Design Calculation of Anchorage Plates for Metal Supports

Abstract

This paper aims to contribute to the design calculation of anchorage plates, whose detailed behaviour is not well known. Due to the briefness of this investigation, readers are invited to amplify and complete it, and if necessary to correct it, since it is probable that a new investigation may include errors of method. The contents can be summarised as follows: 1. The classical design calculation of anchorage plates should be revised since it is based on an inaccurate idea on the actual behaviour and strength potential of mass concrete. Designers should know that this method implies a safety factor of the order of 10. This knowledge should give him confidence in cases of possible error, or when base reinforcements have been omitted, or placed after loading the structure. 2. The new calculation criterion is given in art. 54 of Code IEH-68, which authorises stresses to be increased, though still keeping them within fairly conservative limits. Since currently IEH-68 is the standard calculation code, it is advised that is should be strictly followed, and this paper should not be an invitation to anyone to go beyond the authorised limits given in this code. The purpose of this paper is not to offer a more economic formula, but to clarify ideas. 3. A metal column directly welded to a baseplate, without cross reinforcements, is always outside Code IEH-68, for normal slenderness values. However, this design can be regarded as fairly acceptable in the case of compound columns with separable extrusions (II, ] [, [ ]), acceptable for simple or joined extrusions ([ ], I) as can be inferred from tables 1, 2 and 3 (see the value of ɣ_b)- 4. As a practical guidance, design calculations can generally be based on a stress of 120 kp/cm²