Truss Flashcards
The space within the web of a truss between any two panel points on a chord and a corresponding pair of joints or a single joint on an opposite chord.
Panel
A joint between two or more members of a truss. A truss must be loaded only at its panel joints if its members are to be subject only to axial tension or compression.
Panel point., Node
The space on the chords of a truss between any two adjacent joints made by principal web members with the chord.
Panel length
Either of the two principal members of a truss extending from end to end and connected by web members.
Chord
The integral system of members connecting the upper and lower chords of a truss.
Web
The lower, supported end of an upright timber, rafter, or truss.
Heel
A bearing plate for supporting and resisting the thrust of a truss or girder.
Shoe
A structural frame based on the geometric rigidity of the triangle and composed of linear members subject only to axial tension or compression.
Truss
A truss all of whose members lie in a single plane.
Plane truss
The rigid members forming a truss, subject to axial forces proportional to the rise of the truss. Buckling generally governs the size of compression members, while tensile stresses at the weakest points, usually at the connections, control the size of tension members.
Trussing
A truss member that theoretically carries no direct load and whose omission would not alter the stability of the truss configuration.
Zero-force member
A concentrated load applied to a panel point of a truss. To prevent secondary stresses from developing, the centroidal axes of truss members and the load at a joint should pass through a common point.
panel load
The tensile or compressive stress that is constant through the depth of a structural member subject to axial tenion or compression. The size of the compression members of a truss is governed generally by buckling. The size of the tension members is controlled by tensile stresses at the weakest points, which are usually at connections.
Direct stress
A structure formed by trusses. While rigid in its own plane, a truss must be braced in a perpendicular direction to prevent lateral buckling.
Trussing
The buckling of a thin compressed element of a structural member, leading to failure of the whole.
Local Buckling
Additional bending and shear stresses in a truss member resulting from an eccentric connection or a joint fixed against relative rotation. While trusses are assumed to have idealized pin connections, truss connections in reality may be bolted, welded, or riveted, imparting a degree of rigidity to the joints.
Secondary Stresses
A change in the force of a truss member from tension to compression or vice versa caused by a change in the loading pattern.
Stress Reversal
A truss member subject to tension or compression under varying load conditions.
Counterbrace
A truss having an overall shape derived from the funicular shape for a particular set of loads. The interior members of a funicular truss are zero-force members that serve only to brace compression members but they will carry forces if any changes occur in the pattern or magnitude of the loads.
Funicular Truss
A method for determining member forces in a truss by considering the equilibrium of any portion of the truss assembly.
Method of sections.
A method for determining member forces in a truss by considering the equilibrium of the various joints idealized as points in free-body diagrams.
Method of Joints
The method of labeling the spaces between forces or their lines of action with letters, each force being identified by two letters in the adjacent spaces when proceeding in a clockwise manner around a joint.
Bow’s notation
A graphic method for determining the magnitude and character of the stresses in the members of a truss.
Maxwell diagram
A truss having inclined top chords.
Pitched truss
A lightweight wood truss used in framing a roof, usually prefabricated of 2x4s and 2x6s joined with toothed plate connectors.
Trussed Rafter
Of or pertaining to a flat or pitched truss having vertical web members in compression and diagonal web members in tension.
Pratt
A truss having parallel top and bottom chords. This trusses are generally not as efficient as pitched or bowstring trusses.
Flat Truss, parallel-chord truss
A lightweight, flat wood truss used in framing a floor, usually prefabricated of 2x4s and 2x6s joined with toothed plate connectors.
Trussed Joist
Of or pertaining to a flat or pitched truss having vertical web members in tension and diagonal web members in compression.
Howe
Any vertical member in a pitched truss, esp a king post.
Crown post
Of or pertaining to a pitched truss having only inclined web members.
Belgian
Of or pertaining to a flat or bowstring truss having inclined web members forming a series of equilateral triangles. Vertical web members are sometimes introduced to reduce the panel lengths of the top chord, which is in compression.
Warren
A truss having a curved top chord meeting a straight bottom chord at each end.
Bowstring truss
A timber bowstring truss
Belfast truss
An inclined web member joining the top and bottom chords of a truss.
Diagonal
An inclined web member joining a chord with a main diagonal.
Subdiagonal
A truss having more than two web members radiating from a common point on the bottom chord.
Fan Truss
A Belgian truss having subdiagonals to reduce the length of compression web members toward the centerline of the span.
Fink Truss
A truss having a bottom chord raised substantially above the level of the supports.
Raised-chord truss
A pitched truss having tension members extending from the foot of each top chord to an intermediate point on the opposite top chord.
Scissors truss
A truss having both top and bottom chords curving upward from a common point at each side.
Crescent Truss, Camelback truss
A steel rod serving as a king post.
Kingbolt, King rod
A timber beam stiffened by a combination of diagonal truss rods and either compression struts or suspension rods.
Trussed Beam
A palte for uniting structural members meeting in a single plane.
Gusset, Gusset plate
A metal tie rod serving as a tension member in a truss or trussed beam.
Truss Rod
A truss having timber compression members and steel tension members.
Composite truss
