Cork Institute of Technology. Summer 2006 Structural Design & Detailing I (Time: 4 Hours)

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1 Cork Institute of Technology Bachelor of Engineering (Honours) in Structural Engineering Stage 2 (NFQ Level 8) Summer 2006 Structural Design & Detailing I (Time: 4 Hours) Instructions: 1. The examination is intended as a test of the candidate s: (a) knowledge of structural calculations (b) understanding of design principles (c) ability to track loads through a building (d) ability to design (e) ability to present a design as a detailed drawing suitable for construction purposes Candidates may refer to design code extracts and approved design aids. 2. Attempt any two questions from Section A. Answer all questions in Section B. 3. Use separate answer books for each Section. Examiners: Dr. J. D.Murphy Mr. D. J. Walsh Prof. P. O Donoghue Mr. T. Corcoran Section A Reinforced Concrete (Answer any two questions from this section) A1. Fig.A1 details reinforcement for the central span of a five(5) span continuous beam. The beam has been designed and detailed in accordance with T3.5 and Fig3.24 simplified rules. Materials and nominal cover information is also given. (i) Calculate the ultimate bending moment capacity of the beam section at support D. (12 marks) (ii) Calculate the ultimate shear force capacity of the beam adjacent to support D. (9 marks) (iii) Use the simplified coefficients of Table3.5 (BS8110) to determine the ultimate load carrying capacity (kn/m length) of the beam based on (i) & (ii) above. (4 marks) (Total QA1. 25 marks)

2 Fig.QA(2&3) shows a typical floor plan and sectional elevation of a two storey building of in-situ RC construction. Lateral stability of the building will be provided independently of the main beam and column framing shown. Design information for the building is as follows; Durability and Fire - Nominal Cover: Superstructure:20mm Loading: (Characteristic Values) Dead Loading: Weight of ceiling & services, floor finishes: allow 2.0kN/m 2 (all levels) Imposed Loading: Library /Reading Rooms: allow 4.0kN/m 2 1 st floor: Weight of removable partitions/fittings: allow 1.5kN/m 2 Roof: Allow 1.5kN/m 2 for maintenance access Materials: Concrete : Grade 35 (maximum aggregate size 20mm) Reinforcement: Main high yield steel, f y = 460 N/mm 2 Links mild steel, f yv = 250 N/mm 2 A2. For the three span continuous beam element on grid line 3 at 1 st floor level; (i) (ii) (iii) (iv) Calculate the ultimate design load, per metre length. Sketch the design bending moment and shear force envelopes dimension the critical values on each sketch. (6marks) Design the flexural reinforcement for the beam. Detail the flexural design for support B on the graph paper provided (You should clearly show curtailment information). (11 marks) Design shear reinforcement for a section immediately adjacent to support B take the section on the side towards support C. Calculate the bar bending schedule dimensions A,B&L for your chosen link. (6 marks) Check span A-B of the beam design for compliance with the deemed to satisfy deflection provisions of BS8110:Part1. (2 marks) (Total QA2. 25 marks)

3 A3. (a) Using a neat sketch illustrate the typical lateral stability system for a braced RC building frame; show clearly the load transfer path through the frame. (3 marks) (b) Column C3 is to be of square cross section, 225mm x 225mm, from foundation to roof. (i) Design the full height of the column from roof to foundation level. (Assume a pinned connection between column C3 and its footing). (16marks) (ii) Detail the first lift of the column. Use the graph paper provided. (4marks) (iii) Using the attached form, prepare a bar bending schedule for the drawing produced for A3(b)(ii) above. Show all of your schedule calculations and include the completed schedule with your Answer Book. (2 marks) (Total QA3. 25 marks)

4 Section B Structural Steel (Answer all questions from this section) Question B1 Figure B1 outlines the plan of a floor. The floor is constructed using one way spanning precast concrete slabs. Structural steel beams in a simple structural steel framed building support the slabs. The loading is as outlined below: Dead Loads: One-way spanning PC Slab 4.4kN/m 2 Self weight of UB s 1kN/m Live loads: Gridlines 1-2: Offices Gridlines 2-3: Plant room B1.1. Indicate the loading in terms of unfactored live and dead loads at Column C5. Calculate the unfactored nominal moments: Mxgk, Mxqk, Mygk, Myqk. (13 marks) B1.2. Produce a fabrication drawing of B6 utilising double angle cleat connections. (12 marks) C4 = C5 = 254UC x 73kg/m B9 = 254 x 146UB x 31kg/m B6 = 406 x 178UB x 67kg/m

5 Question B2 Figure B2 indicates a loading diagram for a beam. Intermediate lateral restraints exist at B & C. The beam is connected to a UC by use of flexible end plates at A & D. The loads are given as unfactored dead load (outside brackets) and live loads (inside brackets). Check the suitability of a 533 x 210 UB x 82 kg/m. (25 marks) Deflection Formula Deflection at midspan for two equal symmetrical point loads = [Pa / (24EI)] (3L 2 4a 2 ) where P is unfactored live load, L is length of the beam, a is the distance from the Left hand support to the first point load

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