A Simplified Design Approach - Simplified Design of Reinforced Concrete Buildings - page 2

In the same way, Figure 1-2 shows the percentage of all building projects constructed in various size
categories. Building projects less than 15,000 sq ft dominate the building market.

> 50,000 sq ft(1%)

15,000 to 50,000 sq ft(1%)

< 15,000 sq ft(98%)

Figure 1-2 All Building Project Size. 2002

When all these statistics are considered, it becomes quickly apparent that while most engineers would like to
work on prestigious and challenging high-rise buildings or other distinctive structures, it is far more likely that
they will be called upon to design smaller and shorter buildings.

1.2 COST EFFICIENCIES

The benefit of efficient materials use is not sought nor realized in a low-rise building to the same degree as in a
high-rise building. For instance, reducing a floor system thickness by an inch may save three feet of building height
in a 36-story building and only 3 in. in a three-story building. The added design costs needed to make thorough
studies in order to save the inch of floor depth may be justified by construction savings in the case of the 36-story
building, but is not likely to be warranted in the design of the shorter building. As a matter of fact, the use of more
materials in the case of the low-rise building may sometimes enable the engineer to simplify construction features and
thereby effectively reduce the overall cost and time required to complete the building.

In reviewing cost studies of several nonresidential buildings, it was also noted that the cost of a building's frame and
envelope represent a smaller percentage of the total building cost in low-rise buildings than in high-rise buildings.

In low-rise concrete construction, designs that seek to simplify concrete formwork will probably result in more
economical construction than those that seek to optimize the use of reinforcing steel and concrete, since
forming represents a significant part of the total frame costs. There is less opportunity to benefit from form
repetition in a low-rise building than in a high-rise building.