8 th FIG Regional Conference Surveying towards Sustainable

8 th FIG Regional Conference Surveying towards Sustainable Development Use of Mobile Laser Scanning Complexes for Precise Determination of the Beam Gradient by Metal Bridges Ivo Milev 26 – 29 November 2012 Montevideo, Uruguay

Weser bridge Dreye Strategic infrastructure for the german railways (Track number. 2200, km 229, 2 - 229, 8)

Weser bridge Dreye 1927 construction Hamburg-Bremen-Köln-Venlo 1870 -73 Weser as natural barrier

Content 1 Comparison of the data aquisition methods for bridge sleepers exchange 1. 1 Classic method 1. 2 Data aquisition with laserscanning based multisensor system 2 Steps for data aqusition and calculation using laserscanning 2. 1 Geopositioning of the multisensor system 2. 2 Detection of the bridge beams 2. 3 Processing of the kinematic scans with Si. Rail. Scan 2. 4 Automated generated register of the sleepers with Verm. esn 3 Impression from the building 4 Summary / Conclusion

Comparison of the data aquisition methods for bridge sleepers exchange 1. 1 Classic method Ø levelling the horizontal steel beams (as follow named beams) of the bridge frame. The results are heights relative to the benchmark consoles Ø Tachymetric detection of the beam edges Traditional method used till 2011 -characteristics Ø Average daily output (8 h) with classic method: 250 sleepers Ø Average processing performance (geodetic data total station and leveling) of the measurement : 300 sleepers per day

Classic measuring method Ø time consuming process to record the beams and random mounted bearings (x, y, z) at the right location cost for Si. Po (safety personal of DB AG) and accommodation of the surveyor team. One troop 4 people with 2 hours frequency of exchange looking in both directions 500 m with walkie-talkie ~1000 EUR/day + min two people surveyors Ø Few after work processes, if a hierarchic number system is used during the measuring process Ø Potential difficulties to detect measuring errors (polar tacheometric measuring design without control) Ø Slight graphic documentation of the measuring data, the beams are represented with 4 points Non homogeneous information about the beam surface

1. 2 Data aquisition with laserscanning Ø multisensor system with integrated laserscanner Ø capturing of the whole beam shape (surface heights and edges) in one run via 3 D technique Ø objects that prohibit the seeing of the laserscanner has to be removed if necessary (for instance the security plates) Laserscanning method Ø Average daily output (8 h) with laserscanning method : 3000 sleepers Ø Average processing time for the captured data : 200 sleepers per day – based on the current status of automatization!

2 Steps for measuring and analyzing with laserscanning 2. 1 Geopositioning of the multisensor system Ø Positioning of the scanner above the rails resp. beams Ø Defining the position of the scanner each 20 m via tachymetric free station based on 4 bechmarks (mounted prism adaptors with constant offset) Ø Simultaneously scanning the benchmark points of the track (GV) marked with spheres Rail transition to the bridge

2. 2 kinematic laserscanning of the bridge beams Ø Multi sensor system to scan based capturing of the environment Ø Measurement performance - 2 km/h Ø Short times of track locking Ø Optional: the system could be lifted out of the rails within 8 s, (horn signal) a complete locking of the track is not a must For this bridge it was not possible Each day of surveyor work on the bridge is a big safety risk!

2. 2 kinematic laserscanning of the bridge beams

2. 3. Processing of the laser scans with Si. Rail. Scan • Georeferencing and synchronizing the scans • Cutting out the detected beam geometry • Calculation of the beam heights

Example for a structure change

Structure change Height based color coded beams: Hidden by the sleepers scan overview:

Milled out sleeper

If an 4 cm height difference on the steel beam surface is detected a sleepers milling is necessary cmiling m An automated algorithm is searching for the heights miling m Bearing with plates

Transversal beam with plates • • The coloring of the heights of the beams relieved the control an the detection of the plates (height differences) The standard height on the steel beam is blue, the plates are colored green The height differences are approximately 1, 5 cm Correspondingly the milling for some sleepers has to be adapted

Milled out sleeper with plate - puzzle numered sleepers Nürnberg Approximated fitted height with plates – milling is still needed – 2 cm plates

Corrosion protection damaged – source for outliers by the leveling. Rail force bearer with plates (height coded coloring) Hier sieht man die Höhendifferenzen im Bauwerk – sind über 2, 5 cm. Mit den Lagenwechseln des Trägers und Platten (beim blauen). Durch die Platten wurden die Höhendifferenzen der Träger halbwegs ausgeglichen. Trotzdem musste man dies bei den Fräsungen beachten

Change in the bearing thickness on the top beam belt Rail force bearer with plates (height coded coloring) Hier sieht man die Höhendifferenzen im Bauwerk – sind über 2, 5 cm. Mit den Lagenwechseln des Trägers und Platten (beim blauen). Durch die Platten wurden die Höhendifferenzen der Träger halbwegs ausgeglichen. Trotzdem musste man dies bei den Fräsungen beachten

Bearing plate not detectable by classical surveying Rail force bearer with plates (height coded coloring) Hier sieht man die Höhendifferenzen im Bauwerk – sind über 2, 5 cm. Mit den Lagenwechseln des Trägers und Platten (beim blauen). Durch die Platten wurden die Höhendifferenzen der Träger halbwegs ausgeglichen. Trotzdem musste man dies bei den Fräsungen beachten

Rail force bearer with plates (height coded coloring) The height differences in the structure are shown ~ 2, 5 cm. It‘s still the main point of focus during the menufacturing of the sleepers

Results of the beam measurement homogenity check Gegengleis-Träger mit Plattungen (Höhencodierte Einfärbung)

Results of the beam bending Gegengleis-Träger mit Plattungen (Höhencodierte Einfärbung) Excell graphiken

Si. Rail. Scan processing Results Gegengleis-Träger mit Plattungen (Höhencodierte Einfärbung) • Detection of the sleeper coordinates in pointfiles • Half automated determination of the beams heights for the sleepers • Summary Output of the data in Excel • Transfer of the result heights and coordinates to Ver. esm

2. 4 Generate the sleepers register with Verm. esn Ø Import the coordinates and heights to Verm. esn Ø Setting of the beam widths for calculation of possible not measured points Ø Setting of the designed track geometry (chainage, track, gradient)! Ø Automatic calculation of the sleeper file with the beam heights Ø Automatic calculation of the sleeper files -BRS (optional also in Excel) for the sleeper manufacturer

2. 4 Generate the sleepers register with Verm. esn

3 Impressions of the building structure Bridge over the Weser – frame bridge

…Extracting old sleepers Build in the new sleepers…

. . . Align the sleepers, marking and drilling, then screwing Put the new rails on and lock them

. . . Put on the frame based protectors (yelow)

4 Summary / Conclusion • The demanded precision for the sleeper modernization (3 mm in xy, 2 mm in z) were fulfilled with the multi sensor scanning system and the optimized processing. Brand new and innovative method! • The advantage is the short locking time of the track for the measurement • Half automated algorithms for detecting the beams heights and edges • detection of the beam shapes (heights and edges) in one run via 3 D technique • Continues (complete) model of the beam – not just spots • Complete documentation of every sleeper, beam and the near environment relations in 3 D - preservation of evidence