Improving project outcomes: the observational method

Overview

Civil engineering involves addressing and managing risk, especially during the construction of earthworks, foundations retaining walls and tunnels. The observational method (OM) offers enormous practical advantages in both minimising risk and optimising project outcomes through reducing construction programme, cost and carbon.

Hence, following Ralph Peck’s advice in his seminal 1969 Rankine lecture, any professional involved in ground engineering: ‘needs to be fully aware of the potential value of the observational method and needs to understand the prerequisites for its success’. 

The OM is a powerful practical technique which can provide significant advantages for many civil engineering projects. When used effectively it can, in addition to saving time and cost, enhance collaboration between client, design and construction teams, and enable the construction industry to learn from experience and improve future practice.

Unfortunately, despite this compelling list of advantages, the OM continues to be significantly under-used. Two key constraints are commonly used contract conditions and industry culture. This lecture will explore the advantages and the limitations of the OM, using several case histories to illustrate the lessons learnt and review how key constraints (both technical and commercial) can be overcome.

Recent OM applications highlight the immense power of new technologies in instrumentation/monitoring and numerical analyses to facilitate near real-time back-analyses. These technologies provide a platform for exciting new developments whereby OM could provide:

1. ‘Intelligent digital twins’ for our future built infrastructure
2. The basis for ‘Adaptive Designs’ which could enable a more effective balance between resilient infrastructure (to withstand climate change) and minimising cost and carbon during construction
3. Accessible data bases on full-scale performance, providing an evidence base for more informed selection of design parameters for future projects.

The lecture concludes with recommendations for OM practitioners.