Avaliação do impacto da tensão trativa nos custos de implantação de sistema de esgotamento sanitário.

Abstract

The minimum shear stress is a relevant design parameter in sewage collection networks, as it directly influences the geometric characteristics of the system and the costs associated with its implementation. In this context, this study evaluated the influence of variations in minimum shear stress on the implementation costs of a sanitary sewage system, based on the design of a sewer network in an urban area. Four design scenarios were analyzed for the same network layout, defined by different minimum shear stress values, while maintaining all other hydraulic and constructive assumptions constant. The network design was carried out using the CEsg software, and the resulting physical quantities supported the preparation of cost estimates based on SINAPI unit prices. The results indicated that increases in minimum shear stress are associated with deeper trenches and higher excavation and shoring quantities, leading to an overall increase in implementation costs. The comparative analysis enabled the systematization of results through dimensionless cost factors, as well as the derivation of unit costs and cost equations as functions of minimum shear stress, which can be applied as a decision-support tool in preliminary technical and economic analyses of sewage collection network projects.