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    Tied Foundations-Portal Frame

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    Jaime Manalili Landingin
    Tied foundations are used to take advantage of opposing horizontal forces by connecting foundations together with a tie beam. This reduces the horizontal force that needs to be resisted by the ground. The tie can also reduce movement and foundation costs. When designing tied foundations, consideration should be given to connecting opposing forces with a tie beam to reduce or eliminate the horizontal force. The individual foundations are then designed accounting for the forces resisted by the tie. The tie itself must be designed and detailed to transfer forces without slippage, usually using a tie rod or reinforced concrete beam.

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    Tied Foundations-Portal Frame

    Uploaded by

    Jaime Manalili Landingin
    400 views3 pages
    Tied foundations are used to take advantage of opposing horizontal forces by connecting foundations together with a tie beam. This reduces the horizontal force that needs to be resisted by the ground. The tie can also reduce movement and foundation costs. When designing tied foundations, consideration should be given to connecting opposing forces with a tie beam to reduce or eliminate the horizontal force. The individual foundations are then designed accounting for the forces resisted by the tie. The tie itself must be designed and detailed to transfer forces without slippage, usually using a tie rod or reinforced concrete beam.

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    Portal Framed

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    Tied foundations are used to take advantage of opposing horizontal forces by connecting foundations together with a tie beam. This reduces the horizontal force that needs to be resisted by the ground. The tie can also reduce movement and foundation costs. When designing tied foundations, consideration should be given to connecting opposing forces with a tie beam to reduce or eliminate the horizontal force. The individual foundations are then designed accounting for the forces resisted by the tie. The tie itself must be designed and detailed to transfer forces without slippage, usually using a tie rod or reinforced concrete beam.

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    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    400 views3 pages

    Tied Foundations-Portal Frame

    Uploaded by

    Jaime Manalili Landingin
    Tied foundations are used to take advantage of opposing horizontal forces by connecting foundations together with a tie beam. This reduces the horizontal force that needs to be resisted by the ground. The tie can also reduce movement and foundation costs. When designing tied foundations, consideration should be given to connecting opposing forces with a tie beam to reduce or eliminate the horizontal force. The individual foundations are then designed accounting for the forces resisted by the tie. The tie itself must be designed and detailed to transfer forces without slippage, usually using a tie rod or reinforced concrete beam.

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    of 3

    Tied foundations - Design.

    Introduction
    Tied foundations are often adopted as a means of exploiting to advantage opposing forces. This
    is achieved by linking them together via a tie or tie beam. The effect this has on the design is to
    reduce the horizontal force requiring to be resisted by the ground (see Fig. 12.1 (a)).
    The use of a tie can reduce the amount of movement likely to occur in developing the reaction
    and reduce the cost of the foundation.

    Fig. 12.1 Tied foundation.

    Design decisions
    In any situations where horizontal forces, such as thrusts from portal frames, etc., act in opposite
    directions, consideration should be given to connecting the forces via a tie in order to reduce or
    totally react a horizontal force. For example, if the forces are equal and opposite then the total
    force can be reacted. On the other hand, if the forces are opposite and not equal, the smaller of
    the two forces can be tied and the remainder left to be reacted by foundation 1 or, if a higher tie
    force is used, foundation 2 can also be utilized, thereby reducing the force to be taken in passive

    pressure (see Fig. 12.1 (b)).

    Sizing the foundations


    The main pad foundations are designed in the same way as those previously discussed in Chapter
    11 but taking into account the tie force reaction in accordance with the above considerations. The
    tie itself must be designed to resist the force H1 or H2, as the case may be, and must be detailed
    to
    transfer this force without excessive slip or failure between the bases of the stanchions.
    This is usually achieved by designing a tie rod for the total force using appropriate permissible
    tensile stresses for the steel and ensuring that suitable mechanical anchorage or bond anchorage
    is achieved in the details between the stanchion and tie (see Fig. 12.2).
    In detailing these ties, the detailer should ensure that the tie acts on the centreline of the
    horizontal thrust force or that any eccentricity produced is designed into the foundation by the
    designer. The tie rod itself could contain a turn-buckle for tensioning in order to reduce lateral
    movement due to possible slackness in the rod, alternatively, if adjustment is not required, a
    reinforced concrete tie beam as shown in Fig. 12.3 could be used. Care should be taken to
    ensure axial tension across any connections which may be required in the tie by the use of turnbuckle or male/ female-type plate connectors. In the case of portal framed factories it is often
    desirable to construct the oor slab after
    erection and cladding of the building. In this case the engineer must ensure that all tie members
    are constructed and covered prior to the erection of the steelwork, in order that the presence of
    the tie members does not impede the construction process.

    Fig. 12.2 Tie anchorage.

    Fig. 12.3 Reinforced concrete tie beam.

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