What is the strongest building structure?

Answer 1

Think of it this way, unquestionably the strongest structure is a solid.

But now the compromises begin: Is weight a factor? Is material cost a factor? Does it need to be hollow?

Once these parameters are known, then the loads must be determined. Are the loads static, dynamic, vibratory, etc. Are the loads in shear, torsional, moment, cantilever, etc. Do we need to consider earthquake, thermal loads, or impact loads?

And we must look at the desired building material(s):

steel has the same strength in all directions (isotropic, wood, concrete, and composites are wildly non-isotropic

so the direction of the loads becomes important.

Take the case of a sky scraper. We must consider the shape of the occupied area as well as all the necessary load cases. Thus we end up with a square girder structure which is not the strongest perhaps, but is adequate and meets all the other requirements.

Considering bridges, for short spans the basic AASHTO

concrete girder and deck is extremely durable and strong as well as cost effective. For longer spans we look at arcs of structural steel which are extremely strong and beautiful, or cable suspension/cable stayed designs using concrete piers that can withstand hurricane force winds.

The Eiffel Tower was built for the International Exhibition of Paris in 1889, but despite the age, it remains one of the worlds most brilliant examples of construction.

Some key observations:

1. Notice that it is open, the structural elements are exposed. This reduces wind loads (routinely 100 MPH at the top!) and saves cost.

2. Notice the arches combined with the "X" structural shapes. Arches are very efficient material wise, the "X" prevents buckling.

3. Notice the width at the base. This is an amazingly stable and

strong structure.

4. Steel (actually puddled or wrought iron in this case) members can be rapidly assembled. This required 300 workers for two years. A bargain!

5. Super lightweight: it has been said that a 1 foot high scale model would only weigh as much as a nickel!

Answer 2

Great Pyramid

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