Contract N : CP-IP Project N : FP7-NMP-2007-LARGE-1 Project Start: 01 October 2008 Project End: 31 March 2012

Transcription

1 D11-1 ANNEX A PROJECT INFORMATION: Project Title: INTEGRATED EUROPEAN INDUSTRIAL RISK REDUCTION SYSTEM Acronym: IRIS Contract N : CP-IP Project N : Project Start: 01 October 2008 Project End: 31 March 2012 REPORT INFORMATION: Report Title: WP3 DEMONSTRATION REPORT ANNEX A Date of Issue: July 2009 Rep. Period: 01 October September 2009 Prepared by: VCE Holding GmbH Authors: Wenzel, Helmut Veit-Egerer, Robert Widmann, Monika Jaornik, Paul coordinating person: organisation: fax: telephone: Dr. Helmut Wenzel VCE Holding GmbH wenzel@vce.at Iris Demonstration Report Annex A page 1 of 24

2 IRIS (Integrated European Industrial Risk Reduction System) Bridge Object S101 (Reibersdorf / Upper Austria) Progressive Damage Test ( ) Cross section where tendons were cut through Carriageway Salzburg Carriageway Vienna North South Column which was lowered Helmut Wenzel Robert Veit-Egerer Monika Widmann Paul Jaornik Iris Demonstration Report Annex A page 2 of 24

3 Introduction The flyover S101 is a typical prestressed concrete bridge from the early 1960ies. It was decided to replace it due to insufficient carrying capacity and its maintenance condition (both visual inspection driven rating). At the same time the bridge did not meet the current requirements, as the structure did not fit into the overall traffic and infrastructure concept anymore. In other words demolition was aspired anyway, because the bridge was to small for the location. The major objective of the current progressive damage test is to emphasize refined methods for the analysis of upcoming, slowly progressing damage and its effects on parameters of dynamic response. In the course of the IRIS project VCE (together with the Alpine construction company and the University of Tokyo) takes the opportunity of this certain damage test - given by the bridge operator ASFINAG - to demonstrate the impact of scientific insight and findings with regard to reduced uncertainties to support the decision process of infrastructure owners in the course of cost planning for maintenance and possible rehabilitation measures in general. In the present report the followed measurement agenda from the 10 th to the 13 th of December 2008 is documented. In the end the structuring of the recorded data into several measurements is described. Iris Demonstration Report Annex A page 3 of 24

4 Wednesday Weather observation: Temperature: 2 C; mist, easterly wind with approx. 2 m/s Previous day: sunny weather temp. -9 C in the morning, approx. -2 C at midday Preparations for the progressive damage test - Evaluation of structural safety with regard to the pier s crossbeam and its foundation: 12:56 Start of operation of the BRIMOS-Recorder - placed at the western main girder in the middle of the main span. 13:08 The supporting pier was hydraulically loaded with 120 t (250 bar conform to the bridge pier s regular normal force) 13:25 The bridge was stressed with a test load of 144 t for a period of 10 min (measurement S101REIT_081210A_MAINSPAN file S101REIT_01-05). No cracks or any other indications of damage appeared at the structure 13:40 End of the load test. No reactions at the structure, no cracks or any other indications of damage. Afterwards the load was taken away from the supporting pier. After that the BRIMOS sensor grid was set up and a geodetic levelling was conducted. 17:16 Start of measurement with a dense BRIMOS sensor grid Iris Demonstration Report Annex A page 4 of 24

5 Measuring system Fig. 1: Sensor layout BRIMOS Recorder; 10 th of December 08 sensor position [m] length cross channel direction R1 (BRIREC) Längs length Quer cross Vertikal vertical Tab. 1: Measurement specification - BRIMOS Recorder 10 th of December 08 Fig. 2: Sensor layout - BRIMOS sensor grid 10 th of December 08 Iris Demonstration Report Annex A page 5 of 24

6 sensor position [m] length cross channel direction E weiss_laengs length weiss_quer cross weiss_vertikal vertical E gruen_laengs length gruen_quer cross gruen_vertikal vertical E braun_laengs length braun_quer cross braun_vertikal vertical E gelbgruen_laengs length gelbgruen_quer cross gelbgruen_vertikal vertical E schwarz_laengs length schwarz_quer cross schwarz_vertikal vertical E lila_vertikal length lila_quer cross lila_vertikal vertical E rot_laengs length rot_quer cross rot_vertikal vertical E gelb_laengs length gelb_quer cross gelb_vertikal vertical E blau_laengs length blau_quer cross blau_vertikal vertical E E3_laengs length E3_quer cross E3_vertikal vertical E E6_laengs length E6_quer cross E6_vertikal vertical E E2_laengs length Please pay attention to to an exception E2_vertikal cross between the German and English E2_quer vertical channel denomination E E5_laengs length E5_quer cross E5_vertikal vertical E E4_laengs length E4_quer cross E4_vertikal vertical E E1_laengs length E1_quer cross E1_vertikal vertical Tab. 2: Measurement specification BRIMOS sensor grid 10 th of December 08 Iris Demonstration Report Annex A page 6 of 24

