Mississippi Structural Steel Examination

In structural concrete work, post-tensioning is the method of prestressing in which the tendons are tensioned:

• AAfter the concrete has hardened to the specified stressing strength
• BBefore any concrete is placed around the strand
• COnly while the concrete is still plastic
• DBy welding the strand to the reinforcing cage before the pour

An unbonded monostrand tendon is protected along its length primarily by:

• AA grouted metal duct that bonds the strand to the concrete
• BA factory-applied corrosion-inhibiting coating and extruded plastic sheathing
• CA field-applied epoxy coating after stressing
• DConcrete cover alone, with bare strand laid on chairs

The guaranteed ultimate tensile strength (GUTS) of a standard 0.5-inch Grade 270 seven-wire prestressing strand is:

• A27.0 kips
• B33.0 kips
• C41.3 kips
• D58.6 kips

Unless the approved drawings state otherwise, the maximum jacking force used to stress a 0.5-inch Grade 270 monostrand is:

• A33.0 kips (80 percent of GUTS)
• B20.7 kips (50 percent of GUTS)
• C41.3 kips (100 percent of GUTS)
• D58.6 kips (the 0.6-inch GUTS value)

During monostrand stressing, the safest place for personnel relative to the hydraulic jack is:

• ADirectly behind the ram so the gauge can be read from the strand axis
• BOn the dead-end anchorage, sitting on the pocket former
• CBetween the live-end and dead-end anchors, straddling the tendon
• DTo the side of the jack, never in line with the tendon or ram

A pocket former is installed at a stressing (live) end primarily to:

• AIncrease the strand's GUTS by providing extra cover
• BCreate a recess so the jack can seat on the anchor after the pour
• CBond the strand to the concrete at the live end
• DReplace the wedges after stressing

An encapsulated unbonded tendon system is specified mainly to:

• AAllow the strand to be welded to the rebar cage
• BReduce the required jacking force below 50 percent of GUTS
• CProvide a watertight corrosion barrier at anchors, sheathing, and intermediate points
• DEliminate the need to record elongations

If the plastic sheathing on an unbonded tendon is torn during placing, the installer should:

• ARepair the sheathing with approved tape or a sleeve before concrete is placed
• BLeave the tear; grease on the strand is sufficient protection
• CCut the tendon out and replace it only after the slab is stressed
• DFill the tear with concrete so the strand becomes bonded

A 50-foot 0.5-inch Grade 270 monostrand is jacked to 33.0 kips. Using A = 0.153 in² and E = 28,500 ksi, the theoretical elongation Δ = PL/AE is nearest to:

• A2.3 inches
• B4.5 inches
• C6.8 inches
• D9.1 inches

Monostrand tendons may be stressed only after:

• AThe forms have been oiled, regardless of concrete age
• BThe first finishing pass is complete on the slab surface
• CThe pocket formers have been installed, even if the concrete is still plastic
• DThe concrete has reached the stressing strength shown on the approved drawings

Unless the engineer specifies a tighter limit, PTI/ACI practice accepts a measured monostrand elongation that is within:

• A±1 percent of the theoretical value
• B±20 percent of the theoretical value
• C±7 percent of the theoretical value
• DAny value, provided the gauge reaches 33 kips

In the elongation formula Δ = PL / AE, the term E is the:

• AModulus of elasticity of the strand, taken from the mill certificate or approved drawings
• BElongation tolerance, always 7 percent
• CEffective depth of the tendon drape at midspan
• DEdge distance from the slab to the first chair

On a typical unbonded monostrand, the live end is the end that:

• AIs cast into the slab with no access for a jack
• BReceives the stressing jack, wedges, and elongation measurement
• CMust be flame-cut before the concrete is placed
• DIs used only for electrical grounding of the slab

An 80-foot 0.5-inch Grade 270 monostrand is jacked to 33.0 kips. Using A = 0.153 in² and E = 28,500 ksi, the theoretical elongation is nearest to:

• A3.6 inches
• B5.4 inches
• C7.3 inches
• D11.0 inches

Which field practice is prohibited around unbonded tendons?

