Foundation Design for Pre Engineering Metal Building 6

[Samwise Gamgee]

Has anyone done foundation design for pre engineering metal buildings? Please reference any useful resources or design examples.

 

[1503-44]

I was quite surprised to find that. I enjoyed the workshop visit a lot more than touring the cathedral above. I had to buy a separate workshop ticket though, but well worth it for any engineers in the crowd.

 

[MCORTEZ]

dik, do you have drawings we can use as reference. I am working on a slab for a metal building that will require grade beam and step footing. I'd like to see your design for reference. Thanks

 

[dik]

I don't off the top, what type of foundation are you looking at? Strip footing with walls, spread footings with piers and grade beam? If sloped, a stiffened edge slab is not likely good if the difference in elevation is anything significant. I posted the attached to two earlier posts on this site.

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1641071832/tips/SDF_hnbzzh.pdf[/url]

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/raw/upload/v1641071832/tips/SDF_lm2mw2.dwg[/url]

If a grade beam, it's just a matter of changing the length of the pier, keeping the spread footing at the elevation required. Just be careful that the slope of one footing to the next is less than about 2:1 or 3:1 (H:V).

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

My notes for metal building systems (PEMBs), edit as req'd. Foundations are 'foundations'.

METAL BUILDING SYSTEM (MBS)

MANUFACTURER SHALL BE A MEMBER OF THE MBMA AND SHALL BE CERTIFIED TO IAS AND TO CSA STANDARD A660

THE METAL BUILDING SYSTEM MANUFACTURER SHALL SUBMIT MBS IS COMPLIANT WITH CURRENT EDITIONS OF CSSBI 30M, B8, B15, B20, S8, AND S17, EXCEPT AS NOTED BELOW. SUBMIT CERTIFICATION TO THE [OWNER | CONSULTANT | ENGINEER] PRIOR TO SHIPMENT OF THE PREFABRICATED BUILDING TO SITE

DESIGN STANDARDS FOR THE METAL BUILDING SYSTEM ARE TO MEET THE REQUIREMENTS OF PART 4 OF THE [NBCC | MBC |SBC], CSA STDS S16 AND S136 EXCEPT AS NOTED BELOW

WELDING SHALL BE PERFORMED IN ACCORDANCE WITH CSA W59. MANUFACTURER TO BE APPROVED BY THE CANADIAN WELDING BUREAU, IN ACCORDANCE WITH CSA W47.1 FOR DIVISION 1 OR DIVISION 2

MBS BUILDING TYPE IS [RIGID FRAME CLEAR SPAN | MULTI-SPAN | GABLED | MONO SLOPE]

END WALL FRAMING SHALL BE [EXPANBABLE | NON-EXPANDABLE]

LATERAL BRACING SHALL USE [CROSS-BRACING | MOMENT RESISTING PORTAL FRAMES]

ALL STRUCTURAL STEEL COMPONENTS, INCLUDING ANCHOR RODS SHALL BE CERTIFIED AS WELDABLE. REFER TO ANCHOR ROD NOTES FOR ANCHOR ROD REQUIREMENTS

COLUMN FLANGE BRACING SHALL NOT BE USED UNLESS APPROVED BY THE [OWNER | CONSULTANT | ENGINEER] IN WRITING

SUPPORTING COLUMNS AND BUILDING FRAMES SHALL BE PINNED AT BASEPLATE CONNECTIONS

DESIGN OF THE BUILDING FRAME AND ALL COL MEMBERS SHALL ASSUME THAT ALL FRAME AND COL BPS ARE SUPPORTED ON [1" | 1/4"] OF GROUT

BUILDING LENGTH AND WIDTH SHALL BE MEASURED FROM THE OUTSIDE FACE OF THE GIRT LINE. THE WIDTH OF THE BUILDING SHALL BE IN THE DIRECTION OF THE RIGID FRAME SPAN AND THE LENGTH OF THE BUILDING SHALL BE IN THE DIRECTION OF THE BAY SPACING.

