A força vinculante do projeto na empreitada por preço global: limites aos pleitos de aditivos por omissão de planilha e a matriz de riscos na Lei nº 14.133/2021

The global lump-sum contract regime constitutes one of the most widely used contractual execution methods for engineering works and services in the Brazilian public sector. Despite its statutory provision, contract management recurrently suffers from controversies arising from claims filed by contractors alleging omissions or quantitative discrepancies in the reference budget sheet prepared by the Public Administration. Under the aegis of Law No. 14,133/2021 and the consolidated jurisprudence of the Federal Court of Accounts (TCU), the lump-sum contract characterizes an obligation of integral result, in which remuneration is bound to the delivery of the totality of the object defined by the Basic and Executive Design, rendering the budget sheet a mere auxiliary instrument for stage-based schedule measurements. This study analyzes the binding force of graphic designs and descriptive memorials against omissions in reference cost sheets, delimiting the ordinary venture risk and the admissible inaccuracy margin in basic engineering designs. It is demonstrated that quantitative discrepancies inherent to budget estimation do not justify contractual financial amendments, except for unilateral modifications imposed by the Administration or severe and unforeseeable latent defects. As an indispensable mechanism of governance and legal certainty, the Risk Allocation Matrix clause (art. 103 of Law No. 14,133/2021) is analyzed as an instrument that delineates contractual responsibilities and prevents unjust enrichment for both parties.