Common Steel Erection Problems and Suggested Solutions

1 STRUCTURAL Steel EDUCATIONAL COUNCILTECHNICAL INFORMATION & PRODUCT SERVICED ecember 1993 Common Steel ErectionProblemsand Suggested SolutionsbyJames J. PutkeyAcknowledgementsThe author wishes to thank the following persons for their input, review,and comments on the content of this Steel TIPS publication: Members of the Structural Steel Educational Council Dave McEuen, California Erectors, Bay Area, Inc. William C. Honeck, Structural Engineer with Forell/Elsesser Engineers, information presented in this publication has been prepared in accordance with recognizedengineering principles and construction practices and is for general information only. While it isbelieved to be accurate, this information should not be used or relied upon for any specificapplication without competent professional examination and verification of its accuracy, suitability,and applicability by a licensed professional engineer or architect.

2 The publication of the materialcontained herein is not intended as a representation or warranty on the part of the Structural SteelEducational Council, or of any other person named herein, that this information is suitable for anygeneral or particular use or of freedom infringement of any patent or patents. Anyone making useof this information assumes all liability arising from such Steel Erection Problems ANDSUGGESTED SOLUTIONSList of ProblemsNo. Pa_=e One-Bolt Connections 116. Columns or Bents Tied Together With Non-Bolted Steel Joists 157. Steel Joists Without Bolted Bridging 168. Columns or Bents Tied in With Timber 179. Steel Columns or Partial Bents Not Tied In 1810. Non- self -Supporting Steel Frames 1911.

3 Column Splices Too Low or Too High Above Floor 2012. Columns Interrupted by Beams 2113. Columns Offset From Beam Framing 2214. Revisions and Alternates Not Flagged on Drawings 2315. Double-Framed Beam Connections to Girder 2416. Double-Framed Beam Connections to Column Web 25 Bolting17. Mixed Bolts 2718. Mixed Bolt Diameters 2819. Reuse of High-Strength Bolts 28 Welding20. Prequalified and Non-Prequalified Weld Joints 2921. Extending Continuity Plate for Back-up Bar 3022. Welded Connections to Inside of Column 3123. Restrained Welded Joints 3324. Field-Welded Curb Angles 35 Decking25. Steel Floor Deck Spanning Uneven Surfaces 36 General26. Project Specifications 37 Anchor Bolts1. Low Anchor Bolts 52. Misplaced Anchor Bolts 73.

4 Rotated Anchor Bolt Pattern 94. Inadequate Anchor Bolts for Column Erection 10 Common Steel Erection Problems ANDSUGGESTED SOLUTIONSI ntroductionPrefaceAbout two years ago a structural engineer asked methe following question, "Why don't you write a book-let on Steel Erection ? We keep seeing the sameerection Problems occur over and over again, and itwould be nice to have a reference for erectors,fabricators, and structural designers to either avoida problem or to present a solution to a problem ."The question was posed to two Steel erectors, andthey both thought such a publication would be anexcellent idea. The end result is this Steel publications exist that inform the structuraldesigner on how to select types of Steel , designeconomically, reduce fabrication costs, and how todesign various types of structures or portions ofstructures.

5 But what source of information is avail-able to the designer when the Steel erector makesan inquiry regarding the Steel design or experiencesproblems that require the designer's input? Theseinquiries or Problems may result from: Erection or fabrication errors. Erection procedures or sequences. Faulty work of other trade contractors. Design that can lead to safety Problems . Erection equipment loads into the structure. Changes or alternates requested by the , looking ahead in the construction timetable,one might logically ask the following questions,"What source of information is available to thestructural designer to produce a design that canavoid these Erection Problems ? What are thedetails to avoid? What are the desired details?

6 Whydoesn't the Steel industry provide structural design-ers, and others, with Solutions to Common design-related Problems experienced bythe Steel erector"PurposeThe purpose of this Steel TIPS is to provide struc-tural designers and Steel erectors with a basic andconvenient source of Solutions to Common steelerection Problems that involve the structural and ContentTo provide structural designers with Solutions tocommon Steel Erection Problems , 26 Common prob-lems with Suggested Solutions are provided. Theproblems are divided into six categories: anchorbolts, Erection , bolting, welding, decking, and gen-eral. In each category a specific problem is shownby its title. The problem is then described and thesuggested solution is content of this Steel TIPS does not address thevarious methods of erecting Steel .

7 If the designerneeds to design a structure with unusual features,or with a required Erection procedure or sequence,then a sponsor firm of the Structural Steel Educa-tional Council might be consulted to make certainthe unusual features can be economically Erection Problems presented are not only "com-mon'' Problems , but may also be considered basic,reoccurring Problems . So the content is chosen tobe especially useful to the new structural designer(and maybe experienced designers).Some of the Problems or portions of problemsaddressed in this Steel TIPS are mentioned oraddressed in previous Steel TIPS, or in the AISC publications Modern Steel Construction, and SteelDesign Guide Series. These Problems and theirsolutions are now conveniently gathered into Low Anchor BoltsProblemAnchor bolts are sometimes set with their topslower than the detailed elevation.

8 Two situationscan exist: 1 ) the bolts are placed so Iow that the topof the bolt is below the top of the base plate and theanchor bolt nut cannot be engaged, or 2) the bolttop extends above the base plate, but not highenough to allow full thread engagement of the Tolerances. Section of the AISCCode of Standard Practice requires the owner toset anchor bolts in accordance with approvedanchor bolt plans. [1] The Code provides for a+1/2-inch tolerance for the elevation of the top ofanchor bolts. The contractor setting the anchorbolts should be able to meet this tolerance, buterrors can occur. Section in the Commentaryon the Code of Standard Practice discusses theinstallation of anchor bolts. [2]Bolt Detailing.

9 Anchor bolt detailing is discussedin Chapter 7 of AISC Detailing forSteel Construc-tion. [3] To match the minus 1/2-inch tolerancenoted in Section of the Code, the Steel detailershould allow for at least a 1/2-inch projection of thebolt above the top of the nut. If the anchor bolt isset 1/2-inch Iow, the nut will still obtain full threadengagement. However, when the minus 1/2-inchtolerance is exceeded, the problem of a Iowanchor bolt o l u t i o nExtending the Bolts. Anchor bolts that are setIow are commonly called "short anchor bolts."Short bolts need to be corrected by making themlonger. Two methods of making the bolts longerare threaded couplers and welded " Steel Interchange" feature in Modem SteelConstruction, January 1993, and "Some PracticalAspects of Column Base Selection," SteelDesignGuide Series 1: Column Base Plates, discussthese two methods.

10 [4, 5] For either correctionmethod, the erector must work with the structuraldesigner (and general contractor). If the anchorbolts are designed to resist uplift, in addition toproviding column stability during Erection , then thestructural designer may require special proce-dures. See AISC Manual of Steel Construction, specification J10, page 5-172, for loads on an-chor bolts. [6]Preventative Solution. A"preventative" solutionthat anticipates Iow anchor bolts is to design anddetail anchor bolts with additional bolt include: The structural designer shows a 1-inch bolt pro-jection above the top of the nut in the base platedetails on the structural drawings. This 1-inchbolt projection allows bolts to be set an additional1/2-inch lower than the minus 1/2-inch setting toler-ance provided by the AISC Code of StandardPractice, and still obtain full thread engagement.