SELECTED PROBLEMS CONCERNING MAINTENANCE.pdf

(1399 KB) Pobierz
Architectura 6 (4) 2007, 3–21
SELECTED PROBLEMS CONCERNING MAINTENANCE
OF STRUCTURES
Jan lusarek
Silesian University of Technology
Abstract.
Many building elements, due to their destination, are exposed to the inÀuence
of external environment, often very aggressive. Due to that such building elements should
be protected in a special way. I have presented the outline of problems related with main-
tenance of building structures, taking into account the principles of sustainable building.
I have paid extra attention to the characteristics of local environment conditions and to
their inÀuence on the response of selected building elements. Building materials should be
characterized with such features that will assure that the structures, in which they will be
installed, will meet the requirements referring to service features. In this paper requirements
regarding structural-material solutions for structures, bases for diagnostic tests and the es-
sence of repair and rehabilitation of building structures has been discussed.
Key words:
maintenance of building structures, sustainable building, sustainable develop-
ment, thermal insulation protecting, durability, repair and rehabilitations methods
INTRODUCTION
Many building elements, due to their destination, are exposed to the inÀuence of ex-
ternal environment, often very aggressive. Due to that such building elements should be
protected in a special way. The monograph [Czarnecki and Emmons 2002] is devoted to
the issues of repairing and protecting concrete structures. The issues of repairing con-
crete structures in accordance with European standards were, among others, the subject
of discussions during the conference “Jadwisin 2006” [Czarnecki and
àukowski
2006].
Because in excellent majority of cases we deal with structures made of concrete, the
above mentioned publication may be useful for designing all sorts of repairs and rein-
forcements of the mentioned structures. Taking this all into account, I have prepared this
paper in order to discuss more widely some issues, very important in my opinion. I have
presented the outline of problems related with maintenance of building structures, tak-
Corresponding author – Adres do korespondencji: Jan lusarek, Politechnika l ska, Wydziaá
Budownictwa, Katedra Procesów Budowlanych, ul. Akademicka 5, 44-100 Gliwice,
e-mail: jan.slusarek@polsl.pl
4
J. lusarek
ing into account the principles of sustainable housing [Stawicka-Waákowska 2001, Bryx
2003]. I have paid extra attention to the characteristics of local environment conditions
and to their inÀuence on the response of selected building elements [Starosolski 1976,
Belok and lusarek 2003, Wilk 2004, lusarek and Wilk 2006, Wilk and lusarek 2006].
Requirements regarding structural-material solutions for structures, bases for diagnostic
tests of and the essence of repair and strengthening of buildings structures were discussed
as well.
PRINCIPLES OF SUSTAINABLE BUILDING
Satisfying the needs of society is possible thanks to such shaping of buildings that ma-
kes them friendly for the users. At the same time, they must not interfere in surrounding
natural environment in a considerable way and they must be acceptable from the point of
view of incurred expenditures [Bryx 2003]. Such a point of view is in accordance with the
principles of sustainable development, in particular with the principles of sustainable ho-
using. Moreover, such principles should not only be valid during the process of erecting
new building facilities, but also during the process of maintenance of existing structures
[Bryx 2003]. It is with contentment that one may observe the fact that this sort of appro-
ach is favoured by the entries of chapter 6, entitled: “Maintenance of structures” of the act
of 7.07.1994 – Building Engineering Law [Act of Building Engineering 2003].
The inÀuence of building process on the environment begins on the moment of star-
ting building works, and it ceases on the moment of dismantling of the facility and utili-
zation of what is left of it. Such a process is commonly called technical life cycle of the
structure and the assessment of the impact of this period of time on natural environment
– Life Cycle Assessment [Stawicka-Waákowska 2001]. In most cases the technical life-
-time run of construction of structure corresponds with durability and using period, justi-
¿
ed technically and economically [Stawicka-Waákowska 2001].
Each of the stages of technical life cycle of structure is accompanied by the use of raw
materials such as water or energy mediums. This is why the method of operation and main-
tenance of structures is not neutral to the environment. Taking all that into consideration, the
statement of the author of the paper [Stawicka-Waákowska 2001] seems to be correct – the
assessment of technical life cycle of building product or facility may be a criterion of its im-
pact on natural environment [Stawicka-Waákowska 2001]. Figure 1 presents the technical
life cycle of building facility and product [Stawicka-Waákowska 2001].
CHARACTERISTICS OF ENVIRONMENT CONDITIONS
Analysis of selected parameters of local climate
The term “climate” describes the average weather conditions resulting from observa-
tions carried out throughout tens of years, characteristic for the given area. As “weather”
we understand a certain state of external atmosphere in the given moment, which deter-
mines the inÀuence of meteorological factors occurring in the given place. The following
are meteorological factors: solar radiation, air temperature, air pressure, air humidity,
Acta Sci. Pol.
Selected problems concerning maintenance of structures
5
Fig. 1.
