Introduction to Structural Design in Architecture: Building the Future

1. Introduction to Structural Design Architecture has recorded the great ideas of the human race. Not only every religious symbol, but every human thought has its page in that vast book. - Victor Hugo

2. Structure of a Building The primary function of a building structure is to support and transmit the building loads and forces to the ground. Photos courtesy Tilt-up Concrete Association

3. Characteristics of a Structure • Strength • Stability • Economic Value

4. Structural System • Made up of many smaller structural sub-systems that work together to provide a strong, stable, and cost-effective structure. • Examples of these smaller structural sub-systems include: • Roof • Walls • Floors • Framing • Foundations Structural engineers design these structural systems.

5. Structural Sub-System • Made up of many structural elements that work together to provide a strong, stable, and cost-effective system. • Basic structural elements include: • Beam • Column • Truss • Arch • Vault • Dome Structural engineers design these structural systems.

6. Forces and Loads • A force is any action that causes a change in the shape or motion of an object. • A load is a force that is supported by a structural element. • The terms force and load are often used interchangeably. SNOW WIND

7. Structural Member Forces Tension – A force that stretches or pulls apart a member, resulting in the member elongating. Compression– A force that squeezes or presses a member together, resulting in the member shortening. Shear– A force that acts perpendicular to the axis of the member, causing the internal particles of the member to slide against each other.

8. Beam • A structural element that carries a load that is applied transverse (perpendicular) to its length. • Usually a horizontal member that carries a vertical applied load. • The top fibers of a beam are in compression; the bottom fibers are in tension.

9. Cantilever Beam • A special type of beam that is supported only at one end • The top fibers of the cantilever are in tension; the bottom fibers are in compression

10. Column A vertical structural element that carries an axial force in compression COLUMN

11. Truss • A structural element that is composed of smaller structural members typically configured in triangular arrangements • Some truss members carry a tension force; others carry a compression force

12. Arch • A curved structural element that spans over an open space • In stone arches, the last stone to be placed at the top is called the keystone KEYSTONE

13. Vault A continuous arch that forms a ceiling or roof

14. Dome A structural element that is made up of arches that radiate around a center point to create a half sphere

15. Hybrid Forms • An infinite number of combinations of these forms exist

16. Design Process The same design process used by engineers and designers in other disciplines can be used to design structural systems.

17. Architectural Program • Establishes overall concept and design philosophy • Includes • Location of building on site • Architectural style • Interior space planning • Design elements • Construction materials • Building systems • Encompasses the first four steps of the design process

18. Structural Design Process • An architectural program establishes preliminary structural systems. • The structural engineer must analyze the structural systems and provide a strong, stable, and cost-effective design.

19. Structural Design Process Identify Criteria and Constraints • Additional criteria needed: • Types and magnitudes of applied loads • Load path that each load will follow to the ground

20. Structural Design Process Explore Possibilities • Consider alternate structural configurations, materials, and spacing to improve the design or reduce costs

21. Structural Design Process Select an Approach • Based on structural performance, compatibility with the architectural program, and cost • Based on the possibilities explored, select the optimal design

22. Structural Design Process Develop a Design Proposal • Create a preliminary structural design incorporating the selections for all structural elements

23. Structural Design Process Model or Prototype • Create a model to represent your structural design • Sketches • Structural analysis software • 3D architectural software

24. Structural Design Process Test and Evaluate • Reanalyze structure based on element selections • Structural analysis software • 3D architectural software

25. Structural Design Process Refine • Revise the design as necessary to correct problems with strength, stability, and compatibility with other systems

26. Structural Design Process Create or Make • Based on the final design after revisions • Create working drawings of the structural design

27. Structural Design Process Communicate Results • Distribute the drawings • Include in bid package • Include in construction drawings

28. Image Sources • Tilt-up Concrete Association (www.tilt-up.org)