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You will read about the potential to define mathematically
correlated platforms for shelter design leadership by all related city design
professions. It will involve terms like building design category, forecast
model, design specification template, buildable land area, impervious cover,
unpaved open space, shelter area, core area, parking specification, floor
quantity, gross building area, building footprint, and the shelter capacity,
intensity, intrusion, and dominance implications of correlated design
specification decisions. I hope these terms are not new to you since I’ve
written about them often in the past. If they are, I think you will understand
as you read. They will introduce you to the spectrum of development capacity
options that will determine your ability to define and shelter the activities
of growing populations within the composition of a limited Built Domain that is
needed to protect our quality and source of life – the Natural Domain.
The Baseline
The maximum gross building area (GBA) potential of a given
land area will be the baseline for this discussion. I’m going to use the
forecast model G1.L1 in Table 1, and its master equation in cell B39, to establish
this baseline and address the potential I’ve mentioned with something more than
intuition and experience. I’ve discussed this table many times and have
included the derivation of its master equation in my book, The Equations of
Urban Design. The table addresses the (G1) Building Design Category when
gross land area (L1) is given in cell F3. As a reminder, the G1 category
includes all buildings served by a grade parking lot around, but not under, the
building on the same premise. (A building design category may be occupied by any
occupant activity more commonly referred to as a “land use”. The emphasis here
is not on the compatibility of adjacent land use activity, but on the shelter
capacity of a given land area. Capacity and condition encourages or discourages
activity. Shelter capacity, condition, and location deficiencies discourage
economic development.)
The workhorse for this discussion is Table1. It will be used
to create Tables 2 and 3. The parking assumptions in Table 1 have been entered
in cells A35 and A36. Floor quantity options have been entered in cells
A49-A53; and an assumed gross land area has been entered in cell F3. The
remaining shaded cell variables have been entered as zero to find the maximum
development capacity of the land area given the parking specifications entered.
The result is a prediction of gross building area potential (GBA) in cells
B44-B53 for each of the floor quantity options entered in cells A44-A53. All of
these forecasts are related to the land area given in cell F3. The predictions
represent the maximum gross building area potential of the land area given when
the project area is covered by parking lot and building footprint when the
unpaved open space allocation in cell F11 is zero. This is an extreme condition
but establishes one end of the potential development capacity spectrum for this
building design category, land area, and parking specification.
A Unique G1 Characteristic
Before I go further, I’d like to point out why I’ve drawn a
line under floor quantity 5 in Tables 1, 2 and 3. The line emphasizes a unique
characteristic of the G1.L1 Building Design Category. I’ve mentioned this before
so I ask previous readers to excuse the repetition.
When the value entered in cell A35 of Table 1 exceeds the
value entered in cell A36, the surface parking lot will expand at a greater
rate than the building footprint. Parking quantity and area must expand to justify
increases in gross building area produced by increased floor quantities as the
building footprint area declines. This parking lot expansion eventually shrinks
the remaining building footprint area below a useful floor plan area.
The gross building area (GBA) increase per floor is
calculated in cells B44-B53 of Table 1 based on the values entered for (s) and
(a) in cells A35 and A36 of its Design Specification Template. These GBA values
are repeated in Column B of Table 2. The increase per floor becomes negligible
above 5 because of the relationship just mentioned. The line added below the 5
floor mark emphasizes this characteristic. The request for parking variances
begins when the futility of increased floor quantity is recognized. Parking
variances increase gross building area potential because they reduce the
parking lot area required and expand the potential building footprint area.
They also increase intensity that has been unmeasurable in the past. The
variances, however, do not affect the 5 floor characteristic just mentioned.
The (GBA) predictions made in cells B44-B53 of Table 1
represent the maximum (GBA) potential of the land area given the values entered
in the Design Specification Template of Table 1. A change to one or more of these
values would produce a new forecast.
Shelter Capacity
I also need to introduce the concept of shelter capacity as
a prerequisite to the remainder of this discussion. Gross building area calculations
do not indicate the land area consumed. I have created shelter capacity
calculations for this reason. The shelter capacity of a given buildable land
area is equal to the gross building area square feet planned or present divided
by the buildable land area involved in acres. The resulting dividend is shelter
capacity per acre (SFAC). The calculation makes all building projects
mathematically comparable to the land consumed and has the added benefit of
enabling calculation of the intensity, intrusion, and dominance implied by the
physical presence measured.
