Introduction

EN 1990 forms the basic document of all Eurocodes because it gives the basis of design, i.e., the principles and the requirements for safety, serviceability and durability of structures. The Eurocode philosophy is based on the concept of limit states, either ultimate limit states or serviceability limit states. The occurrence of limit states is verified according to a semi-probabilistic approach. This means that deterministic verifications are being carried out on the base of design values of applied loads and material strength. The design values are obtained from characteristic values, corresponding to 5% or 95% probability of occurrence, multiplied or divided by partial safety factors. The fire resistance of a structure can be assessed using the Eurocodes provided the structure has been designed according to the rules given in the Eurocodes for the ambient temperature situation. The mechanical behaviour of steel structures in buildings at room temperature is assessed on the basis of EN 1993-1-1.