The study investigates the continental influences upon the development of decorative wrought iron in England, Wales and Scotland from 1660 to 1720. The research explores the influence of ornament prints, and the work of blacksmiths and patrons in response to the social, cultural and political ideals of the time. The study analyses the role and effects of the new continental, transmutable designs upon technical practices. It explores the changing role of the architect in the design process and the implications of this for the blacksmith's craft. It examines the complex network of influences upon the evolution of English taste and demonstrates how a variety of different commissions, such as the designs for ecclesiastical, private and public buildings, created an entirely different language of decorative ironwork. The study focuses largely upon ironwork of the finest quality and innovation, located in exterior and interior sites. The physical setting of decorative ironwork is examined. In particular, the diversity and artistic innovation of Jean Tijou's work at St Paul's Cathedral is analysed in terms of the sources of continental influence. It is significant to note that the work at this cathedral spanned twenty of Tijou's twenty-four-year career in Britain. The thesis challenges conventional interpretations of stylistic change, whereby new styles replace old, arguing for an increased awareness of diversity in design styles and a high degree of liberalism in the creation and composition of new designs, until around 1710. The thesis argues that the early part of the period from 1660 to around 1690 was influenced predominantly by the French with antecedents in Italian style whereas the work from around 1690-1710 illustrates the significant impact of Louis XIV's French court style, typified by the work of Jean Tijou, and more restrained Dutch designs. A shift in patronage from royal and aristrocratic commissions to sobre public and academic buildings was reflected in a more restrained and linear style which responded to prevailing notions of English taste. Appendix I provides a catalogue of Continental and English ornament designers who created ironwork ornament prints during 1660-1720 and Appendix II summarises the period's achievements in wrought iron by collecting together for the first time a list of work by British blacksmiths of the seventeenth and eighteenth-centuries.

The main objective of this research project was to develop a new methodology for the assessment of wrought iron structures using a more informed knowledge of the material.A database of tensile test data for wrought iron across the range of all types of structural elements was compiled and analysed to establish the characteristic yield strength for comparison with the value of 220N/mm2 quoted by the UK Highway Standard BD21. It was found that the characteristic yield strength of bar iron is 151N/mm2 and that of plate iron is 187N/mm2.Bending tests of wrought iron beams were conducted to investigate the potential for brittle fracture under static loads, which was observed, and further investigated by conducting Charpy impact tests, where it was found the that ductile to brittle transition temperature of the metal lies in the range 20 to 80oC, whereas that of mild steel, is typically in the range -30 to 10 oC.A new assessment method was proposed that incorporates a 'quality factor' and a 'component significance factor' into the definition of design yield strength. Comparative studies using the proposed method and the existing method were conducted on a trussed highway bridge, a long span iron roof to a railway station and the Clifton Suspension Bridge. The newly obtained lower values of characteristic yield strength tend to dominate the final design strength value of a component, but this may be improved by the expansion of the database. Furthermore, the inclusion of the quality and significance factors offset this effect and their inclusion was validated by proving that a safe yet not overly conservative design yield strength may be established by application of the proposed method.