Quote:
Originally Posted by SteveD
Good additional input from all, above. As I said, there's hundreds of variables involved. When you go very tall, some unit construction costs rise, and just as many unit construction costs drop. The basic floor by floor structural components don't change. As others correctly noted, very tall equates to additional elevator banks, which reduces leasable or sellable per floor SF, stouter structural members with greater cross-sectional area, which also reduces leasable or sellable per floor SF, costlier admixtures for increased strength, etc. However, the complexity level of building a 40-story building is not appreciably different from that of an 80-story building. Same HVAC systems, electrical, plumbing, life safety and fire suppression, etc. For example, the construction cost of the HVAC equipment (heating and cooling) for two 40-story buildings might be greater than the cost of the HVAC equipment needed for one 80-story building. If Trump went 1,000 ft in Atlanta vs. the two 500+ proposed, I might expect the construction costs for the 1,000 footer to be marginally more expensive, but in no way would they approach twice the cost. Whether that would economic sense to do here in Atlanta, that's another issue, but that's not was I referring to in my earlier post. I'm a P.E., Civil, and my job involves (in part) assessing construction costs at commercial facilities nationwide.
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well, adrian smith would disagree with you. i remember him specifically mentioning how costs for things like plumbing and mechanical systems begin to skyrocket once you get into the 100 story range. he said the costs of these systems in the supertall building increased exponentially, they were not linear. like i said, this was just the lecture of a guy who has actually designed some of the tallest buildings in the world, so i tend to believe him.
and for what's it's worth, adrian was not talking about total project cost such as land aquisition, legal crap, marketing, etc. he was talking solely about the construction costs of building a 100 story office building vs. 2 50 story office buildings of the same total square footage. of course there are always variables that can change the quation, butaccording to adrian smith, the construction costs of the 100 story version of the above scenario are much higher, generally speaking.