Structural Engineering

Structural engineers design structures considering:  (1) the imposed architectural, geometrical, circumstantial, and economical constraints, (2) the discrete and combined strengths of the construction materials and structural components, and (3) the possible loads from different sources (self weight, dead load, live load, wind, soil movements, earthquakes, earth pressure, water pressure, etc.). Once created, or in fact, even while under construction, the structure starts withstanding real-life conditions, which are, in a way, different from the assumed design conditions based on prescribed codes. The heart feelings of a structural design engineer are a huge satisfaction of creation, very closely accompanied by a huge responsibility. A physician has the responsibility of one patient at a time, a structural engineer has a never-ending responsibility of all the structures he has ever designed. The responsibility is in fact of the safety of all the tenants, workers, visitors, etc. that happen to be in these structures, at all times. The main concerns of a structural design engineer are:  "How good is doing the structure that we have created?" and also "How long will the structure last without creating any safety risk?" Since all humans naturally tend to forget, traditionally, most structural engineers are worried about the immediate consequences. Public safety and economic issues relate strongly to the latter question. However, there is no simple and accurate answer to this question yet. Structural engineers have to develop a procedure similar to a physician's diagnosis. The "patients" of a structural engineer are not as complex as human patients, but, they never show up to complain about their pains, and worst of all, they never describe the symptoms they feel. Besides, these "patients" are so huge that you can actually walk on them, and therefore, it is technically difficult to develop "health" testing equipment compatible with this size. Also, there is no possibility to capture as many desired "health" responses and have a huge number of "health-monitoring" sensors relative to the dimensions. These strongly limiting factors make testing and "health" diagnosis of structures even more challenging, and require critical thinking and developed creativity, besides high professional skills, in order to get safe and efficient results.

In some countries, periodic inspection of public or even private structures is a common procedure to cover the public responsibility of officials or owners. Professionally speaking, official/administrative/legal cover is the only matter provided by these inspections. Naturally, not much can be expected of an official inspecting only visually/externally and filing extensive paperwork. In most cases--if not in all, the inspectors are not engineers, and cannot comprehend the alarming message of a small-but-critical crack. Besides, as in medicine, the pains or problems do not always show out, and therefore require internal checkup and diagnostic tests. On the other extreme, superficial inspections of externally deteriorated but internally sound structures tend to conclude with decommissioning and demolition of worth-saving structures, wasting large amounts of public funds.

Experimental testing of structures is a sub-specialty of structural engineering. To an unexperienced eye, superficially looking, it may seem simple. Indeed, many think to be capable of carrying out this task. Attaching a couple or as much as possible sensors and getting some measurement readings is not the final goal, even if performed with the most advanced equipment. An experimentalist should be capable to design what is required to measure and for what reason, considering many circumstantial limitations, including funds. Sensors should be placed in the exact required location and direction, to instrument without disturbing the natural behavior of the measured phenomena. Thinking another step ahead, the reason why should also keep in mind what to do with the obtained results and how to compile them into a tangible presentation. The comprehension of the meaning of the measured results is extremely important to get meaningful conclusions. Putting together as much as possible results does not help any engineer to get smart conclusions. In brief, the skill is very delicate and dependent on the smallest of details, if one really cares for accurate results reflecting the reality of the structure, and accordingly design effective engineering measures. No doubt, it first requires a strong foundation of theoretical knowledge and practical comprehension of structural behavior and response, in conjunction with modern and complex computer and technological skills. Successful integration of all these quite different engineering facets characterize the successful experimentalist, who should be at the same time a theoretician, a practical designer, a lab scientist, and a computer whiz. Since there is no graduate school for this sub-specialty, the only way to learn is years of hands-on practice under qualified supervisors, and lots of open-minded observation, accompanied with critical thinking and creativity. The basic first step is to experience small-scale lab testing and acquire a global vision and full control of the whole concept, namely, the design and comprehension of structural experimentation. It is indeed difficult for a beginner to have an encompassing vision and control of a full-size structure, design its efficient testing, and carry out the logistic procedure. After becoming a lab expert, the next step would be field-testing real structures.

"If you would not be forgotten,  as soon as you are dead and rotten,
either write things worth reading,  or do things worth the writing." --Benjamin Franklin

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