Question 1

Riveting practice – terminology: Rivets that are heated and driven on site (not in the fabrication shop) are commonly called what?

Accepted Answer

Introduction / Context: Before high-strength bolting largely replaced riveting, structural connections were frequently made with hot-driven rivets. Understanding the terminology distinguishing shop versus field operations is useful for interpreting older drawings and specifications. Given Data / Assumptions: Rivets heated and driven at the construction site. Shop operations (in a controlled fabrication facility) contrasted with field operations (on site). Concept / Approach: Hot-driven rivets installed on site are typically termed field rivets. If driven with pneumatic hammers in the shop, they are power-driven shop rivets. Cold-driven rivets are unheated and used for small-diameter, light-duty work only, not typical for structural frames. Step-by-Step Solution: Identify location of installation: on site.Apply standard nomenclature: “field rivets.”Recognize power-driven field rivets is also descriptive, but the simplest accepted term is field rivets. Verification / Alternative check: Historic steel construction texts and specifications consistently differentiate “shop” and “field” rivets by installation location rather than by the driving method alone. Why Other Options Are Wrong: Power-driven shop rivets: performed in fabrication shop, not on site. Hand-driven and cold-driven: do not specifically indicate field hot work typical of structural frames. Common Pitfalls: Confusing driving method (hand vs. pneumatic) with installation location (shop vs. field). Final Answer: field rivets

Question 2

Slenderness control under load reversal: A tension member that may be subjected to stress reversal due to wind (i.e., may experience compression at times) should have its slenderness ratio limited to which maximum value?

Accepted Answer

Introduction / Context: Tension members designed primarily for tension can sometimes experience compression under wind or seismic load combinations. Codes place a stricter slenderness limit in such cases to avoid excessive flexural buckling susceptibility. Given Data / Assumptions: Member is usually in tension but may see compression due to load reversal. Slenderness ratio is L/r (effective length over radius of gyration). Concept / Approach: Where reversal of stress is possible, the member must satisfy not only tensile limit states but also the serviceability and stability requirements applicable to compression. A commonly used upper limit for such “tension members liable to reversal” is about 180 to provide adequate stiffness against buckling in compression. Step-by-Step Solution: Recognize potential compression under wind.Adopt conservative slenderness limit to control buckling risk.Select 180 as the maximum recommended value. Verification / Alternative check: Historic working stress provisions and many exam references cite 180 as the limit for tension members subject to reversal; pure tension members may be allowed higher limits for appearance or vibration only. Why Other Options Are Wrong: 200–350: too slender, offering inadequate compression stability under reversal. Common Pitfalls: Treating potentially reversible members as pure tension without checking buckling. Final Answer: 180

Question 3

Slab base design – required thickness: An axially loaded column bears on a slab base with projection a = 8 cm beyond the column face. Given concrete bearing pressure q = 40 kg/cm² and allowable bending stress in the base plate σ_allow = 1890 kg/cm²,…

Accepted Answer

Introduction / Context: Slab bases distribute column loads to concrete foundations. The plate projects beyond the column face and behaves like a cantilever strip under uniform bearing pressure. Plate thickness is chosen so bending stress in the projection does not exceed the allowable value. Given Data / Assumptions: Projection a = 8 cm. Bearing pressure on concrete q = 40 kg/cm² (uniform). Allowable bending stress in steel plate σ_allow = 1890 kg/cm². Projection behaves as a cantilever of width 1 cm with uniform load. Concept / Approach: For a unit-width strip, uniform line load w = q * a (kg/cm). Cantilever moment at the column face: M = w * a / 2 = q * a² / 2. Section modulus for a unit-width plate: Z = b * t² / 6 = t² / 6. Strength check uses M = σ_allow * Z → t = sqrt(6 * M / σ_allow). Step-by-Step Solution: Compute w = q * a = 40 * 8 = 320 kg/cm.Compute M = q * a² / 2 = 40 * 8² / 2 = 40 * 64 / 2 = 1280 kg·cm per cm width.Compute t from M = σ * t² / 6 → t = sqrt(6 * M / σ_allow).t = sqrt(6 * 1280 / 1890) = sqrt(7680 / 1890) ≈ sqrt(4.0635) ≈ 2.016 cm.Adopt practical size: ≈ 2.0 cm. Verification / Alternative check: Alternate formula t = a * sqrt(3 * q / σ_allow) gives t = 8 * sqrt(120 / 1890) ≈ 8 * 0.252 ≈ 2.02 cm, confirming the result. Why Other Options Are Wrong: 1.6 cm: underestimates required section modulus; overstresses the plate. 2.5–3.5 cm: safe but not the minimum thickness demanded by the given data. Common Pitfalls: Using plate gross width instead of unit-width strip for section modulus. Forgetting that projection length is measured from column face to plate edge. Final Answer: 2.0 cm