Rys. 1.
Technical life cycle of building structure and product [Stawicka-Waákowska 2001]
Cykl ycia technicznego obiektu i wyrobu budowlanego [Stawicka-Waákowska 2001]
velocity and direction of wind as well as precipitations. The following are the factors
describing climate: latitude, distribution of land and seas, height above sea level, sea
currents and land shape. Furthermore, depending on the land shape, air pollution, amount
of reaching solar radiation intensity, speci¿c movements of air, we may distinguish local
climate from the climate of the surrounding area [Basi ska and Koczyk 1997, Basi ska
and Koczyk 2001, Kossecka et. al. 2001, Belok and lusarek 2003]. Therefore, local
climate is an effect of greater or smaller inÀuence of local factors [Rietschel 1972, B d-
kowski et al. 1975].
In this paper local climate is understood as conditions of weather state in the area of
the test station. The pattern of chosen local climate parameters (total intensity of solar ra-
diation and temperature of external air) has been elaborated basing on climatic date from
the years 1994–2002 obtained in the laboratory of Ecological Building Division (Faculty
of Civil Engineering-Silesian University of Technology) in Gliwice. The methods of cre-
ating and choosing the representative or typical meteorological year have been described
in the papers [Basi ska and Koczyk 1997, Basi ska and Koczyk 2001, Kossecka et al.
2001]. Climate patterns for the city of Warsaw and Pozna have been elaborated.
In case of elaborating the pattern of local climate the measurement data of total solar
radiation intensity projecting onto horizontal plane was available, as well as that of tem-
perature of external air. Registering of the data was carried out continuously, once a half
hour [Wilk and lusarek 2006].
Figures 2 and 3 present the obtained pattern of local climate in form of average year.
Very important, from the point of view of analysed building elements, is the information
that in the analysed average year there are 39 days of temperature lower than
t
= 0°C
[Wilk and lusarek 2006].
Architectura 6 (4) 2007
6
J. lusarek
Fig. 2.
Rys. 2.
Distribution of average temperatures of external air during a year [Wilk and lusarek
2006]
Rozkáad rednich temperatur powietrza zewn trznego w ci gu roku [Wilk and lusarek
2006]
Fig. 3.
Rys. 3.
Distribution of average values of total intensity of solar radiation during a year [Wilk and
lusarek 2006]
Rozkáad rednich caákowitego nat enia promieniowania sáonecznego w ci gu roku
[Wilk and lusarek 2006]
Solar temperature of external air
Solar temperature of air is de¿ned as hypothetic temperature of air outside the building,
at which penetration of heat through non-insolate partition would be the same as resulting
from insolation with actual temperature of external air (¿g. 4). Solar temperature of external
air may be determined from the pattern [Pogorzelski 1976, Malicki 1977, Smolec 2000]:
t
s
=
t
z
+
AI
c
α
z
(1)
where:
t
s
– solar temperature of external air [°C],
t
z
– temperature of external air [°C],
A
– radiation absorption coef¿cient,
I
c
– intensity of total solar radiation [Wm
–2
],
–2
z
– coef¿cient of heat transfer on the outside [Wm
K].
Acta Sci. Pol.
Selected problems concerning maintenance of structures
7
Fig. 4.
Rys. 4.
Interpretation of solar temperature of external air:
t
p
– temperature of air in the room,
t
z
– temperature of external air,
t
s
– solar temperature of external air (elaborated basing
on Malicki [1977])
Interpretacja sáonecznej temperatury powietrza zewn trznego:
t
p
– temperatura powietrza
w pomieszczeniu,
t
z
– temperatura powietrza zewn trznego,
t
s
– temperatura sáoneczna
powietrza zewn trznego (opracowanie na podstawie Malicki [1977]
In the paper the value of total solar radiation intensity projecting onto horizontal sur-
face has been analysed, as well as the temperature of external air, observed in the years
1994–2002 in the laboratory (see above). From the data [Belok and lusarek 2003, Wilk
2004, lusarek and Wilk 2006] for appropriate seasons the highest and the lowest values
for each of them has been selected. Figures 5–8 presents selected results of analyses of
thermal inÀuences in form of solar temperature of external air (compare with formula
(1)) for the following values of absorption coef¿cient
A
= 1.0 (mat black) and
A
= 0.40
(polished aluminium sheet). The calculations have been also carried out for absorption
coef¿cients of values [Malicki 1977]:
A
= 0.50 (white colour),
A
= 0.90 (bitumen paper),
A
= 0.70 (galvanized metal sheet).
Fig. 5.
Rys. 5.
Maximum values of solar temperature during summer period for different absorption
coef¿cients [Wilk 2004]
Maksymalne warto ci temperatury sáonecznej w okresie letnim dla poszczególnych
wspóáczynników absorpcji [Wilk 2004]
Architectura 6 (4) 2007

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin