Technology has added the science to the art of pouring concrete foundations
text by Barry Herbert
photography courtesy of HERBERT CONSTRUCTION CO.
THE advancements in technology in the past few years have affected the foundation business in a profound way. When I started working in the construction industry 45 years ago, we had very little of what we now consider technology.
To get the full picture of our advancements, we need to look back at some of the devices that weren’t available four decades ago or that have been vastly improved during that time. The list includes calculators, computers, mobile phones, smart phones, fax machines, digital transits, total stations, robotic total stations, computer-aided design (CAD), GPS, laser levels, concrete pumps, boom trucks, aluminum forms, laser-controlled screeds and concrete mixes designs.
Pocket calculators weren’t available until about the mid-seventies. I remember a young engineer coming to work with the first “pocket” calculator I had ever seen. It was about ¾-inch thick and wouldn’t fit in most shirt pockets. The calculator would add, subtract, multiply and divide — that’s all. It had red LED numbers that you couldn’t read outside in the sunlight. On top of that, it cost just over $100 (in mid-seventies dollars). We were, however, absolutely awestruck by what it could do.
Back then, electric adding machines were the rage and worked just fine if you only wanted to add. All concrete yardages were figured by hand or with a slide-rule. We squared our foundations using the Pythagorean Theorem requiring the knowledge of the intricacies of square root. I doubt that many people in construction today can calculate the square root of whole numbers, let alone building dimensions involving feet, inches and fractions of an inch. I know I don’t remember how. Many of the dollar stores now sell tiny calculators for — you guessed it — $1. They will do the same as the mid-seventies version, plus have memory features, and perform square root with the push of a button.
A computer was a machine that took up an entire room; cost millions of dollars and ordinary businesses did not own one. Now they’re as common as concrete contractors at the World of Concrete. Grade school kids not only own them, but can run them better than I ever hope to.
When we needed to order concrete or any other material, we had to leave the jobsite, drive around looking for a phone booth and hope no one else was using it. Then bag phones became available. If you happened to be near a cell tower you might be able to use it without the call being dropped. The per-minute cell charges were outrageous. Now, many plans offer free calling on mobile to mobile calls, and have coverage almost everywhere. Smart phones, combining cell phones with computers, have become almost ubiquitous.
What we now refer to as a fax machine was originally invented by Alexander Bain in 1843 (yes, 1843). But even with many improvements, they never really took off until the 1980s, primarily because the technology wasn’t there to support it. Now every office and many homes have one. Ironically, newer technology has already made the fax machine practically obsolete.
Forty-five years ago, large buildings were laid out using transits; then there were digital transits, total stations and now robotic total stations. Robotic total stations, coupled with modern CAD systems have greatly increased efficiency and accuracy.
Many foundation contractors today draw every job on CAD. This insures that the working drawings they have been given are drawn correctly. Subsequently, each building corner is assigned a coordinate number that is downloaded into a total station. The entire jobsite can usually be laid out with one person and from one location, regardless of steep banks and complicated plans. With the same information downloaded once, the footings and walls can be laid out. Later, after the wall forms are set, the tops of the forms can be verified for correct positioning with the robotic total station prior to placing concrete.
GPS systems, coupled with total stations, are able to position the foundation exactly where it belongs through the use of global positioning satellites. Those same foundations that were constructed using a builder’s level years ago are now built with high tech laser levels.
Back in the 1980s, one of my employees and I spent most of one day laying out a relatively complicated basement with numerous elevation changes. We went home with a feeling of accomplishment and the next day a footing crew was sent out to start forming the footings. About an hour and a half later the crew came back to say that kids in the neighborhood had removed and thrown away every stake we had put in. I’m sure the kids had a lot of fun, but it cost us a day’s work. Today, with modern equipment, it wouldn’t have been nearly as big of a deal to re-establish the corners.
The first concrete pump I remember seeing worked reasonably well – if it was working at all. But you had to have some other means of placing the concrete on standby when, not if, something went wrong.
Conversely, today’s concrete pumps are practically indispensable to most foundation contractors.
Boom trucks or crane trucks were certainly around 45 years ago, but the improvements to them are vast. Our first one had a 16-foot reach from center pin, which meant if you dared drive parallel to the dirt bank you possibly could pick up a stack of forms from inside the basement.
We started with wood forms that we built in my dad’s barn using 4-foot by 8-foot sheets of ¾-inch plywood. Each form weighed about 150 pounds before any concrete stuck to them. Aluminum forms were relatively new then and seemingly cost prohibitive. Most people wouldn’t think of aluminum forms as being high tech, but when we finally could afford them, the advantages were staggering.
Laser controlled screeds for large commercial and industrial projects have been, for a number of years, the best way to construct high quality floor slabs with the least amount of labor.
Recently they have started to move into the residential market and the improved flatness control will be a welcome addition.
New and improved concrete mix designs have allowed contractors to construct better concrete foundations using less cement. Some of the admixtures and cementitious materials used today to improve concrete strengths and workability are actually by-products of other manufacturing processes (e.g. slag and fly-ash). If not used in concrete production, these materials would end up in landfills. This adds to the “green” aspect of an already highly sustainable building material.
These are a few of the advances we’ve experienced in the foundation industry during the last 40-plus years. Considering the rapidly changing technology in just the last four or five years, one would have to wonder what the next few decades will bring. CH
The transit has been replaced with the total station.
Barry Herbert is a 45-year veteran of the concrete industry. He is CEO of Herbert Construction Co., which performs work throughout the Southeast with its corporate headquarters in Atlanta. He’s a member of ACI’s 332 Residential Concrete Committee, is past president of the Concrete Foundation Association (CFA), a CFA Certified Concrete Technician, and in 2009 was presented with CFA’s Robert D. Sawyer Distinguished Service award for his contributions to the concrete foundation industry. Herbert Construction Co. is the 2011 winner of the CFA’s Project of the Year for Concrete homes. For more information, see www.HerbertConstruction.com.