Lately, I have been involved in several bridge construction projects. This is actually the first time in my career that I have gotten a full-time engagement in bridge structure construction. I must confess that I have found bridge construction work to be very interesting. Unlike other types of structures, bridges require a very high level of attention to detail, if one is to get their construction right. There is very little room for mistakes in these projects. Ultimately, I have come to the conclusion that there are four very critical aspects in all projects that entail construction of bridge structures.
Firstly, if you wish to end up with bridges that are structurally sound, you have to ensure that you get the paper-based structural designs right. Unfortunately, some contractors imagine that the development of these designs is ‘just a mere formality’. So a contractor simply tells a structural engineer to get some random design. The engineer is then supposed to proceed to a mail site like www.sbcglobal.net, and once there, log into his or her SBCglobal email – and proceed to send the random design for approval. You therefore end up with a structural engineer coming up with a design, with actually having the benefit of visiting the site of the proposed bridge! This is very wrong, because a genuine effort should otherwise be made, to understand the weight that the bridge will have to bear, the type of soil the bridge will be set up on, the kind of elements of nature the bridge will be up against… and so on. And all these apply even for the smallest bridges: the culverts meant for use on private driveways.
Secondly, if you wish to end up with bridges that are structurally sound, you have to ensure that you get the steel fixing element right. You have to appreciate that in these sorts of structures, it is actually the steel that ends up bearing the weight. You have to ensure that the steel fixing is therefore done right. I have witnessed some conscientious contractors going as far as engaging consultant structural engineers on a full-time basis to oversee the steel fixing.
Thirdly, if you wish to end up with bridges that are structurally sound, you have to ensure that you get the concrete mixing element right.
Fourthly, if you wish to end up with bridges that are structurally sound, you have to ensure that you get the concrete curing right. You have to ensure that you pour the right amount of water, for the right number of days, in order to ensure that adequate curing takes place. Curing often comes across as a simple thing, but failure to do it right can lead to major structural defects — especially for bridge structures.