1 Architecturally Exposed Structural Steel (AESS). Custom curtainwall has been the staple of Enclos Corp that has given us the ability to assert ourselves as one of the lead- ing facade specialty contractors in North America. Along with cladding the exterior of some of the most renowned and expan- sive buildings, we have also incorporated storefronts, cable nets, cable walls, and space frames into our business model. Now we are seeing owners and architects investing more time in the design of not only the main portion of the building, but also the entrances, pavilions, and skylights of their projects. As they begin to express this trend, we too have to accommodate to meet all the requirements set forth and position ourselves to continue to lead the way in all areas of facade design and installation. 2010 enclos 83. AESS. Figure 1. LA Live Podium AESS trusses. As we begin to see this trend take hold, that call out AESS where do we begin?
2 Performed AESS projects. Just the fact way through the matrix categories as the The above processes provide the basic show through is seen on the opposite the most common material used in these The first place we should familiarize that they are a Steel fabricator will not fabrication requirements increase. To fabrication processes required for AESS. side of where the piece was welded. If designs is Steel . The efficient use of ourselves with is ASTM A6/A6M, Stan- qualify them as an AESS fabricator. Truss begin, the basic fabrication requirements You should be able to describe to the cus- required, weld show through is ground by Structural Steel in buildings goes back to dard Specification for General Require- Works International, for example, has the that make AESS different from standard tomer that these are the processes they hand, and may leave a blemish. the 17th century. Structural Steel is the ments for Rolled Structural Steel Bars, following certifications; City of Los Angeles Structural Steel are; will receive unless they specify otherwise.
3 Backbone of many buildings both small Plates, Shapes, and Steel Piling , along Approved Fabricator, ISO 9001 Quality The next level, Category 3, high profile Field Welding Aids Removed Some- and large. In the past, it was general with this Specification we should review Systems Certified, Member of AISC, and Special Care in Processing AESS conditions that are out of reach to touch times field welding aids are not removed practice to hide the Structural Steel behind AISC 303-05, Code of Standard Practice has LEED AP green building profession- Upgraded care in process of fabricating, and can be viewed from a distance of 20 due to Structural integrity issues. If speci- plaster or drywall to mitigate any imperfec- for Steel Buildings and Bridges specifi- als on staff. Be sure to choose carefully trucking, handling, storing, and erecting feet or more . The additional requirements fied, special attention is required in the tions, large connections, or just the raw cally section 10 on AESS.
4 After we gain a when you are selecting your fabricator as the material is required to obtain minimally for this category are; shop and field. look of the material. However, we are basic understanding of the specifications this will make or break your project from acceptable AESS. beginning to see more and more architects and codes for Structural Steel we need the start. Next, you will need to have a full Rolled Members: Minimize Distor- Close Weld Access Holes at Full Pen use Structural Steel in their design as an to get a feeling for what the architect is understanding of each fabrication process Tolerances: One Half Standard The tion When rolling members into various Welds Weld access holes are holes artistic expression prominently displaying trying to communicate through his/her listed in the cost matrix. This is the basic tolerances for Structural Steel frames are shapes, the member will be distorted. in the web of beams and columns to it for physical viewing.
5 We have come design. The AISC (American Institute of platform that will help you identify and set set by AISC Code of Standard Practice. If Distortion must be minimized. allow the welder to weld in areas of the to know this art form as Architecturally Steel Construction) has created a helpful AESS apart from standard Structural Steel . AESS is specified, these tolerances are re- member's web. If they are required to be Exposed Structural Steel (AESS). With matrix to specify techniques that need to In the sections to follow I will talk in more quired to be one-half of those of a standard Bolt Head Orientation Dictated Special closed for aesthetic reasons, special atten- the Steel now on display for everyone to be taken to achieve the different levels of depth about the fabrication, finishing, and Structural Steel . attention is required in the shop and the tion is required in the shop and field. appreciate, Architects want to minimize appearance for AESS.
