FOUNDATIONS REALIZED IN PUNCHED HOLES FOR BUILDINGS PUBLISHEDMonica Mirea, Cristina Otilia Voicu, Carmen Aurelia Peptan
The paper presents at the beginning a synthesis of the technology for realizing foundations in punched holes, the fields of use and the advantages of this technical founding solution. It further analyses the types of equipment used and the modalities of punching the foundation holes, emphasizing their influence upon the improvement of the ground and the increase of the so-realized foundations’ bearing capacity. The use of spherical or truncated cone punching equipment represents a new and original element nationwide. The first punching research in Romania was realized by the team of the Roads and Foundations Department of Timisoara, with punching equipment in the shape of truncated pyramid with the small basis on the bottom. These studies have been finalized in 12 dwelling buildings (Basement+ Groundfloor+4 Floors), located in the area of the County Hospital of Timisoara. The solution will have an impact both theoretical and practical, having numerous applications and opening new horizons in the improvement of the foundation ground by using the punching procedure, since this procedure ensures the realization of buildings on weak soils, through direct, surface foundation. The subsequent deformations under the construction loadings are minimal. The solution of realizing foundation holes through punching contributes to reducing the volume of the excavation and the materials used in the realization of foundations, to cutting down the quantities of materials needing transportation (soil, concrete, steel-concrete, wood for frames, etc.), as well as to the shortening of the execution period. All these elements have a favorable impact upon the environment, finally the costs of the investment being smaller than in the case of the known solutions. The solutions of realizing foundations in punched holes consist in forcing into the ground certain spherical, truncated cone, truncated pyramid shaped equipments (tampers) through striking or vibration. As a result of this mechanical thrust, an area of packed soil is formed around the foundation, within whose limits the mechanical strength of the ground increases and the deformability characteristics decrease. Due to the reduction of the ground deformability, the foundations realized in punched holes can transmit vertical and horizontal loadings in the conditions of small size foundations. Finaly, the paper presents the advantages of using foundations realized in punched holes on soils with lower bearing capacity, for lighter building, including in the agricultural field (temporary storage halls, shelters for agricultural machinery, etc.).
foundations; punched holes; bearing capacity; hemispherical; soil