I did a home 5 years ago. built in 1992. In the middle of the crawl space, 1/2 of the beam sits on a pier. Someone is now saying this beam should be centers on the pier. I can not find anything that says the beam can sit anywhere on a pier as long as there is no lateral movement. I need some documation.
You may find your answer here…
Im sorry. It doesn’t say anything about wood beam sitting on top of a pier. Does it have to be centered on a pier? I believe not.
Need more exact info. I can read your post in multiple ways. Post a pic, or draw out a sketch and post it.
does a beam have to sit on the middle of a CMU when under the middle of the home?
Can 1/2 of the width of the beam ( the beam is two 2X10’s) sit on the on the pier or does the whole 4 inches need to be centered on the pier. This pier is in the middle of the span.
1/2 of beam having bearing on a pier, is this some sort of a joke?
If only half of a beam is resting on its support, then I don’t believe you could call that beam “fully supported”, and the degree to which the support would be adequate would be anyone’s guess. The adequacy of the support would also be affected by which portion of the CMU was bearing the load.
It certainly wouldn’t qualify as best practice.
Note: 2- 2x10 together measure 3 inches, not 4.
This is called an eccentrically loaded pier, and it should be called out for a SE to evaluate. There is a specific, iterative calculation that can be performed to determine stability.
On a rectangular support column the beam should be centered over the middle third, represented by the red diamond in the attached graphic. The wood beam should be fully supported, i.e. no overhang. the technical term for the column is “Middle Third Rule” for a round column you use the “Middle Quarter Rule”.
Randy, nice graphic! when shimmed, how is “beam should be fully supported” defined? what would be the minimum required or prescribed. The width of the pier? what if the pier was over designed?
Without any proper pictures of the actual pier and beam orientation, it is really hard to answer this appropriately.
The standard building practice alone would tell you that a built-up 2 piece beam supported on only one member while traversing the center pier of a span is wrong. As noted in the IRC, any beam bearing on masonry, should be a minimum of 3". There is a reason for that. You do not want bearing of the beam on the shell of the block pier. What you are describing is just like have a beam supported on a pier that is set totally off to one side of a 2’ square footing instead of being in the center. That creates, as an engineer would say, a moment, which is basically the eccentricity of load on the pier creating rotation.
The other reason is common sense. Not knowing the loading criteria, you need to just think of rotation due to the off balance bearing.
You might want to just browse through this link to see if anything in there helps you out to compare to what you should be seeing.
Hope that helps a little.
Good commentary, Marcel!
Simon, Keep in mind the building codes cover common building methods. If you have unusual loads or high concentrated loads a steel bearing plate may be needed. For example a two story house with a stick built roof will transfer some roof load to the 2nd floor and the 2nd floor loads plus the roof loads will be transferred to the 1st floor and the 1st floor loads plus the 2nd floor loads plus the roof load will transferred to crawlspace beam. To complicate the issue if the 1st floor load bearing wall has large openings with a header beam the columns supporting the header beam will induce very large concentrated loads and so on… When doing a visual inspection just remember the house structure works as a system and it is as strong as its weakest link in the system. Describe what you see and document your limitations. The more experience you get the better you will be able to spot items out of the ordinary. We all work with limited information, me included, and try to piece what information we get to determine if something needs further evaluation or not and get up the next day and do it all over again.