Questions and Answers
Offsets of 3 inches or greater in columns shall be accomplished using?
separate, lap-sliced bars
Bundled bars require enclosure in stirrups or ties.
True
For concrete placement volumes for which fewer than ___ samples are taken, tests shall be made from at least _ randomly selected batches.
5
Which of the following is not required in inspection records?
Signup and view all the answers
No 14 and 18 bars have a minimum inside bend diameter of ___DB.
Signup and view all the answers
Anchor bolts embedded in columns and pedestals must be surrounded by at least two NO___ bars or three NO___ bars.
Signup and view all the answers
What is the minimum clear spacing between parallel bars in a layer?
Signup and view all the answers
For what exposure are quantities of pozzolans in concrete limited?
Signup and view all the answers
Conduits and pipes embedded within a slab, wall or beam shall not be larger than ___ the overall thickness and shall not be closer than ___ diameter on center.
Signup and view all the answers
Construction joints in girders shall be offset a minimum distance of ___ times the width of intersection beams.
Signup and view all the answers
High-early strength concrete shall be maintained above 50F in a moist condition for at least the first ___ days when accelerated curing methods are used.
Signup and view all the answers
What is the tolerance for the longitudinal location of bends and ends of reinforcement?
Signup and view all the answers
No 3 through 8 bars have a minimum bend diameter of ___db.
Signup and view all the answers
Horizontal supports for bar offsets shall be placed within ____ inches of points of bending.
Signup and view all the answers
Cast in place, nonprestressed shells with No. 8 bars not exposed to earth or weather require a ___ in cover.
Signup and view all the answers
A nonprestressed column with No. 8 longitudinal bars requires ___ transverse ties.
Signup and view all the answers
For slabs or walls, concrete must be taken for every ___ sq. ft of placement.
Signup and view all the answers
A groove formed to create a weakened plane that regulates the location of cracking caused by dimensional changes is called a ________ joint.
Signup and view all the answers
Reinforcement tolerance shall not exceed ____ specified cover.
Signup and view all the answers
A ____ load is the weight supported by a member from transient, non-permanent sources.
Signup and view all the answers
For stirrup and tie hooks in No. 5 bars and smaller, a standard hook has a ____ degree bend plus 6 db extension at the free end of the bar.
Signup and view all the answers
Reinforcement shall be ____ unless otherwise permitted by the licensed design professional.
Signup and view all the answers
Anchor bolts placed into the top of columns or pedestals shall be enclosed by reinforcement that surrounds at least ___ vertical bars.
Signup and view all the answers
Precast walls used in building interiors with No. 6 bars require ___ cover.
Signup and view all the answers
What is the minimum height to least-lateral dimension ratio for a structural member to be considered a column?
Signup and view all the answers
Strength test samples for concrete must be taken for every ___ cubic yards of placement.
Signup and view all the answers
What minimum number of consecutive tests are required to establish a sample standard deviation with applied modification factors?
Signup and view all the answers
Vertical spacing of ties shall not exceed ____ longitudinal bar diameters, ____ tie diam. or the least dimension of the member.
Signup and view all the answers
What is the minimum f'c (psi) for concrete exposed to freezing and thawing cycles and continuous moisture?
Signup and view all the answers
What is the minimum compressive strength for concrete exposed to moderate sulfate levels?
Signup and view all the answers
What is the limit water to cementitious ratio for concrete in severe freeze-thaw conditions?
Signup and view all the answers
What is the minimum compressive strength (psi) for concrete requiring low permeability when exposed to water?
Signup and view all the answers
What is the permissible air content of a 5500 psi concrete with 1-1/2 in nominal max. aggregate in exposure class F2?
Signup and view all the answers
What is the maximum age of strength test records that can be used to establish a sample standard deviation?
Signup and view all the answers
Samples shall be molded and standard-cured as specified in ASTM ___ and ASTM ___
Signup and view all the answers
What is the minimum compressive strength PSI for concrete requiring reinforcement corrosion protection and exposed to external sources of chlorides?
