Integrated Buildings & Structures

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  • 1.  Building extension project

    Posted 07-03-2019 03:36 PM
    Edited by Tirza Austin 07-03-2019 03:35 PM
    I recently got a project extension of an existing hotel. It consisted of 3 floors including the ground floor. The client needed additional one floor and roof trace. The building is more than 25 years old. I prefer to go with destructive tests specially for columns and need to verify the size of the foundation. I'm looking for suggestions and some guidance on to which extent all of these need to be carried out.

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    Kuranage Akila Nadishan Perera A.M.ASCE
    Ja-Ela- Sri Lanka
    0777487220
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  • 2.  RE: Building extension project

    Posted 07-04-2019 08:58 AM
    ​Can't you rely on structural drawings for the existing building?

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    Amir Eghtesadi Aff.M.ASCE
    Thornhill ON
    1416 9852647
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  • 3.  RE: Building extension project

    Posted 07-04-2019 07:23 PM
    Where is the hotel located? What Code are you using? What is the hotel constructed?

    • I would make sure that the client understands that the building will(should) come up to current Code due to the vertical addition. 
    • The roof was likely not designed to floor loads and will probably need to be rebuilt. 
    • the existing lateral system will not meet current Code and will need to be re-evaluated.
    • i believe the Fire Code requirements change once you go above 3 floors. You'll need to check that too. Is the building sprinkled? 
    • Even if the foundations are adequate for gravity loads they likely will not satisfy the increased lateral loads especially for shear wall/frame anchorage. You can design underpinning pads to account for the increased loads.
    • i would tell the client they need to hire a contractor and an inspection engineering firm(similar to special inspection firm) to determine any components you need prior to design phase. 
    • As built drawings definitely help but you can't always rely on them to be accurate. Verification in field should be noted on your plans.
    • Remember the client will likely try and cut corners or press you hard to not strengthen the building as you have recommended. Client selection is important, prior to working for them an understanding of the required work should be agreed. If you feel like they want to cut corners, walk away from the project.
    I hope my comments help.

    cheers,
    elliot

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    Elliot House P.E.,S.M.ASCE
    W.B. Clausen Structural Engineers
    Emeryville CA
    (415)444-4144
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    Original Message


  • 4.  RE: Building extension project

    Posted 07-04-2019 07:23 PM
    It's really hard to find existing drawings.

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    Kuranage Akila Nadishan Perera A.M.ASCE
    Ja-Ela
    0777487220
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    Original Message


  • 5.  RE: Building extension project

    Posted 07-04-2019 07:25 PM
    Consider designing the building addition (project extension) such that very little load (if any) is carried by the existing structure.  This can be accomplished using cantilevers in the framing, and grade beams cantilevering over new footings.  Footings should be located far enough away that they do not affect the existing ones.  Make sure that a geotechnical specialist analyzes the soil and recommends the design bearing pressure and expected settlement.  Unless the existing drawings indicate otherwise, the footings and columns were likely not designed for the additional loads from an extension (both gravity and lateral loads).

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    Richard Lenz
    LM, ASCE, Retired
    West Chester OH
    (513) 777-5525
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    Original Message


  • 6.  RE: Building extension project

    Posted 07-05-2019 10:38 AM
    I wrote this assuming that the addition was to the side.  If on top, these comments do not apply.

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    Richard Lenz
    LM, ASCE, Retired
    West Chester OH
    (513) 777-5525
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    Original Message


  • 7.  RE: Building extension project

    Posted 07-05-2019 04:47 PM
    Thank you very much for comments. It's vertically increasing two floors up. In Sri Lanka we might have many projects as same condition.

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    Kuranage Akila Nadishan Perera A.M.ASCE
    Sri Lanka
    0777487220
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    Original Message


  • 8.  RE: Building extension project

    Posted 07-06-2019 11:19 AM
    Edited by Tirza Austin 07-06-2019 11:18 AM
    Since, you don't have that executed drawings, it is better to do an analysis with additional floors or roof and identify extra loads to be transferred. Then develop an extra load transferring mechanism and determine a path. Then you will be able to enhance the structural capacity with additional members. Steel members can be used in this purpose. However, proper analysis and understanding is important.

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    Rohana Dasanayake M.ASCE
    Assistant Construction Manager
    Padukka
    940715331700
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  • 9.  RE: Building extension project

    Posted 07-06-2019 02:59 PM
    Edited by Tirza Austin 07-06-2019 02:58 PM
    Thank you very much for your valuable comments. I hope it will be a better option. 


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    Kuranage Akila Nadishan Perera A.M.ASCE
    Ja-Ela
    0777487220
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    Original Message


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