1. 1
The analysisof Urban Form as an assessmenttool of Sustainability
Extented abstract of dissertation for the degree of Master Civil Engineering
Quentin José Manuel Blanpain Silva
Instituto Superior Técnico, Lisbon, Portugal
July 2015
Abstract. This thesis aims to establish a procedure for assessing the sustainability through analysis of the
Urban Forms. In this sense they are chosen two case studies which intend to exemplify the method used,
checking their relevance for evaluating Urban Sustainability and, on the other hand, to test its utility by
selectingandquantifyingparameters inurban areas withdifferent characteristics andperiods of origin.
The Urban Formanalysis of the historic center of Évora allows you to applythe method of UrbanStructural
Units, based on the methodologybyPaul Osmond (Osmond, 2008). This methodprovides an analytical tool
and diagnostics of the built ambient of the historic center and establishes a basis for the evaluation of the
Urban Metabolism.
In the secondcase study, USU’s are selected insevenareasof Lisbon, representingthe principalmoments of
the urban development in the city. The quantification of indicators, based on the range of parameters
established bySerge Salat (Salat, 2011) allows to evaluate and compare Urban Sustainabilityof the selected
zones, byanalyzing the energyconsumptionof buildings. A detailed statisticalanalysisallows to evaluate the
relevance and consistencyof the indicators used andprove the scientific validityof the USU’s methodinthe
assessment andmeasurement ofSustainability.
Tags
Urban Morphology, UrbanSustainability, Urban Metabolism, Urban Structural Units
The main objective of this thesis is the Urban Morphology analysis of built tissues, with different
shapes and periods of construction, for the assessment of sustainability. In order to achieve this goal,
the following objectives were defined:
1) Systematizing the methodologies of Urban Form analysis.
2) Apply the method of Urban Structural Units, developed by Paul Osmond (2008) and evaluate
its utility for the Urban Sustainability assessment.
3) Establish a methodology that allows the comparison of the Sustainability of urban areas with
different periods of origin.
4) Determine the relevance and future possibilities in the application of the methodology used in
this work and the USU’s methodology for Urban Sustainability assessment.
The methodology of Urban Structural Units, by Paul Osmond (2008), is applied to the historic center of
Évora, allowing a critical analysis of the utility of the methodology for the analysis of Urban Form in
general and a first approach for the Urban Sustainability assessment.
The Urban Sustainability assessment is performed by choosing USU’s within seven urban areas of
Lisbon, which characterize the main periods of the development of the city. Relevant indicators for Urban
Sustainability assessment are chosen from the range of parameters established by Serge Salat (2011),
which main objective is evaluate the energy consumption of buildings.
A critical evaluation of the relevance and consistency of the results is assessed through statistical
analysis. A sensitivity analysis allows to sustain these analyzes and check the homogeneity of USU’s.
1 Introduction

2. 2
There are different perspectives and approaches in the analysis of Urban Form, characterized by
the Anglo-Saxon, Italian and French schools (Moudon, 1997). The Analysis of the Urban Form in this
thesis lies in Anglo-Saxon approach.
The Anglo-Saxon school has a descriptive, analytical and explanatory approach and offers the
most complete and detailed type-morphological method of the three schools (Moudon, 1997).
This school initiate with M.R.G. Conzen’s works, who developed in more detail the morphological aspect
of the built environment, called Townscape. Conzen recognized the tripartite division of the Townscape:
Town Plan, Building Fabric and Land and Building Utilization (Whitehand, 2001). The Town Plan is
constituted by four elements: Site, Street System, Plot Pattern and Building Arrangement.
Conzen defined the concept of Plan Units as a combination of the Street System, the Plot Pattern and
the Building Arrangement, which constitute the Town Plan. These elements are grouped and organized
in different combinations constituting different units with a "morphological homogeneity". On a larger
scale of the Town Plan, Conzen identified Plan Divisions as combinations of Plan Units. Conzen also
defined the concept of Morphological Regions, as homogenous areas in terms of its form, which
distinguish them from other surrounding areas (Whitehand, 2001).