Signup and view all the answers
Welding or 'tacking' of crossing bars is usually permitted for reinforcement assembling.
Signup and view all the answers
Study Notes
ACI 318-11 Key Concepts
- Offsets in columns of 3 inches or greater require separate, lap-sliced bars for reinforcement.
- Bundled bars must be enclosed in stirrups or ties.
- For concrete placements with fewer than 5 samples, tests must be made from at least 2 randomly selected batches.
- Inspection records must include mixing, placing, and curing concrete but do not require documentation of cracking.
- Minimum inside bend diameter for No. 14 and 18 bars is 10 times the bar diameter (DB).
- Anchor bolts in columns and pedestals must be surrounded by at least 2 No. 4 bars or 3 No. 3 bars.
- Minimum clear spacing between parallel bars in a layer is the greater of DB or 1 inch.
- Pozzolans in concrete are limited for exposure class F3.
- Conduits and pipes embedded within slabs must not be larger than 1/3 of the overall thickness and should be spaced at least 3 diameters apart.
- Construction joints in girders must be offset a minimum of 2 times the width of intersection beams.
- High-early strength concrete must be kept above 50°F in a moist condition for 3 days when using accelerated curing methods.
- Longitudinal location of bends and ends of reinforcement must have a tolerance of ±2 inches.
- Minimum bend diameter for No. 3 through 8 bars is 6DB.
Reinforcement and Cover Requirements
- Horizontal supports for bar offsets should be within 6 inches of bending points.
- Nonprestressed shells with No. 8 bars not exposed to weather require 3/4 inch cover.
- A nonprestressed column with No. 8 longitudinal bars requires No. 3 transverse ties.
- Concrete for slabs or walls must be sampled every 5000 square feet of placement.
- Contraction joints create controlled cracking and improve longevity of structures.
- Reinforcement tolerance should not exceed -1/3 of specified cover.
Load and Strength Specifications
- Live load is defined as weight from transient, non-permanent sources, while dead load is from fixed, permanent sources.
- For stirrup and tie hooks in No. 5 bars or smaller, a 90-degree bend with 6DB extension is standard.
- Minimum compressive strength for concrete exposed to freezing and thawing cycles with continuous moisture is 4500 psi.
- For concrete requiring reinforcement corrosion protection exposed to chlorides, minimum compressive strength is 5000 psi.
- Concrete must be mixed and delivered in accordance with ASTM C94.
Testing and Lot Requirements
- Strength test samples must be taken for every 150 cubic yards of concrete placement.
- A minimum of 15 consecutive tests is needed to establish a sample standard deviation with modification factors.
- Records of inspection must be preserved for at least 2 years.
- If less than 50 cubic yards of concrete is used, strength tests are not required.
Miscellaneous Specifications
- Reinforcement must be free from contaminants such as mud, oil, and nonmetallic coatings at concrete placement.
- Water must be removed from concrete deposition locations using a tremie.
- All longitudinal bars in nonprestressed compression members require transverse ties.
- The maximum unit weight for lightweight concrete is 115 lb/ft³.
- Beams, girders, or slabs can only be cast or erected once concrete in vertical support members has set and is no longer plastic.
Summary of Specific Technical Details
- Bundled bar spacing must adhere to diameter of single equivalent total bar area.
- No. 9 through No. 11 bars have a minimum inside bend diameter of 8DB.
- Construction joints should be located within the middle third of spans in slabs, beams, and girders to maximize strength.
- Reinforcement in frame members for seismic loads requires ties spaced between 4 and 6 inches apart.
- Samples should be molded and cured as specified in ASTM C31 and C39 for accurate strength testing.
These notes encapsulate essential facts and specifications from ACI 318-11 concerning concrete placement, reinforcement, and testing, providing a comprehensive overview for study and reference.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the key concepts of ACI 318-11, focusing on the critical aspects of concrete construction and reinforcement. This quiz covers essential rules for offsets, bundled bars, inspection records, and more. Perfect for students and professionals in civil engineering and construction.
