Do you remember the popular meme that showed pictures of “What (fill in the blank) thinks I do” and then a picture of “What I really do”? There’s a pretty funny one out there for Civil Engineers. In fact, people hold many misconceptions about the type of work Civil Engineers do. Outside of the industry, people often think that Civil Engineers build buildings or stand around in hard hats viewing plans. Another common misconception is that Civil Engineers only design things like shopping center parking lots, drainage systems, or subdivisions. In reality, civil engineering is a multi-faceted discipline. Civil Engineers work on a wide variety of projects, which do not always fit the bill of a “typical” project. Because of this, Civil Engineers have to exercise a high degree of flexibility and adaptability to meet the challenges each project may hold. We recently had the opportunity to work on a very different project and were able to meet the challenges that came along with it - a lumber kiln.
Understand the business Before I tell you more about the project, let me explain a little about drying lumber. When doing a new and unique land development project, I always find it interesting to learn about the business for which we are designing. For this project we were working on a lumber mill in Alabama. This mill provides cut lumber from mostly “yellow” pine in the typical sizes you would find in any home improvement store. Wood retains a lot of moisture, and although it will naturally dry over time, most lumber providers prefer to dry the wood to facilitate shipping and sales. Large drying kilns are used to do this, essentially operating as giant ovens. Most kilns come in two varieties: batch and continuous. In batch kilns, the lumber is loaded, the doors are shut, and the lumber is dried and then removed. In a continuous kiln (as shown below) the lumber slowly rolls through and dries as it goes. These kilns are larger, but can generally dry timber in higher volumes.
Understand the client The client’s existing mill was getting old, and they were in the process of replacing aging equipment, including adding new continuous kilns. Foresite Group provided civil site design and structural services for the installation of the kilns. The kiln consists of two parallel drying rooms approximately 200 feet long and 33 feet wide. Outside the drying rooms are 22 foot long pits where the timber is loaded onto carts and pushed through the drying rooms. The drying room consists of a continuous mat of steel and concrete with integral troughs where the carts run.
Think outside the box There were several challenges to consider on this project. One was designing a site with no stormwater inlets. Because the heavy forklifts tear up the grates and the pipes clog with woodchips, stormwater inlets were not feasible for this design. Another consideration was the need for a very strong foundation. As I mentioned above, the wood moves through the kilns on rails, and the full length of the rails (400 feet) has to be on a perfectly flat and continuous slab. Did I mention that the site was built mostly on fill? The concrete paving needed to be stronger than normal to withstand the daily loads of the forklifts and trucks. Vibrations from the massive burners, blowers and equipment mean specific designs for foundations. The foundation pour had to be done overnight to limit the impact that the 70-plus trips by concrete trucks would make.
You may have never considered how civil engineering could impact the lumber drying process, but that is one of the unique perks of this discipline—we are often called upon to work on a wide variety of projects, frequently collaborating during the entire life cycle of a project from a rough concept to the last brick laid. The “unique” civil engineering projects are often the most challenging, but can also be the most rewarding.
About Foresite Group
Foresite Group is a multidisciplinary engineering, planning, and consulting firm providing services to public and private sector clients nationwide. Our team’s collaborative process results in creative products and services that help our clients achieve their goals. Our team takes pride in enhancing and developing the cities and communities where we live, work, and raise our families.