6 It begins with the on-site requirements. field for the bolt heads to be orientated in a the imperfections in Steel and be able to AESS basics cover in section 10 of AISC Coping and Blocking Tolerances Mini- particular direction Category 1, high profile conditions that get as close to a perfect product as pos- 303-05, and next moves to the matrix FABRICATION mized Requires that all copes, miters, are within reach to touch and can be view sible. With minimizing these imperfections, which they created starting with Category and cuts in AESS material are to be made Category 2, high profile conditions that are in close proximity , is the highest set stan- comes more precise tolerances and higher 3, which is high profile conditions that are Now that you have found an appropri- with a uniform gap of 1/8 out of reach to touch and can be viewed in dard for AESS. It requires considerably quality finishes, resulting in increased labor out of reach to touch and can be viewed ate AESS fabricator, you will need to close proximity within 20 feet , additional more work, and also a significant cost in- and rising costs compared with the typical from a distance of 20 feet or more.
7 Next, determine what type of processed Steel Joint Gap Tolerance Minimized A clear requirements are as follows; crease over standard Structural Steel . The Structural Steel specifications. There are Category 2 is high profile conditions that you need to purchase, cold formed or hot distance between abutting members of requirements, in addition to all previously different levels of AESS acceptability and are out of reach to touch and can viewed rolled. This can be determined by the 1/8 is required. Welds Ground Smooth In standard listed requirements, are as follows;. standards where if you do not notify your in close proximity within 20 feet . Category shapes required for your project, and how Structural Steel , welds are left in as is manufacturer precisely what to fabricate, 1, is the highest level specified as high you can make the required components Piece Marks Hidden AESS pieces are welded condition with slag and weld spat- Continuous Welds Intermittent welds your project could have higher costs in profile conditions that are within reach to out of the typical Steel shapes.
8 Keep in marked in inconspicuous places whenever ter removed. This is the same for AESS, required for strength, may be required to manufacturing than necessary, or pos- touch and can be viewed in close proxim- mind that cold formed Steel is considerably possible, but there are many cases where however, if it is specified, welds must be be continuous for aesthetic reasons. Spe- sibly not high enough standards resulting ity . There is also the option where the most costly than hot formed Steel , but often these marks are seen. If removal of these ground smooth cial attention is required to avoid distortion in having to re-fabricate or re-finish the user can specify a combination of the 3 is more desired by architects due to their marks is required for aesthetic reasons, of the member. product. In this paper I will layout what you noted categories based on their project sharp corners. Once you have deter- this classification should be specified Welds Contoured and Blended If need to be aware of when installing AESS, requirements.
9 Mined what category of AESS needs to transitions of smoothly grounded welds Mill Marks Removed Steel mill marks and list the different tolerances, finishes, be provided for your particular project, you Surface Defects Minimized In the pro- are required to be contoured and blended, with their heat numbers and producer in- welds, and any other information that may The most important component in achiev- can provide them with the specifications cess of handling the materials, the flanges this process will be done by hand and will formation identifying the material chemistry help you when receiving pricing for any ing the desired look of AESS is the initial required for your project. For simplification of the beams and columns will inevitably leave blemishes around the weld area. and strength, must be removed. AESS products. stage of fabrication. Before fabrication of this paper I will begin with discussing be deformed and scarred. If this classifi- Samples should be submitted for review.
10 Begins however, you will need to find a the basic requirements for AESS from cation is specified, these deformities and Grinding of Sheared Edges Materials When receiving construction documents competent fabricator that has previously section 10 of AISC 303-05, and work my scars will be removed. Weld Show Through Minimized Weld with sheared edges during the fabrication 84 2010 enclos 85. AESS. Figure 2. Different types of fillet welds. process may demand that rough surfaces Weld versus a TIG (Tungsten Inherent adds a thin layer of metal (usually zinc) the Steel galvanically. They can be speci- Figure 3 (left). Cosmetic MIG weld. be deburred and ground smooth Gas) Weld can have significant cost and over the Steel to protect the Steel from fied as organic or inorganic which meet pdf Article - Fire Protection Materials for time implications. A 12 cosmetic MIG rusting. You would generally only need to the requirements for class B slip coefficient Architecturally Exposed Structural Steel Figure 4 (right).