Question 4

Structural steel design – lacing/batten system for built-up columns In built-up steel columns, the lateral system provided to carry shear and keep components acting together is commonly made of which rolled sections?

Accepted Answer

Introduction / Context: Built-up columns (such as pairs of channels, angles, or I-sections combined) require a lateral system—lacing or batten plates—to ensure the individual components act as one member and to transfer shear between them. The question asks which rolled shapes are commonly used to form that lateral system. Given Data / Assumptions: Member is a built-up steel column. Lateral system must resist shear and prevent relative displacement between components. Standard rolled products are available. Concept / Approach: Lacing is often made from flats or angles arranged in single or double systems; battening may use plates or channels where feasible. The governing code requirements address slenderness of lacing bars, spacing, end connections, and shear transfer capacity. Step-by-Step Solution: Identify common lacing shapes → flats and angles.Identify common batten/lateral connector shapes → plates and sometimes channels as stiff connectors.Conclude that flats, angles, and channels are all used in practice for the lateral system. Verification / Alternative check: Design handbooks and steel codes illustrate lacing with flats/angles and battening with plates or short channel pieces, confirming all the listed rolled sections are used. Why Other Options Are Wrong: Each single shape alone is not exclusive; practice includes multiple rolled shapes. “None of these” is incorrect because the listed sections are indeed used. Common Pitfalls: Confusing flange cover plates (for bending strength) with lacing; the latter is specifically for shear and to maintain component alignment. Final Answer: All the above

Question 5

Columns – definition of the load that just maintains a small lateral deflection The maximum axial load that is just sufficient to keep a column in a slightly deflected configuration (neutral equilibrium) is called:

Accepted Answer

Introduction / Context: Column stability is governed by the concept of Euler buckling. At a certain load level, a perfectly straight column theoretically has neutral equilibrium: any infinitesimal lateral deflection will persist without additional load. This load is central to design and is commonly derived from Euler’s formula for ideal columns. Given Data / Assumptions: Axially loaded, prismatic column. Small initial lateral deflection or imperfection may exist in practice. Elastic behavior within the proportional limit. Concept / Approach: The load that just maintains a small lateral deflection (neither grows nor vanishes in the ideal mathematical sense) is the critical load. In many texts it is also termed the Euler buckling load. “Crippling load” is sometimes used loosely for failure load but typically implies inelastic crushing or local instability rather than ideal elastic buckling. Step-by-Step Solution: Recognize the neutral equilibrium condition → Euler concept.Name associated with this threshold → critical load.Differentiate from ultimate crushing (material failure) and from allowable load (service design). Verification / Alternative check: For an ideal pinned–pinned column: P_cr = (π^2 * E * I) / L^2. At P = P_cr, infinitesimal lateral deflection solutions exist without extra load, representing the “just sufficient” definition. Why Other Options Are Wrong: Buckling load: often used synonymously with critical load, but to avoid ambiguity with “crippling,” the precise textbook term is critical load. Crippling/ultimate crushing: refer to material or local failures, not neutral equilibrium buckling onset. Allowable load: includes safety factors and is below critical load. Common Pitfalls: Assuming “crippling” equals “critical.” In design, “crippling” may indicate failure beyond elastic stability, whereas critical load is the elastic buckling threshold. Final Answer: Critical load

Question 6

Continuous beams – criterion for treating spans as approximately equal For design and analysis simplifications, spans of a continuous beam are considered approximately equal if the longest span does not exceed the shortest span by more than:

