1.A. Structural Concepts
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1.A. Structural Concepts

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What is kinematics primarily concerned with?

  • The effect of mass on motion
  • The acceleration of an object
  • The geometry of motion (correct)
  • The forces acting on a body

    • Which unit is commonly used to measure force in the US?

  • Pounds (correct)
  • Newtons
  • Kilograms
  • Watts

    • Which type of force system has lines of action that intersect at a common point?

  • Concurrent force system (correct)
  • Parallel force system
  • Coplanar force system
  • Non-coplanar force system

    • What is the primary difference between kinematics and kinetics?

    <p>Kinematics describes motion without considering forces while kinetics analyzes the effect of forces.</p> Signup and view all the answers

    Which statement regarding the principle of transmissibility is correct?

    <p>The external effect is consistent regardless of where the force is applied along its line of action.</p> Signup and view all the answers

    A rigid body is best described as:

    <p>A matter with fixed parts relative to each other.</p> Signup and view all the answers

    Which of the following accurately defines a coplanar force system?

    <p>Forces whose lines of action lie in the same plane.</p> Signup and view all the answers

    Which type of mechanics deals specifically with the effect of forces on mass and acceleration?

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

    What is the definition of static equilibrium?

    <p>A body acted upon by a balanced force system.</p> Signup and view all the answers

    Which characteristic is NOT important when discussing a force?

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

    Which of the following best defines a resultant force?

    <p>A single force that produces the same effect as multiple forces.</p> Signup and view all the answers

    In a free body diagram, what does the sketch primarily illustrate?

    <p>The forces exerted by one body on another.</p> Signup and view all the answers

    Which type of load is specifically associated with twisting actions?

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

    What does axial force represent?

    <p>A pulling or pushing action over a cross-section.</p> Signup and view all the answers

    What are bending moments primarily associated with?

    <p>Resistance to bending of a member.</p> Signup and view all the answers

    Which of the following is NOT considered an external load?

    <p>Internal Stress</p> Signup and view all the answers

    What is shear force primarily concerned with?

    <p>Components resisting sliding between sections.</p> Signup and view all the answers

    What best describes the action and reaction forces according to Newton's third law?

    <p>They act on different bodies and are equal and opposite.</p> Signup and view all the answers

    What is the formula for calculating stress?

    <p>S = P / A</p> Signup and view all the answers

    What occurs at the yield point in the stress-strain curve?

    <p>Material experiences significant elongation without increased load</p> Signup and view all the answers

    Which of the following statements is true regarding the ultimate strength?

    <p>It represents the highest point on the stress-strain curve</p> Signup and view all the answers

    What is allowable stress commonly based on?

    <p>Yield point or ultimate strength divided by a factor of safety</p> Signup and view all the answers

    What is the purpose of studying the strength of materials?

    <p>To increase safety and efficiency in selecting and proportioning materials</p> Signup and view all the answers

    What does the elastic limit indicate?

    <p>The point at which material starts to yield with no return to original shape</p> Signup and view all the answers

    What is the correct definition of rupture strength?

    <p>Stress at failure, typically lower than ultimate strength</p> Signup and view all the answers

    How is axial deformation characterized?

    <p>Load acting parallel to the member axis, causing elongation or shortening</p> Signup and view all the answers

    What is a common method to determine yield strength in materials lacking a well-defined yield point?

    <p>Offset method</p> Signup and view all the answers

    What does the stress-strain diagram represent?

    <p>The relationship between stress and strain showing various limits and points</p> Signup and view all the answers

    What do dead loads include in the context of structural loadings?

    <p>The weight of the structure and immovable loads</p> Signup and view all the answers

    Which of the following is an example of a movable load?

    <p>Snow on a roof</p> Signup and view all the answers

    What factor is NOT considered when evaluating allowable stress of columns?

    <p>Shape of the column cross-section</p> Signup and view all the answers

    How does the application of live loads affect structural deformation?

    <p>Gradual application leads to the same deformation as static load</p> Signup and view all the answers

    Which type of live load has a fixed magnitude and variable location?

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

    What is the minimum design dead load for 'Ceramic or quarry tile (20 mm) on 25 mm mortar bed' according to the provided guidelines?

    <p>1.10 kPa</p> Signup and view all the answers

    Under which condition does the increase in stress due to live load become significant?

    <p>When applied rapidly</p> Signup and view all the answers

    What is the main cause of flexural failure in beams?

    <p>Exceeding the flexural capacity of the beam</p> Signup and view all the answers

    What characterizes buckling in structural members?

    <p>A sudden change in shape under axial load</p> Signup and view all the answers

    Which statement best defines bending in a structural member?

    <p>Occurs when a transverse load acts perpendicular to the neutral axis</p> Signup and view all the answers

    How does the modulus of elasticity affect material deformation?

