Limit state design method 2 Limit state design method

Limit state design method If you have any doubts, you can check your textbook, pp. 116-117

Limit state design method Lesson 2 Calculation procedures Having defined G = geometric characteristics of the structure Q = external stresses f = resistance of the materials – Checking procedure: it is carried out when all the sizes of the structure and the external stresses are known and we want to compare the resistance of structure R with the external stresses E. R (f, G) ≥ E (Q) – Design procedure: it is carried out when we want to determine the geometric characteristics of the structure already knowing the external stresses and the characteristics of the materials. Geff ≥ G (Q,f) – Testing procedure: it is carried out when the geometric characteristics, the external stresses and the resistance of the materials are known and we want to compare the maximum load that the structure can bear with the load to which it is subjected. Qmax (f,G) ≥ Q

Limit state design method Lesson 3 • Ultimate limit state (ULS): a serious condition of instability that can create environmental and social damage; compromise people’s safety; put the building out of working use. • Serviceability limit state (SLS): less serious damage that can compromise the functionality of the building during use. Overpassing ULS Overpassing SLS Irreversible Reversible Structural failure Damage

Limit state design method Lesson 4 • Scenario E (External) Assessing the parameter that induces the limit state (for example, breaking strength or deformation) depending on the stresses external to the structure under examination (weights, variable loads, heat variations etc.). For example if the chosen parameter is a Moment, the scenario E is the Moment created by the forces that will presumably be applied to the structure. • Scenario R (Resistance) Assessing the same parameter through the analysis of the resistance of a structure, determined essentially by the material and by its size and geometric form. Following the previous example, the scenario R is therefore the Moment which, once applied to the structure, causes the desired limit value to be reached. The result must be R > E Partial coefficients: γQ for variable loads (to be multiplied by) γG for permanent loads (to be multiplied by) γP for pretension loads (to be multiplied by) γM for the characteristics of the materials (to be divided by) γE for the calculus model (to be divided by)

Limit state design method Lesson 5 NOMINAL LIFE ACCORDING TO THE DESIGN FOR TYPE OF BUILDING Type of building Nominal life VN years Classes of buildings and coefficients of use Class

Limit state design method Lesson 8 Elastic section modulus Plastic section modulus Wpx = 2 · Sx Stresses – elastic phase Stresses – complete plasticization

Limit state design method Lesson 11 Load combinations COMBINATION LOAD COMBINATION EQUATION Fd USE USL fundamental SLS characteristic rare frequent quasi-permanent Seismic USL and SLS Ultimate limit states SLS irreversible SLS reversible SL for long-term effects Seismic actions E Where: Partial coefficients Combination coefficients Actions due to permanent loads Actions due to variable loads

Limit state design method Lesson 11 Partial coefficients Combination coefficients USL and SLS UNFAVOURABLE FAVOURABLE CATEGORY Category A – Spaces for residential use Category B – Offices Category C – Spaces subject to crowding Category D – Spaces for commercial use Category E – Libraries, archives, storehouses and spaces for industrial use Category F – Garages and car parks (for vehicles weighing ≤ 30 kN) Category G – Garages and car parks (for vehicles weighing > 30 kN) Category H – Roofings Wind Snow (≤ 1000 m height above m.s.l.) Snow (> 1000 m height above m.s.l.) Heat variations