Ideas for a Dissertation 1

[DaveAtkins]

The recent thread on 1-1/4" guardrail posts started me thinking. It would be nice if a PhD student would write a dissertation on all of those structural engineering situations we face which are difficult to prove by the numbers.

I can think of two right away:

The aforementioned guardrail. Build a guardrail and test it. We would probably be surprised at how much force it could take.

A wood gable roof, with wood roof trusses, with no blocking between the truss heels. Test the diaphragm strength. I wonder if some other part of the roof would fail before the trusses roll over.

DaveAtkins

 

[WARose]

One thing I could kick myself for not doing is a fatigue study of concrete anchors (especially in cracked concrete, where info seems to be lacking). The thing about it is: unlike most grad students, I had the money to pay for such testing (I was working full-time while I was in grad school)......I just opted instead for a non-thesis option (which replaced the thesis with 6 hours of coursework).

 

[Guastavino]

Dave,

Good thread. How about testing steel lintels in a CMU wall with headed studs on top and an open bottom bond beam. See if the studs/wall brace the beam and any composite action.

 

[Ron]

How about closing the huge gap between structural sufficiency and serviceability?

 

[theonlynamenottaken]

Thru-bolted connections to grouted and un-grouted CMU walls.

Concentrated eccentric gravity loads on thin-shells of revolution.

 

[26sig]

I would like to see work done on the Ground Snow Load map in ASCE 7 to reduce the Case Study regions. Some of those zones are mountainous, and some are coastal in the great lakes region but I am willing to bet that a little research could go a long way in this regard.

 

[Lomarandil]

partial composite action in rebar cages

rotational stiffness of elastomeric bearing pads

 

[PMR06]

I'd like to see some updated research into building expansion joints. Its seems like not much new literature exists beyond Tech Report 65 and Fisher's re-hashes of it.

 

[bookowski]

How about a comparison of the efficiency and performance of structures over time in parallel with the increasing complexity of codes - i.e. who is this benefiting. For example until '08 NYC design wind loads were 20psf < 100ft, 25psf < 200ft. etc. and I know of no issues related to this.

In fact it would be interesting to see a study of problems caused by complex codes that are misunderstood or ignored and result in issues.

 

[dhengr]

I’ll bet we could all come up with a number if topics for this list. Not particularly sexy topics, just good old basic problems which have vexed us all, but important nonetheless for the improvement of our profession and codes. If fifteen engineers approach and do the problem slightly differently, which is best and why? I’m all for high level research and theoretical advancement, but a lot of that just complicates the codes and our calcs. and process, it doesn’t really improve the profession or the final structure. That kind of research should have to ruminate for a few code cycles before it finds a fit in the code and process. And, there should be a cost/benefit (engineering time expended/benefit) analysis before full inclusion in the codes. Take these lists of topics and process or methods improvements to your favorite Univ. Prof. who advices Masters and Ph.D. candidates, as food for thought for thesis topics.

 

[tstructural]

Re Bookowski's post above

"How about a comparison of the efficiency and performance of structures over time in parallel with the increasing complexity of codes - i.e. who is this benefiting. For example until '08 NYC design wind loads were 20psf < 100ft, 25psf < 200ft. etc. and I know of no issues related to this.

In fact it would be interesting to see a study of problems caused by complex codes that are misunderstood or ignored and result in issues."

I participated in a study regarding the complexity of the code and whether or not engineers were understanding all of the requirements. I did a simple seismic analysis and designed steel moment frame connections, drag struts and some foundations for their example project. Not a complete building design - just a simple two story building and then just the design of those few elements. I did this for the 2000 or 2003 IBC - I think it was about that time frame.

I was hoping to hear the results - I'm wondering if 90% of engineers got it right or only 30% of engineers got it right. But alas I never heard back. It would be something I would participate in again - not months worth of work mind you but I would donate 80 hours of my time. But, I would insist on hearing what the results of the study were.

 

[bookowski]

TX - The problem there is that it's most likely a self selecting group that is willing to give up time for such an endeavor, and secondly you are likely to be much more thorough in your calcs when it's part of an exercise to determine if you're a nincompoop.

 

[msquared48]

There has been so much discussion here about deflections of stick framed hip roofs with top plate tension members, it would be interesting to see the influence of the roof diaphragm on lateral deflections and how that varied with roof pitch under similar loading conditions.

Mike McCann, PE, SE (WA)

 

[Jerehmy]

Ron - can you elaborate a bit

 

[JStephen]

If you take a circular tank, slosh the liquid toward one side, then apply an acceleration at right angles, you get a net circular motion generated in the liquid. This is how you swirl coffee around in your cup. But that interaction is not included in tank seismic design. Specifically, it involves interaction between the low-frequency and the high-frequency parts of the spectrum. The question is, does actual earthquake ground motion generate any significant effects due to this interaction?