Deterministic Structural Design

Abstract

Current structural design codes use a stochastic approach (SC) in load combination and reliability calculation. This article presents a design model with a deterministic (DC) approach. Currently, design codes have variable load factors (γG ≠ γQ) and constant safety factors (γM) for all loads. This approach makes two significant approximations: It assumes a single material factor for all ratios of permanent to variable loads and across all types of variable loads. This research proposes the opposite strategy: instead of a single material factor, each load is assigned to its own material factor. Such a shift removes those approximations, simplifies codes, and reduces calculation effort. A central challenge in reliability assessment is combining loads. Existing SC methods differ in their reference time and target reliability. The fundamental fact of load–material interaction is that each load acts independently, without influencing others. This deduction results in the DC combination. Safety factors within the Eurocode framework are derived using today’s semi-probabilistic SC methods and a fully probabilistic DC approach. The proposed design model is straightforward, requires minimal computation, meets the target reliability, and yields significant savings in material use.