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# Trusses

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• 1. TrussesDate : 20th May 2012Name Of Professor : Mr. SanjaySubject : Building Construction IIISubmitted By : Fairuz , Barch/8008/10
• 2. Truss & Its Characteristics: A trussis a structure comprisingone or more triangular units .A triangle is the simplest geometric Nodesfigure that will not change shapewhen the lengths of the sides arefixed.[ Triangular Straight unit MembersItis constructed with straightmembersEnds are connected at jointsreferred to as nodes.External forces and reactions tothose forces are considered to actonly at the nodes Hinges Force acting on the members caneither be tensile or compressive.Moments are excluded because allthe joints in a truss are treatedas Hinges or Revolute.
• 3. Truss & Its Component:Heel - The point on the truss where the top and bottom chords intersectSlope - The vertical rise in inches for every 12 inches of horizontal run.Panel Length - The horizontal distance between the centerlines of two consecutive panel pointsalong the top or bottom chord.Peak - The point on the truss where the sloped chords meet.Top Chord - Horizontal distance between the centerlines of two consecutive panel points alongthe top or bottom chord.Continuous Lateral Brace - Members installed at right angles to a chord or web member of atruss to provide stability to the truss. All lateral braces must be stabilized.Overall Height - Vertical distance between bearing and the uppermost point of the peak.
• 4. Truss & Its Component:Wedge - The triangular piece of lumber inserted between the top and bottom chords, usually toallow the truss to cantilever.Bottom Chord - The incline or horizontal member that establishes the bottom of a truss,usually carrying combined tension and bending stress.Splice - The location at which two chord members are joined together to form a single member.It may occur at a panel point or between panel points.Panel Point - Also called a joint, its the location on a truss where the web members and top orbottom chords intersect and are connected by metal connector plates.Web - The members that join the top and bottom chords to form the triangular patterns typicalof trusses.
• 5. Truss & Its Component:Bearing - Structural support, usually a beam or a wall that is designed by the designer to carrythe truss reaction loads to the foundation.Overhang - Extension of the top chord of a truss beyond the outside of the bearing support.Span - The horizontal distance between the outside edges of the exterior bearing supports, orthe bottom chord length, whichever is greater.Bottom Chord Length - Usually the same as the span.Cantilever - The part of the truss that extends beyond its support, not the same as an overhang.Truss Plate – Are plates which are used to connect the members together in the trussmanufacturing process.
• 6. Analysis Of Truss: There are 4 main assumptionsmade in the analysis of Trusssystem :Truss members are connectedtogether at their endsTruss are connected togetherby frictionless pins Truss structure is loaded onlyat joints.Weight of the truss membersmay be neglected.
• 7. Different Types Of Trusses: Flat Truss Bowstring Truss King Post TrussQueen Post Truss Lenticular Truss Town Lattice Truss
• 8. Parallel Chord Truss: Also known as Flat truss Has parallel top chordand bottom chord.The top and bottomchord must be correctlypositioned duringinstallation to ensurestructural integrity ismaintained.Are usually designed tobe supported at the endsonly Often used for floorconstruction.
• 9. Bowstring Truss: Alsoknown asCrescent TrussIs a truss consistingof curved top chordmeeting bottom chordat each end. Has diagonal load-bearing members.Often confusedwith tied arch bridges
• 10. King Post Truss: A kingpost is also knownas crown post trussItis the simplest form oftruss . Is used for simple rooftrusses and short-spanbridges. Truss consists of twodiagonal members that meetat the apex of the truss,.Consists of one horizontalbeam that ties the bottomend of the diagonals togetherThe king post connects theapex to the horizontal beambelow.
• 11. Queen Post Truss: Is similar to a king posttruss Is used for simple rooftrusses and short-spanbridges. Is a supporting postdesigned to span longeropenings than a king post.A king post uses onecentral supportingpost, whereas the queen postuses two.
• 12. Lenticular Truss:A lenticular truss bridgeincludes a lens-shapetruss. It has trusses betweenan upper arch & lowerarch. Upper curves up andthen down to end pointswhile lower arch curvesdown and then up to meetat the same end points.where the arches extendabove and below theroadbed.Mainly used in theconstruction of stadium.
• 13. Town Lattice Truss:Was an alternative toheavy-timber bridges.Truss consists of paralleltop chord & bottom chord Consists of plankswhich are arrangeddiagonally with shortspaces in between them. Treenails, or woodenpins, connect the bridgestimbers at eachintersection of the trusssystem.Mainly used in theconstruction of bridges
• 14. Advantages Of Truss : Are Cost effective. Can be installed quickly even without heavy equipment to lift it into place. Unique properties of a triangular object allow trusses to span across longer distances. A triangular truss maintains its shape, preventing shift and sag. Thus giving stability to the structure. The shape of a triangle allows all of the weight applied to the sides to be redistributed down and away from the center.
• 15. THANK YOU