The design of the suspension bridge is pleasing to the eye, but its design is complex and convoluted. A suspension bridge is a bridge where cables are strung across whatever obstacle it happens to be and the deck is suspended from these cable. Designing abridge is a difficult task that causes many engineers to become quite uneasy. The engineers get that uneasy feeling because once the bridge is built it’s there for a long time, and an unfortunate error of judgment is on view for all to see. Much depends on the location for the bridge to be built, how large a load it will have to carry, and so on. The designers ask themselves, and each other many questions.
Will it cross a river, and have to stand up to strong currents and perhaps flooding? Will it be wide enough for the traffic? Do approach roads need to be built? Will it be high enough for ships to pass below? Will people like the way it looks? Most importantly, will it be safe under all conditions? The decision making process can be made easy, but usually winds up being difficult and long. The process starts with various committees meeting and arguing about the good and bad points of the different ways in which the bridge can be built, and where. After a decision is made the committee gets someone to draw up a specification, which describes what is needed. This specification is published, so that the people who wish to build the bridge can say how they would do it, how much it would cost, and so on. Bridge designers are specialists in the field. They ” ve built many bridges, solved many problems and have a wide range of experience.
The Essay on Horrace King Bridge Builder
... over the Chattahoochee River. At completion, the bridge reached approximately 900 feet long and was built in the Town truss mode. This ... earned Godwin and King reputations as master bridge builders. The flood ... almost all of the main city bridge in Columbus. Godwin repaired both bridges quickly. The first bridge was reopened to traffic by April ...
When the designers have read the specifications some groundwork ideas are sketched up and discussed. Then representing upon their experience they begin to work on the calculations, designing and drawing the bridge. Usually several firms will prepare drawings to be presented to the client. To consider the various ideas more committees are assembled and ultimately a design is selected. The firm, which has received the contract, then allocates the work to contractors who do the actual construction, under the supervision of the designers. The contractors employ sub-contractors to do the work, and then the materials are ordered.
Over the centuries bridge construction has changed. Wages are now higher, and materials are dearer. The bridge builders need to be more careful about how much wood, steel, or stone is used, and how many workers and machines are going to be involved. The handling of materials in the old days was a relatively quiet non-polluting matter of horses and carts, but now the diesel engine has taken over, solving some problems and creating others. The delivery dates for the materials need to be arranged so everything arrives on the site at the right time as far as possible. The quantity ordered is very important because the lack of a material at some stage of the work may hold up the entire undertaking, and add to the cost, for delays are expensive.
Although the first thing is to make sure that the bridge will be strong enough allowing for all of the expected load, the engineers think about the way the structure looks, too. There are some things that look good anyway, when properly designed, and a bridge is one of them. A bridge that used material improperly usually looks skinny and wobbly, or fat and clumsy. Starting with the specification, the engineers need to put in a lot of mathematical work. At one time this was a branch called “statics”, dealing with stationary things; but bridge parts do move; they sway in the wind, give and vibrate. For these reasons statics alone cannot be used to solve all of the problems.
Modern computers now provide engineers with new advanced mathematical computer programs that incorporate all aspects of a bridge. The mathematical side of the work is speed up due to the use of the modern computer, and engineers are able to produce pictures of the finished bridge, before the first material orders are issued, to show what the finished bridge will look like. The suspension bridge is the most distinct and the most difficult bridge to design. They are very pleasing to the eye, which makes them readily recognized. The cables or chains hang down in natural enjoyable curves, and the only thing that can spoil their appearance might be an unfeeling design of the pylons that carry the cables. If they are unsightly they can ultimately ruin the appearance, as they show up from all angles..
The Essay on Bridge Materials Cast Iron
... in different ways, so as every material withstands forces differently. To design a good and safe bridge, an engineer must know the forces in ... stones, bricks, or wood. At that time, those materials were the best thing they could make. Today people use steel instead ... iron, both cast iron and wrought iron were used. The advent of steel replace those material. Nowadays, steel and concrete (reinforced ...
