Designing an Effective Roadside Crash Barrier
Designing an Effective Roadside Crash Barrier
As the number of drivers on the roads today gradually increases, there is now a greater need for a more effective crash barrier. Crash barriers are strong protective barriers mainly used along roadsides to lessen the severity of accidents. Existing barriers have not been designed for the safety of smaller vehicles such as motorcyclists but rather for larger vehicles like SUVs. Since accidents are more frequent than ever before, barriers that are found on roads today are less effective in protecting the safety of passengers and lessening the severity of accidents (Corben 2004). There is a greater need for a more effective crash barrier than ever, as a result of the increase of the number of drivers on the road.
Concrete, W-beam, sand and or water barriers are most abundant crash barriers in existence and on roads today. However, these barriers do not absorb enough energy to sufficiently lessen the severity of crashes and injuries to the passengers. Sand or water barriers are mainly used before a bridge or an exit off a highway, but do not contain the durability needed for a successful crash barrier. These barriers do absorb some energy, but since the car is traveling at such a high velocity, the barriers will be completely destroyed. Also the risk of driving right through the barriers and hitting into the concrete wall behind the barriers is highly likely. Concrete barriers are very strong but do not have the flexibility or compression characteristics needed for an effective crash barrier. These barriers are mainly located in the median of the highways to prevent cars from going into the wrong directional lanes. Although these barriers are less likely to deform or break, they do not compress or flex according to the impact. Thus, once a car crashes into these concrete barriers, the car is most likely to be completely destroyed and the passengers are less likely to be safe. W-beam barriers are mainly found on highways and bridges, and show more compression and flexibility characteristics than concrete and sand/water barriers. These barriers are designed with a bent shape of metal into a “w” shape and installed onto a solid foundation. When cars hit the W-beam barrier, they are less likely to experience deformities, the car is less likely to become destroyed and passengers are safer. However, cars that collide into these barriers are more likely to spin off after crashing into these barriers which could ultimately lead into a larger car crash, consisting of multiple cars. The risk of spinning off back onto the roads is a very dangerous concept that can lead to a very large life-taking accident.
Since there is not one substantially effective barrier in existence, the designing of a crash barrier from low-cost material would drastically change the safety of the roads. The uses of two types of foams, as well as a sheet of metal were used to create the new effective low-cost crash barrier. The foam barrier shows compression and flexibility while having a strong sturdy, dependent foundation. In comparison to the other barriers, the foam barrier shows a larger promise in reaching the goal of a safer road while potentially saving the lives of many.
Today, barriers are developed with the safety of passengers in larger vehicles in mind. However, more and more accidents that occur, involve smaller vehicles such as motorcycles. If crashed into, these smaller vehicles might endure severe accidents and the passengers inside will be less likely to be safe. Four different low-cost building materials were used to construct crash barrier that were effective and abundant. Plastic water bottles, sheet metal (aluminum and steel), and foam blocks (hard and soft types) were used to make the affordable yet effective crash barriers. W-beam barrier and water bottle barriers were simulations of barriers that exist today, and the foam barriers were designed as new more effective barriers. A ramp at a 45 degree angle was created to test the several types of barriers. To simulate a car, a model car made out of wood was designed to crash into the barriers. From the tests, the barrier that was most effective was the redesign foam barrier. With the new data, the redesign foam barrier shows the most promise in furthering the goal of a safer road, lessening severity of accidents and safety of passengers.
Methods and Materials
Phase I- Constructing the Ramp
Using one 61x122cm piece of wood, two L-shaped corner molding strips, a slim piece of wooden board (61x122cm ) and nails. Cut the 61x122cm into four pieces; two identical pieces 53 cm in length and 9 cm in width and the other two are 16 cm by 9 cm. Mark the wooden board at intervals of half an inch, then tape every other dot with a strip of electrical tape, creating many vertical lines for use in determining speed a a later time. Cut the two L-shaped corner molding strips 122cm in length then connect one of the strips onto the wooden board, creating a 45 degree angle. Connect one of the 53cm long pieces of wood to the board, so it supports the rail as well as the board. Then connect one of the smaller pieces of wood to the bottom of the larger piece of wood, which will intern create a box foundation. Connect last rail to the box foundation forming a track large enough for the model car.
