Steel Buildings in Europe

Part 4: Detailed Design 4 – 50 1 2 2 Plan Elevation 1 Local damage not exceeding 15% of the floor area or 100 m 2 , whichever is the smaller, in each of two adjacent storeys 2 Notional column to be removed Figure 6.3 Recommended limit of admissible damage (taken from Figure A.1 of EN 1991-1-7) 6.3.3 Horizontal tying EN 1991-1-7 § A.5 provides guidance on the horizontal tying of framed structures. It gives expressions for the design tensile resistance required for internal and perimeter ties. For internal ties: T i = 0.8 ( g k +  q k ) s L or 75 kN, whichever is the greater (A.1) For perimeter ties: T p = 0.4 ( g k +  q k ) s L or 75 kN, whichever is the greater (A.2) where: s is the spacing of ties L is the span of the tie  is the relevant factor in the expression for combination of action effects for the accidental design situation (i.e.  1 or  2 in accordance with expression (6.11b) of EN 1990 [5] ).The relevant National Annex should give further guidance on the  values to be adopted. Note that tying forces do not necessarily need to be carried by the steelwork frame. A composite concrete floor, for example, can be used to tie columns together but must be designed to perform this function. Additional reinforcement may be required and a column (particularly an edge column) may need careful detailing to ensure the tying force is transferred between columns and slab. Reinforcing bars around a column, or threaded bars bolted into the steel column itself, have been successfully used.