Question 1 (a) (b) A hotel building shown in Figure Q1 is classified as Class 2b by Building Regulations and should be specially designed to avoid disproportionate collapse. Describe and

explain how the steel- framed building should be designed to meet this requirement. [20 marks] The mutli-storey rigid frame shown in Figure Q1 supports concrete floor and roof slabs. Assuming that the frame is not sensitive to sway, determine the effective length ratio (LE/L) for the columns numbered 1, 2 and 3 in Figure Q1. All the column bases are fully fixed as shown in Figure Q1. [15 marks] K 11 Column-length being designed K 21 Distribution factors: K₂ +K₁ K + K₁ + K₁1 + K12 k₁ k₂ = K + K₂ C K₂ + K₂ +K21 + K22 1 CSE6011-B Jan 2023 Paper/Page 3 of 6 K C k K 2 K K 12 22 where K₁ and K₂ are the values of K, for the adjacent column-lengths; K11, K12, K21 and K22 are the values of K for the adjacent beams. Pinned (c) K₁ 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Fixed 0.0 0.5 0.0 Fixed 0.525 0.1 0.2 0.3 Effective length ratio, 0.6 0.575 Р 0.625 0.65 CSE6011-B Jan 2023 Paper/Page 4 of 6 0.4 0.675 Base plate thickness available in mm 10 12.5 15 16 18 20 0.5 0.75 0.6 10.5 0.8 0.7 0.85 c=1,[1,1(317)] Mo) y C = distance from the edge of the effective portion of the base plate; fid=design bearing strength of concrete on the underside of the plate; fy=design strength of the base-plate; YMO = partial safety factor for steel. 22.5 25 30 0.8 K₂ The column section shown in Figure Q1 is a 533 x 210 x 109 UB of Grade S275 steel. The column is subjected to a design (factored) axial load of 600 kN and a design (factored) moment of 200 kNm at the level of the base plate. The details of the base plate connection are given in Detail A of Figure Q1. Calculate the minimum base plate length and thickness required to transmit the column load and moment safety to the concrete foundation. Given that: 0.9 LE = 0.5 +0.14(K₁ + K₂) + 0.055 (k₁ + k₂)² 0.95 0.9 1.0 Pinned [25 marks] Figure Q1 shows a 3-bay, 4 storeys rigid jointed multi-storey frame and the rigid base, detail A. 2 5.0m 100mm All columns: 533 x 210 x 109 UB (S275) All bases are fully fixed Frame centres = 6m 300mm 100mm —— CSE6011-B Jan 2023 Paper/Page 5 of 6 4.0m 100mm 1 F Detail A 6.0m Detail A: Rigid base Figure Q1 4.0m All beams: 305 x 165x 46 UB (S275) Pad foundations: concrete cylinder strength = 35N/mm² || 100mm 4.0m 4.0m 4.0m Question 2 A hotel building has a composite floor with a series of beams at 4.0 metre centres spanning 10m. The beams are 457 × 191 × 89 UB Grade S275 with a composite slab formed using trapezoidal profiled steel sheeting and welded through shear connectors as shown in Figure Q2 (a) Calculate the maximum moment capacity of this composite beam. [25 marks] (b) If only one row of 19mm x 100mm headed studs is used instead of two rows of headed studs as shown in Figure Q2, calculates the maximum moment capacity of the beam. [15 marks] Given that: i. ii. iii. iv. V. Diameter of headed shear stud = 19 mm Height of headed shear stud = 100 mm Ultimate tensile strength of the headed stud = 500 N/mm² Steel decking thickness = 0.9 mm Concrete cylinder strength, fck = 40 N/mm², Ecm If any other assumptions are made, these must be stated. 100 Cross Section CSE6011-B Jan 2023 Paper/Page 6 of 6 150 = 32000 MPa Figure Q2 100 200 Longitudinal Section +8+ 50