Report on the Application of Finite Element Analysis to Historic Structures: Westminster Hall, London

Abstract

Finite element analysis (FEA) is a computeraided modern engineering analysis technique capable of revolutionizing the practice of historic structures research. Only recently applied to historic structures, FEA is a tool available to architectural historians interested in understanding the structural logic and behavior of buildings and their component parts. The case study presented in this paper combines historical research and FEA to explore the performance of one of the greatest medieval heavy timber structures, Hugh Herland's roof trusses at Westminster Hall (1395-1396), and to assess the structural contribution of their prevalent and highly ornamental tracery. The complexity of this analysis, previously unsolvable with the tools available to historians and engineers, provides an excellent opportunity to demonstrate the capacity of FEA working in concert with historical research to clarify structural issues and reveal insights into the construction, longevity, and possible origins of historic structural types. At Westminster Hall we find that the tracery in Herland's trusses performed the role of reducing bending stresses in the principal members and, as a secondary structural system, was responsible for maintaining the structural integrity of the roof over time. These non-aesthetic functions may well have been understood by the designer.