7 Thursday Weather observation: Temperature in the morning: 1 ; mist; no precipitation; no wind. In the course of the day the temperature increased up to + 1. The other weather conditions remained unchanged. Damage test lowering of a column Additional restraint loading case: 07:00 preparing of the cutting line at the north-western column by the Seidl company 07:35 Hydraulic loading of the supporting pier and increase up to 120 t; fixing with adjusting collars 08:12 Start of cutting through the pier 08:35 the first cut is completed. No reaction, no noise, no spalling. A geodetic levelling was conducted at the structure to fix the altitude of the points. All measurement sensors are applied and in operation. 09:07 start of the second cutting 10 cm above the first one. 09:33 finalisation of the second cut. No restoring forces observed 11:00 first lowering of the pier by 1 cm. The adjusting collar was released and adjusted to 1 cm. Subsequently the pier was lowered rapidly and displaced at the adjusting collar. A moderate noise of relaxation coming form the Iris Demonstration Report Annex A page 7 of 24

8 supporting pier was noticed. No cracks or other indications of damage were remarked at the structure. The lowering is clearly visible in the signal of the laser-displacement channel. Alteration at the signals of the measurement system. A slight decrease of the first eigenfrequency already after the cutting and before the first lowering of the pier - was also observed. The plate of concrete which was cut out of the pier was examined in a detailed manner. The concrete quality is very good. Only at one corner a spalling in combination with rust is observable. The concrete reinforcement is in remarkably good condition. The three bolts with a diameter of 26 mm were actually at the position marked on the drawing. The quality is better than having been expected after the visual inspection. 12:00 second step of lowering (second centimetre) analogue to the first step. During the settling a displacement of 21 mm in direction to the middle of the bridge was noticed at the column base. That reaction is not conform to the finite element calculations. According to that there should be just a relatively small inward reaction. Within the next 2 hours no change (cracks or other indications of damage) was noticed. 14:00 third step of lowering (third centimetre) The lowering causes an additional horizontal displacement 10 mm. Due to the fact that the elastic limit was reached at 7 mm of vertical deformation, the total amount of additional 10 mm of lowering could not be accomplished. Based on the performed static calculations the elastic limit was expected at 32 mm of vertical deformation instead of 27mm obtained in reality. This fact can probably be explained by the low temperature during the test (influence of already removed pavement?). At the intact column next to the lowered one - a new horizontal crack appeared. The already existing cracks hadn t enlarged. It was decided to wait one hour to declare if phenomena of structural creeping appear or if the structure remains in the same condition. 15:00 The gap between the adjusting collar and the hydraulic jack did not disappear. This means that no non-linear processes causing a further lowering of the column could be expected. Therefore it was decided to stop the test at this stage. The bridge was lifted marginally to insert compensating plates. Another geodetic levelling stated the final altitude of the bridge deck. The BRIMOS measurement system was prepared for the night and it was decided to continue with the tests - starting at 8 o clock the following morning. Iris Demonstration Report Annex A page 8 of 24

9 Measuring system Additionally to the dense BRIMOS sensor grid the following measurement equipment was installed at the structure during the day: The BRIMOS-Recorder - placed at its new position above the north-western column (the one to be cut & lowered). The laser-displacement unit in the middle of the bridge s main span above the western main girder. One Etna-Recorder in the middle of the bridge s main span (at the western footpath), one on the eastern footpath. The team of the University of Tokyo also arranged their measurement system, which was distributed stepwise all over the structure. Fig. 3: Sensor layout overview - 11 th of December in 2008 Iris Demonstration Report Annex A page 9 of 24

10 Fig. 4: Sensor layout Brimos-Recorder and two ETNA-Recorders 11 th of December 08 Iris Demonstration Report Annex A page 10 of 24

11 sensor position [m] length cross channel direction R1 (BRIREC) Längs length Quer cross Vertikal vertical E1 (Etna) Längs length Quer cross Vertikal vertical E2 (Etna) Längs length Quer cross Vertikal vertical Tab. 3: Measurement specification - BRIMOS- & ETNA-Recorders 11 th of December 08 Fig. 5: Sensor layout - BRIMOS sensor grid - 11 th of December 08 Iris Demonstration Report Annex A page 11 of 24

