1. Changing Technology
Over the years required for the design and construction of a major project, the building materials used will often change in response to new technologies and market conditions. During the 14 years required for its construction, specifications changed many times as new products became available. For example:
- Steel became available and was used instead of iron structural elements.
- Electric lighting was used instead of gas lighting.
- The techniques for building such large caissons had to be developed especially for the project.
Graft, still a problem, was rampant during the time of Tamminy Hall and the Gilded Age. Fortunately, the Chief Engineer responsible for finalizing the design and executing the work, Washington Roebling, was beyond reproach. When he was accused of making a deal to award a contract to a supplier that was not lowest bidder, he denied any wrong doing and stated that:
"if the policy henceforth was to give 'contracts for supplies to the lowest bidder, irrespective of all other considerations, I hereby absolve myself from all responsibility connected with the successful carrying on of this work.'"3. Progress
Asked to compare the Brooklyn Bridge to the Great Pyramid of Cheops, Washington Roebling wrote:
"To build his pyramid Cheops packed some pounds of rice into the stomachs of innumerable Egyptians and Israelites. We today would pack some pounds of coal inside steam boilers to do the same thing, and this might be cited as an instance of the superiority of modern civilization over ancient brute force. but when referred to the sun, our true standard of reference, the comparison is naught, because to produce these few pounds of coal required a thousand times more solar energy than to produce the few pounds of rice. We are simply taking advantage of an accidental circumstance.4. Safety
"It took Cheops twenty years to build his pyramid, but if he had had a lot of Trustees, contractors, and newspaper reporters to worry him, he might not have finished it by that time. The advantages of modern engineering are in many ways over balanced by the disadvantages of modern civilization."
A problem during the construction of caissons was called an accident. Washington Roebling responded by stating:
"To say this occurrence was an accident would certainly be wrong, because not one accident in a hundred deserves the name. In this case it was simply the legitimate result of carelessness, brought about by an over-confidence in supposing that matters would take care of themselves."