SICK DML40 and DL1000 long-range distance sensors impress in construction

Intelligent measurement
technology welcomed with open arms in the construction
sector

At the site of
the High Moselle Bridge in Zeltingen-Rachtig in Germany – the largest bridge
currently under construction within Europe – a team from Trier University of
Applied Sciences is using DML40 and DL1000 long-range distance sensors from
SICK to monitor deformations in the reinforced concrete pillars measuring up to
150 metres in height, as the bridge superstructure is moved into place.

Driving on the B 50 main road heading west toward
Zeltingen-Rachtig from Mainz, it does not take long to identify the reasons
behind the plans for the ambitious ‘High Moselle Crossing’ road project.
Navigating the steep uphill and downhill stretches and the extremely narrow
roads where the Moselle river winds and loops between the Eifel and Hunsrück
mountain ranges, requires an awful lot of concentration. While the route makes
for quite an experience for cyclists and motorcyclists, it is more of a test of
nerves and a health hazard for car and truck drivers – even more so for the
locals. The ‘New B 50 expressway project’ is set to ease this situation, while
filling a huge gap in the highway network. Once finished, the 25-kilometre road will make for a fantastic connection linking up
Belgian/Dutch North Sea ports and cities in Belgium with the Rhine-Main region.
Near Zeltingen-Rachtig, the ‘new B 50’ will
stretch high above the famous steep vineyard slopes of the Moselle valley –
home to the ‘√úrziger Würzgarten’ vineyard, where ‘Grand Cru’ wines are
produced, as well as the ‘Kršver Nacktarsch’, a south-facing slope-based
vineyard with a memorable name in German. And it is in this very stretch
of the High Moselle Crossing that passers-by are
wowed by an impressive construction project in a league of its own – the High Moselle Bridge. It will eventually measure
1.7 kilometres in length and just
under 160 metres in height, meaning that even Cologne Cathedral would be
able to fit underneath it. There is only one bridge taller than that in the
whole of Germany – the Kocher Viaduct in Baden-Württemberg, measuring in at
185.5 metres. The construction work began back in 2011 and the bridge is
scheduled for completion in 2018.

Industry 4.0
digital standards even at the
construction planning phase

SEH Engineering GmbH
(formerly Krupp Stahlbau Hannover GmbH and Eiffel Deutschland Stahltechnologie
GmbH) and Porr Deutschland GmbH make up the team contracted to take on the
construction work. The construction contractor is the Federal Republic of
Germany represented by Landesbetrieb Mobilität Rheinland Pfalz (LBM). Since
2013, the Civil Engineering department at Trier University of Applied Sciences
has been offering support with the construction documentation through a
practical on-site project. The team of students headed up by
Prof. Henning Lungershausen and
Prof. MichŽl Bender is using DML40 and DL1000 long-range distance sensors from SICK to monitor and measure
deformations in the reinforced concrete bridge pillars as the steel box girder
superstructure is moved into place. The
system being used to measure deformations
has been recently developed by the Institute
for Standard Software-Based Applications in Civil Engineering (ISA) at Trier
University of Applied Sciences. Automated deformation measurement is made
possible by the combination of time-of-flight measurement, precision
engineering, smart control, and real time
data processing. The system can locate its measurement target manually or fully
automatically, and then take measurements at a maximum of 1 hertz. A minicomputer can be used to record the
temperature, date, measured value, and resulting deformation in a database in
real time and then visualize this data at
any point. Professor Lungershausen believes that this system will be
crucial in the future of the conservative construction sector: “Industry 4.0
digital standards are even starting to apply more and more at the planning
stage of construction. In the same way
that the transition from drawing boards to CAD workstations 30 years ago
meant a paradigm shift for many, planners are now facing a jump forward that is
likely to be even more significant.”

The High Moselle
Bridge construction team was excited to work on the project with the university
team, which Professor Bender puts down to the fact that the research
methodology perfectly addresses the interests of all of the partners at once:
“We have the very embodiment of a ‘win-win situation’ on our hands here. The
Civil Engineering department from the Trier University of Applied Sciences can
offer scientific expertise and the resources to match, and the construction
companies involved have a keen interest in construction documentation and
application possibilities for new technologies. Project partners from the
hardware and software sectors are attracted
by the opportunity to find out more about possible test scenarios and future
markets.”

At
the end of the day, the use of
SICK solutions within the High Moselle Bridge project is the ideal way for the
company to show off the high levels of reliability, maximum precision, and very
large measuring range boasted by the DML40 and DL1000 sensors. The measurement
process itself is an extremely challenging and exciting undertaking for all
parties involved. After all, thousands of metric tons of steel need to be moved
safely over the concrete pillars, some of which are as far as 210 metres
apart from one another, centimetre by centimetre.

