Preface This Special Publication of the American Concrete Institute consists of papers accepted for the Ned H. Burns Symposium on Historic Innovations in Prestressed Concrete. The included papers were presented in two sessions sponsored by Joint ACI/ASCE Committee 423 at the ACI Fall 2005 Convention. In accordance with standard ACI review procedures@ all papers were peer reviewed by at least two experts in the subject area. The collection of papers in this volume presents a range of topics describing historic innovations in prestressed concrete over the past half-century. Topics include early uses of prestressed concrete by industry pioneers in Europe and the United States@ development of construction techniques and design standards for several different prestressed concrete applications@ and the use of innovative modem materials such as self-consolidating concrete and fiber-reinforced polymers.