To avoid schedule delays and costs associated with out-of-position anchor bolts, you must understand what tolerances your work will be judged by and take the necessary actions to position, align and secure the anchor bolts.Steel Designers Handbook. If A252 is substituted, the EOR should account for its thinner wall, the lower yield strength, and the variable chemistry that may affect the members’ weldability.Out-of-position anchor bolts occur when the measured deviation or variation from the specified location or alignment exceeds the specified construction tolerance. Similar to API 5L, ASTM A252 is not an approved material per AISC 360-16. The tolerances in A252 are more lenient than A500 for wall thickness, and it has no tolerance for straightness.
Aisc Construction Tolerances Manual 15Th Edition
ASTM Tolerances for Round HSS and Pipes ++Table 1-29. ASTM Tolerances for Rectangular and Square HSS ++Table 1-28. Handbook of Construction Tolerances.Aisc steel construction manual 15th edition pdf Chicago The American Institute of Steel Construction.
( 1,2) Even though the architect/engineer should clarify and resolve these tolerance differences, concrete contractors sometimes become involved in construction disputes because of the non-compatible tolerances.ACCC - Anchor Bolt Tolerances 1/1The American Institute of Steel Construction (AISC) Structural Steel Educational Council,Steel TIPS (Technical Information and ProductServices),As shown in Table 1 and Figure 1, AISC tolerances place limits on the variation between centers of any two bolts in a group (Item 1), centerlines of bolt groups (Items 2 & 4), and centers of anchor bolt group from column lines (Item 5). Tolerances provided by the American Institute of Steel Construction (AISC) are more restrictive than anchor bolt tolerances provided by the American Concrete Institute (ACI).Tolerances in concrete construction We need greater clarity and realism in specifications and also agreement on how tolerances are to be measured and what to do in specific instances of noncompliance By the Editorial Staff of Concrete Construction When a contractor finds that something won’t fit, or when the architect or owner thinks that theFor the steel erector, Division 5 of the specifications references AISC 303 “Code of Standard Practice for Steel Buildings and Bridges” while Division 3 of the specifications for the concrete contractor typically references ACI 117 “Specifications for Tolerances for Concrete Construction and Materials”. Unfortunately, the tolerances are not compatible. One East Wacker Drive, Suite 700.The concrete and steel industries both provide anchor bolt tolerances. AMERICAN INSTITUTE OF STEEL CONSTRUCTION. On the Code of Standard Practice.
(4) Even using plywood or steel templates to position, align and secure anchor bolts, it is highly unlikely the concrete contractor can satisfy the AISC tolerances shown in Table 1. Therefore, it is critical for concrete contractors to understand what tolerance applies to the concrete work – AISC or ACI tolerances? AISC recommends that Division 3 of the specifications require anchor bolts to be set in accordance with the AISC 303 “Code of Standard Practice”. (3) A tolerance of ± 1/16 inch is neither realistic nor achievable. AISC’s tolerances combined with oversize holes in the base plates ensure the steel structure can be easily erected without modifying the structure.For anchor bolts to satisfy both AISC and ACI’s tolerances, Suprenant and Malisch claim anchor bolts must be located within ± 1/16 inch of their specified location. The only compatible tolerance between AISC and ACI is the top elevation of the bolts (Item 3). As shown for (Item 7), AISC has a very strict or zero plump tolerance for bolts whereas ACI does not specify a plumb tolerance.
So, don’t rely on oversize holes to mitigate out-of-position anchor bolts. (3,5)Concrete contractors seldom control the size of the base plate holes. (3) As shown in Table 2, AISC’s recommended oversize-hole diameters for 3/4 and 7/8 inch bolts are too small as compared to oversize hole sizes suggested by ACI. However, that may not be the case for 3/4 and 7/8 inch diameter bolts.
For a bolt tilt of 5 degrees and a 6 inch bolt projection, the difference between bolt location as measured from the top of the bolt and top of the concrete can be as much as 1/2 inch. If the anchor bolt is not perfectly plumb, the location of the top of the bolt will not be the same as along the concrete. However, anchor bolts locations are commonly verified by measuring to the top of the bolt. It is standard practice to layout the location of anchor bolts along the top of the concrete.
Dennis Purinton with Purinton Builders, Inc. Too improve layout accuracy, make a plan on where and how to measure and double check your layouts.How to Position, Align and Secure Anchor BoltsUse one or two anchor bolt templates securely attached to the formwork to position, align and secure anchor bolts. Also, the accuracy of the anchor bolt location depends on the accuracy of the measuring tape and the layout or reference lines. Using these measuring points require estimating the centers which introduce more measuring errors and uncertainties.
If the reinforcement cannot be repositioned or will not meet tolerances after repositioning, contact the architect/engineer. Similar to a single template, use two nuts per bolt per template.If necessary, reposition steel reinforcement that interferes with anchor bolt location or alignment. The bottom template should be located close to the concrete and the top template located near the top of the anchor bolts. For a template to work correctly, use two nuts per bolt with the template sandwiched in between.For tall bolt projections and to minimize anchor bolt variations from plumb, use two templates. Purinton says it is just important to mark the template alignment relative to the foundation as measuring and drilling the bolt holes in the correct location. Makes plywood anchor bolt templates in the shop as shown in Photo 2.
Aisc Construction Tolerances Install A New
(6)C) Depending on the situation, it may be possible to cut off the base plate from the column and install a new base plate that accommodates the misplaced anchor bolts.D) For misaligned or bent anchor bolts (Photo 3) that will not allow the base plate to fit over the bolts, consider bending the bolts into position. In lieu of drilling new holes and epoxying new anchor bolts, consider welding a new bolt to the side of the projecting bolt stub. Drilling new holes can be difficult due to existing steel reinforcement and reinforcement should not be cut unless approved by the architect/engineer. Below are some repair options for different conditions:A) For anchor bolts misplaced by less than one bolt diameter, field cutting to enlarge or slot the corresponding holes in the steel base plate is the best option.B) For anchor bolts misplaced by more than one bolt diameter, consider cutting off the misplaced bolts, drill new holes in the correct location, and set new anchor bolts with epoxy. After installing, recheck the location and alignment of the anchor bolts.Mitigating misplaced or misaligned anchor boltsOf course, the type of repair depends on how much the anchor bolt or group of bolts are out of position or how much an individual bolt is out of plumb.
J., Steel Tips – Common Steel Erection Problems and Suggested Solutions, Structural Steel Educational Council, December 1993, www.steeltips. ACI 117.1R-14 Guide for Tolerance Compatibility in Concrete Construction, American Concrete Institute (ACI), 2014, A., Steel Design Guide 1, Base Plate and Anchor Rod Design, 2 nd Edition, American Institute of Steel Construction (AISC), 2006, R., Tolerances for Cast-in-Place Concrete Buildings, American Society of Concrete Contractors (ASCC), 2008, ACI 117-10 (Reapproved 2015) Specifications of Tolerances for Concrete Construction and Materials and Commentary, American Concrete Institute (ACI), 2015,
0 kommentar(er)
