Bridge Design Process In order to begin we must start our design process with the first step. We have to identify the need. The scenario is that we need to connect two pieces of land or structure so that a car must be able to pass through it. In this project we are to design and construct a bridge for a matchbox car. The bridge must be made of balsa wood and glue only. It must support its own weight, the load of the matchbox car, and additional weights that will be added. Next we must identify what problem is given.
In this scenario our problem would be that we have a car that wants to travel between the two areas that the bridge is attached. We have only certain materials that can be used in constructing our bridge. And using those certain materials it must be of a particular size. And once those criteria have been met we must have a strong bridge that will carry the weight of the car and any additional weights placed on it. This bridge must have a truss design. Step three of our design process we search for ideas.
From our research we know that the triangle is the strongest shape in construction and this is why trusses are made up of triangles. Our bridge must be a truss bridge design. So we have done research as a group and individually on the different truss bridge designs. There are many different truss designs that already exist. So we have done internet research into the trials and tests put on these different designs to see what features are stronger than others. Then we look at the project constraints that are given to us.
The constraints that we have are materials, roadbed size, cross section size, p opening, and overall bridge width. The materials can only be balsa wood and glue. Glue can not be on surfaces that are not bonded. The roadbed is where the matchbox car must be able to pass along the bridge. The roadbed must also be able to accommodate the loading block with footprint, which is required for adding weights. There are also measurement constraints on the roadbed. The cross section wood members must not exceed one-eighth by on-eighth inch.
Span opening must be approximately four hundred millimeters. The bridge has a minimum width of fifty millimeters with no maximum width constraint. There is no minimum or maximum height requirement. The design criterion is the fifth step in the design process. The criteria would include the cost, reliability, weight, maintenance, appearance, compatibility, safety, noise level, effectiveness, durability, feasibility, and acceptance. Cost is very manageable for our design since the only materials will be balsa wood and glue, which are relatively easy to find.
The whole idea for the bridge design was something that could safely carry the weight of the car and the weight of the loading block plus all the weights that will be added. So therefore, when picking the design, we chose something that we thought would be reliable enough to carry all the required weights while safely allowing the car to pass through without flexing or collapsing. We also tried to make our bridge as light in weight as possible for the design because we will be competing for the lightest bridge if ours carries our predicted weight.
The design appearance is very symmetrical which is pleasing to the eye. It is nothing too complex, which makes it very acceptable. This bridge is very compatible with any location orenvironment. Since our design is a very open design the noise level would be minimal since it is not enclosed. It is, overall, a very durable and feasible design. Step six in the design process is to find alternative solutions. Before we came up with our final bridge design we had many alternative solutions to the problem that would fit the need. In our group we have seven members.
So we each individually did our own research about the materials, about trusses, and about different bridge designs. After that research we each came up with our own individual bridge design that we thought would be sufficient for the need. We then made a sketch of that bridge in our group journal. Then during our next meeting, we discussed each bridge and the strengths and weaknesses of each bridge. And from all those alternative solutions we came up together, using something from each individual idea, with a bridge design that was the best for the final product.
For the analysis part of the bridge, we focused mainly on design. Because this is a truss bridge, and the strongest structural shape is a triangle, we knew that we had to focus on the trusses in the bridge. We did research on the stronger and weaker truss designs. Through our research we found that the bridges that contained more triangles were the bridges that ended up holding up the best tostressbeing added. Along with the design, the physics behind the trusses were of equal importance.
We included a truss analysis along with our bridge to determine if the weight that the bridge has to support will be distributed along the length of the bridge evenly. Other factors that we took into account are how the bridge was going to be loaded. We knew the weight was going to be anchored to the middle of the bridge so we had to make sure that the weight would be evenly distributed to keep from collapsing. Our criteria from our decision matrix came from many different places. Before we each picked a bridge to input into our group journal, we had done a lot of research.
We had to research what a truss bridge was and what made them strong. Then we had to incorporate those ideas into our design. So once each of us had picked a bridge that we thought was sufficient for a final product that design still had to convince the other members of the group before it was chosen as the one design for the overall product. The final design was something that we all agreed would withstand the weight. For the specification part our project we have many things. First we have all our bridge ideas sketched in our journal. We then have a detailed AutoCAD drawing of our final design.
And we have a truss analysis of the angles of our trusses in our portfolio. The Bridge Design Process: The Abstract We are given a project, or a problem, where we need to attach two masses with a bridge so that a car may be able to pass through it. The bridge must meet certain criteria and constraints. It must carry the car and added weights and still be safe. But before we can determine a bridge design, we must use our ten step design process to come up with a sufficient design. The following report goes in depth on that process and our decision process.