• AUsing the strand as a welding ground or burning near an unprotected tendon
• BSupporting the tendon on chairs to the specified profile
• CRepairing torn sheathing with approved tape before the pour
• DRecording gauge pressure and elongation for each tendon

After each monostrand is stressed, the installer must document at least:

• AOnly the date the concrete was finished
• BOnly the color of the sheathing
• COnly the number of chairs under the tendon
• DThe tendon identification, gauge pressure (force), and measured elongation

Theoretical elongation for a tendon is 7.25 inches. Using the PTI/ACI ±7 percent check, the acceptable measured range is nearest to:

• A7.00 to 7.50 inches
• B6.75 to 7.75 inches
• C6.25 to 8.25 inches
• D5.25 to 9.25 inches

The nominal diameter of a #5 reinforcing bar is:

• A3/8 inch
• B1/2 inch
• C5/8 inch
• D3/4 inch

Grade 60 reinforcing bar has a specified minimum yield strength of:

• A60,000 psi
• B40,000 psi
• C75,000 psi
• D270,000 psi

When reinforcing bars must be welded in the field, the CRSI/AWS-preferred specification is:

• AAny ASTM A615 bar, because all carbon-steel rebar is weldable without procedure
• BASTM A706 low-alloy bars, welded to AWS D1.4 procedures
• CGrade 270 seven-wire strand used as a substitute for #5 bar
• DEpoxy-coated A615 bars welded with an uncoated electrode

For concrete cast against and permanently exposed to earth, ACI/CRSI minimum concrete cover to reinforcing bars is:

• A3/4 inch
• B1-1/2 inches
• C2 inches
• D3 inches

A 20-foot-wide slab is reinforced with #4 bars at 10 inches on center, first and last bars at the edges. How many bars are required in that direction?

• A25
• B20
• C24
• D30

The most common tie used to hold crossing bars in slabs and walls is the:

• ACadweld sleeve
• BSnap tie (wrap-and-snap)
• CMechanical coupler rated as a Type 2 splice
• DPuddle weld at every intersection

Unless the drawings show a Class A splice, the usual tension lap splice for reinforcing bars is a Class B splice, which is:

• AOne-half the tension development length ld
• BEqual to the bar diameter only
• C1.3 times the tension development length ld
• DAlways 12 inches, regardless of bar size

The tie wire most commonly used to place uncoated reinforcing bars is:

• A16 or 16.5-gage black annealed wire
• B3/8-inch Grade 60 rebar bent into rings
• CStainless aircraft cable
• DBare copper electrical wire

To hold the top mat of a two-mat slab at the specified cover, CRSI practice uses:

• ALoose bricks stacked on the bottom mat
• BWood 2x4s left in the pour
• CNails driven into the form soffit
• DHigh chairs or standees bearing on the lower mat or the form

A #8 reinforcing bar has a nominal diameter of:

• A5/8 inch
• B1 inch
• C1-1/8 inches
• D8 millimeters

The maximum number of reinforcing bars permitted in one bundle is:

• ATwo
• BSix
• CFour
• DEight

When placing epoxy-coated reinforcing bars, CRSI practice requires:

• ACoated tie wire and coated or non-metallic bar supports, with coating damage repaired
• BBare black tie wire so the coating is scratched and bonds to the concrete
• CWelding at every intersection instead of tying
• DRemoving the epoxy from the entire lap so black bars can be used as splices

A 24-foot-long wall is reinforced with one curtain of #5 vertical bars at 12 inches on center, including a bar at each end. Using 1.043 lb/ft for #5 bar, the approximate weight of those verticals (each 8 feet long) is:

• A167 lb
• B209 lb
• C251 lb
• D501 lb

Tension lap splices are generally not permitted for which bar sizes?

