No abstract

Idealised data have been derived for the compressive strength of a number of concretes for fire safety design. The data are derived from the author's own research including test series not published before and from more than 400 other test series comprising approximately 3000 specimens known from literature and personal contact. The data cover a variety of concretes with aggregates such as siliceous materials, limestone, granite, sea gravel, pumice, and expanded clay to fire-resistant concrete based on chamotte or Danish mo-clay. Processes are briefly described that are responsible for the deterioration of the materials when they are heated and when they are cooled down after a fire. In addition, it is explained how variations of the concrete composition influences the deterioration. Necessary characteristics of design methods are derived for variable fire courses based on analyses of consequences of material deterioration. The paper serves as a basis for a number of papers presenting calculation methods developed by the author for load-bearing capacity of any structure of any concrete at any time of any fire exposure. Some of these methods and related materials data are adopted in the CEN: ENV 1992-1-2 code and national codes such as the Danish DS411. The present paper serves as a part of the documentation for the methods and it is therefore also a supporting document for these standards.

No abstract

Synopsis The anchorage failure of reinforcing bars is analysed, and it is shown that two modes of failures are possible: splitting or bond failure. It is concluded that the anchorage capacity cannot be estimated by means of a standard specimen, since splitting failure is dependent upon the geometry of the cross-section. A simple method for calculating the resistance to splitting is proposed, and a test method for determining the bond strength is presented. Test results are shown from a series of 280 specimens exposed to various maximum temperatures, and a relation between the bond strength and the ultimate limit stress of concrete under plane strain conditions is indicated. The influence of high temperatures upon the anchorage resistance is explained, and the theory is illustrated by examples.

Idealized 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 fireexposed 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 idealized representation is compared with test data and with other idealized 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.