Performance Based Design: Why Aren’t We Leveraging It to Its Full Potential? Managing Opportunity, Safety, and Contract Risk-PPT Presentation

PPT Presentation

Pdf Summary

The presentation argues that the Observational Method (OM) can improve safety, cost, and schedule when used from the start of a project—not only to address problems during construction. The method begins with a design based on the most probable ground conditions, identifies uncertainties and possible deviations, and establishes measurable monitoring criteria. Construction observations then inform whether the design should be maintained or adjusted.<br /><br />Despite its potential, OM is not widely used because it can be time-consuming, difficult to structure, and perceived as increasing risk. Conventional prescriptive designs do not eliminate risk and may create false confidence, overlook critical failure mechanisms, encourage selection based mainly on lowest cost, and require unnecessary materials.<br /><br />The presentation draws on projects including St. Paul’s Anglican Church, The Vincent condominiums, and Cedarvale Station. Cedarvale illustrates how contracting can support risk-based design: an exclusive support-of-excavation subcontractor worked under a design-build target-price arrangement with an assigned contingency, agreed time-and-material rates, and savings and overrun-sharing provisions. Such mechanisms can align incentives, share risk, and reduce excessive base-cost contingencies.<br /><br />Successful OM requires early collaboration among the owner, designer, and contractor; a clear geotechnical baseline and subsurface information; contingency designs for a range of conditions; construction details; and action plans linking monitoring results to implementation decisions. Designers also need incentives that reflect their contribution to project savings, along with protection from risks outside their control. Effective monitoring is essential both to manage technical risk and to give engineers confidence in adapting the design.<br /><br />The presentation concludes that contracts and project teams should be structured to enable informed design adjustments, making the OM a practical route to safer, more economical, and timely outcomes.

Keywords

Observational Method

geotechnical design

risk management

construction monitoring

project uncertainty

design adjustment

subsurface conditions

target-price contract

contingency planning

collaborative project delivery