Model Arch Bridge and tha Design Improvement Essay - 2

Model Arch Bridge and tha Design Improvement - Essay Example Bridges are designed to withstand both live and dead loads. Dead loads are loads that do not change, such as the structure’s weight. These include the sidewalks, deck, railings, and the concrete or steel load-carrying members. Dead loads account for the considerable and significant percentage of stress in load carrying members. The second load, live load, changes; the change can be due to decreased or increased pedestrian and traffic loading. When designing a bridge, safety and strength of the structure are the most important considerations. The shape and overall design of the bridge were decided by the group. The shape of the bridge was sketched to full size on a white piece of paper. The sketch was used in to guide the popsicle sticks as shown in figure 2. The last step was to glue popsicle sticks on beams of the deck in order to come up with a bridge deck. The final structure is shown in figure 4. The whole procedure was carried on the first and second final structures. The first bridge weighed 193.6 grams while the second one was 245.1 grams. The first bridge supported a maximum load of 6,613 grams, concentrated at mid-span, while the second was 21, 818 grams. The loads to weight ratio of the first and second bridge were 34.2 and 89.0 respectively. Arch increase stability as it provides resistance to the forces that act in the bending of the bridge. The weight is redirected from members to ends of the bridge by arches; hence forces are evenly distributed for the better structure as shown in figure 5. The second bridge was strengthened in areas that loads were concentrated, that is at abutments and load points. The second bridge was also reinforced to increase their strength triangular shapes were used in preventing rectangles from leaning. A top lateral bracing was used in the prevention of buckling sideways during loading due to compression members like the top chord.