Recent content by jamesm

Thanks for the help. I got the moment figured out finally, I calculated it with AutoCAD after calculating the moment of a few known sections to make sure I was doing it right.

The second moment of area is what I am looking for. I understand the need for parallel axis theorem, but I do not follow this: "you must also calculate how the MOI changes when the axis is rotated with respect to the principal centroidal axis.". This is what I'm using to get my data for...

Thanks for the answer. That is similar to what I was thinking. I will have to calculate the moment of inertia for the columns myself since the cookbook answer (9.28 in^4) is most likely calculated using the columns own neutral axis.

Good morning PF, I am having some difficulty finding info on calculating a composite moment of inertia. The section I am working with is 8 separate columns (WT5x15) arranged evenly spaced around the circumference of a circle. You can see what I'm taking about in the attached jpg. I found...

If I decide to stick with the slide bearing idea I will probably use Teflon or UHMW Polyethylene since it has a lower coefficient of friction. I did find that the UHMW has a compressive strength of 3000 psi. The pressure that the column exerts on the UHMW will be ~150 psi so I'm thinking it will...

Thank you for the link. The ring girder is holding up a large pipeline filled with water. The most significant loading on the ring girder will be from the weight of the contents of the pipe and a possible moment caused by the friction resisting the columns tendency to slide laterally. (as...

I could use some guidance as to how I would analyse the stresses in a ring girder similar to the one shown in the attached picture. I have found the stress in the columns that support the ring but I do not know how to find the maximum stress in the ring. The best I have been able to come up with...

I am going to attempt to use a sheet of HDPE between a concrete footing and the base of a column to allow the column to move with thermal expansion in the structure it is supporting. My question is how can I determine if the HDPE will be crushed by the weight of the column and no longer act as a...

I am currently working on a project where I need to determine the minimum thickness required in some exposed steel penstocks. It seems to be a straight forward project, however I have been having trouble finding information on calculating the internal pressure increase due to water hammer in the...