Engineering: Past vs. Present

I recently spent the weekend in Colonial Williamsburg and had an opportunity to look at a lot of the old buildings.  I started to think about the state of engineering, or lack thereof, during that time period.  Structural engineering is based upon calculus; Sir Isaac Newton had just developed calculus, so that tool was not available to the architects and engineers of that time.

So how did they do their engineering?  It was the good ole philosophy, let's build it and if it falls down, we'll put some bigger, stronger pieces in place.  The craftsmen of that time had to have a strong sense of what worked and didn't in terms of resisting loads.  I am sure back then they were much more familiar with forces of gravity than lateral loads, such as earthquakes and hurricanes.  Today a lot of that innate sense is still possessed by the tradesmen.  It is often difficult to tell carpenters who have been in the business for a long time that what they have been doing for umpteen years will not work on paper or in our models.  There are a lot of connections and forces that we have to idealize in our models, hence we have to tell the tradesmen to do it the way we have drawn.

So to the tradesmen out there, keep your innate sense of what works and what doesn't, as it is a time tested tradition, but try to see it from the engineer's point of view as well.

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The Engineer's Approach

This is going to be an unusual blog, not that most of my blogs aren’t unusual.  This blog will give you a glimpse into the mind of an engineer.

As some of you may know, I am a sailor.  Last year I was offered a free Hobie Cat to use for the summer.  I immediately jumped on the offer and put it on the beach at 58^th Street, the last street to the north that has a sea wall.  Nestling the boat against the seawall was nice until the past round of Northeasters hit the oceanfront.  The sand was pushed up to the top of the seawall and almost completely covered the boat.  All I could see was a small amount of the trampoline showing with two bits of bow sticking out. 

A normal person would solve the problem of extracting the boat by digging it out, and that is how I started.  After digging for about an hour I projected at least another three to four hours of digging to get the boat clear.  To make matters worse there were boats on either side of my boat, so I did not want to pile sand on the other boats.  

I was taking a break from the digging and spied a 4 x 6 timber that was flotsam from the recent storm.  That’s when my engineering brain kicked in.  As Archimedes once said, “Give me a lever long enough and I can move the world.”  Well, I did not have to move the world, just a Hobie Cat. After several rounds of digging for access and using my lever, the boat was free of the sand.  The total time using the lever was 30 minutes; much less than the 3 more hours of digging I had projected!  

So as you can see, using an engineering mindset can be very helpful at times.  I will conclude this blog with a statement from my wife Ellen, “being married to an engineer is wonderful, they can fix anything.”  Well, we can at least make the task easier.

FEMA Deployment

On Wednesday, September 30^th, I left town with a small FEMA Task Force module to do water rescue training at the Guardian Training Center in Perry, Georgia.  We were to assist other groups attending at the same time.  The NYFD was there along with Maryland Task Force 1; it was a learning experience for me to work closely with the rescue component of the Task Force.  We drove back Friday through the rain in South Carolina.  Saturday morning I received a call that Virginia Task Force 2 was being put on alert and should be ready to head to South Carolina.  By the time Sunday evening rolled around I thought we would be stood down, but the alert came through to report to the training center for deployment.  By midnight we were on the road to Columbia to assist with the aftermath of the flooding.

There were two engineers on the deployment, Brian Crowder and myself, which were each assigned to one of the Rescue Teams.  Our tasks were mainly centered around assisting the rescue teams with scouting the damaged roadways, welfare checks, and damage assessment of the residences in Richland County.  We spent several days in Richland County and were then relocated to Dorchester County.  While in Dorchester County we had similar tasks along with putting the Task Force boats into the Edisto River to insure all residents were safe and accounted for.  I also assisted the fire department with a response to a building that was damaged by a car; they were so busy with the flooding they did not have the resources to respond to normal calls.  A week after departing we returned back to Virginia Beach.

Shortly after, on October 17, I taught the structural component for 72 firefighters at the Structural Collapse Technician School in Virginia Beach.  The firefighters that attended will graduate with skills that enable them to respond to structural issues.

This recent crisis has me reflecting on the benefits engineers can provide to a community, beyond the design work that we do.  A fellow FEMA engineer is involved in the Engineers Without Borders organization which helps communities throughout the world.  Engineers are necessary for almost all the designs required in society today, and we can also help the community and world at large when unique situations arise.