Phase II- Constructing the Model Car
From the 61x122cm, cut a piece of wood 24cm in length and 9cm in width. Connect the four 2.5cm skate board wheels to the piece of wood with bolts.Wheels should be 11 in apart from one another. Make sure wheels are not too tight because then the wheels wont move f reely. In the middle of the model, nail a wooden cylinder 6cm in length, which will be used to hold the weights.
Phase III- Constructing the Barriers
Four different barriers are created and designed. The foam block barrier was created by connecting two different types of foam together. One type of foam is a soft block and the other is a harder rectangular piece of foam. Wrap a sheet of aluminum around the foam blocks to give support, and nail the sheet into the harder foam. Cover the harder foam with pieces of thin wood to act as a supportive layer. The water bottle barriers were created by cutting two plastic half liter water bottles in half. Fill bottom portion of water bottles with water. Cover both bottles with Parafilm and an extra sheet of Parafilm over both bottles connecting them. This barrier resembles the water or sand barriers that exist today, near bridges or highways. The w-beam barrier was creating by bending a 13cm. by 25cm. sheet of galvanized steel into a W shape. The redesigned foam block was creating using a block of perforated foam covered with a sheet of aluminum. Cut a “w” shape out of the back of the foam. A w-beam barrier was placed inside.
Phase IV- Testing Barrier
Put ramp on a long wooden table. Hot Glue the barrier to a 193 cm long piece of 61x122cm, so barrier would not move. Put the wood in front of the textbooks to hold it steady for impact. Added a five pound weight to the simulation car and placed it at the top of the ramp. Let car roll down, video taped the impact, and used an accelerometer to measure acceleration as well as recoil. Repeated the steps three times for each barrier.
Charts and Tables
Fig (ADD NUMBER) indicates that the barrier absorbs much of the energy but sowed too much recoil, possibly causing the car to spin off back into the road, which could lead to a larger accident .Fig (ADD NUMBER) shows that the W-beam barrier does not absorb much of the energy, and shows a lot of recoil, indicating that the car will most likely spin back off into the road, possibly causing larger accidents. Fig (ADD NUMBER) portrays the absorption of the most amount of energy, while showing no recoil. Since no recoil was recorded, this would indicate that a car traveling at a high velocity, will go right through the barrier, possibly crashing into a wall. Fig (ADD NUMBER) indicates that the Redesigned Foam Block Barrier was the most effective due to the large absorption of energy while showing a little amount of recoil
The statistical analysis shows the difference between the four barriers. The redesigned foam block was portrayed as the most effective barrier. The difference between the p value and the sample variance shows that the values of the foam block and the foam block redesigned barriers are highly significant compared to that of the water bottle barrier and w-beam barrier.
Graphs, statistics and tests all signify that the design criteria were met. Crash barriers were made from affordable everyday materials and withstood several tests. Graphs show that barriers made, Foam Block Barrier and Foam Block Barrier Redesign, worked better than existent barriers. Water Bottler Barrier and W-Beam Barrier are simulation of barriers that are in use today. However, barriers created show an increase in energy absorption and flexibility, making them more effective than existent barriers. Redesign barrier absorbed the greatest amount of energy, causing the barrier to be the most successful and effective.
The car traveled at 3.22 km/h, simulating a crash. The original foam block barrier allowed the car to wedge itself underneath the barrier. Through video analysis we can see that the car hits and bounces off. The water bottle barriers allowed for energy to expand outward through the water however if the car had enough momentum it would crash through the barrier in a wall. The W-beam barrier absorbed a great deal of energy but the car came off at an angle. The redesigned foam barrier absorbed the greatest amount of energy. Since it was soft and also had the structure of the w-beam it allowed for a safe crash.
Building barriers on a larger-scale to simulate the barriers used today. Building crash barriers with a spoiler system, which acts as an accessory yet absorbs some of the impact. The use of aerated concrete as an arrestor bed to slow an out of control car down. Developing, designing and testing more crash barriers composed of affordable everyday materials.