Accepted Answer

Introduction / Context: In continuous beam analysis, many approximate methods and code tables assume “approximately equal spans.” This assumption allows redistribution patterns and coefficient-based bending moments to be applied with acceptable accuracy. Given Data / Assumptions: Multi-span continuous beam in building or bridge work. Uniform load patterns and typical end conditions. Concept / Approach: Design handbooks often define approximately equal spans when variation is limited to about one-tenth. Keeping span lengths within ±10% supports the use of simplified moment and shear coefficients and avoids large shifts in internal force distribution. Step-by-Step Solution: Define tolerance → longest ≤ shortest × 1.10.Apply to coefficient tables/coarse analysis → valid if within this band. Verification / Alternative check: When spans differ by more than about 10%, exact analysis shows non-uniform moment envelopes; approximate equal-span coefficients become less reliable. Why Other Options Are Wrong: 5% is overly restrictive and not necessary in practice. 15–25% permit significant differences that invalidate “equal span” simplifications. Common Pitfalls: Using equal-span tables without checking span variation; this can underestimate peak negative moments over shorter spans or supports. Final Answer: 10%

Question 7

Riveted plate connections – name of the joint when two plates are connected end-to-end with two cover plates Two main plates placed end to end and joined by cover plates on both sides form which type of riveted joint?

Accepted Answer

Introduction / Context: Riveted joint taxonomy distinguishes lap joints from butt joints. When two plates meet end-to-end (butt) and cover plates are applied, the naming depends on whether the cover is on one side or both sides. Given Data / Assumptions: Two main plates meet end-to-end. Two cover plates are provided (one on each side of the joint). Concept / Approach: End-to-end plate connections are butt joints. With two cover plates, it is specifically a double-cover butt joint. This arrangement is symmetric and improves load transfer, often allowing higher efficiency than single-cover configurations. Step-by-Step Solution: Identify joint geometry → end-to-end plates → butt type.Count cover plates → two → double-cover butt joint. Verification / Alternative check: Standard steelwork texts diagram lap joints (overlap of main plates) vs. butt joints (cover plates bridging a gap). The described case matches the double-cover type. Why Other Options Are Wrong: Lap joints involve overlapping main plates, not end-to-end placement. Single-cover butt uses only one cover plate. Zig-zag/chain descriptors refer to rivet pitch arrangement, not the joint type described. Common Pitfalls: Confusing rivet pitch patterns (zig-zag vs chain) with joint category (lap vs butt). Final Answer: Double-cover butt joint

Question 8

Elastic properties – typical range of Poisson’s ratio for structural steel within the elastic limit Within the elastic range, Poisson’s ratio for carbon structural steel generally lies in the range:

Accepted Answer

Introduction / Context: Poisson’s ratio ν is the negative ratio of lateral to longitudinal strain under uniaxial loading. For structural steel, knowing ν helps with 3D stress–strain relations, plate theory, and dynamic analyses. Given Data / Assumptions: Isotropic, homogeneous steel in the elastic regime. Typical structural grades used in buildings and bridges. Concept / Approach: For common structural steels, ν is typically around 0.30. A reasonable range used in design calculations spans approximately 0.25–0.33, covering variation with composition and heat treatment while staying in the elastic domain. Step-by-Step Solution: Identify the accepted design range → 0.25 to 0.33.Confirm that other listed ranges are either too low, too high, or nonsensical (decreasing bounds). Verification / Alternative check: Elastic constants relationships: E = 2 G (1 + ν) and K = E / (3(1 − 2ν)) produce realistic G and K for steel when ν ≈ 0.3. Why Other Options Are Wrong: 0.33–0.35 and 0.45–0.50: too high for ordinary structural steel in elastic range. 0.15–0.20: too low; typical of some ceramics, not steel. 0.25–0.24: invalid interval ordering. Common Pitfalls: Confusing Poisson’s ratio of steel (≈0.3) with that of concrete (≈0.15–0.2) or rubberlike materials (≈0.49). Final Answer: 0.25 to 0.33

Question 9

Riveted joints – simple plate-tearing efficiency in terms of pitch and hole diameter If p is the rivet pitch and d is the gross hole diameter, the joint efficiency with respect to plate tearing (neglecting rivet shear/bearing) is:

