Journal of Architectural Engineering

Current architecture, engineering, and construction (AEC) design processes often rely on precedent to resolve complex decisions. However, changes to stakeholder concerns, design methods, and building products devalue much of this precedent knowledge. Project teams need to clearly communicate their decision rationale to develop consensus about design decisions. This study reviews a broad range of relevant theory from decision-based design, decision analysis, decision theory, linguistics, logic, organization theory, and social welfare. Rationale is defined as a set of assertions regarding distinct components (i.e., managers, stakeholders, designers, gatekeepers, goals, constraints, alternatives, and analysis) that support design decisions. Conditions of clarity (i.e., coherent, concrete, connected, consistent, credible, certain, and correct) are also defined. These definitions are used to measure the clarity of assertions, components, and the rationale as a whole. Taken together, this rationale clarity framework (RCF) provides a structured view that enables an objective evaluation of design decision methods.

This paper measures and improves the clarity of design rationale on an architecture, engineering, and construction (AEC) project and observes the effects. The rationale clarity framework (RCF) defines decisions in terms of components of rationale—managers, stakeholders, designers, gatekeepers, objectives (constraints and goals), alternatives, and analyses (impacts and assessment of stakeholder value). RCF defines relations and conditions of clarity for each component—coherent, concrete, connected, consistent, credible, certain, and correct. Using RCF, the rationale clarity of decisions was observed and documented on an industry case project. A decision-assistance methodology that seeks to clarify rationale, called MACDADI, was then implemented and costs and benefits from each team member’s perspective were observed. Future work is identified that can lower costs and increase benefits of clarifying rationale.

The allowable capacity of conventional roof-to-wall metal connectors is based on results of unidirectional component tests that do not simulate triaxial aerodynamic loading effects induced by high-wind events. The results of wind and wind-driven rain tests conducted at a full-scale facility were used to create a database on aerodynamic and aerohydrodynamic load effects on roof-to-wall connectors. Based on these results, three axial mean force components (triaxial mean loads) were combined into a series of resultant mean force vectors. A new test protocol was then developed for roof-to-wall connectors under simulated triaxial loading as opposed to simple uniaxial loading. The findings confirm that current testing methods tend to overestimate the actual load capacities of metal connectors. The performance of a nonintrusive roof-to-wall connector system using fiber-reinforced polymer (FRP) ties was also tested and compared with that of a traditional metal connector under simulated aerodynamic loads. The test results demonstrated the validity of FRP ties as an alternative to hurricane clips for use in timber roof-to-wall connection systems.