Swing Design Concepts and Considerations

Preface

• The course Structural Design I is the first in a series of courses on designing structures.
• The course is integrated with Applied Mechanics.
• The course provides a fundamental understanding of structural analysis, application of materials, and the principles of design.
• The goal of the course is to develop insight into force distribution, design, and composition of simple structures.
• The course also introduces the structural design process.

Definition of a Structure

• A structure is a physical system meant to direct loads from one place to another.
• In buildings, this involves safely distributing loads (from people, furniture, wind, etc.) to foundations and then to the subsurface.

History of Construction

• Early structures were pressure-based (walls loaded in-plane) using materials like timber, stones, and bricks.
• The oldest surviving structures include Dolmens and Stonehenge.
• The Egyptians used predominantly stone due to its availability and constructed simple structures like load-bearing walls and flat roofs.
• Ancient Greece saw advancements with vaults and arches, to provide large spans.
• The Romans further developed these techniques using concrete and arches, enabling larger structures.
• The Gothic style (13th century) was innovative in using flying buttresses to withstand horizontal forces.
• The arrival of new materials like iron and steel in the 18th and 19th centuries led to new structural forms and greater spans.
• The mid-19th century saw the development of reinforced concrete which improved performance, allowing for larger spans.

Structural Systems

• Structures are classified based on how they carry loads:
  • Compression systems (columns, walls, arches, and shells).
  • Tension systems (cables, and tension systems).
  • Bending systems (beams, and floors).
  • Portal frames (combination of vertical and horizontal elements).

Structural Materials

• Natural: Timber, and stone.
  • Characteristics well-known to craftsmen.
  • Quality can vary.
• 人工製品 (Artificial): Steel, aluminium alloys, and concrete.
  • Produced using controlled factory processes.
  • Consisten quality.
• New materials: Fiber-reinforced composites.
  • Still developing, quality varies greatly depending on research.

Structural Safety

• Structural design ensures loads acting on the structure are less than the structure's resistance.
• Loads include: permanent loads (e.g., self-weight), variable loads (e.g., live loads, wind), and accidental loads (e.g., earthquakes, explosions).
• Safety is evaluated by using load factors and material factors.

The Design Process

• The design process starts by understanding the client's needs and their requirements (design brief and program of requirements).
• Design involves researching appropriate locations, investigating and comparing different options for materials, methods, and structural shapes.
• The final design phase refines the design, which includes considerations for structural calculations and design details. (This is often done via a computer supported design process).

Loads

• Permanent: Loads like self-weight, dead loads and pre-stress.
• Variable: Live loads like people, furniture, wind, and snow.
• Accidental: Occur infrequently, high-impact events, like for instance explosions and earthquakes.

Codes of practice

• Eurocodes cover all aspects of calculating loads and resistance of structures.
• Eurocode 1 (EN 1991) gives details on load calculations.

Types of Structures:

• Columns
• Walls
• Arches
• Beams
• Floors
• Portal frames
• Trusses
• Guyed structures
• Tensile structures

Columns (additional details)

• Columns transfer vertical loads down to the base.
• Stocky and slender columns differ by their cross-sectional area relative to their height.
• Buckling is important to consider when designing slender columns using an equation determined by Leonard Euler.
• Stocky columns are more resistant to buckling.

Column-Floor Connection

• A concrete floor supported by columns involves significant shear stresses at the connection (punching shear).
• Details in the column-floor connection, such as head plates or mushroom slabs, enhance the connection's stiffness.

Column-Beam Connection

• Timber and steel column-beam connections must be designed taking into account the tensile and compressive strengths of the different material and connections.
• Steel column-beam connections use end plates (or welding) for stress distribution around the joint.

Stability of Blocks and Towers

• Stability of structures depends on the position of the center of gravity and the base(larger base = more stable.)
• Horizontal forces increase instability risk.
• Preventing toppling requires proper positioning and size of the base.

Global Dimensions

• Rules of thumb relate global dimensions of structural elements to their span.
• Using these rules provides rough estimations early during design.

Questions Chapter 1

• (Referencing the questions in chapter 1, provide detailed answers).

Questions Chapter 2

• (Referencing the questions in chapter 2, provide detailed answers).

Questions Chapter 3-8

• (Referencing the questions in each chapter, provide detailed answers).

Appendix A

• Rules of thumb for global dimensions (concrete, steel, timber) for various structural elements.

Appendix B

• Extensive bibliography of books and journal articles on structural mechanics and design.

Appendix C

• Glossary of technical terms used in the textbook (architectural and engineering).