• A#3 and #4 only
• B#5 and #6 only
• CAny bar smaller than #11
• D#14 and #18

Stirrups and column ties are typically detailed with 135-degree hooks because:

• AA 135-degree hook is easier to fabricate than a 90-degree hook
• BThe extra bend is only a shipping restraint and is opened after placing
• CThe hook must embed in the confined core so it does not open under load
• DACI requires every longitudinal bar to end in a 135-degree hook

A 30-foot wall has two curtains of vertical #5 bars at 12 inches on center, each curtain including a bar at both ends. How many vertical bars are required?

• A62
• B30
• C31
• D60

Clear spacing between parallel reinforcing bars, unless the drawings require more, shall be at least:

• AThe finish-paint thickness on the form
• BOne bar diameter, 1 inch, or 4/3 the maximum aggregate size, whichever is largest
• COne-half the bar diameter only
• DEqual to the slab thickness

Under OSHA 1926.760, each employee engaged in steel erection on a walking/working surface with an unprotected side or edge more than which height shall be protected from falls (except as provided for connectors and controlled decking zones)?

• A4 feet
• B6 feet
• C15 feet
• D30 feet

OSHA 1926.755 requires every column to be anchored by a minimum of:

• A4 anchor rods (anchor bolts)
• B1 center anchor rod
• C2 anchor rods on the strong axis only
• D6 anchor rods if the column is a tube

A multiple-lift (Christmas-tree) rig under OSHA 1926.753(e) may hoist a maximum of how many members, rigged at least how far apart?

• AThree members, 3 feet apart
• BEight members, 4 feet apart
• CFive members, 12 feet apart
• DFive members, 7 feet apart

During final placing of a solid-web beam, OSHA 1926.756 requires that the hoisting line not be released until the member is secured with:

• AA single tack weld at one end
• BAt least two bolts per connection, of the specified size and strength, drawn up wrench-ti…
• COne drift pin in each hole
• DA nylon choker left around the beam

Before steel erection begins, OSHA 1926.752 requires written notification that footing, pier, and wall concrete has attained:

• A75 percent of the intended minimum compressive design strength, or enough strength to sup…
• B10 percent of design strength from a laboratory-cured cylinder only
• CAny strength, as long as the forms have been stripped
• D100 percent of 28-day strength plus 7 additional days

OSHA 1926.754(c) requires headed shear connectors on beams or joists to be installed:

• AOn the top flange before the member is hoisted so connectors can be shop-welded
• BFrom inside a controlled decking zone as soon as the first sheet is landed
• CAfter the metal decking or other walking/working surface has been installed
• DOnly on the bottom flange so they cannot trip anyone

A controlled decking zone (CDZ) under OSHA 1926.760(c) shall not exceed which size, and unsecured decking in the CDZ shall not exceed which area?

• A30 feet by 30 feet, and 500 square feet unsecured
• B90 feet wide and 90 feet deep from the leading edge, and 3,000 square feet unsecured
• C200 feet by 200 feet, and 10,000 square feet unsecured
• DNo size limit, provided everyone is tied off

A trained connector working more than 15 feet and up to 30 feet above a lower level must, under OSHA 1926.760(b):

• ABe protected by a safety net only; personal fall arrest is prohibited
• BWork without any fall equipment available on the member
• CBe protected by a completed guardrail before making the first bolt
• DBe provided a personal fall arrest, positioning, or restraint system and wear the equipme…

A cover over a roof or floor hole during steel erection must, under OSHA 1926.754(e)(3):

• ASupport twice the weight that may be imposed, be secured, and be painted or marked HOLE o…
• BBe any scrap plywood, unmarked, if it looks thick enough
• CBe a smoke dome or skylight, which OSHA always accepts as a cover
• DSupport only the weight of one worker and may be left unsecured

On a multi-story steel frame, OSHA 1926.754(b) requires a fully planked or decked floor or nets within which distance under the erection work?

• AEight stories or 80 feet, whichever is greater
• BFour floors or 48 feet, whichever is greater
• CTwo stories or 30 feet, whichever is less
• DOne floor only, regardless of height