IS6 - Plane Truss.pdf

TOPIC 6 : BASIC STRUCTURAL SYSTEM PLANE TRUSS 1.0 Structural Principle The TRIANGLE is the only hinged polygon that has an inherently stable s...

TOPIC 6 : BASIC STRUCTURAL SYSTEM PLANE TRUSS 1.0 Structural Principle The TRIANGLE is the only hinged polygon that has an inherently stable shape. It is geometrically rigid. A TRUSS is a structural assembly based on the GEOMETRIC RIGIDITY OF THE TRIANGLE. The triangulated truss members distribute loads to supports through a combination of pin-connected members that are in either pure COMPRESSION or TENSION (no bending or shear) and all thrust forces are resolved internally. DTA30333 | BUILDING STRUCTURE | KOLEJ KEMAHIRAN TINGGI MARA PASIR MAS 22  TOPIC 6 : BASIC STRUCTURAL SYSTEM PLANE TRUSS 2.0 Truss Members CHORD The principal members of a truss extending from end to end and connected by web members. Top chord and bottom chord. WEB The integral system of members connecting the top chord and the bottom chord of a truss. NODE A joint between two or more members of a truss. 3.0 Types of Trusses There are TWO main types of trusses: PLANE TRUSSES have all members in a single plane. SPACE TRUSSES have members in a 3-dimensional configuration. Plane Truss Space Truss DTA30333 | BUILDING STRUCTURE | KOLEJ KEMAHIRAN TINGGI MARA PASIR MAS 23  TOPIC 6 : BASIC STRUCTURAL SYSTEM PLANE TRUSS 4.0 Classification of Plane Trusses 4.1 Pitched Truss 4.2 Flat Truss / Parallel-chord Truss DTA30333 | BUILDING STRUCTURE | KOLEJ KEMAHIRAN TINGGI MARA PASIR MAS 24  TOPIC 6 : BASIC STRUCTURAL SYSTEM PLANE TRUSS 4.3 Arched Truss 4.4 Composite Truss DTA30333 | BUILDING STRUCTURE | KOLEJ KEMAHIRAN TINGGI MARA PASIR MAS 25  TOPIC 6 : BASIC STRUCTURAL SYSTEM PLANE TRUSS 5.0 Support 5.1 Single Layer Support Trusses and girders supported on COLUMNS. Trusses and girders supporting PURLINS. Spacing of truss = Span of purlin Spacing of purlin = Type of ROOF FINISH 5.2 Double Layer Support Trusses supported on VALLEY BEAMS or LATTICE GIRDERS, which are supported on columns. Less number of columns. Trusses supporting purlins. DTA30333 | BUILDING STRUCTURE | KOLEJ KEMAHIRAN TINGGI MARA PASIR MAS 26  TOPIC 6 : BASIC STRUCTURAL SYSTEM PLANE TRUSS 5.3 Splayed Poles Support Spring out at top of column heads. 4 nos. splayed poles. Minimise number of columns at human height. Maximise support for trusses at roof level. Span of truss is reduced. Section Equal spacing for trusses. Angle of splay and height of column head to be adjusted in order to arrive at equal spacing for trusses. Plan DTA30333 | BUILDING STRUCTURE | KOLEJ KEMAHIRAN TINGGI MARA PASIR MAS 27