Load Combinations in Structural Design
24 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What do dead loads include in the context of construction design?

  • The weight of temporary structures
  • The load of people and furnishings inside the building
  • The weight of all materials of permanent construction (correct)
  • The dynamic effects of wind and earthquake forces
  • In the absence of definite information, which option is acceptable for determining dead loads?

  • Applying only theoretical weights based on design
  • Estimating weights based on visual inspections
  • Using average values across similar structures
  • Using the minimum values in specified tables (correct)
  • What is the uniformly distributed dead load that must be designed for floors in buildings with changeable partition locations?

  • 2.0 kPa of floor area
  • 1.5 kPa of floor area
  • 0.5 kPa of floor area
  • 1.0 kPa of floor area (correct)
  • Which of the following best defines dead loads for a structure?

    <p>Static loads that do not change over time</p> Signup and view all the answers

    Which of the following components is NOT considered part of dead loads?

    <p>Occupant furniture</p> Signup and view all the answers

    What characteristic of dead loads is emphasized in structural design?

    <p>They consist of permanent materials within the structure.</p> Signup and view all the answers

    When designing for dead loads, what additional consideration is required specifically for office buildings?

    <p>Support additional loads due to movable partitions</p> Signup and view all the answers

    What items are typically included in the calculation of dead loads?

    <p>Components like stairways and ceilings</p> Signup and view all the answers

    What does the symbol D represent in load calculations?

    <p>Dead load</p> Signup and view all the answers

    In which load combination is the dead load D multiplied by a factor of 0.9?

    <p>0.9<em>D</em> + 1.6<em>W</em> + 1.6<em>H</em></p> Signup and view all the answers

    Which of the following best describes a dead load in structural design?

    <p>The weight of the structure and fixed elements</p> Signup and view all the answers

    Which load includes factors for temperature change, shrinkage, and movement?

    <p>Self-straining force</p> Signup and view all the answers

    What is the factor for live load in places of public assembly as denoted by f1?

    <p>1.0</p> Signup and view all the answers

    In the combination 1.2D + 1.6W + f1L* + 0.5(Lr or R), which load is included as a variable?

    <p>Roof live load</p> Signup and view all the answers

    What is the primary consideration for a retaining wall in structural engineering?

    <p>Resisting lateral soil displacement</p> Signup and view all the answers

    Which load is referred to when discussing the load due to lateral pressure of soil and water?

    <p>Dead load</p> Signup and view all the answers

    What characterizes live loads in a building structure?

    <p>They are produced by the use and occupancy of the building.</p> Signup and view all the answers

    Which of the following accurately describes dead loads?

    <p>They include forces from the weight of building materials.</p> Signup and view all the answers

    What is an example of a variable load on a structure?

    <p>Occupancy loads due to furniture and equipment.</p> Signup and view all the answers

    Which of the following statements about dead loads is false?

    <p>They occasionally vary in magnitude.</p> Signup and view all the answers

    In the context of structural loads, what is the primary distinction between dead loads and live loads?

    <p>Live loads vary over time, whereas dead loads are constant.</p> Signup and view all the answers

    What types of loads are excluded from the definition of live loads?

    <p>Both A and B.</p> Signup and view all the answers

    Which of the following is NOT considered a permanent load?

    <p>The weight of occupants and furnishings.</p> Signup and view all the answers

    What is the consequence of neglecting dead loads in structural design?

    <p>Potential structural failure or instability.</p> Signup and view all the answers

    Study Notes

    Load Combinations Using Allowable Stress

    • Structures must resist critical effects from specified load combinations defined in Section 203.4.
    • Basic load combinations include:
      • D (dead load) + F (fluid load)
      • D + H (hydrostatic load) + F + L (live load) + T (temperature effects)
      • Other variations include live load or rain load combinations.

    Special Seismic Load Combinations

    • Seismic design incorporates specific load combinations as required by Sections 208 or Chapters 3-7.
    • Notable combinations:
      • 1.2D + f1L* + 1.0Em (earthquake load)
      • 0.9D + 1.0Em
    • f1 varies based on occupancy and live load conditions.

    Dead Loads

    • Consist of the weight of construction materials including walls, floors, and equipment.
    • Actual weights should be used; minimum values are permitted in the absence of accurate data.
    • Partition loads in flexible spaces must accommodate an additional dead load of 1.0 kPa.

    Live Loads

    • Defined as loads from building use and occupancy, excluding dead loads, environmental loads, or construction loads.
    • Permanent loads have minor variation over time, while all other loads are classified as variable.

    Load and Resistance Factor Design (LRFD)

    • Proportions structural elements ensuring no limit state is reached with load combinations.
    • Employed mainly in the design of steel structures.

    Strength Design

    • A method used primarily for concrete structures to ensure computed forces from factored loads do not exceed design strength.

    Structural Wall Classifications

    • Bearing Wall: Supports significant vertical loads (metal/wood stud walls over 1.45 kN/m, masonry/concrete walls over 2.90 kN/m).
    • Nonbearing Wall: Does not support vertical loads.
    • Exterior Wall: Defines building's outer boundary; has a slope of 60 degrees or greater.
    • Parapet Wall: Extends above the roof line.
    • Retaining Wall: Prevents lateral soil displacement.

    Combinations of Loads

    • Structures must resist combinations specified in Sections 203.3 or 203.4, with special seismic requirements as outlined in Section 208.

    Symbols and Notations

    • Common load symbols defined:
      • D = Dead load
      • E = Earthquake load
      • F = Fluid pressure load
      • H = Soil and water lateral pressure load
      • L = Live load
      • P = Ponding load
      • R = Rain load
      • T = Temperature-related forces
      • W = Wind load

    Strength Design Load Combinations

    • Factored load combinations include:
      • 1.4(D)(F)
      • 1.2(D+F+T) + 1.6(L+H) + 0.5(Lr or R)
      • Specific ratios for earthquake, wind, and other variables.

    Other Loads Consideration

    • For ponding load (P), factor into design as 1.2P when necessary.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    week-2.docx

    Description

    This quiz covers the essential load combinations used in allowable stress design for structural engineering. It focuses on basic load combinations and special seismic load combinations crucial for ensuring structural integrity. Test your knowledge of these fundamental concepts.

    More Like This

    Use Quizgecko on...
    Browser
    Browser