Once the broad organizing architectural intention has been established, it becomes evident that a series of elemental technical problems must be addressed in order for design to proceed. These focal and critical technical issues become the basis for selecting appropriate building systems. To be appropriate, such systems must both satisfy the program requirements and fulfill architectural intentions. The dictates and frequently differing demands of these essential problems create a series of generative tensions and enliven the design process. Resolution of these key ideas is often the most complex and problematic task of architectural design; they often seem as contradictory as they are essential.
Inevitably, conflicts and contradictions arise between and among the critical technical criteria. These oppositions may arise in any of several contexts: between the program and the site, between the code and the architectural intention, between the program and the budget, or any combination of the possible design elements. As conflicts, these challenges are frequently what become the generative tensions that evoke the most imaginative design innovations. For organizational purposes, critical technical issues can be discussed in three categories:
• Inherent issues arising from building use
• Contextual issues generated by technical situations surrounding the project
• Intentional issues evolving from the architect’s ambition for the project
At the Museum of Flight, the architectural intention became the largest driver of critical technical issues. For the aircraft collection to appear to hover in flight, it would have to be suspended from the roof structure by steel cables. For the planes to be presented against the sky, the roof itself, as well as most of the walls, would have to be glass. Consequently, Nelsen was faced with the selection of a structural system to carry large dead loads over long spans without obscuring the view. He also required an envelope system capable of providing views and admitting daylight but resistant to solar heat gain and to ultraviolet degradation of the entire collection. In the echo of these issues were secondary questions: How would the mechanical systems fit in, and what would be left of the interior for displays?
Inherent Issues
Inherent, or built-in, issues always arise from a basic investigation of the building type at hand and knowledge about its typical use. Libraries need diffuse natural light and the ability to carry heavy book stacks, airports need well – defined circulation patterns and a great variety of services, and museums need flexible display space and protection for the collection. Whatever the building type, there is always a set of related critical technical issues that fundamentally define the problem and are thus part of the rational component of the built solution.
The inherent issues of the Pacific Museum of Flight differed somewhat from those of the usual museum. The large size of aircraft objects in the collection changed the normal relationship between viewer and display case, for example, and the air shows held periodically on the adjoining Boeing Field runway added another dimension. Storing and rotating the collection of exhibits was also a unique problem. Other challenges were more typical of museums in general—lighting, circulation, egress, and security.
Contextual Issues
Every project is affected by specific and special technical circumstances of its context. Identifying these circumstances is essential to satisfying the critical technical issues. Special circumstances can include site conditions, code requirements, highly critical programmatic constraints, harsh climatic environment, or any other factors unique to the project.
Code requirements were among the critical contextual issues for the Pacific Museum of Flight. The building code of the local jurisdiction, King County, included an energy code specifying allowable annual energy use per square foot of building. To obtain a construction permit, the architect would have to certify that the actual energy use of the building would fall within the budget. County officials used annual audits to validate compliance, and fines would be imposed for violations. In the end, this matter had to be negotiated because the code had no good provision for a building use that matched the museum and made little allowance for daylighting. Nonetheless, a strict energy use budget was established and the design was expected to deliver a suitably energy-conserving building.
A second contextual technical consideration was the poor soil conditions of the site. Load-bearing capacity was very low, and the site was subject to tidal flooding that inundated the subsoil periodically, effectively giving the site a very high water table. Although these contextual circumstances were not as formative as the energy code requirements, they did suggest a lightweight structure.
Issues of Intention
The third and most significant source of critical technical issues is the tension between architectural intent and the project program. Difficult building programs often require that the architectural intention encompass a strategy for meeting the client’s basic objectives. Norman Foster’s design of suspended floors hung from double-height trusses at the Hong Kong and Shanghai Bank is discussed as one such example of the alignment between strategy and intention (see case study #25). In other cases, such as the Museum of Flight, complex requirements are generated primarily by the architect’s intention.
Nelsen’s “as if in flight” ambition for the museum was clearly the springboard for everything that followed. Transparent structure and envelope are the most direct consequences, but all other decisions can be shown to align with this starting point. The one grand intention became the genesis, protagonist, and binding agent of all the systems in the Great Gallery. Simplicity may have dictated a less complicated approach; the collection could have been displayed in a hangar, for example. But this straightforward solution would have led to only a marginally satisfactory and everyday sort of building. The difference between the two results illustrates how important integrated systems are to cohesive architectural solutions. It also illustrates how the nonordinary aspect of architecture arises from ambitious and well-founded intentions.