Analysis Construction of Balsa Wood Bridge - Report Example

Name: Course: Tutor: Date: Summary Report of Balsa Wood Bridge Introduction The following paper offers a summary report of a project undertaken by students to build a balsa wood bridge. The team’s role was to make a concept bridge made of low density balsa wood, and determine the bridge’s failure load. The paper will aim to provide a detailed analysis of the project, starting from the problem definition to how the team undertook the project’s preliminary investigations. A summary of the team’s conceptual design will also be provided, starting from the development of their initial design ideas, how they were able to assess their alternatives and how they selected their material design. The paper will also summarize the team’s detailed analysis section, from the stability and static calculations they made, their project drawings and the project design costs analysis. Finally, the paper will also analyze the team’s recommendations and conclusions that they made. The paper begins by providing the project’s problem statement and objectives. The problem statement was to design and build a concept bridge with its objective being to determine the maximum load that it could hold at its mid-span. The bridge’s shape was also defined as any static truss shape strictly made up of low density balsa wood. The bridge’s height, length and width dimensions were also provided, with the bridge’s maximum weight defined as 700 grams. Other objectives that were to be met included finding the unit members’ force and calculating the bridge’s overall reaction. Lastly, the project was also undertaken to determine the bridge’s stress and contrasting it to the material strength. The team consequently undertook a background study followed by preliminary investigations. The preliminary investigations were centered on trusses, which are the structures that are connected to form a typical triangle. The first type of truss bridge analyzed was the Howe Truss Bridge. This is the type of truss bridge that contains numerous diagonal and vertical members, which slope towards the bridge’s center in an upward direction. The second type was the Pratt Truss, which contains diagonal members slanted downwards and towards the bridge’s center. In this type of truss, the diagonal members are only subjected to tension forces, while the vertical members are subjected to compression forces. The third type of truss analyzed by the paper is the K Truss, which follows the idea of splitting the bridges vertical members into smaller sections, which are subject to compression. Finally, the paper has analyzed Warren Truss type of bridges, uses equilateral triangles to distribute the weight load. After conducting the preliminary investigations, the team was henceforth able to develop the conceptual design ideas. From the four proposed designs, the team then undertook deliberations among themselves to determine the most sufficient conceptual design and settled on Warren Truss model. The team further provided two key sub-functions of the Warren Truss that would ensure its effective implementation. The first sub-function was on its joint, which was the point where two members or even more would connect together. The members would be connected to each other using either glue or pins, to form the required joints. The second sub-function that the team was also able to analyze was on Warren Truss overall shape. Key among the team’s reasons for the model included its feature of using equilateral triangles, which ensured that the load acting on the bridge was evenly distributed. On the overall shape of the bridge, the team also included the model’s vertical members, which were useful in reinforcing the bridge’s overall strength. The paper has also presented pictures and drawings of both the joints and overall shape of the bridge that offer a visual appeal of the Warren Truss conceptual design model. The paper then offers an analysis of how the team was able to generate numerous alternatives for their joints and shapes of the final product. On the type of joints that the team would embark on, that paper has offered four distinct types of those joints. The types of joints that the team would embark on have also been visually represented in form of drawings, to offer efficient illustrations. The first alternative joint is cutter members. This type of joint has been illustrated as one that involves cutting the members into holes, followed by fixing members into those cutting to form a joint. The second type of alternative joints presented is the pin joints. This type of joint involves cutting one member joint into a pin, followed by forming holes on the other member. The joint is consequently formed by inserting the pin-shaped member into the hole created. The third type of joint that the paper has presented is the model joint type. From the illustration, the method involves shaping members into different shapes and sizes followed by modeling them together to form a joint. The last alternative type of joint that has been presented is the glued joint. It involves forming a joint via sticking the members together using glue. Lastly, the team presented visual drawings of the final bridge’s model. The paper consequently presents an assessment of the different types of joints and shapes of the Warren Truss model. The first type of joint that underwent the assessment was the pin joint. The team agreed that though the pin joint type might have been the best choice, the method was impractical owing to the fact that low density balsa could not be cut into the required shapes. The cutter member was identified as the second best choice as the members stay on their position as required. The method was also ruled out as it encourages loss of material over strength. Finally, the team agreed on the glued joint type, due to its simplicity in making and that strong glue holds every member in place. Other types were also ruled out, owing to balsa wood being too light and delicate. The paper then offers an analysis of the team’s assessment process of the most applicable shape. K-Truss was ruled out due to its complexity owing to its numerous slanting members and the fact that the team was beginners in bridge designing. Triangular Warren was found out to require a lot of materials and henceforth not cost effective. Warren truss was chosen as the best and final shape. The reasons that the group presented involved the reason that the method consists of vertical members that further reinforced the bridge. Another reason was due to its equilateral triangles that ensure load subjected to the bridge is distributed. The paper also analyzes the team’s selection process of the appropriate materials. The team would use low density balsa wood as per the requirements. The team also agreed to use Bison kit Universal Adhesive due to the fact that it took longer time to dry, that allowed for alterations to be made. This was in contrast to superglue that was ruled out since it dried fast and never offered enough time to make alterations. The preliminary cost analysis would include analyzing the costs of balsa wood, paper blades, chart paper and Bison kit universal adhesive. The total initial costs amounted to a total of 168 AED. The expected labor time for the project completion was initialized to 10 days. The paper also presents a detailed analysis of the team’s project. The bridge was found out to be statically stable, based on the number of joints and members in the bridge. The static equation was used to calculate the bridge’s stability. The paper then offers an analysis of three types of forces from thee members and joints. The forces included compression, tension as well as the zero force members. From statistics the maximum force that a member in tension could hold was found out to be 294 Newton. On the compressive force, a member was found out to hold a maximum of 118.70 Newton for a 39cm member. From the paper’s final calculations also, the maximum tensile force was calculated as 1.385F based on one side of the truss. The maximum tensile force was found out to be 1.124F, using the static calculation of the truss. The paper finally calculated the critical load using the Euler’s formula of buckling. The formula uses Young’s modulus of elasticity, effective length of members in addition to the moment of inertia. Using the three variables, the critical buckling load was found out to be 518.77 KN, which is the maximum load the bridge can hold. The final cost analysis was found out to be 210 AED, with the increase emanating from increased time spent on construction and visual modifications. The items used included five pieces of Balsa wood, two sachets of paper blades, two bottles of super glue, two bottles of Bison adhesive and one piece of chart paper. Conclusion and Recommendations The paper finally concludes by giving reasons why the Warren Truss was the best choice. The paper’s conclusion section also shows that they successfully finished the design dimensions as stipulated by the instructor. The team also acknowledges that the bridge could be reinforced further by applying much stronger glue, and possibly building a newer bridge prototype. On the recommendations section, the team presented two recommendations. The first included constructing truss design on top and bottom of the bridge, rather than on the horizontal. The final recommendation involved using a medium density wood in contrast to the low density wood, as it would hold much heavier load. Read More