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9
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International Masonry Conference 2014 in Guimarães
9
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International Masonry Conference, Guimarães 2014 1
Perforated masonry – light weight construction
ORTLEPP, SEBASTIAN
1
; SCHMIDT, FALCO
2
ABSTRACT:
Perforated Masonry has high permeability to air, noise, heat and light. Due to this fact, particular
applications are favoured. Thereby result favourites for its applications. Even in projects with limited
resources, the use of a light and air permeable structure is recommended because this type of
construction is efficient, quick and easy realizable. This separate casting wall shows in unheated
rooms its particular advantages of special light effects. A starting research project at the Technical
University of Dresden deals with the behavior of lightweight construction for publishing new results for
the load bearing capacity.
Keywords: Perforated masonry, load bearing element
NOTATION
A
m
cross section;
V volume
V
S
volume of the Unit
V
L
volume of the hole
m mass
m
S
mass of the unit
m
L
mass of the hole = 0
ρ
Mw
global density
ρ
S
density of the unit
l
S
unit length
l
L
space length
p
L
space ratio
p
C
contact ratio
g dead load of the wall
1 INTRODUCTION
Perforated masonry is defined by a regular solid brick wall, in which the gaps between two
adjacent units are either openings or filled with non-load bearing material. The construction without
fillings is characterized by transmission of air, noise, light and heat. An important factor for the of the
definition of perforated masonry is the size of the gaps, which can not be used to pass-through the
wall.
In addition to this subject there is a small kind of camouflage. A particular need for visual protection
exists not only for the private sector to keep the personal sphere, but also for the public domain. It is
1)
Dr.-Ing, TU Dresden, Chair of structural design, Germany, Sebastian.ortlepp@tu-dresden.de
2)
Dipl.-Ing. Falco Schmidt, TU Dresden, Chair of structural design, Germany, lehrstuhl.tragwerksplanung@mailbox.tu-dresden.de
Ortlepp / Schmidt
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International Masonry Conference, Guimarães 2014
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noteworthy that a view to the outside similar to curtains or shades is possible. To the inside a dimly
perception is possible. The voids in the wall that are created by eliminating certain brick along its
height and length allow privacy while allowing light, air and muffled sounds to pass through the wall.
Perforated walls have been used especially in hot climates where partial blocking of the sun was
desired, yet allowed air flow to help cool the interior.
Besides the previously mentioned physical properties, there are some important features, which
provide information about possible applications and benefits of this construction method. Comparing
to the common masonry, this has relatively low mass that causes, the low density of a perforated
masonry wall. From these approaches, equation (1) for determining the density of perforated masonry
results, considering on the density of a unit, neglecting the mortar and other building materials is
given:
S
L
S
S
L
S
S
S
S
L
S
S
LS
LS
Mw
l
l
1
l
l
1V
m
V
l
l
V
m
VV
mm
V
m
(1)
2 REVIEW ON BUILDINGS
2.1. Residential buildings
The most common application of perforated masonry was found in residential buildings [1],
preferably in external walls of single or two-storeys buildings as non-structural or curtain wall.
Generally the perforated masonry is used to design intentions for exposure as well as a visual barrier.
Furthermore the exterior walls of the house in Marfa / Texas (Figure 1) can be seen as an exception
because it bears the load coming from the roof.
a)
b)
Figure 1. Marfa House in Texas; a) Perspective, b) View from southwest [2]
2.2. Public buildings
The museum of Nasu / Japan, designed by Kengo Kuma the gaps in the wall exist rarely, only in
every third layer of units. This example is a significant limiting case to common masonry. Due to the
fact that this is a load bearing wall, this example is included, see Figure 2.
Figure 3 shows a successful way for ventilation, temperature regulation and exposure. Peter
Zumthor praises his "filter walls" (see [14]) at the Museum of art „Columba" in Cologne. Also in this
situation the main feature of the use is not load bearing, but the exposure to light.
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Figure 2. Stone-museum in Nasu, interior view [3]
a)
b)
Figure 3. Museum of art „Columba“ in Cologne; a) Interior view [4], b) External perspective [13]
2.3. Official Buildings
The police station in Schoten / Belgium, can be taken as an example and is particular of interesting.
Here the perforated masonry is obviously used as a screen for the personal safety in the building.
(Figure 4). Figure 5 shows a highly perforated masonry wall dictated by usage requirements. The
number and size of openings is based on the desire to bring light and air through the wall. The more
highly perforated the wall, the weaker the wall.