Shelter capacity (SFAC) is calculated in cells F44-F53 of
Table 1 based on the equation in cell F43; the gross building area values
calculated in cells B44-B53; and the buildable land area calculated in cell
G10. In this example, the shelter capacity calculations represent the maximum
development capacity of the 1.738 acre land area given based on the design
specification values and floor quantity options entered in Table 1.
The relationship between land, building, pavement, and open
space will demand increasing attention as populations continue to expand and we
come to realize that land preservation beyond our Built Domain is a mandate and
not a choice.
Column B4-B13 in Table 2 repeats the shelter capacity values
calculated in cells F44-F53 of Table 1. The remaining columns reflect the
changes that occur when the zero unpaved open space value in cell F11 of Table
1 is replaced by the values in cells B3-M3 of Table 2. Each column in Table 2
calculates the shelter capacity produced in Table 1 for the floor quantity
options entered in cells A4-A13 when the unpaved open space percentage is
amended to equal the constant at the top of each column in Table 2.
Reading across rows 4-13 in Table 2 defines the shelter
capacity reductions that occur when the unpaved open space percentage increases
in row 3.
When all design specification values remain constant in the
G1.L1 forecast model (except for the unpaved open space percentage in cell F11),
Table 2 shows that: (1) increasing the unpaved open space percentage (S)
required on the buildable land area (BLA) of a project will reduce the gross
building area (GBA) potential of the area, and (2) an increased floor quantity
(f) cannot recover a GBA loss when a significantly greater unpaved open space
percentage (S) is required.
The entire range of shelter capacity implications associated
with the unpaved open space increases in cells B3-L3 are shown in the columns
of Table 2.The intensity implications of the increased unpaved open space
allocations in Table 2 are recorded in Table 3. Both of these tables have been
created from Table 1 by modifying the unpaved open space percentage in cell F11
of Table 1 to equal each of the percentages in Row 3 of Table 2 and Row 23 of
Table 3.
Intensity
Physical intensity is a condition we feel but haven’t been
able to measure. I doubt, however, that many will disagree that it has an
effect on those adjacent to, or surrounded by, its presence. In fact, I believe
that physical intensity has at the very least a social, psychological,
environmental, and economic impact. This is why I created the Implication
Module in Table 1. It measures intensity in relation to the building design
categories and design specification decisions that determine its scope.
The Implications Module in Table 1 is based on the gross
building area (GBA) predictions in cells B44-B53. It first measures shelter
capacity (SFAC) in Column F for each of its GBA predictions. It then measures
the intensity (INT), intrusion (INTR), and dominance (DOM) implied by the shelter
capacity calculations in its succeeding columns using the equations in cells
F43, G43, H43, and J43.
Table 3 records the intensity created per floor when the
open space in Row 23 increases to mirror the increases in Row 3 of Table 2. As
expected, intensity declines with the increasing percentage of unpaved open
space provided per floor and increases within each open space category as floor
quantity increases.
Tables 2 and 3 calculate the capacity and intensity options
related to the design specifications entered in Table 1. The additional options
that could be produced are not hard to imagine when you realize that there are
26 shaded design specification locations in Table 1, and that Tables 2 and 3
will change whenever one or more of these shaded values is modified.
It is inevitable that shelter design decisions become a
guessing game with sprawl and excessive intensity as potential outcomes when
the palette of design specification decisions is not understood mathematically
correlated and intensity targets are not defined with knowledge based on
pre-existing research.
Choice
Table 1 uses extreme design specification choices to define
one end of the development capacity spectrum when parking value (s) equals 400
and (a) equals 250. The shelter capacity limits in Column B of Table 2 and the
intensity levels in Column B of Table 3 measure the implications of these
extreme choices. The remaining columns C-M in Table 2 present the shelter
capacity reductions that occur when unpaved open space percentages increase in
cells C4-M4.
The intensity levels in Columns C-M of Table 3 also decline
with the increased unpaved open space percentages in Table 2. The tables
clarify the choices available and implications involved. There are many more
than presented. They change whenever one or more design specification values in
the shaded cells of Table 1 change. The choices are in our hands. Measurement
and evaluation of existing projects can help us understand the related consequences
of design specifications, shelter capacity, and intensity decisions for all
building design categories within a correlated mathematical spectrum of shelter
capacity options. Evaluating these choices can help us acquire a better
understanding of the places we create around the shelter we inhabit within the
limited Built Domain we must define.
Walter M. Hosack: August, 2023
Photo by David Brooke Martin on Unsplash
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