Accepted Answer

Introduction / Context: Joint efficiency compares the strength of a riveted (or bolted) joint to that of the unperforated plate. One basic check is plate tearing across a pitch length—important when evaluating longitudinal joints in tanks, boilers, and plate girders. Given Data / Assumptions: Single-row riveted joint in a uniform plate. Plate tearing considered over one pitch length p. Rivet hole diameter (gross) is d. Ignore rivet shear and bearing for this simplified efficiency expression. Concept / Approach: Net section width resisting tension across the pitch line is (p − d). The unperforated (gross) section width is p. With constant plate thickness and tensile strength, efficiency against plate tearing is the ratio of net to gross section area. Step-by-Step Solution: Net area / Gross area = (p − d) / pTherefore, η = 1 − d/p Verification / Alternative check: Including multiple rows or staggered holes modifies the net-section calculation by adding or subtracting diagonal ligament effects, but the single-row, straight-pitch case reduces to η = 1 − d/p. Why Other Options Are Wrong: d/p or p/d do not represent a net/gross area ratio for tearing. (p − 2d)/p corresponds to two holes per pitch line, not this case. (p − d)/(p + d) has no basis in net-section derivation. Common Pitfalls: Using nominal rivet diameter instead of hole diameter (which is larger); always use gross hole size when finding the net section. Final Answer: η = 1 − d/p

Question 10

Allowable-stress column design – identifying the secant formula applicability For steel columns with slenderness ratio up to about 160, which expression represents the “secant formula” approach for determining allowable compressive stress (symbolica…

Accepted Answer

Introduction / Context: The secant formula is a classical elastic-stability expression that accounts for column deflection under eccentric loading. It refines allowable stress beyond simple Euler or straight-line formulas and is applicable up to moderate slenderness (often quoted up to about 160). Given Data / Assumptions: Elastic behavior, pinned or equivalent end conditions through effective length L_e. Eccentricity e at load application producing bending plus compression. Symbols: σ_y (yield stress), n (factor of safety), P (axial load), A (area), E (modulus), r (radius of gyration). Concept / Approach: For an eccentrically loaded column, the maximum stress at extreme fiber is influenced by second-order effects. The secant formula relates the bending magnification to sec( k ) where k = (L_e / r) * sqrt( P / (AE) ). In allowable-stress design, σ_allow is obtained by ensuring the amplified combined stress does not exceed σ_y / n. Step-by-Step Solution: Write extreme-fiber stress: σ_max = (P/A) + (Pe / Z) * sec(k)Impose σ_max ≤ σ_y / n → rearrange for an equivalent allowable compressive stress expression.The compact symbolic option matching this dependency is the listed secant form with the magnifier sec(k). Verification / Alternative check: At very small k (stocky columns), sec(k) ≈ 1, reducing to direct compression with modest eccentricity. As slenderness grows, sec(k) increases, reducing allowable stress—consistent with stability behavior. Why Other Options Are Wrong: Pure σ_y/fs or constant fractions of σ_y ignore slenderness and second-order effects. Linear knock-down forms without the secant term do not capture the geometric nonlinearity inherent in buckling. Common Pitfalls: Using the secant formula beyond its intended λ range or without correct effective length; misapplying e as initial crookedness instead of load eccentricity. Final Answer: σ_allow = (σ_y / n) * [1 + ( (Pe)/(AE) ) sec( (L_e/r) * sqrt(P/(A*E)) ) ]^−1

Question 11

Failure modes in riveted joints – which types can occur under load? A riveted joint may experience which of the following failure modes when loaded?

Accepted Answer

Introduction / Context: Assessing riveted (and bolted) joints requires checking several limit states. The joint capacity is the minimum of plate tearing, rivet shear, rivet/plate bearing, and edge-distance related failures. Given Data / Assumptions: Concentric tensile loading across a riveted line. Adequate fabrication but finite edge distances and pitches. Concept / Approach: Typical checks include: (1) Plate net-section tearing across holes, (2) Rivet shear, (3) Bearing of rivet against plate or plate crushing at hole, (4) Block shear and edge tearing (splitting) if edge distance is inadequate. Any of these can govern and must be verified. Step-by-Step Solution: Evaluate plate net-section strength → prevent tearing.Evaluate rivet shear capacity → avoid shear failure.Evaluate bearing on plate and rivet → avoid localized crushing.Check edge distances and stagger → avoid splitting or block shear. Verification / Alternative check: Design codes specify minimum pitch and edge distances and provide nominal strengths for the above limit states. The controlling capacity is the least of these checks. Why Other Options Are Wrong: Each individual failure can occur; the comprehensive and therefore correct selection is “All the above.” Common Pitfalls: Ignoring edge-distance rules, using nominal rivet diameter instead of hole diameter for net section, and overlooking block shear paths. Final Answer: All the above

Question 12

In steel design, consider a built-up beam. If y1 is the distance from the neutral axis to the extreme compression fiber (edge), what is the expression for the actual bending compressive stress fbc at that edge?

