Structural Engineering Exam (SE) Lateral Forces — Buildings Depth Syllabus

Lateral Forces — Buildings Depth syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Lateral Forces — Buildings Depth in Structural Engineering Exam (SE), not a summary of it.

1. 1

   Seismic Detailing of Concrete Systems (ACI 318)

   4 topics

   • Special Moment Frames
     • Strong-column weak-beam and joint shear
     • Confinement and transverse reinforcement detailing
   • Special Structural Walls
     • Boundary element design and shear capacity
     • Coupling beams and diagonal reinforcement
   • Diaphragms and Collectors in Concrete
   • Ductility, Capacity Design, and Detailing Requirements
2. 2

   Seismic and Wind Design of Steel Systems (AISC 341/360)

   4 topics

   • Special and Intermediate Moment Frames
     • Prequalified connections and panel zone design
     • Demand-critical welds and protected zones
   • Concentrically and Eccentrically Braced Frames
     • Brace design and capacity-limited forces
     • Link design and rotation in EBFs
   • Buckling-Restrained Braced Frames and Special Plate Shear Walls
   • Seismic Connection Design and Overstrength Demands
3. 3

   Lateral Design of Wood and Cold-Formed Steel

   4 topics

   • Wood Shear Walls and Diaphragms
     • Sheathing capacity, nailing, and aspect ratios
     • Overturning, hold-downs, and chord forces
   • Cold-Formed Steel Lateral Systems
     • Strap-braced and sheathed shear walls
   • Drag Struts, Collectors, and Anchorage in Light Framing
   • Load Path Continuity in Light-Frame Buildings
4. 4

   Lateral Design of Masonry Systems (TMS 402)

   4 topics

   • Masonry Shear Wall Design
     • In-plane shear and flexural capacity
     • Reinforcement detailing for ductility
   • Special Reinforced Masonry Shear Wall Requirements
   • Out-of-Plane Seismic Wall Behavior
   • Anchorage of Masonry Walls to Diaphragms

Lateral Forces — Buildings Depth flashcards for Structural Engineering Exam (SE)

21 of 64 cards from the Lateral Forces — Buildings Depth deck — real questions with worked answers.

1. In an ACI 318 Special Moment Frame (SMF), what design philosophy governs the relative flexural strength of columns versus beams at a joint?

   The strong-column/weak-beam principle. The sum of column flexural strengths must exceed the sum of beam flexural strengths at each joint: $\sum M_{nc} \geq \tfrac{6}{5}\sum M_{nb}$, forcing hinges to form in beams rather than columns.

2. For an SMF beam, where must transverse reinforcement (hoops) be provided as confinement, and over what length from the column face?

   Hoops are required over a length equal to $2h$ (twice the member depth) from the face of the support, where plastic hinging is expected. The first hoop is placed within $50\,\text{mm}$ (2 in.) of the column face.

3. What is the maximum hoop spacing in the confined region of an ACI 318 SMF beam?

   The smallest of: $\tfrac{d}{4}$, six times the smallest longitudinal bar diameter ($6d_b$), and $150\,\text{mm}$ (6 in.).

4. How is the design shear force for an SMF beam determined (capacity design for shear)?

   From probable moment strengths $M_{pr}$ developed at both ends (using $1.25 f_y$ and $\phi=1.0$) plus tributary gravity load: $V_e = \dfrac{M_{pr1}+M_{pr2}}{\ell_n} \pm \dfrac{w_u \ell_n}{2}$.

5. In computing probable moment strength $M_{pr}$ for capacity design, what steel stress and strength reduction factor are used?

   A stress of $1.25 f_y$ to account for strain hardening/overstrength, with strength reduction factor $\phi = 1.0$.

6. What is the minimum specified concrete compressive strength permitted for special seismic systems (SMF, special walls) per ACI 318?

   $f'_c \geq 21\,\text{MPa}$ (3000 psi). For lightweight concrete in special systems, $f'_c$ is generally limited to $35\,\text{MPa}$ (5000 psi) unless demonstrated otherwise.

7. In a Special Structural (Shear) Wall, when are special boundary elements required by the displacement-based (strain) approach of ACI 318?

   When the neutral axis depth $c \geq \dfrac{\ell_w}{600\,(1.5\,\delta_u/h_w)}$, with $\delta_u/h_w \geq 0.005$. If the compression zone exceeds this, the concrete strain exceeds about $0.003$ and confined boundary elements are needed.

8. By the stress-based approach, special boundary elements in a structural wall are required when the maximum extreme-fiber compressive stress exceeds what value?

