What other methods can we use other than computers to design a bridge?

Question

What other methods can we use other than computers to design a bridge? If yes, why. If no, why. How do we use a computer to design a bridge? What are the things we must consider before building a bridge like the safety of bridge?

Answer 1

Using a small scale model

Answer 2

Computers can be used to model an entire bridge from the foundation peirs to the deck and supports. These tools allow structural engineers the ability to acuratly calculate the stresses and forces in each and every element on the bridge. Without computers theses force could only be calculated with a lifetime of work.
Before computers most of the forces were just estimated using the structural theory of the day, conservative methods were used to more or less analize the stresses, also the bridges built at the time were not as complicated as those built today and as such required less intensive calculations.

At the time these forces would be bumped up by a saftey factor to make sure the strcuture was indeed safe, However today we have better methods that include overestimating the applied loads and underestimating the true strength of the materials being used in order to ensure that the probablity of the loading being too strong and the bridge being too weak are reduced to an acceptable amount.

Since computer based finite element software has become available, easy to use and accurate. A lot of engineers use these tool to help in their design, but they are not an ends in themselves and hand calculations, models and analysis are done to comfirm the computer model. these methods are always used to ensure the accuracy of the model and so that no mistakes are made at any point on the bridge.
There is a famous quote that "What an engineer can complete on the back of an envelope is more important than 100 computer programs"

Answer 3

Engineers for centuries have been designing bridges and many other structures using paper and pencil and slide rules or just computations before computers. By looking up or computing the strengths of materials and the dynamics of the structure, they come up with the design.

When doing the design by hand, they always put in a “fudge” factor to assure the structure would withstand the stresses involved plus a little more. Now with the advent of computers, they are designing the structure to the exact point they want to save time and costs. In my opinion, that is why newer structures are failing at a greater rate than older (pre computer) structures.

JUST MY OPINION – BASED ON NO REAL EVIDENCE

Answer 4

Computers have been around, and useful, for about 30 years. Bridges have existed for thousands of years, and some scientists say some natural bridges have existed for 10's of thousands of years.

There are some useful strategies to build a bridge:
-copy nature
-sheer dumb luck
-kluge it
-use geometry & math & science
-optimize using computers.

If you want to know more about structural engineering without using computers get any text on structural engineering that was written in the 1960's or earlier.

Answer 5

Study bridges from around the world. Find bridges that cover similar geology and geography. (Rock formations, bridging over a lake, bay, in a city, out in a country, etc.)
Find one with similarities in the place to be bridged, and adapt that to your situation.
Here is a good start below.

Answer 6

no, bridges were never designed before the computer.

Answer 7

How did we design things before the invention of computer?

Answer 8

The good, almost forgotten method of using a draftsman's pencil, paper, protractors, and other engineering tools.. all the tools used prior to the advent of the computer