Steel Buildings in Europe

Part 4: Detailed Design 4 – 22 c max w w w w w w tot 1 2 3 w c is the precamber in the unloaded structural member w 1 is the initial part of the deflection under the permanent loads on the relevant combinations of actions w 2 is the long-term part of the deflection under permanent loads w 3 is the additional part of the deflection due to the variable actions of the relevant combinations of actions w tot is the total deflection as the sum of w 1 , w 2 , w 3 w max is the remaining total deflection taking into account the precamber Figure 4.2 Definitions of vertical deflections Table 4.2 summarises typical vertical deflection limits used in Europe. Table 4.2 Vertical deflection limits Deflection limits Country w max w 2 +w 3 Comments France Roof, in general L /200 L /250 Roofs frequently carrying personnel other than for maintenance L /200 L /300 Floors, in general L /200 L /300 Floors and roofs supporting plaster or other brittle toppings or non- flexible parts L /250 L /350 Floors supporting columns (unless the deflection has been included in the global analysis for the ultimate limit state) L /400 L /500 When w max can affect the appearance of the building L /250 - These values are given in the French National Annex to EN 1993-1-1 and should be used unless otherwise agreed with the client. The values of the deflections calculated from the characteristic combinations should be compared to these limits. Germany There are no national deflection limits. The limits should be taken from manufacturers’ instructions (technical approvals) or should be agreed with the client. Spain Roofs, with access for maintenance only - L /250 Roofs in general L /300 Beams and floors, without fragile elements L /300 Beams and floors, supporting ordinary partition walls and rigid floor finishing elements with expansion joints L /400 Beams and floors, supporting fragile elements such as partition walls, facades envelopes or rigid floor finishing elements L /500 Beams supporting columns L /500 Beams supporting masonry walls L /1000