Reinforcement data for fire safety design

Abstract

Idealised materials data are derived from a number of test series reported in the literature and made by the author. The data cover a variety of reinforcing steels from mild steel, deformed bars and cold-worked bars to cold-drawn prestressing steels. Processes are described that are responsible for the deterioration of the materials when they are heated and cooled down. A simple expression is established for the description of deterioration curves for fire-exposed materials such as concrete and reinforcement by means of five parameters that may be used as input data for structural fire safety calculations instead of the more troublesome application of curves or tables. This new idealised representation is compared with test data and with other idealised curves for the materials presented, and recommended design values are given. Warnings are given for misleading curves and expressions from the structural codes. The paper serves as a basis for a number of papers presenting calculation methods developed by the author for the loadbearing capacity of constructions of any concrete at any time of any fire exposure. Some of these methods and materials data are adopted in the CEN code and national codes such as the Danish DS411. The paper serves as a part of the documentation for the methods and is therefore also a supporting document for these standards.