Reference Thread: thread176-453592
I ran across this thread referenced above which has been closed; however, it was a good question and it didn't appear that anyone had answered the original post. I had the same question/concern as the original poster, and so I researched this topic. I...
I know this isn't the conventional structural question, but I haven't had any response in the vibration forum. The question is a mix of vibration and stress. I have a pendulum with a spring attached. I can determine a relationship to predict the natural frequency of the system. Where I'm...
I'm not sure of the best forum to post this question, so I thought I would try here. I have a pendulum with a spring attached. I can determine a relationship to predict the natural frequency of the system. Where I'm having trouble is finding a relationship to predict the maximum bending...
If a structure is flexible (NF < 1 Hz), then we must calculate the flexible gust factor. If the structure has a stiffness which is significantly different in each direction, do we still base the gust factor on the lowest natural frequency for the entire structure? Or is the intent to...
I am working on Gasoline Storage Sphere built sometime in the 60's and they have indicated the material is A-212-A. I have found lots of information on A-212-B, but I can't find any properties for A-212-A. Can anyone tell me the difference between Grade A and B?
Are spheres usually designed...
I have a pressure vessel that was not originally designed or constructed to ASME Sec. VIII, Div. 1. It wasn't designed or constructed to any code that I can determine. In API-510 Para 7.7 there is a section for "Evaluation of Existing Equipment with Minimal Documentation". I've followed this...
I am building a home, and have a brick arch over an entry way. Due to a mistake, the arch is wider and flatter than originally intended. I don't have any experience with masonry, and was looking for some guidance on how to confirm that this arch is adequate to support the weight of the brick...
I have a question regarding tank design per API-650. I have a small (30 ft OAH x 12.5 ft OD) tank that is shop fabricated. The tank is in a very high wind zone, and I am verifying that the tank is adequate for overturning. My question is whether you must consider the tank to be empty (no...
I have a pipe that has a hot gas (air at low velocity) on the inside (800 Deg. F). On the outside of the pipe I have a 90 mph wind blowing across the pipe (70 Deg. F). I’m trying to determine the average steel temperature on the pipe itself. The pipe itself is Carbon Steel 70" OD and 0.3125"...
I'm not sure if this is the right place for this question, but I thought I would at least start here. Does anyone know what code or standard governs the certification of personnel baskets which are lifted by cranes?
Are there any guidelines for designing structural steel to be suitable in cold climates? I'm speaking primarily to the issue of brittle fracture. I know the ASME pressure vessel code has a lot of brittle fracture criteria for vessel design, but I'm trying to find similar design information for...
We have a cold separator vessel which has an MDMT of -50 Deg. F, which was achieved by impact testing the material. We are now wanting to further decrease the MDMT of the vessel to -55 Deg. F. My question is that as I understand ASME Sec. VIII Div. 1 and API-579, you either impact test the...
I am working on a piping system which caries petroleum products. The piping is not supported well laterally, and in the past when the pipe has experienced sudden increases in flow rate, it has caused the piping to move on it's supports. I think the simple solution is to provide adequate...
Does anybody know how to create a drawing or sketch in Excel which is dynamically driven by values in the spreadsheet? In other words, if I have a spreadsheet which designs a certain component, is it possible to create a sketch of that component within excel where the dimensions of the...
I am working on a project which involves a mast on top of a high rise building in Ft. Lauderdale. We are interested in taking field measurements of the mast to determine the frequencies for the 1st three modes of vibration as well as measure the structural damping of the mast. Can anyone...
I have a large mass that is to be suspended in the air by a hoist. On the mass I want to attach a safety cable, which would support the mass in the event that the hoist failed. It is possible that the mass could fall some distance before the safety cable becomes engaged. My question is that...
I have a situation where a client has a Pressure Vessel which is 30+ years old and not code stamped. The vessel meets the pressure and size criteria requiring it to be per ASME code (based upon Current code). I have two questions:
1) Does the Code address this situation? Is there a way to...
I have a stack that is made of stepped columns that get progressively smaller in diameter as you approach the top. It is a free standing stack. My question is how do you determine the theoretical effective length factor (K) for each section of the stack? It seems to conservative to use a K =...
I have a situation where I have two concentric pipes, with the outer pipe slightly larger than the inner pipe. The outer pipe is free to rotate about the axis of the pipes. There are Axial Forces (along the axis of the pipes) and radial forces being transferred from the outer pipe to the inner...
