Designing lots of base plates at once

[milkshakelake]

I keep getting situations where I need to design like 6-70 base plates. It's tedious. What's a quick way to do it?

Current method: Grouping the base plates into 5-10 different types based on loading and calculating those in Tedds
Pros: Uses software I already purchased
Cons: Takes a day. Takes even more time if loading changes. Hard to determine which load combination will control when grouping them.

Method I'm thinking of: Making an Excel sheet. Input a few base plate sizes, and check each column with all load combinations.
Pros: Will be fast. Will take results from FEM program and have output in a few minutes.
Cons: Will take days to develop the Excel sheet. I'll be the only one who can modify or troubleshoot the sheet (nobody else in my company knows VBA). Won't take advantage of software I already purchased. If I make a mistake, a building could collapse (this problem is true for any calculation but becomes magnified when it's repeated thousands of times for all columns and load combinations).

Another method I'm thinking of: Make a table with standard base plate sizes and welds calculated for different column sizes and loading conditions.
Pros: Fast. Even a drafter will be able to use it.
Cons: There are so many different possible loadings and column sizes that I'm not sure if this is feasible.

Also, I'm focusing on base plates here but this is a general question for all tedious calculations that come from results from FEM analysis. There are other cases like this, such as bearing plates, foundations, and anchor bolts.

 

[mbstruct]

If they're gravity columns with negligible moments, could you not just run the design on a few standard column/baseplate configurations and figure out max loadings to create a table that you can use in the future? Then when you have more complex loadings or configurations, you jump back into the software to analyze. Might be an oversimplification for what you're working on, but for small to medium size buildings I think that could improve your workflow.

 

[XR250]

Can you simplify the situation by just designing a few base plates for the worst loading and using them throughout? Might be some economy with the fabricator even if the material is more expensive.

 

[phamENG]

If most your base plates are leaning columns, I might approach it this way:

-Determine a list of most commonly used columns.
-For each column, design a base plate for the maximum compression load it can handle at the shortest reasonable unbraced length (probably 8 to 10 feet, but you know your projects better than me). Use that for all gravity only columns.
-For each column, determine the maximum reasonable tension load (if there is one). Then break it down into ranges - maybe 3 per column size? 0-Xkips, x-Ykips, Y-Zkips. Design a tension baseplate and anchorage for X, Y, and Z kips.
-Write a VBA program that, based on your 3D analysis output, will assign detail A, B, C, or D to a particular column.

The rest of them - braced frame column bases, moment bases, etc., get their due attention and are designed in detail each time.

You spend a few days worth of time designing these several permutations, but then you have a nice and easy standard to fall back on. The calculation itself is done ahead of time using reliable software, and the VBA script is little more than a bunch of IF THEN loops.

 

[KootK]

Another method I'm thinking of: Make a table with standard base plate sizes and welds calculated for different column sizes and loading conditions.
Pros: Fast. Even a drafter will be able to use it.
Cons: There are so many different possible loadings and column sizes that I'm not sure if this is feasible.

I like that one. Lately, I've been fantasizing about trying to bring back the monographs of old but, at the same time, utilizing basic spreadsheet & programming technology. It would go something like this:

1) For a particular project, identify the likely kinds of columns involved (HSS/WF etc).

2) Fire up then monograph generator and make project specific interaction diagrams for the appropriate column base plates.

3) Either select the base plates by hand from the monograph or, if you're feeling fancy, program something that runs through the load cases and makes the selection by comparing the loads to the same function that would have generated the monograph.

I really do feel like modern design practice has a big gap in it in this regard. A talented ETABS jockey can design all of the major parts of a building in a day but, then, the design of the stuff at the level of detailing takes forever. That, in part, because we seem to have collectively forgotten much of the time saving rationalizations that our ancestors used to rely upon.

 

[milkshakelake]

@mbstruct True, good idea. Max loading makes sense for gravity columns.

@XR250 I generally have like 5-10 different designs. I guess I could simplify it.

@phamENG Thanks, this is much simpler than what I was planning to do. I was planning to make VBA to run different standard base plate sizes for each column and load combination with code checks in Excel, and have it pick the most efficient one. Designing the base plates by hand or in a different program will eliminate a lot of the potential errors and coding.

@KootK With today's technology, I haven't used a monograph ever. A lot of thought has to go into making one, considering different scenarios and what to keep constant or change. I don't think I'm equipped mentally for something like that. It's a fantastic idea though, and something I'll start thinking about.

 

[skeletron]

The same amount of work goes into making a standardized connection table as a monograph. It would depend on how the User connects to the data: numbers in rows, or lines on a graph.

@phamEng has a pretty good breakdown of how to set it up with the most value. I think you'll eventually need to do all 3 methods in the complete validation process. For me, I would make the TEDDS (MathCad, SMath, handcalc, etc) sheet as a real quick n dirty calc sheet. Then I would move on to putting time into an Excel program and put all the automated functionality into that. Validate it with the TEDDS sheet (or whatever handcalc method) and then find out how to spit data out into a standardized table. This is how we would set up standard connection design tables.

During that process you could probably break out the sections that generally work, and use those as go-to pre-eng solutions.

 

[milkshakelake]

and then find out how to spit data out into a standardized table

Now that I think about it, Excel directly to AutoCAD would be a great way to do column schedules on a project by project basis. Time to do some research.

 

[bones206]

Ram does baseplates and foundations in an automated way. I think RISA does via the Connection module with a Hilti Profis plugin. That being said, I do see value in reducing the base plate types to a handful of standard shapes for simpler fabrication, setting anchor bolts etc.