The methodology developed in this school aims to identify and classify buildings in "Types". In
this approach, a city consists of Basic Types (dwellings) and Specialized Types (churches, palaces…)
(Pereira Costa, Stael de Alvarenga, Safe, & Cleide, 2013).
In its work, Caniggia establish a distinction between the spatial and temporal relationships,
characterized by the concepts of Copresense and Derivation, respectively (Kropf, 1993) and established
a hierarchy of the urban form, divided into two scales (Building and City), which are subdivided into four
different levels: Elements, Elements of Structures, Systems of Structures and Organizations of Systems.
The urban fabrics are characterized by three entities: the Plot, the Pertinent Strip and the Built route.
Based on the subdivisions of Conzen and Caniggia, K. Kropf establishes a renewed hierarchy of urban
form. This hierarchy use the general definition of the form and the first four levels of Caniggia (Materials,
Structures, Divisions, buildings) and consider the level of Conzen’s plot. The reference point of Kropf
synthesis is the Lot, emphasizing its three-dimensional nature and eliminating the consideration of the
Land Use (Osmond, 2008). In this hierarchy the different elements of the urban form can be identified
in different levels of specificity, increasing the level of resolution of the forms that are to be identified
(Kropf, 1993).
Osmond establishes a system for the Urban Form analysis, linking the updated hierarchy of Karl
Kropf (1993) and the concept of Urban Structural Units, developed by Stephan Friedrich and Duhme
Pauleit (1998). Thus, it creates an updated hierarchy for the analysis of the Urban Form, linking
2 State of the art
2.1 Anglo-Saxon School and M.R.G. Conzen legacy
2.2 Italian school and the system of G. Caniggia
2.3 Hierarchy of Built Form, by K. Kropf
2.4 Paul Osmond and USU´s methodology

3. 3
hierarchies of Built Form and Open Spaces, a decomposition of the space through the Space Syntax
method, an inclusion of the urban infrastructure networks and, indirectly, the geophysical properties of
the area. This final hierarchy is the basis for the definition of USU´s and allows you to include the concept
of Surface Sealing, which distinguishes the pervious and impervious surfaces, and the introduction of
the attributes of vegetation. The methodology established by Osmond aims to support the evaluation of
urban form in terms of urban metabolism and Urban Ambience.
The USU´s are homogenous areas regarding to the type, density and arrangement of the urban
form and the open spaces, which defines different configurations of the built environment (Pauleit &
Duhme, 1998). This homogeneity and uniformity of the shape of each unit are the basis for their
distinction. The authors Pauleit and Duhme, Wickop and Böhm (1998) outline the concepts of
"Homogeneity physiognomy" and "uniformity" as relevant characteristics for distinguishing USU’s.
The method of USU´s is applied in the historic center of Évora, classified as World Heritage by
UNESCO and delimited by the medieval wall.
Legend:
a – Historic Evolution of Évora
b – Urban Significant Structure of Évora
Figure 1 Évora Historic center maps (1)
Initially we proceed to the study of the historical evolution of Evora (Figure 1, a), in order to identify the
dynamics and organization of the built area, thus allowing the identification of some Built Space units
which characterize the study area, such as the Mourish or the Jewish Quarter. The application of the
method begins with the first division of the study area into two types of spaces: the Open Spaces (parks,
cultivated areas, public space) and the Built Spaces (Figure 2, c). This division begins with the definition
of the Urban Significant Structure of the area (Figure 1, b), which allows you to show the built elements
(white) and the open spaces (black) and thus observe the form of the urban area, in a neutral and
detached form from the architectural and ideological reality way. The Open Space USUs are defined
within the delimited Open Spaces. The procedure is repeated for the Built spaces. The next step is to
3 Application of the USU’s method in Évora
ba

4. 4
identify the pervious and impervious surfaces within the city (Figure 2, d). The identification of the
various types of surface provides an important parameter for the differentiation of the USU´s.