Advancing Technology

As a new school year begins, it makes me think back to my first year at Virginia Tech (which by the way was called Virginia Polytechnic Institute and State University at the time).  It was the first year that the slide rule was not used anymore and it was required to have an electronic calculator.  I had an approved Rockwell that could do amazing things like sine, cosine, and tangent without the use of a CRC table of values.  I’m sure some of the professors were grumbling about the introduction of calculators.  

We were exposed to that new-fangled machine, the computer.  We had to type out key punch cards to develop our exciting program that would count from 1 to 10.  In order to do this we had to find a key punch machine on campus, type our program in Fortran, and hand the cards to our professor.  He would then take the cards to a compiler to get our results. Usually on the first pass there was a card punch error, a hanging chad, and we would have to retype the card.  Later in my college career we befriended some physics students who had a compiler in their building, this allowed us to bypass the crowded compiler in the computer center.  

As I reflect back on those days, it amazes me how far technology has come throughout my career. Now there is a computer on every desk and my phone has more computing capacity than all the computers combined in my days at Tech.  It has sped up the design process and allowed us to be more efficient in our work.  The models we create are far beyond anything we dreamed of in school.  Some people miss the good old days, but I am glad to be where we are and to have this technology at our fingertips.  Engineering has benefited greatly from the advances and I wonder what the next generation will have at their disposal for producing exciting designs.

Building in Belize

Imagine what it’s like for a structural engineer to go to a Central American country to help construct a classroom where there’s no real enforcement of building codes or standards. That’s what I just did!

I have been to Holy Cross Anglican School many times in the past, but this was the first time I have actually been involved in the erection of structural components. Our team set a 2 x 4 rafter that was 26 feet long with a splice point at 16 feet from the ridge. It was a hardwood 2 x 4, but it’s remarkable to me that it could span that far and still support the roof and a couple of people. This is standard practice for the area and does not affect life safety, so I jumped in to help build and erect it. The density of the hardwood makes nailing and cutting the wood interesting since most pieces required pre-drilling before nails could be set.

It was definitely a hard week of work, but it keeps me grounded and reminds me of how rough the workers in the field have it (especially those who do not use nail guns!). It is good practice for all engineers to swing a hammer and cut some wood from time to time; it gives us an appreciation that putting things down on paper (or on the computer) is much easier than putting it together in the field.

Atypical Engineering

I recently returned from Structural Specialist Training in California for the USACE and FEMA USAR system (there’s a lot of abbreviations for you!).  I am on the VA Task Force 2, USAR team and we respond to large scale disasters.  Having an engineer on the team keeps the Task Force members safe.

When responding, we often deal with structures that are in very unstable condition; this is a difficult mindset for engineers to operate in.  We are trained to make sure that the structures we design are able to withstand the design loads set forth in code, but in situations like these structures have severe damage and could fall down at any second.  The Task Force members do not need us to tell them that the building is unsafe, anyone could see that; they need us to explain to them the risks involved for potential further collapse and/or the safest way to enter and exit the building.  Additionally, we might have to develop a shoring plan to access any people that may be trapped in the building.

It is a very challenging, but rewarding form of engineering and I am very proud to be able to call myself a member of a very select group of engineers in the FEMA USAR and USACE system.

Real World Issues with Lateral Loads

One of the hardest things we have to do as structural engineers is explain to builders/contractors why something that they know they can build in the field will not work when we design it on paper.  The following is a typical situation, we size a ridge beam for a cathedral ceiling and the framer tells me that he has never needed to do this before, either followed or preceded by, I have been doing this for at least 20 to 30 years. So here is the simplest explanation for why it seems that at times we make life difficult for contractors.

One main reason is the fact that we have to design for lateral loads, such as wind events and earthquakes. Gravity is present 100 percent of the time so a contractor is used to building for that force.  Design lateral events however, may span years between events or may never occur during a building’s life, so there is no intuitive development of what is needed to resist those forces.  One look at the devastation in Nepal shows that structures can withstand gravity loading for years, yet crumble under lateral loading.

The other variable we have to deal with is the actual connection of material; we model connections using either a pinned or a fixed condition.  In the field there is really no such thing as a pure pin, there is always some type of rotational restraint.  For example, with a nailed wood connection we can’t model a fixed connection until someone develops a way to weld wood together; I don’t think a pine tar welding rod is in our future.  

So when a structural engineer tells you something won’t work it is usually because the total lateral and gravity loads over-stress the structure or our model of the structure does not work.  We are here to prevent things from falling down and to remain usable even after design loading occurs.  The end goal is to work with builders and contractors to make sure that the buildings we create are usable and safe for years to come.