Training - Open Web (Truss Rafters)

(Revised: 04/01/08)

Gussets and Web Members:

·         Web members are detailed with a "Bypass Alignment" that reduced the need for some gussets.

·         Gussets and Welds are detailed at web members when the weld is not adequate.

Rod Bracing Connections:

·        At Purlins and Bar Joists, all Rods (RK) must be connected with a Brace Rod Plates (RPSA & RPLA), welded to the underside of the FO.

·        At Purlins with Box / Tube Struts, all Rods (RK) must be connected with Rod Pads to a SQW7477 or SQW7473 adjacent to the GCR or MZE clip.

·        Rod Pads are bolted to the Brace Rod Plates (RPSA & RPLA) with 1 1/4" x 3" or 3/4” x 2 1/4” bolts.

·        The Brace Rod Plates reference detail has a Dim A of 0". Do not revise the Dim A for the FO thickness.

·        Do not use Rod Slots in the stem of the open web, slots can be used in the column haunch.

·        Do not revise the web member length or Dim A at the Brace Rod Plates.

·        If a SQW7477 is detailed in the Column Haunch, revise it to a 7RWB0564076 (Weld Side 2 to FO).

Detailing Warnings:

·         Modify the A325 Bolt lengths at all Purlins and Bar Joists at the Brace Rod Plates.

·         1/2" Dia. Bolts = (1/8" Purlins or 1/4" Joist Seat) + FO thick + 3/4" RPSA & RPLA + 11/16" to grip.

·         3/4" Dia. Bolts = 1/4" Joist Seat + FO thickness + 3/4" RPSA & RPLA + 1" to grip.

·        At Composite Purlins, Revise the additional ship loose clip (GC4) to be a shop welded clip.

Frame Detailing for Open Web is the same as Solid Web for the following connections:

·         Purlins or Bar Joists to the outside flange.

·         Flange Braces to the inside flange.

·         Endpost and Interior Columns to the inside flange.

·         Locating Holes, Clips, Stiffeners, Brackets, Miscellaneous Plates to the Flanges or Web (Stem).
·         Note: When locating data on the Web, it must be on either the Outside or Inside Stem.

For additional information on Open Web, please refer to the following Controlled Documents:

·  Design Manual

· Product and Procedures (PnP)

· Standard Erection Details (SED's)

· Weld Standards 

Open Web Frame Types. · Rigid Frame Truss. · Continuous Truss. · Truss Beam (rafters not defaulted to Flat Bottom). · Truss Lean-to.

Modified Warren (default) Warren (Optional Check Box) Modified Warren (Large Min. Panel Distance)

Web Configurations. · Modified Warren (default). · Warren. · Modified Warren (Min. Panel Distance).

	Extended Plates (default). Top Stem Extended plates will not detail at bar joists with less than 5" seats.
	TWC and Gussets. TWC at Splice Plates - C6x8.2 is detailed as a Clip on the Web. Flange and Web Gussets are detailed as Clips (GP's and MP's). Flange Gussets may be displayed as a triangle, even though they are manufactured as rectangles.

	Single / Double Web Members Single web members are shown in the color Salmon. Double web members are shown in the color Red.
	Frame Member Data The Frame Member Data screen is slightly different on Truss Frames. Top and Bottom Chords If you highlight either the Top or the Bottom Chord of the same Truss and press Properties, the Member Data Screen will show the all the information for the entire member (Splice Plates and Web Members).
	Display (Elevation View) When a Truss Rafter is selected on the Frame Information Screen, the Rafter will be displayed in the main graphic window.

T-Shape Thickness The only field that can be revised on a Top or Bottom Chord on this screen is the Thickness. Revisions will update the entire T-Shape (Flange and Stem).

Web Member Mark Number The Mark Numbers can be revised to any valid TLN or TLB number. Revisions will automatically recalculate the Welds and Gussets. Web Member Quantity The qty will be updated based on the Mark Number. Web Member Adjusts All adjustments must be done from Adjust 1. Adjust 2 will be automatically calculated. Web Member Max. Length The length in the Mark Number cannot exceed this dimension. View The selected web member will be highlighted. Inserting and Deleting This screen does not allow you to Insert or Delete Web Members.

	Adjusting Web Member Lengths. Adjusting Web Member Lengths will automatically Re-Design and Re-Detail the Splice Plate, Gussets, and Welds. In this Sample, The Weld was increased during the Whitmore Section check but the Splice Plate did not need to be lengthened to match the Gusset depth.
	Adjust Lattice option. This option is similar to an Undo Button. It will delete user changes and automatically re-detail the original Web Member Lengths, Gussets and Welds.

	TWC A web member may be designed between the splice plates. They will have a quantity of 0 and are replaced by a TWC in the Frame Data screens. When required by design, additional bolts may be required to connect the TWC's together. 2TWC will be detailed for this condition, this will not happen very often.

Splice Plates Low Eave Section The bolting plates are numbered as shown. The numbers may vary.
Intermediate Section The bolting plates are numbered as shown. The numbers may vary.
Ridge Section The bolting plates are numbered as shown. The numbers may vary.
Gussets Gusset Work Points	Gusset Work Points Shown are the work points for gussets / miscellaneous plates, the work point is the leading edge of the gusset measured from End-1 (ridge / high side).

	Rod Plates. Rods with Rod Pads detail to the large hole in the new RPSA & RPLA clips.
	I/A Frame. I/A Frame the ability to Move, Add, and Delete Splice Plates. They will be located 1'-0 up from the nearest secondary location.

Open Web - Review Job from Design

When you start detailing an Open Web job, there are a few items that you want to look for that may need to be addressed by the Designer.

Review all of the Rod Bracing Break Locations	Always make sure that the Break Locations on the roof Bracing Tiers are at Secondary Members. Try Not to use Endpost or System Generated locations.
Shallow Haunch	If the depth at the column is extremely shallow, you may want the designer to re-run the frame using Vertical Haunch.
Purlins at Haunch	Check for interference with at Extended Haunch Plates and the MP Plate Gussets. You may want Design to relocate the Purlin String.