COMPARATIVE ANALYSIS OF TWO SLAB SYSTEMS: BIDIRECTIONAL RIBBED SLAB VS. DECK IN THE CITY OF MACHALA

Abstract

This study analyzes the structural and economic performance of two slab systems used in buildings in Machala (Ecuador): the bidirectional ribbed concrete slab and the steel-concrete composite deck slab. Through ETABS modeling and under local (NEC-SE) and international (ACI, AISC) codes, deformations, internal stresses, and unit costs were evaluated under gravitational loads. Results indicate that the steel deck slab exhibits lower costs per square meter (≈90 USD/m²) due to its reduced thickness (10 cm) and material optimization, while the bidirectional ribbed slab demonstrates superior deformation control in upper floors (≤18.33 mm), complying with the *L/240* normative limit. Both systems meet shear resistance requirements, though the steel deck requires secondary beams to mitigate critical deformations.

 The research emphasizes that system selection depends on factors such as building height, applied loads, and budget. For commercial projects with economic constraints, the steel deck proves efficient, whereas the ribbed slab is ideal for residential or taller structures due to its rigidity and geometric adaptability. Technical recommendations include standardizing local catalogs for metal profiles, validating numerical models with empirical data to minimize discrepancies, and complementing designs with geotechnical studies in soft soils. This work provides evidence-based criteria to optimize the selection of structural systems in Machala, balancing safety, efficiency, and costs.