Legend:
c – 1st Division: Delimitation of Open and Built Spaces
d – Pervious and impervious surfaces
Figure 2 Évora Historic center maps (2)
Figure 3 Final division with Urban Structural Units in Évora
c d

5. 5
The consideration of the first division (Figure 2, c) and surface types (Figure 2, d) allows you to make
the final division in USU´s (Figure 3). The Open spaces are divided in four types of USU´s, with different
utilization (Table 1). Similarly eight types of USU´s are selected within the Built Spaces, according to
various Urban Intensities (percentage of built spaces or urban density and number of floors). The
differentiation between the different units is based on the road network (major axis configuration of the
streets and intersections), the configuration of blocks and the percentage of pervious surfaces.
Table 1 Description of each USU´s Type
USU´s Types Description Characteristics Examples
Type 1
Open Space: Vegetation and
cultivation areas
Areas with lots ofvegetation or cultivation, with few buildings.
Pervious surfaces >80%
Type 2 Open Space: Gardens Walking areas and gardens, with some trees and grass areas. Public garden
Type 3 Open Space: Parking areas Pervious surfaces characterized by white gravel compacted soils. Car parks
Type 4 Open Space: Squares
Public quares within the urban fabric. Few trees. Impervious surfaces
essentially characterized by the Portuguese sidewalk.
Giraldo Square
Type 5
Low Intensity: Little isolated
buildings
> 50% ofpervious surfaces.
Type 6
Low Intensity: large isolated
buildings
Large isolatedor goupedbuildings withfew storeys. Sometrees.>50%
permeable surface.
Primary School
Type 7
Medium Intensity: Littlelow-rise
buildings
Less pervious surfaces (<50%), located inside ofblocks. Residencial
buildings with 1 a 2 storeys.
Mourish Quarter
Type 8
Medium Intensity: Largelow-rise
buildings
Few pervious surfaces (<50%). Large buildings with 1 a 2 storeys. Arena
Type 9
Medium Intensity: Little hight-
rise buildings
Few pervious surfaces (<50%), located within the blocks or private
gardens. Residential buildings with 3 or more storeys.
Type 10
Medium Intensity: Large hight-
rise buildings
Few pervious surfaces (<50%). Large buildings with 3 ormorestoreys. University, hospital
Type 11
Hight Intensity: Low-rise
buildings
Few pervious surfaces (<10%). Buildings with 1 a 2 storeys. Jewish Quarter
Type 12
Hight Intensity: Hight-rise
buildings
Few pervious surfaces (<10%). Buildings with 3 or more storeys.
Built areas around Giraldo
square
Figure 4 Zones chosen for the analysis in Lisbon
4 Urban Sustainability assessment in urban áreas of Lisbon

6. 6
This study aims to evaluate and compare the Sustainability of urban areas in Lisbon, with different
tissues and periods of origin, characterizing the different period of urban development in the city. Thus
are chosen Urban Structural Units in seven areas of Lisbon (Figure 4 and Table 2), where are calculated
indicators in order to characterize the energy consumption of buildings in each study zone. In the figure
above, the oldest to most recent selected areas are: Zone 1-Mouraria (Moorish Quarter), Zone 2- Bairro
Alto, Zone 3 – Baixa, Zone 4 – Av. Novas (New Avenues), Zone 5 and 6 – Olivais Sul (South Olivais),
Zone 7- Parque das Nações (Expo).
Table 2 Study areas datas
Zone 1 –
Moorish quarter
Zone 2 –
Bairro Alto
Zone 3 –
Baixa
Zone 4 –New
Avenues
Zone 5 –Sth
Olivais, dwellings
Zone 6 –Sth
Olivais, towers
Zone 7 -
Expo
Units
Period oforigin XII XVI XVIII XX 1960 1960 1998 -
Area(m2) 72733 41912 60347 140337 64147 31277 86710 m2
Area(ha) 7,27 4,19 6,03 14,03 6,41 3,13 8,67 Ha
Resident Population 2092 961 342 1447 222 755 2466 Inhabitants
N. dwellings 1509 946 467 958 99 300 1082 Dwellings
N. buildings 354 203 92 111 94 12 61 Buildings
The indicators used for the Urban Sustainability assessment (Table 3) are chosen within the set
of parameters of Salat (2011).
