Methodology to Analyze the Stability of Bench Marks Applied for Settling Measurements of Buildings Foundation

Abstract

In this work, one type of vertical bench mark is presented for the realization of the Vertical Local Geodetic Network for the control and analysis of settling foundation elements. The revision of the previous norm NBR 6122/96 to the current norm NBR 6122/2010, contributed in Brazil to the obligation of the services of measurement of settlings in buildings with more than 60 m in height. This increased the demand for geodetic surveys to control the performance of building foundations. The vertical geodetic network determined by the high precision geometric leveling method materializes a vertical Reference System for the establishment of heights reference standards and investigation of vertical displacements of elements of the foundations of buildings, for example, of shoes and blocks. For economic reasons, in this work, the "static" Level References were embedded in pillars of building structure outside the domain of the work, with more than 50 years of post-construction and installed on Franki stakes. For this reason, it was necessary to create a Vertical Local Geodetic Network to transport height to the work, which allowed the study of the vertical behavior of three types of materialization of level references: embedded in building structure pillars; superficial and fixed on sidewalks; fixed at two meters deep and immediate to the building. So, this work aims to present the methodology to analyze the stability of bench marks used for the measurement of settlements in buildings under construction and post- construction.