COORD X-BRACING ELEMENTS WITH ARCH TO PREVENT CONFLICT WITH OPENINGS

COLUMN LOCATIONS SHALL BE AS SHOWN ON THE STRUCTURAL DRAWINGS

BUILDING HEIGHT SHALL BE MEASURED FROM FINISHED FLOOR TO THE INTERSECTION OF THE INSIDE SURFACES OF THE ROOF AND WALL COVERING

WALL GIRTS SHOULD BYPASS RIGID FRAMES

MIN ROOF PITCH SHALL BE 2:12 U/N

ROOFING SHALL USE [STANDING SEAM | THROUGH-FASTENING] ROOF

MIN ROOF PITCH FOR STANDING SEAM ROOF PITCH SHALL BE 1/2:12 U/N

WALL AND ROOF PANELS SHALL BE 26 GA MINIMUM THICKNESS

ROOF PANELS SHALL BE 24 GA MINIMUM THICKNESS FOR STANDING SEAM ROOFS

PREFABRICATED METAL BUILDING SYSTEM SUPPLIER SHALL SUPPLY ALL ANCHOR RODS, NUTS AND WASHERS TO SECURE THE BUILDING TO THE FOUNDATION. ANCHOR RODS ARE TO BE DESIGNED FOR ALL HOR AND VERT LOADS
BUILDING FRAME TOTAL LATERAL DEFLECTION AT THE HAUNCH SHALL NOT EXCEED [H/120 | H/360 | H/600 (PROVIDING CRANE SUPPORT)] WHERE HEIGHT IS THE HEIGHT OF THE WALL

THE TOTAL COMBINED LIVE LOAD DEFLECTION FOR THE GIRTS AND SIDING SHALL NOT EXCEED L/240

THE TOTAL LIVE LOAD DEFLECTION FOR THE ROOF DECK SHALL NOT EXCEED L/240

THE TOTAL LIVE LOAD DEFLECTION FOR THE ROOF PURLINS SHALL NOT EXCEED L/240

THE TOTAL LIVE LOAD ROOF GIRDER DEFLECTION SHALL NOT EXCEED L/180

THE BUILDING MANUFACTURER SHALL PROVIDE A 25 YEAR WARRANTY FOR ROOF AND SIDING FINISH

THE BUILDING MANUFACTURER SHALL PROVIDE A 10 YEAR WARRANTY FOR LEAKAGE

THE BUILDING MANUFACTURER SHALL PROVIDE A 10 YEAR MANUFACTURERS ROOF WARRANTY AND A 15 YEAR SIDING WARRANTY AGAINST DEFECTS IN MATERIALS

THE CONTRACTOR SHALL CARRY A 5 YEAR WARRANTY AGAINST DEFECTS IN WORKMANSHIP
THE BUILDING SHALL BE COMPLIANT WITH THE REQUIREMENTS OF [ASHRAE 90.1 | THE CURRENT NATIONAL ENERGY CODE]

MATERIALS SELECTED SHALL MINIMISE GALVANIC CORROSION. PROVIDE SUITABLE INSULATING MATL AS NECESSARY

THE MBS SUPPLIER SHALL PROVIDE FOR SUPPORT OF ANCILLARY STRUCTURAL ELEMENTS WHERE NOTED ON THE DWGS. THE METAL BUILDING SUPPLIER SHALL PROVIDE FOR REDUCED DEFLECTION LIMITATIONS AS REQUIRED FOR ATTACHMENT AND SUPPORT OF OTHER BUILDING COMPONENTS

SHOP DRAWINGS SHALL SHOW THE ANCHOR SETTING LOCATIONS FOR THE BUILDING. ANCHOR SETTING DWG SHALL SHOW:
ANCHOR ROD LOCATIONS, TYPE, DIA, PROJECTION AND LENGTH, MAX AND MIN REACTIONS BASED ON THE LOAD COMBINATIONS STIPULATED IN THE BUILDING CODE IN EFFECT IN THE PROVINCE WHERE THE PROJECT IS LOCATED SHALL BE PROVIDED (A TABULAR FORM SHOWING LOADING REACTIONS FOR VARIOUS LOAD CASES IN NOT ACCEPTABLE)