Table 3 Indicators results
Indicators
Zone 1 –
Moorish quarter
Zone 2 –
B. Alto
Zone 3 –
Baixa
Zone 4 –New
Avenues
Zone 5 –Sth
Olivais,dwellings
Zone 6 –Sth
Olivais,towers
Zone 7 -Expo Units
UtilizationIndex 2,1 2,5 3,2 2,6 0,3 0,9 2,0 -
% Land Cover 56% 68% 57% 47% 17% 11% 27% %
Average Number of
Storeys
3 3 5 5 2 7 8 Storeys
Dwellings Density 207 226 77 68 15 96 125 dwellings/ha
Impervious surface
rate
83% 99% 100% 93% 63% 69% 94% %
Proportion of
Green Areas
17% 1% 0% 7% 37% 31% 6% %
Intensity of
Inersections
4 7 3 1 1 3 3 n./ha
Medium Distance
between
Intersections
88 42 76 149 319 110 96 m
FractalDimensions
ofstreets
0,106 0,325 0,169 0,001 0,361 0,124 0,057 -
Energetic
consumption
averageof
Certificates
188 193 195 134 168 130 137
KWh/m2.
year
Energetic Intensity
per capita
6791 9524 21256 13340 14957 6180 7187 KWh/hab
Energetic Intensity
per surface
195 218 120 138 52 149 204 KWh/m2
Passive Volume
rate
44% 36% 55% 33% 65% 54% 33% %
Energy
Consumption for
heating
80 90 49 56 21 61 84 KWh/m2
Energy
Consumption for
cooling
35 39 22 25 9 27 37 KWh/m2
Compactness 6,9 5,1 6,8 9,6 9,7 9,1 7,4 -
4.1 Calculation of indicators

7. 7
Energy intensity indicators have been obtained through Energy Performance Certificates (EPC),
existing in dwellings of the buildings of each zone. The classification of each energy certificate
corresponds to a percentage range of the reference consumption of the site in the analysis. (Santos,
2010) The consumptions in each zone are calculated by the product of the Average Consumption of
Certificates with the average area of the dwellings (Table 4) and the total number of dwellings (Table
2). The results thus obtained correspond to values of both Energy Intensity indicators. The Energy
Intensity per capita is the division of this result by the number of local residents of each zone and the
Energy Intensity by surface is the division of this result by the total area of each zone.
Table 4 Mean value for areas of dwellings
Zone 1 –
Moorish quarter
Zone 2 –
B. Alto
Zone 3 –
Baixa
Zone 4 –New
Avenues
Zone 5 –Sth
Olivais, dwellings
Zone 6 –Sth
Olivais, towers
Zone 7 -Expo Units
Medium area
ofdwellings
50 50 80 150 200 120 120 m2/dwelling
The observation of the inicial results allows to identify the most pertinent indicators in order to
analyse the characteristics of each study area and to evaluation the energy consumption of the
buildings. Then, the correlations between each of these indicadors with the Energetic Intensities are
measured (Table 5).
Table 5 Correlations of the indicators wtih Energetic Intensities indicators
Indicators Energetic Intensity per capita(EIc) Energetic Intensity per surface (EIs)
Utilization Index (UI) 0,344 0,464
% Land Cover (LC) 0,246 0,471
Average Number ofStoreys (NS) -0,271 0,335
Dwellings Density (DD) -0,551 0,894
Medium Distancebetween Intersections (DI) 0,256 -0,841
Compactness (C) 0,083 -0,704
Results in red are statistically significant at a 5% significance level while the results in orange is
significant to a level of 10%. The three indicators identified are use in a multivariate analysis (Figure 5).
