TRUSS TERMINOLOGY - All-Fab Building Components

1 TRUSS TERMINOLOGYBEARING WIDTH The width dimension of the memberproviding support for the TRUSS (usually 31 2 or 51 2 ). Bearing must occur at a TRUSS joint That structural portion of a TRUSS which extends beyond the support. The cantilever dimension ismeasured from the outside face of the support to the heeljoint. Note that the cantilever is different from the An upward vertical displacement built into atruss bottom chord to compensate for deflection due todead The outer members of a TRUSS that define theenvelope or CHORD An inclined or horizontal member that establishes the upper edge of a TRUSS .

2 This member is subjected to compressive and bending CHORD The horizontal (and inclined ie. scissor trusses) member defining the lower edge of atruss, carrying ceiling loads where applicable. This member is subject to tensile and bending stresses. (On asimply supported non-cantilevered TRUSS ).CLEAR SPAN The horizontal distance between insidefaces or PLATE A galvanized steel plate with teethpunched out on one side, which is hydraulically pressed orrolled into both sides of a joint to fasten chord and webmembers A main TRUSS supporting secondary trusses framing into joint in a pitched TRUSS where top and bottomchords The point of intersecrion of a chord with the webor webs or an attachment of pieces of lumber (eg.)

3 Splice).LATERAL BRACE A permanent member connected to aweb or chord member at right angle to the TRUSS to restrain the member against a buckling failure or the trussagainst The extension of the top chord beyond theheel The chord segment between two adjacent POINT The point of intersection of a chord with theweb or Highest point on a TRUSS where the sloped top Either horizontal 2x member at the top of a stud walloffering bearing for trusses or a shortened form of connectorplate, depending on usage of the CUT Top chord cut to provide for vertical (plumb)installation of CUT For pitched trusses only - the sloping cut ofupper portion of the bottom chord at the heel (PITCH) The units of horizontal run, in one unit ofvertical rise for inclined members.

4 (Usually expressed as 3:12,5:12, etc.)TIE A temporary bottom chord brace, may be omitted if ceiling is attached directly to bottom chord and provides adequate lateral pre-built structural member capable of supportinga load over a given span. A TRUSS consists of one or more triangles in its TRUSS Any TRUSS in which the top chord is slopedand the bottom chord is TRUSS A TRUSS which has the top chord parallel to thebottom chord over the entire length of the Members that join the top and bottom chords to formthe triangular patterns that give TRUSS action.

5 The membersare subject only to axial compression or tension forces (nobending). | Brandon | Saskatoon | Edmonton CONFIGURATIONSTRUSS TERMS The terms below are typically used todescribe the various parts of a metal plate connectedwood TRUSS . The TRUSS profile, span, heel height, overallheight, overhang and web configuration depend on thespecific design conditions and will vary by BASIC TYPES OF TRUSSES The pitched or commontruss is characterized by its triangular shape. It is most oftenused for roof construction.

6 Some common trusses arenamed according to their web configuration, such as theKing Post, Fan, Fink or Howe TRUSS . The chord size and webconfiguration are determined by span, load and spacing. Alltruss designs are optimized to provide the most economicalapplication. The parallel chord or flat trussgets its name fromhaving parallel top and bottom chords. This type is oftenused for floor | Brandon | Saskatoon | Edmonton platepanel lengthslope12span (out-to-out of bearings)bottom chord lengthcantileverbottom chordsplicewebpeaktop chordcontinuous lateral bracewedgepanelpointbuttcutheelheightove rallheightSTANDARD ROOF TRUSS CONFIGURATIONSPARALLEL CHORD4X2 FLOOR TRUSS WITH CHASE2X4 FLOOR OR ROOF TRUSS (CAN DESIGN WITH A CHASE AS WELL)

7 | Brandon | Saskatoon | Edmonton CONFIGURATIONS The following examples representsome of the possible variations on the basic types of trusses. Theonly limit to the design is your WORD ABOUT TRUSS SHAPES Although we have triedto show a few basic TRUSS shapes in the preceding pages; spacedoes not permit the inclusion of all the possible shapes orstyles. Only single span cases have been illustrated; however, many ofthe shapes shown are suitable for multi-span single TRUSS supported at three or more bearing points is notuncommon also not flexibility of the All-Fab TRUSS system is one of its main advantages.

8 In fact, our computer software programs can handle just about any shape that a designer could PARALLEL CHORDVAULTFLAT VAULTSTUDIO VAULTTRAY OR COFFERBARREL VAULTMULTI-PIECEDOUBLE INVERTEDPOLYNESIANGAMBRELROOM-IN-ATTICBO WSTRINGDOUBLE CANTILEVERTRI-BEARINGCLERESTORYCANTILEVE RED MANSARD W/PARAPETSHIPDUAL PITCHMONOHALF SCISSORSHALF HIPSLOPING FLAT