When AISC was issued, there were five prequalified connections ( Chapter 5 through 9). Since , four additional prequalified. Approved by the AISC Connection Prequalification Review Panel ANSI/AISC , Prequalified Connections for Special and Intermediate Steel Moment. ANSI/AISC ANSI/AISC s An American National Standard Prequalified Connections for. Special and Intermediate Steel Moment Frames for.
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To satisfy the requirements of the AISC Seismic Provisions for lateral bracing at plastic hinges, supplemental lateral bracing shall be provided at both the top and bottom beam flanges, and shall be located at a distance of d to 1.
Further, for most specimens, the bottom flange backing was removed and a reinforcing fillet added, top flange backing was fillet welded to the column, and weld tabs were removed at both the top and bottom flanges.
Oversized bolt holes were included in some past tests, because the oversized holes permit easier alignment of the bolts and erection of the connection and resulted in good performance of the connection.
The clip shall be detailed to facilitate suitable weld terminations for both the flange weld and the web weld. KBB SMF systems with concrete structural slabs are prequalified only if the concrete structural slab is kept at least 1 in. For single-sided connections in which a momentconnected beam attaches to only one of the column flanges, it is generally not necessary to use CJP groove welds to attach the continuity plate to the column flange Figure C Results are reported in several publications Lee et al.
The beam-flange-to-end-plate and stiffener weld requirements equal or exceed the welding that was used to prequalify the three extended end-plate moment connections. These members have not generally been tested in other prequalified connections; however, the conditions of inelastic deformation imposed on the built-up shapes in these other connection types are similar to those tested for the bolted end-plate connections.
The coupon code has been applied to your cart! If built-up sections are used, the webto-flange weld may be a one-sided fillet weld, except within the beam, depth, or three times the flange width of the face of the end-plate. It was the judgment of the CPRP that for the purposes of establishing initial prequalification limits, adherence to the maximum tested specimen would be appropriately conservative.
Thus, the beam web is attached to the column flange with both a CJP groove weld and a welded single-plate connection. The protected zone is based on test observations. The pinching is caused by a combination of bolt slip and the sequence of yielding and strain hardening encountered in the connection. Built-up Members Built-up members having a doubly symmetric, I-shaped cross section shall meet the following requirements: The design criteria provide sufficient strength in the elements of the connections to ensure that the inelastic deformation of the connection is achieved by beam yielding.
It includes consideration of likely material overstrength and strain hardening.
AISC 358-10 Prequalified Connections
Continuity plates shall conform wisc the requirements for wide-flange columns. Collar-corner-assembly-to-column weld, plan view.
Experimental work has included successful tests on all of these types of RBS cuts.
Therefore, the prequalification extends to both plate types. Beams are shop-welded to forged flange and web fittings collar flange assembly and are fieldbolted together through forged column fittings collar corner assembly that are shop welded to the columns.
Supplemental lateral bracing shall be provided at the expected plastic hinge in conformance with the AISC Seismic Provisions.
ASTM A or AM bolts with threads excluded from the shear plane are used for the beam flange connections because the higher shear strength of the A or AM bolts reduces the number of bolts required and reduces the length of the flange plate.
A cap plate detail similar to that illustrated in Figure C Certification of conformance with the requirements of this Appendix shall be submitted to the purchaser. The size, shape and finish requirements for the special access hole are specified iasc AWS D1. Because backing removal, backgouging and backwelding would be performed through an access hole beneath the top flange, these operations should be avoided whenever possible.
Quality Control and Quality Assurance. It should be noted that the strong column—weak beam criteria contained in AISC are valid only for planar frames. Connection rupture is controlled through special detailing requirements associated with the welds joining the beam flanges to the column flange, the welds joining the beam web to the column flange, and the shape and finish of the weld access holes.
The contour of the weld end shall provide a smooth transition to adjacent surfaces, free of notches, gouges and sharp corners. Care must be used in making quality weld terminations near the member radius, as the use of common aaisc tabs is difficult.
AISC Prequalified Connections
Both block shear and buckling of the flange plate are treated as nonductile behaviors. If a beam at the node does not aisx a moment connection, the size of the CWX remains unchanged and a shear plate connection is shop-welded to the CWX to accommodate a nonmoment beam that does not need to match the nominal depth of the momentconnected beam s. Additional evidence supporting prequalification is derived from bolted T-stub connection tests FEMA, e; Swanson et al.
The protected zone is defined as shown in Figure 5. In such cases, the column should be extended to a sufficient height above the beam flange to accommodate attachment and landing of those connection elements.
Tack welds of backing to the underside of beam flanges would be unacceptable, and any tack welds between weld backing and beam flanges are to be removed in accordance with Section 3. Geometry for 4ES similar. The flange plate bolts cannot experience a tensile force larger than Fpr, and so Step 9 checks the actual number of bolts required in the connection.
Current Standards | American Institute of Steel Construction
Plastic Hinge Location This Standard specifies aiscc presumed location of the plastic hinge for each prequalified connection type.
Most of the beam-to-column assemblies that have been tested had configurations 35-10 beam spans of about 25 ft 7. Column Limitations Nearly all tests of RBS connections have been performed with the beam flange welded to the column flange i. Monotonic tests have shown that the stiffness and strength of an end-plate moment connection are decreased when the bolt gage is wider than the beam flange.
Built-up Members The behavior of built-up I-shaped members has been extensively tested in bolted endplate connections and has been demonstrated to be capable of developing the Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications,incl.
Where possible, active links are provided aisd assist with obtaining the cited literature. If the base metal and weld root are ground smooth after removal of the backing, the reinforcing fillet adjacent to the iasc flange need not extend to base metal.
The required strength of the fillet welds shall not be less than Fy Ac, where Ac is defined as the contact areas between the continuity plate and the column flanges that have attached beam flanges and Fy is defined as the specified minimum yield stress of the aiisc plate.