W10: Structural Engineering

• What does a Structural Engineer design?

  Structural systems and elements in civil works
• What is the design process in structural engineering?

  Determining location, material, and size of elements to resist forces acting in a structure
• What are the steps in the engineering design process?

  1. Identify the problem
  2. Explore alternative solutions (Research past experience, Brainstorm, Preliminary design of promising solutions)
  3. Analyze and design one or more viable solutions
  4. Testing and evaluation of solution (Experimental testing (prototype) or field tests, Peer evaluation)
  5. Build solution using available resources (materials, equipment, labor)
• What is the design process in structural engineering?

  1. Select material for construction
  2. Determine appropriate structural system
  3. Determine forces acting on structure
  4. Calculate size of members and connections to avoid collapse or excessive deformation
• What are dead loads in structural engineering?

  Permanent loads like self-weight of structure
• What are live loads in structural engineering?

  Transient moving loads like occupants and vehicles
• What forces can act on structures?

  Gravity, wind, earthquakes, rain/snow, Fluid pressures
• What are the two types of forces acting in structures?

  Vertical (gravity) and lateral (wind, earthquake) forces
• What are the types of global stability issues in structures?

  • Sliding
  • Overturning (w/ tilt)
• What is compression in structural elements?

  Forces that push materials together
• What is tension in structural elements?

  Forces that pull materials apart
• What is bending in structural elements?

  Forces that cause materials to curve
• What is torsion in structural elements?

  Forces that twist materials
• What is the formula for stress?

  Stress = Force / Area
• What is strain?

  Strain = DL (deformation added) / Lo (original length)
• What does the Modulus of Elasticity (E) represent?

  E = Stress / Strain

  e.g. rubber band
• What are the types of stress-strain behavior of materials?

  • Linear Elastic (bumabalik sa original position)
  • Non-linear Elastic
  • Elastic-plastic
  • Non-linear Plastic
• What materials are commonly used in civil engineering?

  • Stone and Masonry
  • Metals (Cast Iron, Steel, Aluminum)
  • Concrete (sand & cement - fine, gravel - coarse)
  • Wood
  • Fiber-Reinforced Plastics
• What are the components of concrete?

  • Sand (Fine Aggregate) - 26%
  • Gravel (Coarse Aggregate) - 41%
  • Cement (Binder) - 11%
  • Water - 16%
  • Air - 6%
• What is strength in structural engineering?

  Ability to withstand stress without failure
• What is stiffness (rigidity) in structural elements?

  • Property related to deformation
  • Stiffer elements deform less under load
  • Depends on type of material, shape, and configuration
• How do structural elements provide stability for lateral loads?

  • Racking Failure of Pinned Frame (can move sideways)
  • Braced Frame (may slope sa gitna)
  • Infilled Frame (may laman)
  • Rigid Joints (corners are thicker)
• What is the moment (rotational) equilibrium formula?

  Moment = Force x Distance
• What is the equilibrium of forces in statics?

  • Forces are vectors defined by magnitude and direction
  • statement of equilibrium (Net force at a point = zero)
  • Net force at a point is determined using a force polygon
• How is force calculated in a simple structure?

  • Use geometry to find side lengths
  • Calculate forces based on angles and loads
• What is one role of a Structural Engineer?

  Design of buildings and infrastructures
• What is another role of a Structural Engineer?

  Retrofit of old and historic buildings
• What is a role of a Structural Engineer related to excavation?

  Shoring and excavation
• What is a role of a Structural Engineer regarding damaged buildings?

  Repair and inspection of damaged buildings
• Where do Structural Engineers typically work?

  • Government organizations
  • Private developers
  • Consulting firms
  • Research and academia
• What are the forces in structural elements

  tension, compression, bending, torsion
• What are the typical structural systems?

  • arch (eg. old structures)
  • truss (compression - up, tension - down) (e.g. ware houses)
  • frame (eg. fly overs)
• strength on structural engineering depends on what?

  type of material and force (tension or compression)
• 2 types of failure when stress is applied

  tensile failure (break), compressive failure (buckle)
• Two main types of stiffness

  Axial and Bending stiffness
• Axial stiffness formula


  stiffness= T/DL or Tensile force/ deformation
• Formula for bending stiffness

  stiffness = Force/ Displacement
• 12 steps of construction

  1. clearing of the ground
  2. site layout and staking (gridlines)
  3. excavation
  4. compacting ang laying of PCC
  5. Foundation rebar and column starter bars
  6. concreting of foundations
  7. concreting of column and bitumen paint applications
  8. Setting up perimeter blocks
  9. backfilling and compacting
  10. tie beam reinforcement, grade slab, and concreting
  11. Rebar works and concreting of columns
  12. beams and slab works
• Forces in structural elements

  • tension
  • compression
  • bending
  • torsion