Accepted Answer

Introduction / Context: Bending stress distribution in beams is a fundamental topic in strength of materials and steel design. Whether the beam is a rolled section or a built-up section, the flexure formula connects internal bending moment, section properties, and fiber distance from the neutral axis to compute compressive or tensile stresses. Given Data / Assumptions: M is the bending moment at the section under consideration. I is the second moment of area (about the neutral axis for the bending plane). y1 is the distance from the neutral axis to the extreme compression fiber (edge). Plane sections remain plane and the material is linearly elastic within the working range. Concept / Approach: The elementary flexure (bending) formula states: sigma = M * y / I. Stress varies linearly with y; it is compressive above the neutral axis (in sagging) and tensile below. For the extreme compression fiber, y = y1, so the actual bending compressive stress is computed directly by substituting y1 into the formula. Step-by-Step Solution: Start with the flexure relation: sigma = M * y / I.Select the compression edge: y = y1 (distance from N.A. to the extreme compression fiber).Compute: fbc = (M * y1) / I.If desired, use section modulus Z = I / y1 to write: fbc = M / Z (equivalent when y = y1). Verification / Alternative check: Cross-check by computing Z about the compression edge (Z = I / y1). Then fbc = M / Z. Both forms are algebraically identical and yield the same stress. Why Other Options Are Wrong: Forms such as I / (M * y1), M / (I * y1), or (I * y1) / M invert or scramble the flexure relation. They do not match the linear-elastic bending theory. M / Z is correct only if Z corresponds to the same edge, which is implicit but often not stated in quick formulas. Common Pitfalls: Using the wrong axis for I; mixing up y for tension vs. compression side; applying plastic section modulus instead of elastic section modulus when the question clearly assumes elastic behavior. Final Answer: fbc = (M * y1) / I

Question 13

Tension member made of two channel sections: how should the allowance for rivet (or bolt) holes be made when calculating the net area?

Accepted Answer

Introduction / Context: When computing the net effective area of a built-up tension member, deductions must be made for fastener holes along the critical (governing) section. For members composed of two channels, the deduction rule ensures the most critical potential failure path is considered. Given Data / Assumptions: Member comprises two channel sections acting together in tension. Holes may lie in webs or flanges depending on connection detail to the gusset plate or splice plates. Objective: determine the correct allowance for hole deductions. Concept / Approach: The design convention is to deduct the greater of two possibilities because the net section must be safe for any plausible failure path: (1) two holes from each web (since each channel has one web, two channels give two web holes), or (2) one hole from each flange (two flanges per pair considered along the likely path). Taking the greater deduction gives a conservative net area. Step-by-Step Solution: Identify where the governing line of fasteners lies (webs or flanges).Compute net width by deducting relevant hole diameters multiplied by plate thickness(es).Adopt deduction as: two holes from each web or one from each flange—whichever is more. Verification / Alternative check: Trace potential zig-zag or straight failure paths across the section and ensure the chosen deduction covers the least net area (most critical path). Why Other Options Are Wrong: Deducting only webs or only flanges could underestimate the critical path; choosing “whichever is less” is unsafe. Common Pitfalls: Ignoring stagger corrections on zig-zag paths; using nominal hole size instead of standard hole diameter for deductions; missing the thickness appropriate to the fastened element. Final Answer: Two holes from each web or one hole from each flange, whichever is more

Question 14

In plate-girder terminology, the distance between the outer faces of the two flanges is called the ______ of the girder.

Accepted Answer

Introduction / Context: Correct geometric definitions in plate girders are essential for analysis and detailing. Terminology such as overall depth, clear depth, and effective depth are frequently examined in steel design problems. Given Data / Assumptions: Two flange plates (or flanges) separated by a web plate. We want the term for the full distance from the outside face of the top flange to the outside face of the bottom flange. Concept / Approach: Overall depth is defined as the full, outside-to-outside distance between the flanges. Clear or effective depth may exclude cover plates, fillets, or refer to centroidal lever arm used in simplified bending calculations, but the standard term for outside-to-outside is overall depth. Step-by-Step Solution: Identify the two outermost flange faces.Measure the perpendicular distance between them.Name this dimension: overall depth. Verification / Alternative check: Check detailing drawings: overall depth is the dimension used for fabrication clearances and envelope sizing; effective depth is more a design-derived measure linked to the neutral axis location. Why Other Options Are Wrong: Clear depth or effective depth exclude certain components or are used in different contexts; “design” or “net” depth are not standard terms for outside-to-outside geometry. Common Pitfalls: Mixing effective lever arm (distance between resultants) with geometric overall depth; ignoring cover plates that increase the outside dimension. Final Answer: overall depth

Question 15

Tacking rivets for compression plates (not exposed to weather): what is the maximum permitted pitch relative to the outer plate thickness?

