The assessment and design of modifications to existing structures are substantially different from the design of new structures. Existing materials and elements typically must be assessed and used as-is in the completed project. Existing construction also constrains what construction means and methods are feasible requiring greater consideration of constructability in design. Since the existing conditions typically limit the ability to investigate, these projects are subject to greater uncertainty than new construction projects. This requires proactive risk management from project planning through completion.
In addition to the knowledge of structural analysis and current codes and standards required for new design, consideration of an existing structure requires an understanding of the behavior and pathology of a structural system, as well as the methods used to design and construct it. Without these skills, an engineer might be unable to exploit the intended behavior of the existing structure and would be compelled to impose a more familiar, modern structural system on it.
Richard J. Driscoll, Consulting Engineer (RJDCE) helps clients assess existing structures and manage the risk associated with alterations and repair. The practice presents experience observing and investigating existing structures and analyzing the effect of new loads. RJDCE’s services for existing structures is informed by, and informs, its forensic and foundation experience.