Dimensionamento à luz da NBR 6118 (ABNT, 2023) de uma viga-Calha pré-fabricada protendida

Abstract

This study addresses the design, according to NBR 6118 (ABNT, 2023), of a prestressed prefabricated channel beam with an "I"-shaped cross-section, focusing on the application of the Limit Curve Method to define the ideal cable layout. To this end, a brief review was conducted on Magnel diagrams, the Pass-Through Spindle Method, and the Limit Curve Method to establish efficient combinations of prestressing force and cable eccentricity, reducing the need for iterative processes in structural designs. Additionally, a case study was carried out involving the design of a 15-meter-long prestressed prefabricated channel beam made of 40 MPa concrete and low-relaxation steel strands (CP-190). The study detailed the calculation of forces and stresses under different loading conditions, verifying serviceability limit states (SLS) and ultimate limit states (ULS). In conclusion, the use of the Limit Curve Method proved to be highly practical and effective in ensuring the safety and optimization of pretensioned prestressed elements.