The modified life cycle cost method for the risk-based design of excavation projects

ABSTRACT

The life cycle cost (LCC) design method tries to improve conventional design practices with different costs, such as risk costs, over the life cycle of the structure in the design procedure. The present study introduces a modified life cycle cost (MLCC) approach for the design of excavations. Some modifications proposed in the typical LCC design method include considering the effect of risk aversion/seeking of decision-makers in the main LCC formula by a risk-seeking factor and taking in the effect of risk exposure time on risk cost by a risk duration as an impact factor. The risk-seeking factor is obtained by identifying the risky behaviour of decision-makers based on the expected utility theory. The risk duration impact factor is evaluated by analysing statistical information about high-risk excavations versus their lifetime. The novel MLCC design method is evaluated in real deep urban excavation projects and the method is applicable for design and yields sensible outputs.

KEYWORDS:

• Deep urban excavations
• LCC
• risk cost
• risk aversion
• utility functions
• unknown risks

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Some data and models as mentioned below that support the findings of this study are available from the corresponding author upon reasonable request: Geotechnical data of case studies; Finite element models; Calculation models supporting the presented charts.