Geotechnical study in Manresa

In Manresa, formations made up mainly of sandstones, conglomerates and flysch predominate, accounting for approximately 75% of the substrate. These materials, for the most part competent, offer good bearing capacity and stability, which facilitates the execution of shallow direct foundations for most of the buildings. In certain occasional areas where fine sands, silts or soft clays are present, it may be necessary to check the compaction or avoid shallow foundations if the substrate is not very competent. The overall permeability is low; however, there is the possibility of isolated near-surface aquifers that could affect local ground behaviour.

Seismicity in Manresa is very low, with only 3 recorded events over 30 years and a maximum magnitude of 1.9, so it is considered a minor constraint in the structural design. Nevertheless, special attention should be paid to the potential presence of karst in the substrate, as its existence may involve areas with underground cavities or dissolution processes, which requires thorough ground verification before defining the type of foundation. The non-clayey substrate rules out the risk of expansivity; therefore, the main aspect to control in the geotechnical study in Manresa is the presence of karstification in the ground supporting the structure.