SE Exam flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Dead load

Gravity load from permanent construction: structural framing, slabs, walls, finishes, and fixed equipment. ASCE 7 Chapter 3 requires it to be included in every gravity load combination.

Tributary area

Area of floor or roof supported by a member, used to convert distributed load into member load. One-way members use span times spacing; two-way panels split along 45-degree lines from the corners.

Live load reduction equation

L = L0(0.25 + 15/√(KLL·AT)), where AT is tributary area in square feet and KLL is 4 for columns and 2 for beams and one-way slabs.

Reduced live load limits

A reduced live load may not fall below 0.50 L0 for members carrying one floor, or below 0.40 L0 for members carrying two or more floors, per ASCE 7.

Basic LRFD gravity combination

1.2D + 1.6L + 0.5(Lr or S or R) governs when floor live load dominates; a companion case places roof load at full 1.6 factor and floor live at 1.0.

Snow load on flat roof

pf = 0.7 Ce Ct Is Pg, where Ce is exposure factor, Ct thermal factor, Is importance factor, and Pg ground snow load; sloped roofs apply an additional Cs factor.

Impact factor for elevators

Elevator loads applied to their supports include 100 percent impact; light machinery uses 20 percent and reciprocating machinery 50 percent, per ASCE 7 Section 4.6.

Composite beam horizontal shear

V' equals the lesser of AsFy and 0.85f'cAc; the required number of shear studs is V' divided by the nominal single-stud strength Qn.

Required plastic section modulus

For a compact braced beam, Zx required equals Mu divided by φFy with φ = 0.90; the available moment φFyZx must equal or exceed the factored moment.

Compact section limit

AISC flange and web slenderness ratios must not exceed their plastic limits so the section can reach its plastic moment before local buckling occurs.

Column effective length KL

K depends on end restraint: 1.0 pinned-pinned, 0.5 fixed-fixed, 0.7 fixed-pinned, 2.0 fixed-free. Slenderness KL/r is preferably kept at or below 200.

Flexural buckling stress Fe

Fe = π²E/(KL/r)². When KL/r is at most 4.71√(E/Fy) the column buckles inelastically and AISC uses Fcr = 0.658^(Fy/Fe)·Fy.

Two-way slab load split

Panel corners are divided by 45-degree lines; each supporting beam receives the triangular or trapezoidal area adjacent to it, which sets its distributed load.

Punching shear at slab-column

The critical perimeter lies d/2 from the column face; factored shear stress vu = Vu/(bo·d) must not exceed the design punching shear strength per ACI 318.

IBC deflection limits

Floor live-load deflection is limited to L/360, roof live-load deflection to L/240, and roof total deflection to L/180; plaster ceilings commonly require L/360 under total load.

Gravity load path continuity

Every element must transfer load through a continuous path from the point of application to the foundation, and connections must be designed for the forces in that path.

Seismic base shear

V = CsW, where Cs equals SDS/(R/Ie), is capped by SD1/(T·R/Ie) and is not less than 0.044 SDS Ie times the seismic weight.

Approximate period Ta

Ta = Ct hn^x, with Ct 0.028 and x 0.8 for steel moment frames, 0.016 and 0.9 for concrete moment frames, and 0.020 and 0.75 for other systems.

Vertical distribution exponent k

k equals 1.0 for fundamental periods of 0.5 second or less, 2.0 for 2.5 seconds or more, and is linearly interpolated between those limits.

Story drift limit

Allowable drift is 0.020 hsx for Risk Categories I and II, 0.015 for III, and 0.010 for IV; drift is computed as Cd times elastic drift divided by Ie.

Redundancy factor rho

The redundancy factor equals 1.3 by default. It may be taken as 1.0 only when the structure satisfies the specific conditions of ASCE 7 Section 12.3.4.2.

Torsional amplification factor Ax

Ax = (δmax/δavg)², bounded between 1.0 and 3.0. It applies when torsional irregularity exists and amplifies the accidental torsional moment.

Velocity pressure qz

qz = 0.00256 Kz Kzt Kd Ke V² in psf with V in mph; Kz varies with height and exposure, and Kd is 0.85 for buildings.

Gust effect factor G

G is taken as 0.85 for rigid structures whose fundamental frequency is at least 1 Hz; flexible or dynamically sensitive structures require the Chapter 26 procedure.

Internal pressure coefficient GCpi

GCpi is plus or minus 0.18 for enclosed buildings and plus or minus 0.55 for open and partially enclosed buildings; it is combined with the external pressure coefficient.

Diaphragm design force Fpx

Fpx equals the story shear multiplied by wpx/Σwi, bounded between 0.2 SDS Ie wpx and 0.4 SDS Ie wpx for the diaphragm being designed.

Stability coefficient theta

θ = PxΔIe/(Vx hsx Cd). When θ is 0.10 or less second-order effects may be ignored; otherwise displacements and forces are amplified by 1/(1−θ).

Overstrength load combination

(1.2 + 0.2SDS)D + Ω0E + L + 0.2S and (0.9 − 0.2SDS)D + Ω0E are used where the code requires elements to be designed for overstrength seismic forces.

Response modification factor R

R reduces elastic seismic demand to the design level by crediting ductility and overstrength; systems with higher R values carry stricter detailing and configuration requirements.

Deflection amplification factor Cd

Cd converts elastic analysis displacements into expected inelastic displacements; it multiplies the elastic drift before comparison with the allowable story drift limit.

Wind exposure categories

Exposure B is urban or suburban terrain, C is open terrain with scattered obstructions, and D is flat unobstructed terrain or water; rougher exposure raises Kz.

Seismic design category

Categories A through F are assigned from the risk category, SDS, and SD1 values, and they govern the permitted structural systems, analysis procedures, and detailing requirements.