    <p>Low modulus materials are less resistant to elastic deformation</p> Signup and view all the answers

    What is the relationship described by Hooke's Law?

    <p>The relationship between stress and strain in a material</p> Signup and view all the answers

    Which type of failure occurs due to insufficient shear resistance?

    <p>Shear failure</p> Signup and view all the answers

    What causes bending stress in a structural member?

    <p>Transverse load acting perpendicularly</p> Signup and view all the answers

    Which diagram illustrates different types of beam failures?

    <p>Types of beam failures diagram</p> Signup and view all the answers

    Which phenomenon occurs gradually due to increasing axial load?

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

    Which type of stress is illustrated in the diagrams of the document?

    <p>Shear stress and normal stress</p> Signup and view all the answers

    Study Notes

    Structural Concepts

    • Rigid body: A body whose parts are fixed relative to each other, simplifying analysis.
    • Force: Causes a change in the body's state of motion; characterized by magnitude, line of action, and direction.
    • Force system: Arrangement of forces acting on a body, classified as coplanar or non-coplanar.
    • Types of force systems: Concurrent (lines of action intersect), parallel (lines of action are parallel).
    • Principle of transmissibility: External effect of a force is constant regardless of application point along its line of action, but internal effects are dependent on the point of application.

    Principles of Static Equilibrium

    • Static Equilibrium: A body with balanced forces is at rest.
    • Free body diagram: A sketch displaying forces exerted on a body, helping analyze equilibrium.
    • Strength of materials: Studies the relationship between external loads and their internal effects on bodies.
    • Types of external loads: Axial, twisting (torque), bending loads, and combinations.

    Stress-Strain Relationships

    • Stress: Force per unit area (S = P/A).
    • Strain: Unit deformation.
    • Proportional limit: The point where stress is directly proportional to strain (Hooke's Law).
    • Elastic limit: Stress beyond which the material doesn't return to its original shape when unloaded.
    • Yield point: Significant elongation without increased load, used for steel design.
    • Yield Strength: For materials lacking a defined yield point, it's determined by the offset method.
    • Ultimate stress/strength: Highest stress value the material can withstand.
    • Rupture strength: Stress at failure (lower than ultimate in structural steel).
    • Allowable stress: Limited to values below the proportional limit, often based on yield or ultimate strength divided by a factor of safety.

    Types of Failure in Beams

    • Flexural failure: Occurs when the load exceeds the beam's flexural capacity.
    • Shear failure: Results from insufficient shear resistance between beam materials.

    Bending and Buckling

    • Bending: Caused by a transverse load perpendicular to the neutral axis, creating bending stress.
    • Buckling: A sudden change in shape under axial load, occurring due to increasing axial load.

    Hooke's Law - Axial Deformation and Modulus of Elasticity

    • Modulus of elasticity: Measures a material's resistance to elastic deformation.
    • Hooke's law: Describes the relationship between stress and strain in a material.

    Structural Loadings

    • Prevailing Design Load: Considers axial load, material overstressing, and buckling.
    • Dead loads: Weight of the structure and permanently attached items.
    • Minimum Design Dead Loads: Includes values for ceilings, acoustical boards, gypsum boards, coverings, insulation, floor finishes (e.g., cement, tile, terrazzo, wood).
    • Movable loads: Loads that can be moved, often applied gradually (e.g., storage contents).
    • Live loads: Loads varying in position, classified as movable and moving loads.
    • Impact: Increase in stress due to rapid application of a load.
    • Snow and ice loads: Considered movable, as they don't always cover the entire roof.
    • Minimum Uniform Live Loads: Vary for different building types (e.g., hospitals, offices, schools).
    • Minimum Roof Live Loads: Depend on roof slope.

    Lateral Loads

    • Wind loads: Important for large structures with open interiors.
    • Soil pressure: Active pressure is about half of vertical pressure, while passive pressure is about four times the vertical pressure.
    • Hydrostatic pressure: Loads on dams, tanks, calculated using hydraulic principles.
    • Earthquake forces: Structures must be designed to withstand earthquake effects, especially horizontal accelerations.
    • Centrifugal forces: Act on curved bridges, treated as moving loads.
    • Longitudinal forces: Horizontal forces acting along the roadway (e.g., forces on a bridge).

    Structural Forms

    • Steel-cable structure: Efficient for carrying loads through tension.
    • Flexible membrane: Carries loads by tension, similar to many cables side-by-side.
    • Arch: Inverted cable structure, conforming to the equilibrium polygon based on the load.
    • Shell: Membrane with flexural stiffness and strength (like an arched cable), often made of reinforced concrete.
    • Planar truss or planar framework: Supports concentrated load with a two-member arch.
    • Space framework: Supports three-dimensional structures, using a tetrahedral nucleus.
    • Framed structure: Beams can be cantilevered or end-supported, commonly used in modern construction.

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    Module 1 - Structural Concepts (Atlas)

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