For the Three Little Pigs, It's Not That Simple Anymore

Throughout my career of more than 30 years as a consulting structural engineer designing buildings, rules and regulations have become increasingly complex. This has become even more obvious during my several terms of service on the Masonry Standards Joint Committee (MSJC), which addresses the building code requirements for masonry structures. How far will the rules and regulations go?

Remember the three little pigs? Children know that a house of bricks is stronger than a house of sticks, and a house of sticks is stronger than a house of straw. Simple! But in today’s world of structural engineering and complex regulations, the story would need to be amended.

The pigs knew they needed to design houses so the big bad wolf wouldn’t blow their house down. Every project needs to have design criteria. Today, we review multiple pages in the wind loading chapter of ASCE 7 to find out what the wind load is to resist wolf breath loading. It’s not there, so we have to apply some judgment. But what if we get it wrong? Will the pigs sue the structural engineer of record? Further, do we need to consider progressive collapse? No real guidance here either.

The first pig wants to build a house of straw. As the structural engineer we look in the Building Code for the reference standard, and to our surprise there is none for straw structures. We go to the local Building Department for guidance, but without the proper ICC-ES report we are out of luck. No Building Permit and no straw house result in an unhappy pig client. The upside? No straw house for the wolf to blow down.

The second pig wants to build a house of sticks. We have a little more success here as there is a reference standard for wood design in the Building Code. But as we start our calculations we realize there are dozens of complex design equations. We don’t have the proper timber design software. Documentation on the material properties of the sticks is not available. We figure out the number of hours needed to design the structure, obtain the necessary test results, and provide all the details, and realize the cost of designing the simple timber structure is more than the cost of the building. Another unhappy pig client! Again the upside—there is no house of sticks for the wolf to blow down.

Finally, the third pig wants to build a house of bricks. No problem. There is a reference standard for masonry design; good specifications for bricks, mortar, and reinforcing steel; and plenty of trained brick layers. We start the design and realize that we don’t know the Seismic Design Category because we don’t have a geotechnical report. We get the third pig to hire a geotechnical engineer and learn that we need piles, have a liquefaction problem, and are in Seismic Design Category E. It’s a good thing the third pig has lots of money because the brick house costs a small fortune to build. On the plus side the brick house can resist a hurricane, or possibly a tornado, because of the seismic design controls.

Huffing and puffing and kidding aside, I’m proud to be part of a profession that works so strenuously to protect the public interest, whether wolves are at the door or not. The complexities that structural engineers and their clients face are integral to ensuring the safety of those who live, work, and learn in the buildings we design.

With the challenges of natural disasters such as earthquakes and tornados, the potential for more terrorist attacks, and the higher standards imposed through sustainability and other construction initiatives, masonry construction research presented at last month’s North American Masonry Conference and at similar gatherings is receiving more visibility and consideration than ever before. As a result, building codes continue to be scrutinized and improved around the world.

We may sometimes "huff and puff," but our profession rises to the challenge.

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  • Keith Itzler
    Keith Itzler
 
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