland cement (OPC) and a mixture of OPC and natural hydraulic lime (NHL). After curing for 28 days, the specimens were subjected to 25 and 50 dry–wet aging cycles to evaluate their degradation behavior. Subsequently, the specimens underwent flexural and compressive strength tests. This study reveals that the specimens with the mixed binder of ordinary Portland cement (OPC) and natural hydraulic lime (NHL), after 50 aging cycles, reached toughness values in the descending branch compared to the total toughness obtained in the flexural–displacement diagram, of 17% and 27% for the treatment with NaOH and hornification fiber, compared to 3% and 10% obtained for the matrix with an OPC binder. Therefore, the inclusion of NHL as a matrix binder provided better softening behavior than those with only the OPC binder, providing better protection of the fibers against environmental alkalinity due to matrix alkalinity. In addition, the hornification treatment better preserved the fibers throughout the aging process.

In the new construction of a seventeen-storey building, a provisional prop of fourteen-meter height, horizontally braced on two intermediate levels, has been used. Despite the fact that structural logic suggests that it can be cut without having any added safety precautions, the structure of the building, made up of cores and reinforced concrete slabs working spatially, indicates that certain mechanisms be introduced so that, in the event that different and worse behaviors than expected are detected, the process can be stopped and the consequences of the new situation observed can be analyzed. For this purpose, two pairs of four metallic cantilevers were introduced at mid-height with four hydraulic pistons. In addition, the best position of a series of strain gauges as well as transducers were analyzed. At first, a load test was carried out to check that the brackets worked correctly. Once this step was verified, the abutment was cut, and the results were read. The results of stresses and deformations were compared with those expected, always being satisfactory. Finally, four provisional profiles were placed in case after a few days the structure suddenly gave way. The research focuses on obtaining an efficient control system and achieving total security throughout the process, with the comparison of the results strictly necessary for this case. Few resources were used so as not to make the work excessively expensive. We have found important divergences, on the side of security, between calculation and reality. We have also considered that the construction process has an impact on the final results. In the same way, the rigidity of the temporal abutment must be considered before the calculation. All these factors have generated a lower-than-expected deformation in an 8 m cantilever.