   $0.2 f'_c$. They may be discontinued where the stress drops below $0.15 f'_c$.

9. What two failure modes must a Special Structural Wall be designed to preclude in favor of flexural yielding?

   Diagonal tension (shear) failure and lateral instability/crushing of the compression boundary. Capacity design and confined boundary elements ensure ductile flexural behavior dominates.

10. For a structural wall, what is the upper limit on nominal shear strength $V_n$ regardless of reinforcement provided?

    $V_n \leq \dfrac{5}{6}\,A_{cv}\sqrt{f'_c}$ in SI (or $10\,A_{cv}\sqrt{f'_c}$, psi), where $A_{cv}$ is the gross area of the wall web.

11. Give the nominal shear strength equation for a structural wall combining concrete and steel contributions.

    $V_n = A_{cv}\left(\alpha_c \lambda \sqrt{f'_c} + \rho_t f_y\right)$, where $\alpha_c = 0.25$ for $h_w/\ell_w \leq 1.5$, $0.17$ for $h_w/\ell_w \geq 2.0$ (linear interpolation between), and $\rho_t$ is the transverse reinforcement ratio.

12. What is a structural diaphragm and what are its two primary in-plane actions?

    A diaphragm is a horizontal (or sloped) structural element that transmits inertial/lateral forces to the vertical lateral-force-resisting elements. It acts as a deep horizontal beam carrying in-plane shear and bending; chords resist bending (flange forces) and the web resists shear.

13. What is the role of a collector (drag strut) in a diaphragm?

    A collector 'collects' or drags diaphragm shear forces and delivers them to the vertical lateral-force-resisting elements (walls/frames) that are shorter than the diaphragm width, providing a continuous load path along the line of resistance.

14. Per ASCE 7, collectors and their connections in higher seismic design categories must be designed for forces including what amplification?

    The overstrength factor $\Omega_0$. Collector design forces use the load combinations with overstrength ($E_{mh} = \Omega_0 Q_E$) to ensure the collector remains essentially elastic while the LFRS yields.

15. How is the chord force in a flexural diaphragm computed from the in-plane moment?

    $T = C = \dfrac{M}{d}$, where $M$ is the diaphragm in-plane bending moment (like a simply supported beam, $M=\tfrac{w L^2}{8}$) and $d$ is the depth (distance between chords).

16. Distinguish a flexible diaphragm from a rigid diaphragm in terms of force distribution to vertical elements.

    A flexible diaphragm distributes lateral force to vertical elements by tributary area (deflects significantly, like a series of simple beams). A rigid diaphragm distributes force in proportion to the relative stiffness of the vertical elements and transmits torsional (including accidental torsion) effects.

17. Per ASCE 7, when may a diaphragm be idealized as flexible without calculation?

    Untopped steel deck or wood structural panel diaphragms in light-frame construction with certain limits, and diaphragms in one- and two-family dwellings, may be idealized as flexible. Concrete-filled metal deck and concrete slabs are generally idealized as rigid.

18. What does 'capacity design' mean in seismic detailing?

    A design method where a ductile yielding mechanism (fuse) is deliberately chosen, and all other elements/actions (shear, connections, columns) are designed with sufficient overstrength to remain elastic while that fuse develops its probable/expected strength, ensuring ductile rather than brittle behavior.

19. Define ductility (displacement ductility ratio) in seismic design.

    The ratio of maximum displacement to yield displacement: $\mu = \dfrac{\Delta_{max}}{\Delta_y}$. It measures a system's ability to undergo large inelastic deformations without significant loss of strength.

20. What is the equal-displacement approximation used to relate elastic and inelastic seismic response?

    For longer-period structures, the peak displacement of an inelastic system approximately equals that of an elastic system, so $R \approx \mu$ (the response modification coefficient roughly equals the ductility demand). For short-period structures the equal-energy rule $R=\sqrt{2\mu-1}$ is more appropriate.

21. What is the purpose of the response modification coefficient $R$ in ASCE 7 seismic design?

    $R$ reduces the elastic design force to account for a system's ductility, overstrength, and energy dissipation: $V = \dfrac{S_{DS}}{R/I_e}\,W$. Higher $R$ (more ductile, well-detailed systems) means lower design base shear.

See more Lateral Forces — Buildings Depth flashcards →

Planning Lateral Forces — Buildings Depth for Structural Engineering Exam (SE)

Lateral Forces — Buildings Depth (Structural Engineering Exam (SE)) FAQ