Accepted Answer

Introduction / Context: Tacking rivets or bolts are used to keep built-up compression elements acting as a unit (preventing buckling out of their own plane between primary connectors). Codes specify maximum spacing limits that depend on exposure conditions and plate thickness. Given Data / Assumptions: Compression plates are not exposed to weather. We are checking the limit for tacking rivet pitch relative to the thickness of the outside plate. Concept / Approach: Typical practice (as reflected in many exam standards and legacy code guidance) limits the pitch of tacking rivets in compression members to the lesser of an absolute dimension (e.g., 300 mm) or a multiple of the outer plate thickness. For non-exposed plates, the multiple is 32 t; for weather-exposed, a tighter spacing such as 16 t is adopted. Step-by-Step Solution: Identify condition: not exposed to weather.Adopt the governing code multiple: 32 * t.Also ensure the absolute limit (e.g., 300 mm) is satisfied in practice alongside the multiple. Verification / Alternative check: Compare with the stricter weather-exposed case (often 16 t or a smaller absolute value). Non-exposed allows a larger spacing. Why Other Options Are Wrong: 16 t and 24 t are too restrictive for non-exposed; 36 t and 40 t exceed typical permitted limits and may allow plate separation or local buckling. Common Pitfalls: Forgetting that the absolute cap (like 300 mm) may govern even if 32 t is larger; applying the wrong exposure category. Final Answer: 32 times the thickness of the outside plate

Question 16

Classification of rolled steel angle sections in structural steel design includes which of the following types?

Accepted Answer

Introduction / Context: Angle sections are widely used as bracing, truss members, and secondary framing. Knowing their classifications assists in selecting members with suitable leg dimensions and properties. Given Data / Assumptions: We are considering standard classifications used in steel construction and fabrication. Bulb angles are commonly recognized in shipbuilding and certain standards. Concept / Approach: Rolled angle sections are generally classified as equal-leg angles, unequal-leg angles, and bulb angles (the latter with a bulb on one leg to enhance properties). Each category serves different design needs and connection details. Step-by-Step Solution: List common angle categories: equal, unequal, bulb.Confirm all are legitimate classifications.Select “All the above”. Verification / Alternative check: Review steel section handbooks: equal and unequal angles dominate building practice; bulb angles are documented for specialized applications. Why Other Options Are Wrong: Picking only one category omits standard alternatives and would not reflect the full classification range. Common Pitfalls: Assuming bulb angles do not exist in rolled products; confusing angle categories with tee or channel sections. Final Answer: All the above

Question 17

Fastener layout terminology in riveted/bolted joints: the imaginary line along which a row of rivets or bolts is placed is called the ______.

Accepted Answer

Introduction / Context: Accurate terminology is essential when laying out riveted or bolted connections on shop drawings. The reference line used to position holes influences edge distances, gage (gage) distances, and stagger. Given Data / Assumptions: We refer to the standard naming of the reference line that defines a row of fasteners. Common terms exist, but only one is the accepted technical term in this context. Concept / Approach: The gauge line (often spelled gage line in some codes) is the reference line parallel to the member edge along which fastener centers are set. Pitch is then measured along this line. Other listed terms are not standard or are used in different trades. Step-by-Step Solution: Identify the line used to place a continuous row of holes.Recall standard nomenclature: “gauge line”.Select the corresponding option. Verification / Alternative check: Connection detailing manuals show gauge distance (from edge to gauge line) and pitch spacing along the gauge line. Why Other Options Are Wrong: “Rivet line” is informal; “scrieve line” and “back line” are not standard for steel connection layout; “pitch datum” is not a conventional term in this context. Common Pitfalls: Confusing gauge line with centerline of the member; misapplying edge distance versus gauge distance. Final Answer: gauge line

Question 18

Beam-to-beam connection with one angle at the bottom (seat) and one angle at the top for restraint is commonly termed what type of connection?

