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    Roof Truss Estimation

    Uploaded by

    Md. Rokibul Hassan Roki
    This document provides information about estimating a roof truss for a workshop, including: - Trusses are composed of interconnected members that hold external forces in static equilibrium. - The basic building block is a triangle, and large trusses are made by connecting multiple triangles. - There are three main types of trusses: simple, compound, and complex. - Common types of roof trusses include Pratt, Howe, Fink, saw tooth, bow string, and crescent trusses. - Key truss components and terminology are defined, like bays, spans, rises, chords, and diagonals. - An example problem is worked out estimating the members of

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    Roof Truss Estimation

    Uploaded by

    Md. Rokibul Hassan Roki
    245 views6 pages
    This document provides information about estimating a roof truss for a workshop, including: - Trusses are composed of interconnected members that hold external forces in static equilibrium. - The basic building block is a triangle, and large trusses are made by connecting multiple triangles. - There are three main types of trusses: simple, compound, and complex. - Common types of roof trusses include Pratt, Howe, Fink, saw tooth, bow string, and crescent trusses. - Key truss components and terminology are defined, like bays, spans, rises, chords, and diagonals. - An example problem is worked out estimating the members of

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    This document provides information about estimating a roof truss for a workshop, including: - Trusses are composed of interconnected members that hold external forces in static equilibrium. - The basic building block is a triangle, and large trusses are made by connecting multiple triangles. - There are three main types of trusses: simple, compound, and complex. - Common types of roof trusses include Pratt, Howe, Fink, saw tooth, bow string, and crescent trusses. - Key truss components and terminology are defined, like bays, spans, rises, chords, and diagonals. - An example problem is worked out estimating the members of

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    245 views6 pages

    Roof Truss Estimation

    Uploaded by

    Md. Rokibul Hassan Roki
    This document provides information about estimating a roof truss for a workshop, including: - Trusses are composed of interconnected members that hold external forces in static equilibrium. - The basic building block is a triangle, and large trusses are made by connecting multiple triangles. - There are three main types of trusses: simple, compound, and complex. - Common types of roof trusses include Pratt, Howe, Fink, saw tooth, bow string, and crescent trusses. - Key truss components and terminology are defined, like bays, spans, rises, chords, and diagonals. - An example problem is worked out estimating the members of

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    of 6

    Estimation of a Roof Truss for Workshop

    Introduction
    The truss or framed structure are composed of interconnecting members and are supported in such a
    manner that they can hold applied external force in static equilibrium. It must hold in equilibrium is
    gravity force that are applied as a consequence of its own weight. Typically, the joint connections are
    formed by bolting or welding the end members together to a common plate, called a gusset plate. The
    basic building block of a truss is a triangle. Large trusses are constructed by attaching several triangles
    together. A new triangle can be added truss by adding two members and a joint.

    Definition of Truss
    A truss is a configuration, which is designed to sustain inclined, vertical, horizontal loads accruing at or
    between its points of support.

    Types of Trusses
    They are mainly three types
    1. Simple,
    2. Compound,
    3. Complex.

    Fig. simple truss Fig. Compound truss Fig. Complex truss

    Types of Roof Truss


    1. Pratt truss,
    2. Howe truss,
    3. Fink truss,
    4. Saw tooth truss,
    5. Bow string,
    6. Crescent. Etc.

    Fig: Pratt truss Fig: Howe truss

    Fig: Saw Tooth truss Fig: Bow string truss


    Fig: Crescent truss Fig: Three-Hinged Arch

    Basic Terminologies of a truss


    Bay: Bay is the distance between two main trusses.
    Span: Span is the distance between supports of a truss.
    Rise: The rise of a truss is vertical distance between apex and line joining the supports.
    Pitch: The ratio of the rise to the span is called the pitch.
    Top Chord: The uppermost line of members which extend from one support to the other through the apex is called
    the upper chord.
    Bottom Chord: The bottom chord consists of the lowermost line of members extending from one support to other.
    Vertical: Vertical members connecting top and bottom chords.
    Diagonal: Inclined members connecting top and bottom chords.

    Fig: Terminologies of a Truss System

    Fig: Components of a Truss


    Fig: Bracing System of truss

    A Typical Compound Fink Roof Truss

    Fig. Compound fink truss


    Worked Out Problem
    A Howe type roof truss was designed from the following data:
    Design Data:
    Span = 40 feet
    Span-to-rise ratio (pitch) = 4:1
    Rise = 10 feet
    Bay distance (truss-to-truss distance) = 25 feet.
    Exposure category: Exposure A
    Truss is supported on brick wall of height = 12 feet.

    3@7.45’ = 22.36’

    3 @ 3.33’ = 10’

    6 @ 6.67’ = 40’
    Solution:

    The various members of the truss network are designed as follows: Table: Calculation of total
    weight of the truss members
    Total weight of steel members = 702.611 lb
    Unit Price = A tk/lb
    Total Cost= 702.611 ×A = X1 tk
    Erection and Welding Cost = 10% of total cost= X2, Estimated cost=X1+X2 tk

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