Interação solo x estrutura: análise de um caso de obra com acompanhamento dos recalques desde o início da construção

Abstract

The control of settlement instrumentation since the start of construction has contributed to the better understanding of the compressibility of different sedimentary deposits on Rio de Janeiro, allowing the measurement of correlations proposals that result in estimates of settlement with smaller uncertainties. In the present thesis emphasizes to contribute to more a case of construction and extending the existing database. Beside to the measurement of soil compressibility, the settlements instrumentation helps the designer of structures in obtaining more real load distribution and its comparison with the originally previous loads. In fact, the new recommendations of the updated standard foundations, NBR 6122 (2010) recommend, in its item 5.5 that "In structures in which the deformability of the foundations can influence the load distribution, should be studied the soil structure interaction". In this building, specifically, the expected settlements are small, and it is a case where it is not expected significant load redistribution. The building in this thesis is a residential of two floors type, a penthouse, water tank and engine room, ground floor without underground, situated on a site of 780 m2, located in the neighborhood of Recreio dos Bandeirantes, in Rio de Janeiro. The building contain the structural elements that are reinforced concrete with characteristic strength the concrete compression major or equal to 20 MPa and CA-50 steel. The slabs are massive with variable thickness from 8 to 13 centimeters and the internal and external walls in ceramic bricks. The other elements such as beams and columns have very different geometrical sections. As a structure of small height and unconventional plan, its numerical modeling does not always provide loads on similar support to other simpler considerations distribution load. The foundations are in Franki type piles of short length, based on sandy soil with high compactness. The compression resistance characteristic of the concrete is 20 MPa. The building has 22 columns and 41 piles, and the measurements of the settlement were made on 18 columns since the start of construction. The piles have average lengths of about 4.20m and are composed of piles 24 with 350mm of diameter, and 17 piles with 400mm diameter. The loads on the foundations are between 600 and 1900 kN, as reported in the project. The geotechnical investigation was accomplish through 3 SPT (Standard Penetration Test). The drilling were made to an approximate depth of 18 meters and revealed a relatively homogeneous geotechnical profile with layers of sand throughout the profile. The water level was found at an average depth of 4.50m. In this construction, specifically, the expected settlements are small, and a case where it is not expected significant load redistribution. The analysis of this building is relevant in comparing its results with the new premises of NBR 6122 (2010).