COMPREHENSIVE REVIEW OF TIME-DEPENDENT DEFLECTION AND CREEP BEHAVIOUR IN POST-TENSIONED CONCRETE SLABS WITH LONG-SPAN STRUCTURAL SYSTEMS IN COMMERCIAL BUILDINGS

Abstract

Post-tensioned concrete slabs represent a critical structural solution for modern commercial buildings, particularly where long spans and reduced self-weight are essential. However, time-dependent deflection and creep behaviour significantly influence the long-term serviceability performance of these systems. This systematic review comprehensively examines the mechanisms, prediction models, and practical implications of creep and shrinkage in post-tensioned concrete slabs used in commercial construction. Through analysis of over 40 peer-reviewed studies, this review synthesizes current knowledge on: (1) fundamental creep and shrinkage mechanisms in prestressed concrete; (2) deflection prediction methodologies across major design codes (ACI 318, Eurocode 2, Indian Standards); (3) effects of material properties, construction sequencing, and environmental factors on time-dependent behaviour; and (4) comparative assessment of reinforced versus post-tensioned systems. Key findings reveal that long-term deflections in post-tensioned slabs can reach 40-60% of immediate values without adequate prestress levels, with creep losses accounting for 15-20% of initial prestressing force. Numerical modelling using finite element analysis demonstrates superior accuracy (85-95%) compared to simplified methods (78-85%). This review highlights the critical importance of integrating time-dependent effects into preliminary design stages, accounting for construction sequencing, and implementing robust monitoring protocols for serviceability verification. Recommendations for future research include development of refined prediction models for high-performance concrete mixtures, investigation of prestress losses under extreme climatic conditions, and enhancement of design code provisions for composite structural systems in commercial applications.