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Point load on basement slab

jar546

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Applying the prescriptive provisions how did the owner size the LVL without consulting an engineer? For essentially the same price an engineer could size the LVL and address the foundation issue.
We accept cut sheets from the manufacturer showing exactly how the lvl will be used. Most of the manufacturers have PE on staff to provide these so we don't need to go to an outside engineer.
 

rktect 1

Gold Member
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Location
Illinois
So they are produced to a standard:
R502.1.2 Prefabricated wood I-joists. Structural capacities
and design provisions for prefabricated wood I-joists
shall be established and monitored in accordance with
ASTM D 5055.
R502.1.3 Structural glued laminated timbers. Glued
laminated timbers shall be manufactured and identified as
required in ANSI/AITC A190.1 and ASTM D 3737.
R502.1.4 Structural log members. Structural log members
shall comply with the provisions of ICC-400.
R502.1.5 Structural composite lumber. Structural
capacities for structural composite lumber shall be established
and monitored in accordance with ASTM D 5456.
R502.1.6 Cross-laminated timber. Cross-laminated timber
shall be manufactured and identified as required by
ANSI/APA PRG 320.

That standard is then used to produce manufacturers installation instructions (span charts)..

What's the problem?...Do you require engineering when someone uses joist hangers or do you use the manufacturers installation instructions?

R502.6 Bearing. The ends of each joist, beam or girder shall
have not less than 11/2 inches (38 mm) of bearing on wood or
metal and not less than 3 inches (76 mm) on masonry or concrete
except where supported on a 1-inch by 4-inch (25 mm
by 102 mm) ribbon strip and nailed to the adjacent stud or by
the use of approved joist hangers.

As hangers are not really prescriptive....It is whatever we will "approve"........
Boom,.....done and done.
 

Beniah Naylor

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Messages
311
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Manhattan, Kansas
Whether the solution is an I-joist or an LVL the manufacturers report is not a proscriptive provision recognized by the code.
Not code, but it is an alternative material and method that we accept in our jurisdiction that we deem to be satisfactory and complies with the intent of the provisions of the code.

The whole issue here is that we have a fairly small municipality and we try not to be too rigid if we can tell something will probably work. If we had a larger jurisdiction, there is no way I would take the extra time to study out something like point load on a slab when I could just tell them to put in a footing or get an engineer.

I certainly don't want anything structural to fail, but if it had turned out to be a simple calculation that I was comfortable with I would have been willing to work with people, if I could verify that the structure would be safe. But, the simple answer to make them put in a footing definitely is easier for me...

I appreciate these answers, they were really helpful.
 

jar546

Chief Cook & Bottlewasher
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Not code, but it is an alternative material and method that we accept in our jurisdiction that we deem to be satisfactory and complies with the intent of the provisions of the code.

The whole issue here is that we have a fairly small municipality and we try not to be too rigid if we can tell something will probably work. If we had a larger jurisdiction, there is no way I would take the extra time to study out something like point load on a slab when I could just tell them to put in a footing or get an engineer.

I certainly don't want anything structural to fail, but if it had turned out to be a simple calculation that I was comfortable with I would have been willing to work with people, if I could verify that the structure would be safe. But, the simple answer to make them put in a footing definitely is easier for me...

I appreciate these answers, they were really helpful.
How do you verify the LVL is properly sized?
Do you require a layout from the manufacturer for I-Joist systems?
 

Mark K

Platinum Member
Joined
May 12, 2010
Messages
2,133
The standards for LVL and I-joists provide the user with the allowable values to be used in the calculations. The manufactures span charts while useful are not code. Implicit in span charts are certain assumptions. In the code are span charts for sawn lumber but not for engineered lumber.

It would be informative if you can show us a standard included in the IBC or IRC to determine the capacity of joist hangers.

Is the code what was legally adopted or is it "...whatever we will "approve"...." Then why do you need a building code?
 

Mark K

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At what point does the building department transition from checking for code compliance and in effect becomes the de facto engineer of the project? When this line is crossed most legal theories would recognize that the building department legal immunity no longer exists
 

jar546

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At what point does the building department transition from checking for code compliance and in effect becomes the de facto engineer of the project? When this line is crossed most legal theories would recognize that the building department legal immunity no longer exists
I don't believe there is a fine line, I believe it is our duty to work within the scope of the code. All span tables are the result of engineering. If every single job had to be engineered, although to you, it may be utopia, to the rest of the world it is not practical. We are not specifying the job, we are ensuring that what was submitted meets the intent of the code, which may include using data from manufacturers such as Simpson Strong-Tie provides in their manuals. You, as an architect may provide a drawing with specs but if we find out that you spec'd out the wrong metal ties for the lateral load then we will will question you on it. We are not telling you what to use, just telling you that what you spec'd out is inadequate.

