Bridge Bundles Case Study

Initially, suspension bridges before 1940 were made of piers, towers, wires, anchorages, and roadways. Piers were the main foundation for the suspension bridges. There usually were two of them, which were made out of cement and were entrenched in ground underneath the body of water that the bridge was spanned across. Towers were built on top of the piers to provide a means of connection for the roadways and wires. Wires were connected to the towers, roadways, and anchorages to provide tension support for the weight of the bridge. The anchorages were large cement platforms that were planted into the ground on either side of the land so that the wires could be connected to it. Lastly, the roadways were the main point of the suspension bridge. They usually were wide enough to provide four lanes of traffic and stretched from one side of the bridge to the other. This was the basic design of the suspension bridges

We needed to fully utilise our knowledge by applying all the basic concepts in physics such as dynamic equilibrium and knowing the stiffness of the materials to build strong miniature bridge using given items to withstand the weight applied.

Calculations were performed to determine the effectiveness of the design of the platform. Allowing for a safety factor of 1.5 times the design weight of 10kg and considering the bridge must not be overdesigned; plans were made for the bridge to fail at 25kg, 2.5 times that of the design weight. According to the calculations, the bridge would hold a load of over 15kg and experience failure at 20kg in the members. These calculations were later disproven in the testing, breaking 8kg earlier than expected, due to unforseen errors. An analysis of the bridge design and calculations has been included at the end of this report.

The final primary component of a suspension bridge is the deck, or the roadway upon which cars drive and pedestrians walk. The deck is built from massive pieces of steel-reinforced concrete hoisted into the air and laid into place upon the bridge. Deck pieces are connected with bolts and rivets, then suspension cables connect each section of deck to the main

•September/2016 - After the layout of the gravel and topsoil has been accomplished the next process is to begin the building of any bridges over waterways and boardwalks to include low, wet spots that were unable to be dugout. Due to the use of equestrian or ATv usage the bridges will need to be structurally strong using items such as steel or high strength treated lumber.

The Truss Bridge by Riley and Dustin We decided to go with different types of truss bridges so that we will have a strong bridge. The truss bridges is one of the quickest bridges to put up and also is the cheapest so is could also be one of the strongest kinds of bridges. The position of the bars give it a great strength so it can hold a great amount of traffic. The unique triangle design of the bridge truss allows it to span longer distances with less swaying. Unlike the other bridges during natural disasters a truss bridge will most likely stay together and won’t shift a lot.

During the construction, two half-spans being assembled 50 meters above ground level had a misalignment of 4.5 inches or 114mm in camber. It was suggested by John Holland & Constructions to use a kentledge to weigh down the higher section of bridge. It so happened that they had ten, eight tonne concrete blocks on site. These were placed halfway along the higher span to

Our group created a Pratt bridge design in order to maximize our efficiency with the limited amount of resources we were given. We also chose this type of bridge because it was simple and allowed for us to complete it within the given time frame. Our bridge was constructed using ⅛” x ⅛” balsa wood sticks, string, cardboard, paper, and a lot of hot glue. The balsa wood was used to make the frame, the cardboard was used to act as a level plane for the cans to stand on and as reinforcement for the sides of the bridge, and the paper and string were both used to construct the remaining roadbed. Balsa wood was used for the frame because it acts as a sturdy foundation. Cardboard was used as a level place to set our cans because of how smooth, flat, and sturdy it is. Cardboard was also used and attached to the sides of our bridge, as well as some of the joints, because it is very sturdy and does not pull apart or flex easily. Lastly, we used string and paper for the

The construction process of our model suspension bridge went smoothly. We designed a blueprint that showed our bridge in a life size scale. The materials used to build our bridge included two 18 inch tall two by fours for the anchoring towers of the suspension bridge, one 30

It is shaped in a way to transfer weight to the towers and anchors with its tension (O'Connor, 1971, p. 372). Cables are made of high strength wires spirally bound to form a rope (O'Connor, 1971, p. 372). Vertical cable suspenders that are fastened to the main cables hang the actual roadway. Stiffening girders and trusses are along the side of the bridge to distribute concentrated loads and help to keep the motion of the bridge at a minimum (Troitsky, 1994, p115).

The bridge that I build in class was a Warren Truss. It turned out to be a decent little bridge. It weighed 21.4 ounces so that put it on the lighter side of the bridges compared to the rest of the class. It wasn’t the lightest, but it was down with the smaller ones. It ended up holding right around thirty pounds and I’d say that not too bad. I knew my bridge was going to be on the lighter side, but I was okay with that because I knew that would maybe help me out in the long run by having a better overall ratio. I didn’t calculate what the ratio actually was, but I think I did alright considering what my bridge weighed and how much it held. It’s kind of crazy that a tiny bridge like that could hold 30 pounds.

As one looks across a gap in between two land masses, a thought of how one could cross comes to mind. When one thinks of this, a bridge comes to mind. Although they might now know what kind, a suspension bridge is the first idea. They picture something like the magnificent Golden Gate Bridge, one of the most recognizable structures in all of the world. Although suspension bridges now span over miles, they had very humble beginnings. The evolution and expansion of suspension bridges is a topic worthy of this very essay.

The first force is tension, which is a pulling force. Compression, the second force, is a pushing, or squishing, force that shortens the length of an object. All bridges encounter these two forces and must balance each other out. If not, the bridge will result in buckling or snapping. Buckling takes place when compression overcomes tension while snapping is caused when tension overcomes compression. To prevent this, the forces must be transferred, or spread out evenly. Other forces involved when designing bridges are torsion and shear. Torsion is a twisting force caused by high winds that is commonly found on suspension bridges. Shear stress takes place when two parts in an object are forced in opposite

Superstructure bears the load that is being passed over the bridge and it transmits the forces caused by the same to substructure. Load received from the decking is transferred on to the substructure by Bearings. They also distribute the load evenly over the substructure material as it may not have sufficient strength to bear the superstructure load directly. Piers and Abutments are the vertical substructures which transfer the load to the earth in the foundation. Wing walls and returns are constructed as the extension of

Bridgé : A bridgé is a struçturé built t0 span physiçal 0bstaçlés suçh as a b0dy 0f watér, valléy, 0r r0ad, f0r thé purp0sé 0f pr0viding passagé 0vér thé 0bstaçlé t0 véhiçlés, pédéstrians, çastlés étç. Théré aré many différént désigns that sérvé uniqué purp0sés and apply t0 différént situati0ns.