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  • 1.  Can we convert Load bearing structure to Frame Structure?

    Posted 11-14-2023 10:04 AM

    What are the potential risks associated with the conversion of Load bearing structure to Frame Structure, and how can they be mitigated?



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    Ahmad Jamal Khan S.M.ASCE
    Abbottabad
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  • 2.  RE: Can we convert Load bearing structure to Frame Structure?

    Posted 11-20-2023 10:41 AM

    Frame structure is more strengthening but cost high, now a days since the walls are of big blocks bonding efficiency less so frame structure is recommended. For the framed structure alignment of columns and beams is a skilled job to take torsion some eccentricity is needed. A balanced load bearing structure has been framed effectively not always. Area of the ground floor having several spans interior walls bending moment are high so thickness must be more this can be over come by frame structure. 

    It's convenient and safe to give strip mat foundation with mullions for two or three floors. 



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    Alex Thomas R.Eng, C.Eng, M.ASCE
    Senior Site Engineer
    Geo Structurals Pvt Ltd
    CochinAlexThomasR.Eng, C.Eng, M.ASCEIndia
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    Original Message


  • 3.  RE: Can we convert Load bearing structure to Frame Structure?

    Posted 11-28-2023 10:21 AM

    My my main thought when it comes to the differences between load bearing & frame structures focus on lateral design along with all the load path components.  Going from load bearing to frame seems easier when it comes to lateral because a bearing wall system would presumably have the diaphragm & shear walls needed.  



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    Kevin Muich P.E., M.ASCE
    President
    Madison WI
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    Original Message


  • 4.  RE: Can we convert Load bearing structure to Frame Structure?

    Posted 11-29-2023 10:06 AM

    Is it a multi-story structure? are you removing ALL the load bearing walls? If not, you're potentially creating an inverted pendulum lateral system. but maybe that is a moot point. Also, are there bar joists? Most structures that want to remove LB walls will place the new steel frame "inside" of the skin from the wall. This can be very complicated if its bar joists. if you're placing the new flame in the same plane as the masonry, you have to consider temporary framing to hold up the existing roof/floor system. Still a mess if bar joists frame the horizontal planes. Also, with multi-story buildings, the  diaphrams wil frequently be broken by continuous LB walls. Consequently you'll need create a band-aid across those "gaps" and reanalyze the affected diaphrams. . . or place a steel frame at each occurence with its own lateral support. Of course that is still complicated because the LB wall can vary in width from probably 6" to 12"+. the beams will generally have 6 inch-ish flanges. is there actually adequate seating of the horizontal members on the new steel flange. if the bays on each side are significantly different spans, a cap plate to provide suitable seating may induce a lot of torsion. And then there is deflection if its multi-story and you're only removing say one floor of LB wall. L/600 or 0.3" is difficult to get with long  spans and/or short (vs tall) beams. how much clearance do you need beneath your steel that you're doing this? How long of a span is needed or desired that this is an option?

    Anyway, those are the initial thoughts that crossed my mind. I could probably think of more pitfalls if I spent another hour on it.

    Oh! spread footings for the columns could be a bitch too.

    -Nathan



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    Nathan Smith P.E., M.ASCE
    Engineer
    Greensboro NC
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    Original Message


  • 5.  RE: Can we convert Load bearing structure to Frame Structure?

    Posted 11-30-2023 08:08 AM

    IF THE LOAD BEARING STRUCTURE IS ALREADY IN LACE AND NOW IT IS INTENDED TO CONVERT IT TO A FRAMED STRUCTURES, IT MAY BE DIFFICULT AND NOT RECOMMENDED. THE POINT ALSO INDICATES THE LACK OF PLANNING IN THIS CASE. A FRAME WITH INFILLS CAN BE ERECTED AS ITS CONSTRUCTION WILL BE EASIER AND WILL FOLLOW SOME STANDARDS BUT THEN IT SHOULD BE CONSIDERED THE ROLE OF IN-FILLS FOR SEISMIC LOADS. IT MAY BE POSSIBLE THAT IT WORLD ENHANCED TE IN PLANE STIFFNESS BUT THEN WHAT TO DO ABOUT THE PUSH OF INFILL WALLS TO COLUMNS OR WHETHER SOME ALTERNATE SCHEME IS APPLIED. SO INITIAL PLANNING IN VERY ESSENTIAL AD ONE SHOULD NOT RUN INTO EXECCUTION IN HURRY.



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    Syed Rizwan M.ASCE
    Professor
    NUCES -FAST
    Lahore
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    Original Message


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