Figure 5 multivariate analysis
The “Analyse 1” model is significant: 𝐸𝐼𝑠( 𝐷𝐷, 𝐷𝐼) = 0,457. ( 𝐷𝐷) − 0,248. ( 𝐷𝐼) + 131,673 . Dwelling
Density is the indicator which best explain the energetic consumptions per surface.
4.2 Statistical analysis

8. 8
A sensitivity analysis is performed with 31 new study areas, chosen within the initial seven areas in
order to assess the relevance of the statistical analyzes (Table 6 and Figure 6) and the consistency of
homogeneity assumptions of USU´s, made in defining the study areas.
Table 6 Sensibility analysis: correlations
Indicators Energetic Intensity per capita (EIc) Energetic Intensity per surface (EIs)
Dwelling Density (DD) -0,224 0,895
Medium Distancebetween Intersections -0,210 -0,308
Figure 6 Sensibility analysis: multivariate analysis (EIc, to the left, EIs, to the right)
Figure 7 Sensibility analysis: Correlation Eis x DD
Table 7 Average and standart deviation values in each zones
zone
Energetic consumption
average ofCertificates
Energetic Intensity per
capita
Energetic Intensity per
surface
DwellingsDensity
Medium Distance between
Intersections
Average Std. Dev.. Average Std. Dev. Average Std. Dev. Average Std. Dev. Average Std. Dev.
1 219 32 8.271 1.470 261 27 245 59 93 11
2 207 17 15.862 10.863 269 83 264 91 44 3
3 221 45 28.033 26.446 112 105 62 53 59 1
4 134 10 14.977 2.739 163 91 81 44 134 21
5 164 42 15.205 3.928 72 24 22 5 155 64
6 130 5 6.318 511 180 103 114 61 120 28
7 126 20 6.910 1.449 194 53 128 23 92 8
The significance of the model obtained for the analysis of Energetic Intensity per surface is increased.
The sensibility analysis confirm the Dwelling Density as the most relevant indicator in the energetic
consumptions assessment. This analysis also allows to assess the homogeneity of USU´s selected in
Lisbon. In this case, the Zone 2 and 3 present the lower level of homogeneity, while the Zone 5 present
the highter level.
0
100
200
300
400
0 100 200 300 400
EnergeticIntensity/surface
(EIs)
Dwelling Density(DD)
EIs x DD - Sensibilityanalysis
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
4.2.1 Sensibility analysis

9. 9
The USU´s methodology offers several maps for the study area: a map of Urban Ecology,
illustrating the vegetation structure, a map of the built areas and the open spaces and, a map of USUs
which allows to assess the organization of the city and the Urban Metabolism. These maps can
complement traditional municipal plans, as the Land Use map. 197 USUs have been identified, divided
into 12 types. The historic center of Évora is thus characterized by built-up areas of small buildings with
few floors, with few pervious surfaces, located largely in private spaces inside the blocks. This method
reveal some sustainable characteristics of the study area, such as a compact urban area constituted by
a built fabric quite diverse and complex. The high complexity of of Évora, caused by several changes
and adaptations of the city over the centuries, reveals the resilient feature of the city. The Urban
Intensities associated to each type of USUs enables analyzing the urban metabolism, that is, the various
flows existing in the city. This Metabolism reveals the important role of Giraldo and Sertório Squares
and the main streets linked to these spaces. The observation of Urban Metabolism can be deepened
by quantifying certain indicators, within the identified units.
The oldest areas of Lisbon have higher values of Utilisation Index and Land Cover Percentage.
The observation of the results shows that the old quarters with traditional forms have higher densities
and compacity, compared with modern areas, with lower buildings. The increase in urban density is thus
not achieved through buildings with many floors but may become possible through traditional blocks
with an average number of floors.
The Energetic Intensity by surface have more significant results with the Dwelling Density, the medium
Distance between Intersections and the Compactness These three indicators are then used in a
multivariate analysis, in order to obtain a model able to analyze and explain the Energetic Intensity by
surface. The significant results of the multivariate analysis corresponds to the analysis of Energetic
Intensity per surface with the Dwelling Density and the medium Distance between Intersections. This
model shows a good correlation (R = 0.931) and can explain 86.7% (R2 = 0.867) of Energetic intensity
per surface: 𝐸𝐼𝑠( 𝐷𝐷, 𝐷𝐼) = 0,457. ( 𝐷𝐷) − 0,248. ( 𝐷𝐼) + 131,673. Dwelling Density is the indicator that
best explains the Energy Intensity by surface in the several analysis. The analyzis reveal that an
increase of urban density is related to a reduction of consumption per surface. The compact traditional
Blocks have less energy loss through their facades and are characterized by a lower Energetic Intensity
per surface, thus confirming the results of Serge Salat work, although the result of Compactness, in the
multivariate analysis model was not statistically significant. The sensitivity analysis repeated the
statistical analysis by replacing the initial seven study zones in thirty-one smaller units. This analysis
allowed to determine the relevance of the statistical results and homogeneity assumptions of USU´s
used in the Urban Sustainability assessment in this work.
The calculation of some indicators used in the analysis of Urban Sustainability revealed some
limitations. Demographic data refer only to the values of the resident population and residential
5 Discussion of results
5.1 Analysis of urban form in Évora
5.2 Urban Sustainability assessment in Lisbon
5.2.1 Limitations of the analysis

10. 10
dwellings, thus excluding the values of other activities (commercial, offices and services). So there are
errors in the results of some indicators that generate inequalities in the comparison between the different
study areas. These errors were mainly observed in the calculation and the statistical analysis of the
Energetic intensity per capita, which is very inconsistent, particularly in the Zones 3 and 4, and have a
low level of significance, in a statistical way. Both Energetic Intensities were calculated using the values
of Energy Performance Certificates (EPC), related only to residential dwellings. The Energetic
Intensities used in this work does not correspond to the total consumption in selected areas because
they do not consider the consumption due to other existing activities in buildings or other consumptions
(transports, street lighting…), and assign a greater weight of the active part of the energy efficiency of
dwellings, derived from the calculation of energy efficiency certificates mentioned above (Ferreira &
Pinheiro, 2011). The values of the Passive Volume rate can contribute to the analysis of the passive
part of energy consumption but shown a lack of precision and consistency. However, this analysis could
be performed through correlation with other indicators, such as the percentage of glazing and the level
of shading of the buildings considered.
The application of USU´s methodology in the historic center of Évora revealed a built form,
compact and complex, as several sustainable features. The method allows you to analyse, in a
qualitative way, the Urban Metabolism of the area.
The analyzis revealed a higher correlation with the Energetic Intensity per surface, which is best
characterized by the Dwelling Density. The Medium distance between Intersections and the
Compactness have also good correlation, although not statistically significant.
This thesis presents a coherent and practical methodology for assessing the Sustainability of urban
areas with different fabrics and periods of origin. The methodology shows the possible relationships
between the analysis of Urban Morphology and Sustainability. The Observation of the traditional forms
of cities shows tissue adapted to the respective terrains and climates and, in this way, their study may
be particularly relevant to the understanding of urban sustainability.
There is a possibility of using different types of urban tissues identified in this work as part of a library
or inventory of existing forms, as suggested by Professor Karl Kropf during the ISUF conference in June
2014 in Porto. The methodology established in this study can identify many of these types of tissue and
connect each of them to average energy consumption.
Ferreira, J., & Pinheiro, M. (2011). In search of better energy performance in the Portuguese
buildings-The case of the Portuguese regulation. EnergyPolicy,39(12),7666–7683.
Retrieved from http://dx.doi.org/10.1016/j.enpol.2011.08.062
Kropf, K. S. (1993). An enquiryinto THE DEFINITIONOFBUILT FORMINURBAN MORPHOLOGY -
volumeoneandvolumetwo.PhD thesis, Department of Geography, Faculty of Arts,
University of Birmingham.
Moudon, A. V. (1997). Urban morphology as an emerging interdisciplinary field. Urban
Morphology,1,pp. 3–10.
6 Conclusions
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