Figure 4. Police station in Schoten / Belgium [9]
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International Masonry Conference, Guimarães 2014
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Figure 5. Air Vent at Seaport Hotel, Berkley, Michigan, USA Boston, Massachusetts, USA [15]
2.4. Buildings of education
Generally, in all considered educational institutions, perforated masonry is primarily used as a
curtain wall for exposure. Here, noteworthy is the London School of Economics, where the curtain
wall reaches a height of up to twenty meters, Figure 6.
The confidence in the manner of construction of the perforated masonry, although the curtain wall
has no load-bearing function describes essentially the aim of using the perforated masonry in the
future as a load bearing structure.
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International Masonry Conference Dresden 2010
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Figure 6. New Students Centre London / England, visualization [5]
2.5. Sacral buildings
In almost all considered sacral buildings with perforated masonry, the air and light permeability
have only a minor role.
An exception is the property wall of the New Apostolic Church of Stendal / Germany, Figure 7. The
perforated masonry as fencing can also found in many other places. Obviously, it was built to save
dressed stones and to create a small aesthetic accent.
Figure 7. New Apostolic Church of Stendal / Germany [1]
An important example of the use of perforated masonry in religious buildings is the house of
churches in Heilbronn / Germany. It is one of the few cases where glass panels between the stones
exist (Figure 8), and where this translucent type of construction was used in the interior. It was
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International Masonry Conference, Guimarães 2014
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decided to use glass and perforated masonry to create interesting lighting effects. The ground plan
demonstrate, that this inner wall has a non load-bearing function (Figure 8b).
Figure 8. Room of Silence [7]
The crematorium in Askar / Norway can be classified as a load bearing structure made of
perforated masonry. In this example it can be seen, that, open gaped masonry pillars support the top
slab, which is necessary for the stiffening and stability (Figure 9).
Figure 9. Crematorium of Askar / Norway [6]
2.6. Special buildings
In 1864, the blacksmith Friedrich August Frohnberg of Plauen, a district of Dresden build next to
his restaurant an observation tower (Figure 10). This observation tower has in the upper third a
perforated masonry to expose the tower interior.
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Figure 10. Bearing perforated masonry for exposing the tower Dresden-Plauen / Germany [1]
Another example, a former warehouse of a blast furnace plant, is located on the former industrial
area of 1852 in Dortmund / Germany. To show the former production conditions, the warehouse was
extensively renovated and the fillings between the steel were made of perforated masonry based on
the original design in the past (Figure 11).
Figure 11. West Phoenix exterior view / Dortmund [8]
2.7. Summary of the analysis
Generally, it can be stated that there are very few buildings where perforated masonry has a load-
bearing function. Special reasons of air condition or geographical priorities are not recognizable. Also,
a special group of planners and architects can not to be filtered out. Buildings of regional architects
and of "well-known architects”, as well as unnamed architecture are all equally represented.
3 STRUCTURAL ASPECT OF PERFORATED MASONRY WALLS (PMW)
3.1. Masonry-Codes
The design and construction of reinforced and unreinforced masonry is included in the German
standards and in the Eurocode. The application of these rules is limited to masonry with head joints
without gaps. There is only a distinction in filled, partly filled and unfilled head joints.
In Contrast, perforated masonry is a construction in which the head joint is gapped whereby no
kind of stress can be transferred.
It should be noted that the stress of the units with increasing space rate increases too - even when
only the weight of the perforated wall is present Eq. (2). With increasing the space the load
transmitting contact surface reduces twice as strong as the load from its self weight, Eq. (3). Figure 12
shows the stress incensement in relation to a common wall without perforation.
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LS
ll
g
(2)
LS
L
L
ll
l
p
LS
LS
C
ll
ll
p
(3)
0
2
4
6
8
10
0 0.2 0.4 0.6 0.8
space length
l
L
stress increasement
l
L
Figure 12. Load distribution of a perforated masonry wall
The mechanical properties of the common solid masonry can be considered as generally known. In
contrast, perforated masonry is currently barely - and if so, mainly used as a non-load bearing
structure -. As already described, main applications in detail are the facades [10], [11] and non
structural element in buildings (Figure 13).
Perforated masonry – light weight construction
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a) b)
Figure 13. Perforated facades made of a) bricks [10] and b) clinker [11]
Nowadays considerable efforts are done for the design and the verification of walls made of
perforated masonry. This can be seen in the structural analysis for the rehabilitation of the tower in
Dresden-Plauen / Germany in 2003 [12]. Here every unit was basically considered separately where
the verification of tensions was individually. Due to the low degree of structural-capacity utilisation
(about 10%) of the units, this approach was possible.
3.2. Load bearing capacity of perforated masonry
No rules of thumb exist for perforated walls because of the wide variety of uses. The potential of
the perforated masonry as a structural element is obviously the light weight construction, with or
without low requirements in sound, fire and privacy protection. Applications can be found in
supporting interior walls, stairwells of single family house and external walls of buildings, such as
storehouses. In addition, perforated masonry exhibits an aesthetic lightweight construction.