Again, LVL manufacturers will provide cut sheets showing the exact use and loading of each LVL. I don't need their span tables but I will accept them as an alternative method and material when there is sufficient evidence from the manufacturer that it is being used within the design and meets or exceeds the loading.
 

Mark K

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We accept cut sheets from the manufacturer showing exactly how the lvl will be used. Most of the manufacturers have PE on staff to provide these so we don't need to go to an outside engineer.
Does the manufacture have an engineer stamp and sign the recommendations? What does your state licensing law say. The need to have a professional engineer involved is determined by the states licensing laws and not by he building code or the policy of the building department.
 

redeyedfly

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Location
Minneapolis, MN
Does the manufacture have an engineer stamp and sign the recommendations? What does your state licensing law say. The need to have a professional engineer involved is determined by the states licensing laws and not by he building code or the policy of the building department.
They do extensive testing and provide ESR reports, all done by engineers. Lumber yards will also size and stamp engineered lumber for projects. Are you suggesting Weyerhauser just guesses at their technical specifications? Is there something more complicated about sizing simple span beams from Weyerhausers tables than from the IRC tables for dimensional lumber?

When is the last time you even heard of a structural failure in IRC construction? Light frame structures are exceedingly redundant structurally.

You seem to be making a problem where there isn't one.
 

Mark K

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I am just pointing out that if your state licensing laws require a professional engineer sign and seal documents then either the manufacturers, or lumber yards, engineer must stamp and sign the document or the Owner must hire an engineer to to provide the engineering oversight. The building code or the building official cannot change the licensing law.

From a legal perspective until the building code provides span tables for engineered lumber there are no span tables that can be quoted to establish compliance. This is not a question of the validity of the manufacturers calculations but rather a reflection of the legal reality.

While light frame construction is fairly forgiving, individuals who do not know what they are doing can create situations where there is non compliance. My experience is that licensed engineers are less likely to cause these problems related to their scope of services.

There is a need to have a discussion of he difference between the plan checker and inspectors checking for code compliance and acting as the designer of the project. This is of concern because of liability exposure but also because a building department employee who lacks an engineering education may not identify a problem.
 

redeyedfly

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I am just pointing out that if your state licensing laws require a professional engineer sign and seal documents then either the manufacturers, or lumber yards, engineer must stamp and sign the document or the Owner must hire an engineer to to provide the engineering oversight. The building code or the building official cannot change the licensing law.

From a legal perspective until the building code provides span tables for engineered lumber there are no span tables that can be quoted to establish compliance. This is not a question of the validity of the manufacturers calculations but rather a reflection of the legal reality.

While light frame construction is fairly forgiving, individuals who do not know what they are doing can create situations where there is non compliance. My experience is that licensed engineers are less likely to cause these problems related to their scope of services.

There is a need to have a discussion of he difference between the plan checker and inspectors checking for code compliance and acting as the designer of the project. This is of concern because of liability exposure but also because a building department employee who lacks an engineering education may not identify a problem.
I think the relevant code sections are provided above to establish that engineered lumber is in compliance if it follows the manufacturers published technical requirements. I AM a structural engineer and I don't think you need an engineer to design typical IRC. I was sizing Microllams long before I ever set foot in an engineering classroom.

Fun fact, the SEOR typically doesn't design I-joists for IBC projects. They delegate it to the I-joist supplier. They are a deferred submittal and come with a PE stamp from the supplier. They'll provide the same service for IRC.
 

Mark K

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redeyedfly​


You have obviously practiced structural engineering in another state than I have. In California the SEOR does design/select the I-Joists and there is no need for the I-joist supplier to provide an engineers stamp since the SEOR's stamp is all that is needed. By the way in California Civil Engineers can be the EOR for most projects.

The fact that the supplier has an engineer stamp and sign the design supports my contention that there is no prescriptive provisions, such as span tables, for engineered lumber and that an engineers involvement is needed.

Whether you you need an engineer to design a typical IRC project really is two questions. They are, can a non licensed individual perform the tasks and whether it is legal under the licensing laws. The answer to the first is largely subjective. While there are some non-licensed individuals can produce a "satisfactory" design in some situations, those without the technical training often do not have an appreciation of their limitations. I have seen too many individuals who believe they know more than they really do. The real question is how much risk/uncertainty are you willing to accept.

Compliance with the licensing laws is a separate issue that is defined by the state licensing laws and not by the building code or the preferences of the building official. Unless there is a clear exemption in state law an engineers involvement is needed.

From a building code perspective the manufacturers published technical requirements are not relevant. What is relevant are the standards adopted by the code and the properties of the manufacturers I-joist derived from a testing program defined by the code standards. Yes the engineer should be aware of the manufacturers recommendations but that is not a code compliance issue.
 

redeyedfly

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redeyedfly​


You have obviously practiced structural engineering in another state than I have. In California the SEOR does design/select the I-Joists and there is no need for the I-joist supplier to provide an engineers stamp since the SEOR's stamp is all that is needed. By the way in California Civil Engineers can be the EOR for most projects.
Nearly all structural engineers are civil engineers, a few are architectural engineers. In California you need to be an SE to sign as an SEOR, not a PE.
You might want to look a little closer at who is actually signing the I-joist designs. The SEOR will size the I-joists for coordination with arch but they leave the final detailed design to the supplier. If the SEOR is laying out the location of every I-joist to accommodate all superimposed loads and other coordination for MEP they are wasting their fee.

