Stress!

One way to think about stress is simply load divided by area. This is an interesting concept to consider with regards to emotional health. But what about engineering? In the physical world and built environment, stress is all around us. That’s bad, right?

Maybe not. Stress may be handled without deformation or failure if sufficient strength is available. As engineers, we often look at stress and loading in terms of tension, compression, shear, bending and other modes and combinations. We also think about the materials that we are working with to understand how they will react to stress. Soil, for instance, is relatively strong in compression but has almost no strength in tension. (Think about pushing soil together in your hands versus pulling it apart.)

A good client of ours recently asked us to consider two trenchless crossings involving jacked steel pipe installed on a curve. With these designs, the stress analyses become fairly complex. Not only does compression need to be considered, but also bending and hoop stresses and combinations of stresses. Because the pipe will be in compression, we also need to consider local buckling effects. Then, after the pipe is installed, the stresses imposed during operation must be considered as the curved pipe is pressurized. For all of these calculations, safety factors are used to reduce the risk of pipe over-stress.

That sounds like a lot to think about, and it is, but solving complex problems is part of what makes engineering fun. So, my advice is, if you feel your load is exceeding your area, take a break. Don’t stress out!