Problems! 1

[yungenr1]

During shop drawing review, we looked at a few of our composite beam cant. designs again because of the connections used by the detailer.

During this review, we've found that the our program (RAM Steel) designs cant. beams as pinned at the column, so the only moment was that from the cant. When I fix this connection, as it actually is, the moment is greater and then my moment value provided to the detailer is no longer valid (it is lower) and the beam design is over stressed by about 5-10%.

This is for a single beam (occurs) 5 times (changing from one size (8" flange) to a 10" flange (2 weight sizes) fixes the problem. I'm not sure how to tell my boss (it is his stamp, but I did the design.)

Some of our columns don't work either in random locations due to the program not putting moment from the moment connection into the column.

What should I do? Right now I feel like just quitting and staying away from structural engineering forever.....Sigh.

 

[strainman]

A good motto for every engineer to live by: "The closer a misstake gets to the end user the more it will cost."

 

[shepherd]

If you are not requiring the column to develop flexure for lateral load resistance, you could detail it as it's designed. Let the beam pass over the column and stack the column above. Likely to require beam web stiffeners, but the acutal beam and column sizes will not change.

 

[SLTA]

Bill LeMessurier was a really great guy. I worked at LeMessurier Consultants for a bit before grad school, and learned a lot from him and others there about how to be a "proper" engineer. Everyone makes mistakes! Just own them and get it fixed, and learn from them.

So, yungenr1, what did you decide to do?

 

[engphila]

Also, instead of doing just a mea culpa with your boss, think about presenting a solution along with your 'discovery'. Problems are much more palatable when their served with fixes.

engphila

 

[yungenr1]

Thanks everyone for your encouragement and support.

After reviewing the drawings, we were actually ok on a number of the moment connection/beam/column designs that I had originally thought we wouldn't be.

We had to change 3 columns lifts from W12x40s to W12x58s. (Not a huge deal)

Then for the instance where we had some cant. through columns, which weren't part of a lateral system, we simply removed the backspan moment connection. The cant. is only 3' and is not heavily loaded so the moment induced from this cant. into the column is less then the unbalanced moment of a full moment connected beam.

I thought it would be a lot more work than it was.

Thanks for calming the nerves.