THE BUILDING SHALL BE INSULATED AND THE PREFABRICATED METAL BUILDING SUPPLIER SHALL SUPPLY ALL NECESSARY THERMAL BLOCKS AND INSULATION

INSULATION SHALL BE PROVIDED BY MBS SUPPLIER

PURLIN BRACES ARE TO BE PROVIDED IN ACCORDANCE WITH CSA S136, CLAUSE 8. IN PARTICULAR, FOR A STANDING SEAM ROOF SUPPORTED ON MOVABLE CLIPS, BRACES PROVIDING LATERAL SUPPORT TO BOTH TOP AND BOT PURLIN FLANGE ARE TO BE PROVIDED. THE NUMBER OF ROWS SHALL BE DETERMINED BY ANALYSIS BUT IN NO CASE TO BE LESS THAN 1 FOR SPANS UP TO 23 FT. OR LESS THAN 2 FOR SPANS GREATER THAN 23 FT

FOR COATING SYSTEM, REFER TO COATING SYSTEM NOTES

THE BUILDING SHALL BE COMPLIANT WITH THE REQUIREMENTS OF FM GLOBAL FOR AN [1-60 | 1-75 | 1-90] RATING


Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[yudkib]

I haven't posted on here in forever, but wanted to jump in and say the model of the Sagrada Familia is quite impressive. Thanks for sharing that. As to when that sort of modeling came about, I heard in school that inverted catenary arch footbridges predated the ancient romans. They would hang a cable between landings, scribe it, make the corresponding falsework and build the stone arch support off of that. I would think that's 2nd/3rd century BC at the very latest. Quite primitive by comparison to Gaudi, but I would think catenary domes were not far behind and its ultimately a very similar principle. Gaudi just accounted for differences in mass because of the size of the structure.

 

[SandwichEngine]

Dik,

I have a question about your standard notes. Why do you require the building to be in compliance with FM Global?

FM Global is an insurance company that essentially says that if you design your building more stringently than the normal codes, it's less likely to pay a settlement and therefore will give you a reduction in your insurance. In order for a building to actually be compliant to FM Global, the particular FM Global requirements of the roof (1-60, 1-75, etc.) must be determined based on loading and geometry and they won't be the same for the entire roof. You would also have to design your building as partially enclosed in most cases, apply a 1.15 factor to your wind loading, not reduce live load, calculate roof snow differently, etc. Requiring this when FM Global insurance isn't actually being sought could add substantial unnecessary cost to the building.

A lot of times however, a note like the one above will be interpreted as just providing roof and wall systems that have been tested to whatever FM Global requirement you choose. When that happens, you limit the possible systems on a building considerably. For example, MBCI is a panel manufacturer that makes dozens of roof and wall panels. They only have 3 that they've paid to have tested for FM global. All of them have been tested for wind loading and an engineer could use any of them to work for the loading on a building. If you restrict them to only the one's they've tested for FM Global and the client is not actually seeking FM Global insurance, you've taken away many options and possibly increased cost arbitrarily. One example of an arbitrary increase in cost is standing seam roof panels tested for FM Global always use floating or sliding clips, whether or not they are required. This may sound inexpensive but that itself would add thousands of dollars to any project.

 

[dik]

In addition to the MBS notes above,I also include supplemental loading requirements for dead and live loads applied to purlins, frames and haunches.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dik]

These are notes that I use for all projects and are part of a 400K text file that I edit for each project. Not all clients require FM Global compliance, and if they don't, then the note is removed. FM Global forces an additional loading and likely durability. I personally don't like MBS buildings; I consider them 'throw away' structures after 25 years. If you have to modify them in almost any fashion you void any warranty they might have had.

Having said that, I appreciate the level of engineering that goes into the design of them.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik