In recent years, you likely have started hearing more and more about 3D printing. Currently, 3D printing is being used in medical and industrial fields and even to make art and jewelry. Another area that they are starting to use 3D printing is civil engineering. There has been a lot of research done and it is still in its early stages but different applications in this field are already starting to pop up.
A major reason why people are looking into the use of 3D printing for civil engineering applications is that it can reduce the amount of money invested on tools for manufacturing and the associated labor. The initial investment cost tends to be high but is usually a one-time cost. Right now, 3D printing is being used in a construction process called contour crafting which is used to make 3D homes. This process tends to be fast, uses less energy, and produces little to no waste and therefore this will continue to grow and become used more widespread.
Figure 1: Creating a wall with a 3D printer
Construction technology concept with 3d rendering robot welder build house
Figure 2: House in Russia built in one day
3D printing of concrete can save a lot of time, reducing a 2-week job to just 3-4 days. It also removes laborers from common construction-related injuries. Companies in countries like Brazil, Italy, and Russia to name a few, have been using this technology to build homes that are able to withstand their respective climates. This process may run into some problems trying to be implemented in the U.S. by the many codes and standards. Townships and other governing bodies don’t currently recognize this process as a construction method and the associated plans and calculations are different than ones that these governing bodies are used to. This can cause some reluctance to accept such a process but if they are allowed on a case to case basis and studied then, this process may eventually be more common.
Have you ever experienced a situation where just because you work in a specific field that people think you know everything about it? After the pedestrian bridge in Florida collapsed back in March, I have received the question of what happened to it numerous times. Family, friends, and people I’m just meeting for the first time have asked why it collapsed and act like I should know what happened to it since I work in the Civil Engineering field but in reality, I don’t work with bridges at all and have no idea what happened to it, so I decided to do some digging.
One of the first issues was that the project was behind schedule and over budget (wait, aren’t all projects?). In addition, the engineers were asked to move the signature pylon of the bridge to accommodate for possible future road expansion, changing their design (below image shows a rendering of the final design). Videos that captured the incident show that part of a prefabricated segment of the bridge started crumbling on the same end where the pylon redesign was to be located. The pylon was to be installed later into the project with each prefabricated section being able to withstand all the forces they would experience before completion of the project. An engineer had reported cracks in the same location where the bridge failed two days prior and stress testing was being conducted the day of the collapse. There was even a meeting the same day in which engineers and state officials discussed whether the cracks in the structure presented a safety risk.
Some engineers involved in trying to find the reason behind this collapse have said that any slight modification to a bridge design is inviting possibilities for failures. The same care and attention that the original design had does not always continue once a change is proposed and designed for. The proposed design change put the engineering team further behind schedule and over budget. This project was being federally funded and the engineering team was worried that funding might run out before they could complete it causing them to further try to speed up their designs.
Engineers and other officials are still looking into the exact cause of the bridge’s collapse while FDOT and the engineering team responsible have been hush-hush for the most part. Although all projects are different, a valuable lesson can be learned from this. Time and money are always key driving factors for projects, but they should never be able to dictate the final design. It may take some more time and money, which leads to unhappy clients, but sometimes that is what is needed for a successful project.
Engineers are constantly being challenged with the task of trying to find cheaper alternatives for projects to save money for their clients. This presents a challenge because it is not always easy to find an alternative while maintaining the same characteristics that accommodate the standards and regulations that the project’s design must meet. Engineers are turning more and more to geosynthetics to help them accomplish these goals.
Geosynthetics are synthetic materials that are used in contact with soil, rock, or other geotechnical materials and have a wide range of forms and applications. The main categories that these geosynthetics fall into are geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells, and geocomposites. Each of these has different applications and products that can be tailored to most jobs. They can be used to replace different raw materials such as cement, steel, rocks, and soil and can provide the same characteristics at a fraction of the price.
Filtration, drainage, separation, reinforcement, and protection are just a few areas where geosynthetics are becoming more prevalent. Some examples of uses include soil reinforcement structure, the separation between in-situ and imported soil to avoid mixing, filtration behind hydraulic structures, and erosion control blanket to protect the top of the slope and avoid erosion. Companies continue to test and research their geosynthetics to find more uses and to find ways to improve their characteristics to make them more favorable for designers.
The use of geosynthetics continue to grow as engineers become more familiar with them and as they become more viable options then what is normally commonplace. The cost benefits continue to make geosynthetics more popular and something that engineers will be turning more and more too. So, the next time you think there is no solution to your problem, remember that the solution may already be right under your feet.