Newly developed bridge
displacement system

The companies working on the High Moselle Crossing are
relying on a newly developed system when it comes to moving the girder bridge. The bridge is being moved using what is known
as the ‘incremental launch method’. This
involves a team of bridge construction specialists assembling the steel box
girders, upon which the road will later be built.
Gradually out of huge pre-fabricated individual components following on from
the abutment on the Hunsrück side. Once several individual components have been
put together as ‘sections’ of a certain length, they are pushed over the
pillars using hydraulic presses. Further new sections are then being added on, with this process set to be
repeated 13 times until the bridge reaches the Eifel side. With a view to solving the problem of
introducing heavy horizontal loads on the tops of the pillars, Eiffel
Deutschland Stahltechnologie GmbH developed the patented ‘BVS 2011’ remote
incremental launch method. This uses
stationary hydraulic presses to apply the forces required to move the bridge
proportionally at each supporting point. The displacement and friction forces
should, in theory, cancel each other out as a result. To minimise friction, the bearings on the displacement beam
constructions are fitted with Teflon
sliding plates. That way, deformation of the bridge pillars is ideally ruled
out altogether. When it comes to bridge construction, safety is the top
priority. Michael Arz, a qualified engineer
and Construction Manager at SEH, had already seen great results from the team
from Trier University of Applied Sciences at the documentation phase completed
ahead of starting on the project: “We had to find someone we could trust to
perform the deformation measurements and the project team from Trier University
of Applied Sciences simply impressed us with their concept once again”.

The impressively large sensing
range of the DML40 and DL1000 sensors

The DML40 and DL1000 long-range
distance sensors from SICK proved to be ideal laser measurement units. “Long-range distance sensors from SICK are
designed for very large ranges. The pulse time-of-flight method allows for
measuring ranges of up to 1,500 metres up to a reflector. On that basis,
we knew that this was the exact device we were looking for to complete our task,”
explains Professor Bender. The
resolution of the distance sensors, which fall under IR Laser Class 1, can be
adjusted between 0.001 and 100 mm. Depending on the measuring distance, the
accuracy of up to -10 mm can be achieved for single measurements and
6 mm for repeat measurements.

The sensors are installed in a hall at the abutment on
the Hunsrück side along with the rest of the equipment forming the measurement
system. The university team uses the lasers to target reflectors (foil or glass
triple reflectors) that have been attached just underneath the displacement
unit on each of the pillars. Before the measurement is taken, the reference value has to be defined. To determine the zero setting of the
measurement system, each of the pillars is
recorded over a long period and (ideally) at different temperatures. It
does not matter whether the displacement process takes place during a cold
winter or warm summer, as the sensors have a rugged metal housing that can
withstand temperatures fluctuating between -10 and
+55 degrees Celsius.

To start with, the displacement unit is moved into position and contact is made with the hydraulic
press. Once all of the units have been set up, the workers wait for
Construction Manager Michael Arz to give the signal, and then they all start the displacement
presses at the same time, thereby moving the superstructure. They keep in
contact with the team taking the measurements via radio, as the students
monitor the measured values in real time using the measurement system. Construction
Manager Arz is notified immediately if any discrepancies are spotted.

Balanced force theory confirmed by measurement results
from the DML40 and DL1000

When the very first
measurement results from the DML40 and DL1000 sensors were analyzed, the calculations run by the civil
engineers were confirmed right away. The
forces exerted during this remote displacement process being performed on the High Moselle Bridge do almost cancel each
other out during displacement. In each case, the maximum force is always exerted on the pillar at the start or
end of the displacement bearing’s impact on the system, and this effect comes down to the synchronicity of the system.
Shortly after displacement starts, the system evens out to the point that
discrepancies are minimal.

With each displacement lasting several days, full
concentration is required from everyone
involved in the High Moselle Bridge project and
tensions run high. Given that this process is not automated, the work on the
construction site depends on the extensive experience and knowledge of all of
the workers. Continual monitoring and the use of intelligent measurement
technology to keep track of processes are therefore huge benefits that ensure
that the construction project runs smoothly. Professor Bender offers up
some glowing feedback on the project: “Thanks to our outstanding cooperation
with SICK and SEH Engineering as our contracting party, we have been able to
develop an innovative measurement system that is currently proving a success
during work on the High Moselle Bridge. We are confident that it also has huge
potential for further construction projects going forward. On top of all that, this
interdisciplinary project is a fantastic addition to the practical training we
offer our students.”

Written by Arin Gharibian,
Field Sales, SICK Vertriebs-GmbH, Düsseldorf

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