I'm not going to show you again where the code allows engineered lumber prescriptively, others have done that. You go ahead and die on this pointless hill.
 

Mark K

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In California a Civil Engineer can sign for any structural work with the exception of hospitals and public schools. All Structural Engineers are registered Civil Engineers. Thus in these cases the engineer taking responsibility for the design of the structural work can be a Civil Engineer without the structural authority. In reality the vast majority of engineers signing for structural work are Structural Engineers even if not required by licensing law. In these cases it is their authority as a Civil Engineer that allows them to act as the engineer or record for the structural work.

Not all jurisdictions would accept I-joists as a deferred submittal.

California does not recognize architectural engineers as being a separate license. I am a CE and a SE and my undergraduate degree was in architectural engineering. While California recognizes that a CE is a PE there is no generic PE license, instead engineers are licensed by discipline.

It needs to be appreciated that licensing laws vary in different states. In addition local practice can vary.
 

Mark K

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Who can identify the standard referenced in the CBC or one of the reference standards referenced by the CBC that defines the required testing for joist hangers?
 

classicT

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Not into CA, but per the IRC, this is what I will hang my hat on.

R502.6 Bearing
The ends of each joist, beam or girder shall have not less than 11/2 inches (38 mm) of bearing on wood or metal, have not less than 3 inches of bearing (76 mm) on masonry or concrete or be supported by approved joist hangers. Alternatively, the ends of joists shall be supported on a 1-inch by 4-inch (25 mm by 102 mm) ribbon strip and shall be nailed to the adjacent stud. The bearing on masonry or concrete shall be direct, or a sill plate of 2-inch-minimum (51 mm) nominal thickness shall be provided under the joist, beam or girder. The sill plate shall provide a minimum nominal bearing area of 48 square inches (30 865 mm2).

Note that the word "approved" is italicized, meaning that it is a defined term. Per Ch. 2, definition as follows.

[RB] APPROVED. Acceptable to the building official.

So not to be blunt, but I think it is due.... "It is approved because I say it is", is an acceptable answer. Simpson/MiTEK/etc. all have sufficient documentation and testing to support the design and use of their products. If used per the manufacturers specifications, it is well within my authority as a building official to accept the use of these products.
 

Mark K

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We need objective criteria that has been properly adopted. Then the acceptance by the building official would be based on whether the products complied with the standard.

We are a country of laws not an authoritarian state where individuals act as the sovereign.

Many states would consider delegating the decision to a non governmental entity such as Simpson to be illegal.

The words "acceptable to the building official" are an illegal power grab by building officials.

How would you feel if the police gave you a ticket with no other justification that the police officer wished to? According to the proposed interpretation a criminal has more rights than the individual who applies for a building permit.
 

jar546

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Not into CA, but per the IRC, this is what I will hang my hat on.

R502.6 Bearing
The ends of each joist, beam or girder shall have not less than 11/2 inches (38 mm) of bearing on wood or metal, have not less than 3 inches of bearing (76 mm) on masonry or concrete or be supported by approved joist hangers. Alternatively, the ends of joists shall be supported on a 1-inch by 4-inch (25 mm by 102 mm) ribbon strip and shall be nailed to the adjacent stud. The bearing on masonry or concrete shall be direct, or a sill plate of 2-inch-minimum (51 mm) nominal thickness shall be provided under the joist, beam or girder. The sill plate shall provide a minimum nominal bearing area of 48 square inches (30 865 mm2).

Note that the word "approved" is italicized, meaning that it is a defined term. Per Ch. 2, definition as follows.

[RB] APPROVED. Acceptable to the building official.

So not to be blunt, but I think it is due.... "It is approved because I say it is", is an acceptable answer. Simpson/MiTEK/etc. all have sufficient documentation and testing to support the design and use of their products. If used per the manufacturers specifications, it is well within my authority as a building official to accept the use of these products.
I'm with this guy.
 

jar546

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Palm Beach County Florida
We need objective criteria that has been properly adopted. Then the acceptance by the building official would be based on whether the products complied with the standard.

We are a country of laws not an authoritarian state where individuals act as the sovereign.

Many states would consider delegating the decision to a non governmental entity such as Simpson to be illegal.

The words "acceptable to the building official" are an illegal power grab by building officials.

How would you feel if the police gave you a ticket with no other justification that the police officer wished to? According to the proposed interpretation a criminal has more rights than the individual who applies for a building permit.

Which is why I use the search function of the Florida Building Code Commission to find products like this:
 
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