Tanque.NSR10: Computational Analysis and Design of Reinforced-Concrete Rectangular Liquid-Retaining Tanks under the Colombian Code NSR-10 and ACI 350.3

Abstract

Background. Reinforced-concrete liquid-retaining structures require tedious calculations and the interpolation of design charts and tables – a frequent source of human errors with structural consequences. In the Colombian context, design is governed by the NSR-10 building code, whose Título C adopts ACI 350 for environmental structures, complemented seismically by ACI 350.3, with the Portland Cement Association (PCA) manual as the reference analysis tool.

Methods. The author presents Tanque.NSR10, a computational tool for the analysis and design of rectangular reinforced-concrete liquid-retaining tanks, developed in C#/.NET 8 with an Avalonia interface. It analyses walls, roof and base slabs and recommends thicknesses and reinforcement per NSR-10 Título C, ACI 350.3 and the PCA manual, combining bilinear interpolation of the Chapter 3 wall tables (staggered grid of fifteen (b/a, c/a) combinations) with the Marcus corner combination, Housner’s twomass seismic method and the Mononobe–Okabe dynamic earth pressure, and completing the design with flexure, shear and service crack-control checks (fs,max, durability factor Sd).

Key Results. Verification relies on three complementary strategies: double reading of the PCA tables (manual transcription and OCR, with corner symmetries and physical constraints); an automated suite of 822 assertions and 144 unit tests; and exact reproduction of the worked Example 1 of the 1 PCA manual (coefficients, shears and service moments), with the observed differences in ultimate moments explained by the load and durability philosophies of each code. Two original contributions are reported: the identification of the uniform-load nature of the seismic Case 7 tables, and a conservative, monotonicity-justified extension of the tabulated domain.

Conclusions. Tanque.NSR10 provides a verified, reproducible and norm-grounded tool for the analysis and design of rectangular liquid-retaining tanks, eliminating silent simplifications and documenting every domain degradation explicitly.