Accepted Answer

Introduction / Context: Steel beam connections can be framed, seated, or moment-resisting. A common shear connection uses a bottom seat angle to support gravity load and a top angle (cleat) for stability. Given Data / Assumptions: Connection uses a bottom angle (seat) carrying bearing. Top angle provides lateral restraint and simple shear transfer. No web stiffener under the seat is mentioned. Concept / Approach: With a seat angle but no dedicated web stiffener plate under the beam reaction, the connection is termed an unstiffened seated connection. If a stiffener plate is provided in addition to a heavier seat, it becomes a stiffened seat. These are generally classified as simple (shear) connections, not moment-resisting. Step-by-Step Solution: Recognize the presence of a seat angle at the bottom.Confirm the top angle provides restraint but no stiffener is specified.Classify as “unstiffened seated connection”. Verification / Alternative check: Connection manuals show unstiffened seats adequate up to a certain reaction; larger reactions require a stiffened seat (web stiffener) to prevent local web crippling. Why Other Options Are Wrong: “Stiffened seat” needs stiffeners; “moment-resisting” implies rigid end-plate or flange-plate connections; “generic seated connection” is imprecise. Common Pitfalls: Overestimating moment capacity of simple seated connections; neglecting bolt slip and bearing checks at the top angle. Final Answer: Unstiffened seated connection

Question 19

Use of lug angles in steel connections: which statements are correct regarding where lug angles are typically used or avoided?

Accepted Answer

Introduction / Context: Lug angles are short auxiliary angles used to attach the outstanding leg of an angle (or outstanding flange/leg of other sections) directly to a gusset, improving load transfer and reducing eccentricity. Given Data / Assumptions: Single-angle members often have one leg outstanding from the gusset plate. Double-angle members back-to-back have more balanced connection lines and generally do not need lug angles. Channel members with an outstanding flange may use lug angles in some layouts. Concept / Approach: For single-angle members, lug angles help bring the line of action closer to the centroid and increase the effective connected area. When two angles are back-to-back (double angles), connections are typically symmetrical, so lug angles are unnecessary. Channels can use lug angles to connect the outstanding elements effectively. Step-by-Step Solution: Identify connection eccentricity and outstanding elements.Use lug angles where they improve direct load paths (single angles, certain channel details).Avoid them for balanced double-angle arrangements. Verification / Alternative check: Design handbooks show detailing examples where lug angles are recommended for single angles and some channels but omitted for double angles. Why Other Options Are Wrong: Individually selecting only one statement ignores the broader practice; hence “All the above” is correct. Common Pitfalls: Failing to check lug angle capacity and bolt group design; ignoring the additional fabrication and inspection complexity. Final Answer: All the above

Question 20

Column splice design when the upper column does not provide full bearing over the lower column: which assumptions are made for force transfer in the splice?

Accepted Answer

Introduction / Context: Column splices are required for construction practicality and alignment. When bearing is incomplete (mismatch of profiles or partial contact), the splice must transfer axial force and any incidental moment safely through plates, flanges, and bolts/welds. Given Data / Assumptions: Upper column does not fully bear on the lower column over the complete area. Splice plates and bearing plates are provided. Design must account for axial load and possible moment due to misalignment or construction tolerance. Concept / Approach: The bearing plate is analyzed as a short (deep) beam spanning between flange/web contact areas of the lower column. Axial load is shared by the flanges and web; flange forces can develop a couple with opposing reactions in the lower column to equilibrate moment. Splice bolts/welds are designed for the remaining forces and to clamp the assembly. Step-by-Step Solution: Model plate action: bearing/filler plate as a short beam.Distribute axial load to flanges and web; check flange couple for moment.Design splice fasteners/ welds for shear and any unbalanced moment. Verification / Alternative check: Check bearing stresses, plate bending, bolt shear and bearing, and ensure compatibility with column section properties and construction tolerances. Why Other Options Are Wrong: Each individual assumption represents part of the complete behavior; the correct comprehensive assumption set is “All the above”. Common Pitfalls: Neglecting unintended moments; underestimating plate bending; ignoring erection tolerances and fit-up gaps. Final Answer: All the above

Steel Structure Design Questions