EXAMPLE 6. BUILDING VALUATION & REDESIGN STUDY

EXAMPLE 6: "STUDY FOR THE VALUATION AND REDESIGN OF A BUILDING ACCORDING TO THE CANC. 16 The combinations of actions, both for the failure limit states (basic and accidental combinations) and for the operational limit states, are made in accordance with the current Regulations in force and with the corresponding combination coefficients of the variable actions ψi. 4.4.3 Resistors α) For the resistances of each structural element, the safety check (see § 4.1) is carried out with material properties generally dependent on the nature of the critical quantity to be checked (forces or deformations): If the safety check is carried out in terms of intensive quantities ("forces") , the properties of the existing materials of a particular (individual) structural element are generally represented by their average values reduced by one standard deviation (or simply their average values, see Chapter 9), and the properties of the added materials are represented by their characteristic values as provided for in the relevant Regulations. In this case, the material safety factors shall be taken as in §§ 4.5.3.1 and 4.5.3.2. The calculation of the stiffnesses is done according to § 4.4.1.4. If the safety check is carried out in terms of deformation quantities (displacements, rotations, etc.) , the properties of the materials are generally represented by their average values. See also the following. See also § 4.1.4. In this case, the material safety factors are approximately equal to unity (§ 4.5.3.3). The shape of the operation When the assessment study of a structure concludes that intervention is required, the engineer, adopting one or more strategies, chooses the form of intervention based on general and technical criteria. Before any reference is made to the strategies, formulas and selection criteria, it is useful to clarify the terms "intervention", "repair" and "reinforcement". The term structural " intervention " means any work which results in the desired change in the existing mechanical characteristics of an element or structure and which has the effect of modifying its response. Any intervention is either repair or strengthening. The term ' repair ' means the process of intervention on a structure damaged by any cause, which restores the pre- damage mechanical characteristics of the structural elements of the structure and returns it to its original load-bearing capacity. The term ' strengthening ' means the process of intervention in a structure, with or without damage, which increases the load-bearing capacity or ductility of the element or structure to a level higher than that of the original design. The choice of the intervention scheme is part of one or more strategies aimed at improving the seismic behaviour of the structure under consideration and consists of the modification or control of key parameters.