303SD Structural Steel Design Project Brief Report SEM 2 | Ngee Ann Polytechnic, Singapore

Ngee Ann Polytechnic

School of Design & Environment (DE) STEEL DESIGN

Project           Structural Steel Design [20%]

Project Brief

Your company has been appointed as the Civil & Structural consultant, PE or QP (Civil), for the development of a five-storey building shown in Annex A.

The development consists of a 5-storey commercial building constructed of steel frame. The suspended floors are precast and are supported on structural steel beams.

• The four upper floors (Level 2 to 5) are designed for general office load plus an allowance for moveable partitions, and
• The ground floor (Level 1) is used as a retail premises.

The building is provided with a central core containing two lifts, a general staircase, and an access well for services to all floors. The reinforced concrete shear walls enclosing these areas provide lateral stability to the structure as a whole.

An additional fire escape staircase (not shown) will be attached to the outside of the building.

Structural Design Report

The structural design report shall be in the format prescribed by BCA including,

• Design Criteria (refer to BCA requirement) o Codes/references used o  Design assumptions e.g. Braced frame, simple construction, etc. o    Design parameters e.g. steel grade, imposed loads, etc.
• Design of critical members (beams and columns) using Blue Book o ULS: Show that member resistance > Worst load effect, i.e. moment, shear, axial compression etc., for all the critical

o SLS: Show that allowable deflection > max deflection due to unfactored load on critical beams.

• Design of critical members & connections using Green Book o Beam-to-beam connection o Beam-to-column connection o     Column base connection

Scope & assumptions

The set of reports covers only the design of structural steel members and their connections, excluding any precast & reinforced concrete members and foundation.

The lateral systems provided are assumed to be adequate in resisting the horizontal loads, as such, the building has been classified as a braced frame and suitable for simple construction. Hence, the beams and columns can be designed for gravity loads only and their connections as pinned joints.

Design Information

Design the structural members, i.e. beams and columns, using hot rolled universal sections of Grade S355 steel.

Density of reinforced concrete is 25 kN/m³. You may assume the grade C30/37 concrete and preliminary sizes for the following (if requires):

• Ground beams 350 x 500
• Ground slabs 250 mm thick, and
• Column stumps 500 x 500 x 1000 high (top of footing to top of ground slab/beam), or other sizes deemed more appropriate.

i) Slab

Permanent actions:

• Thickness of precast slab to be 150mm.
• Load due to walling, cladding and window = 5 kN/m
• 25 mm screed & tiles = 1.2 kN/m² (retail & office floors)
• 50 mm screed & waterproofing system over RC flat roof = 1.7 kN/m² (Roof only)
• Suspended ceiling & services = 0.5 kN/m²

Variable actions:

• 1^st floor: Shopping areas
• 2^nd floor: Office areas o Movable partition load = 1.0 kN/m² Roof is accessible for maintenance only.

ii) External RC Wall

• • 1m high 200 mm thick precast wall on roof

iii) Beams (for braced frame)

• • All beams are to be designed as fully restrained.
  • All beams have pinned ends unless otherwise stated.

iv) Columns (for braced frame)

• • Beam loads at support are axially transferred onto the column.
  • Column is subject to nominal moment acting at least 100 mm away from the face of the flanges and web of the column section.

[20% of 303SD] Project Assignments

● [65%] Design the assigned steel members (beams & columns) and connections using:

1. Blue Book (Steel Building Design: Design Data)
2. Green book (Simple Joints to Eurocode 3)
3. SSSS Design Guide (Design Guide for Buildable Steel Connections to EC3)

● [35%] Project video presentation

1. Beams, level 2, vertical edge Load & design
2. Beams, level 2, vertical internal Load & design
3. Beams, roof, vertical edge Load & design
4. Beams, roof, vertical internal Load & design
5. Columns, internal, level 1-2 Load & design
6. Columns, internal, level 2-3 Load & Design
7. Columns, horizontal edge, level 1-2 Load & Design
8. Columns, horizontal edge, level 2-3 Load & Design
9. Columns, vertical edge, level 1-2 Load & Design
10. Columns, vertical edge, level 2-3 Load & Design
11. Columns, corner, level 1-2 Load & Design
12. Columns, corner, level 2-3 Load & Design
13. Columns, corner, level 5-Roof Load & Design
14. Beam-column connection Design for worst load
15. Column base plate connection Design for worst load

AnnexA

Propose the size of a structural steel (beam and column) system to replace the following (RC beam and column) layout.