24 Piotr Marciniak, Ireneusz Wyczałek, Zdzisław Pawlak
( Boscato et al. 2016; Anastasi, Lo Re and Ortolani 2009;
Ye, Su and Han 2014; Lorenzoni et al. 2016). The vast ma-
jority of such measurements use integrated sensor systems
that enable a comprehensive assessment of the observed
parameters (Noel, Badway 2017).
During the structural assessment of the church in Doma-
chowo, the authors decided to combine various methods.
Usually, to assess the stability of buildings geodetic meth-
ods are applied, including precision tachymetry (Barsoc-
chi et al. 2021). Such methods enable precise observations
of displacements not only in engineering structures, but
also in historic buildings (Gil et al. 2021; Petrovič et al.
2021). In order to increase the precision and frequency of
measurements, the authors used hybrid solutions that com-
bined tachymetry with a system of remote sensors installed
on the building and in its vicinity.
Description
of the research project
To fully diagnose the physical behavior of and to moni-
tor the building, the authors used a combined measurement
method featuring both static and dynamic measurements
(tachymetry and inclinometers, respectively). Long-term
studies were made monthly comprising three constituents
related to two reference points that were considered stable.
This was conducted using the tachymetric method. Short-
term measurements used one of the typical monitoring
techniques based on inertial tilt sensors (inclinometers).
The authors called this combination the “Dynamic-Static
Method” (DSM), which can be useful for analyses of both
structural displacements of buildings, including wooden
churches, and of other structures that are susceptible to
dynamic deformation (Marciniak, Pawlak and Wyczałek
2023; Pawlak, Wyczałek and Marciniak 2023)
1
.
The authors used a measurement grid containing six xed
measurement points and four bi-axial inclinometers. To
con trol the accurateness of the static tachymetric measure-
ments, they set an additional point, and to control the read-
ings of the inclinometers, they installed two additional sen-
sors. To assess both the dynamics and statics of the building
at the examined points, they designed a diagram of com-
plementary measurements using tilt sensors and a weather
station. The thus collected data made it possible to evaluate
the correlation of the tilt readings with the indications of
wind gusts and the temperature on both sides of the church.
The static measurements were made using the tachy-
metric method with a 1-sceond Leica TCRP 1201+ and
reective foil targets. Based on the results of 15 double
series of measurements, discrepancies between the series
in the range of –1 mm to +1 mm were revealed, albeit the
most common values were in the range of ±0.2 mm. This
analysis illustrates the technical and accuracy capabil-
ities of the tachymetric method in evaluating the stabili-
ty of a structure exposed to periodic dynamic pressures.
1
A detailed description of the research and its outcomes were pre-
sented at conferences and in publications which provided the basis for
the present text (Marciniak, Pawlak and Wyczałek 2023; Pawlak, Wy-
czałek and Marciniak 2023; Wyczałek 2022).
The obtained accuracy parameters are consistent with the
results of similar measurements and guarantee accurate
spatial resolution of the stability assessment of the studied
structure. The actual results prove that specic features of
wooden structures, even very old ones, do not undergo per-
manent deformation despite intensive pressures.
Dynamic monitoring requires continuous or quasi con -
tinuous monitoring of vibrations and inclinations or chang-
es in other physical parameters. Earlier studies successfully
used POSITAL FRABA ASG15 inclinometers with wire
data transmission in the CANOPEN standard. In the dis-
cussed case, two such inclinometers were applied to ver-
ify
the readings of a new set of wireless BWSENSING
WF-WM400 inclinometers made using MEMS technolo-
gy. Such sensors can be powered by solar energy or DC
chargers. They can measure inclinations in very high fre-
quency (up to 50 Hz) and then transmit the signals remote-
ly via a Wi-Fi network.
In the basic version, four inclinometers powered from
the power grid were installed on the site. The readings were
collected synchronously every 2 seconds via a local Wi-Fi
server, saved to disc and then remotely downloaded via the
Internet. After an initial test, the authors set the frequency
of recording the readings at every 10 seconds. Based on the
analysis of the observations, the authors concluded that the
records of inclinations in one point changed up to ±15 mm
during intense winds in October 2021, taking into account
the adjustments resulting from the absence of plastic trans-
formations within the investigated structure (Fig. 5).
In order to compare the results of the inclination mea-
surements with the weather conditions, the latter were re-
corded. To do so, a SENCOR 12500 Wi-Fi weather station
was set up near the buildings. This comprised a base with
a thermometer (inside the building) and a set of sensors:
two thermometers, a barometer, an anemometer, and a rain-
fall meter. With access to the Weathercloud website, it was
possible to remotely view the measurements of the station
in a 10-minute cycle. The measured data was also collected
within the same cycle. It was then remotely downloaded to
a *.csv le and subsequently processed and analyzed using
the authors’ own methods and software. Afterwards, this
data was compared to the inclinometer readings.
An important issue was to synchronize the data. Due
to the available frequency of the data collected from the
weather station, the authors assumed that all the readings
would be processed into 10-minute cycles for further anal-
ysis. For the purpose of a joint examination of the results,
the authors decided that the results of a single tachymet-
ric reading would be grouped into one-month blocks that
would include readings of the weather conditions, readings
from the four WF/WM400 inclinometers and a maximum
of two readings from the WGS15 control inclinometer for
both axes.
The church in Domachowo was monitored for 24 months
simultaneously with the wide-ranging conservation work
inside the building. Some of the measurements were taken
during a very quiet time in spring and summer, whereas
some in winter when relatively strong gusts of wind had
a signicant impact on the characteristics of the readings.
During the latter period, the authors obtained an interesting