Despite its correlation to conventional masonry, the structural behaviour can not be transferred to
perforated masonry. Under compressive stress of each single unit a compression at the border sides
occurs, whereas the central region remains unloaded (Figure 14). Perforated masonry has reduced
contact surfaces at the horizontal joints to transfer the shear and compressive stress, therefore an
increase of stress will occur in comparison to a common masonry wall.
Figure 14. Compressive stress in the vertical direction of bricks
In the case of out-of-plane bending and parallel to the bed joints, there appears still a pure shear
rotation in the bed joints (see Figure 15). A positive acting of a line of pressure, a model which is used
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for the design of basement walls, does not appear because of the lack of a pressure contact on the
head surfaces of the units.
l
u
l
l
a)
b)
Figure 15. Shear rotation due to out-of-plane bending, a) unloaded wall, b) wall deformed
In contrast to common shear walls made of masonry, in which the bricks are loaded either to
tension or shear forces at the horizontal joint, the load bearing behaviour changes on perforated
masonry to a bending and shear stress in the individual units (see Figure 16).
compression
tension
F
Figure 16. Compressive stress in the vertical direction, struts and ties of a perforated shear wall
Perforated masonry – light weight construction
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International Masonry Conference Dresden 2010
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A further critical issue is the transfer of the thrust strut through the “hole cross-section”. By the
perforated manner there is only a fixed angle available to transfer the diagonal forces. But generally
the strut runs from upper corner in diagonal direction to the lower corner, so the resultant of the thrust
strut must run around the holes, which is only possible with additional bending stress of the units.
4 OUTLOOK
Perforated masonry has not been systematically investigated for its load bearing behaviour yet.
Due to the obvious lack of knowledge, it is necessary to do specific studies on the structural design of
this kind of masonry.
With the increasing acceptance of open constructions and because of that of perforated masonry
engineers currently still miss a principal model to be able to design walls made of perforated masonry
as a load bearing structure. At present the background information of the capacity is missing. The
outcome of a prospective research project at the Technical University of Dresden will illustrate the
structural behaviour of perforated masonry walls and will contribute in both economic and safe
structural design of this kind of construction.
REFERENCES
[1] Schmidt, F.: Analyse der bestehenden und möglichen Anwendungsgebiete des
Lochmauerwerks. thesis, TU Dresden, faculty of architecture, 2013
[2] Joy, R.: The Marfa House. GA Houses 109, 2009, pp. 34-35.
[3] The Phaidon Atlas of contemporary World Architecture. Comprehensive Edition, Phaidon pub.,
New York, 2004, p. 141
[4] Bauwelt, cover, Auratischer Überbau, german, Bauverlag BV GmbH, Berlin 2007
[5] O'Donnell; Tuomey: London School of Economics New Students' Centre. GA Document 117,
2011, p. 138-143
[6] The Phaidon Atlas of contemporary World Architecture. Comprehensive Edition, Phaidon
Verlag, New York, 2004, p. 222
[7] Raum der Stille im Heinrich-Fries-Haus, Heilbronn, Architecture Office, Arno Lederer, Jorunn
Ragnarsdottir, Marc Oei, Stuttgart, In: Architektur und Kalksandstein, Hannover, 2011
[8] http://www.hagemeister.de/nl/projecten/civiele-techniek/details-topobjekt/maschinenhallen-
dortmund, 23.10.2012
[9] http://maps.google.be, Gasketelplein, Schoten 2900 Schoten, Antwerpen, Vlaams Gewest,
17.5.2013
[10] Kurz, D.; Bühler, B.: Schulhaus Holderbach, Zürich-Affoltern: Gesamtinstandsetzung nach
Minergie. Building department of the city of Zurich, 2010
[11] TOPOBJEKT Ideen, Impulse und Innovationen für Architekten. Ed.: Hagemeister GmbH & Co.
KG, Klinkerwerk.
[12] Friebel: Static report to the tower "Hoher Stein", Gocht & Mensch ingenieure gbr, Dresden,
2000, issued by the Parks Commission of the City of Dresden, 2012
[13] Müller, H. F. O.: Energiegerecht und nachhaltige Architektur in Mauerwerk. Mauerwerk 13
(2009), Issue 5, S. 316-322
[14] Adam. H.: Reduktion und Sinnlichkeit - Peter Zumthor: Columbaria, Art Museum of the Cologne
Archdiocese. In: Archithese, 1.2008, pp. 22-28
[15] Trimble, B.: Design of unique landscape walls and their using in building facades. 12th
Canadian Masonry Symposium Vancouver, June 2-5, 2013