12 sensor position [m] length cross channel direction E weiss_laengs length weiss_quer cross weiss_vertikal vertical E gruen_laengs length gruen_quer cross gruen_vertikal vertical E braun_laengs length braun_quer cross braun_vertikal vertical E gelbgruen_laengs length gelbgruen_quer cross gelbgruen_vertikal vertical E schwarz_laengs length schwarz_quer cross schwarz_vertikal vertical E lila_vertikal length lila_quer cross lila_vertikal vertical E rot_laengs length rot_quer cross rot_vertikal vertical E gelb_laengs length gelb_quer cross gelb_vertikal vertical E blau_laengs length blau_quer cross blau_vertikal vertical E E3_laengs length E3_quer cross E3_vertikal vertical E E6_laengs length E6_quer cross E6_vertikal vertical E E2_laengs length E2_vertikal cross E2_quer vertical E E5_laengs length E5_quer cross E5_vertikal vertical E E4_laengs length E4_quer cross E4_vertikal vertical E E1_laengs length E1_quer cross E1_vertikal vertical Laser 28 5 Laser_X cross Laser_Z vertical Laser_Z_Glatt vertical-smoothed Please pay attention to an exception between the German and English channel denomination Tab. 4: Measurement specification - BRIMOS sensor grid 11 th of December 08 Iris Demonstration Report Annex A page 12 of 24

13 Friday Weather observation: Temperature: 0 C, partly cloudy, light snowfall during the night, wind velocity 3 m/s from the west; snow is lying on the structure (this means that the structure s temperature is below 0 C) Damage test lowering of a column: No settlement of the column during the night, it is still in the elastic region. No changes were noted Iris Demonstration Report Annex A page 13 of 24

14 08:00 reinitialization of the measurement system which was running during the whole night The laser, the Brimos-Recorder as well as the two Etna-Recorders were set up again. Identical to the day before the Brimos-Recorder is situated directly above the column which was cut through, whereas the Etna-Recorders were situated on both sides midspan. A levelling was performed. 08:35 Lifting of the column a little bit above the original level, steel plates were inserted. A levelling was performed afterwards. 08:49 End of returning the column into its initial position (after the lowering test). The new level was approx. 6 mm above the original one. A quiet noise caused by the load distribution was noticed. The cracks at the opposite column are closed again. This means the reinforced concrete is in successful operation again. The decisive horizontal cracks move analogue to the deformations. A levelling was performed afterwards. 12:50 A levelling was performed. The temperature raised up to 2 C, the snow is melting but remains longer on the structure itself then in the surrounding area. Iris Demonstration Report Annex A page 14 of 24

15 Damage test intersecting tendons: 13:10 Start of exposing the cables, which are easy to find by cutting the concrete. 13:43 End of exposing the cables. The concrete quality is quite good (just as the protection concrete). The cables are externally undamaged, not rusted and well filled. 13:45 Cutting out of a 10 cm long piece of the first cable. The strands shortened to 2 mm less in length. No noises were noticed. Another levelling was made afterwards. A visual inspection was done at the structure but no cracks or other new indications of damage were found. In the afternoon a vibrating roller was working next to the bridge (westward) causing vibrations which were clearly noticeable on the bridge particularly after the first cable was cut through. 15:45 The second cable was intersected. After the second cable was intersected the strands shortened similar to those of the first one. Single wires were removed to find out whether they corrode or not. No rust was found. The bridge did not show any indications of structural changes, cracks etc. A levelling was done, without any obvious deviation regarding the previous one. During the night all 15 sensors of the measurement grid were kept in service whereas the recorders as well as the laser-based displacement measurement were removed. Subsequently to every scheduled step of the experimental campaign a visual inspection was performed in order to detect possible damage indications. After the first cable was cut through an extensive inspection was done but no new damages could be found. The crack formation at the north-eastern column was investigated accurately. Altogether six cracks in relatively constant distances were observed. After the bridge was returned into Iris Demonstration Report Annex A page 15 of 24

16 its initial position the cracks were closed again. The distances between the cracks were measured as follows: cm. Conclusions until now: The bridge s manufacturing quality with regard to the used materials is generally quite good. The only apparent defect is the too low reinforced concrete cover (coverage). The load bearing capacity seems to be 15% higher than the computed value. The structure s behaviour fully correlates with the expectations, unexpected effects did not occur. Even if the structure was seriously damaged, it still indicated a good, redundand nature. The analytical investigation predicted local losses (e.g. at the bottom of the column) which did not occur on site. Local damages at the internal prestressing did not induce geodetically confirmed changes. The measurement system had registered all changes and enables an accurate assessment of changes in the structure s integrity as well as the load bearing capacity. Bending moments and axial forces related to internal restraint (shrinkage effects confirmed by frame analysis) were relieved completely due to creeping. No associated reactions were observed. Iris Demonstration Report Annex A page 16 of 24

17 Measuring system Additionally to the dense BRIMOS sensor grid the following measurement equipment was installed at the structure during the day: The BRIMOS-Recorder above the north-western column (the one to be cut & lowered). The laser-displacement unit in the middle of the bridge s main span above the western main girder. One Etna-Recorder in the middle of the bridge s main span (at the western footpath), one on the eastern footpath. Fig. 6: Sensor layout overview - 12 th of December in 2008 The sensor-layout of the BRIMOS- and ETNA-Recorders as well as the one of the BRIMOS sensor grid is identical to the one the day before. Iris Demonstration Report Annex A page 17 of 24

18 Fig. 7: Sensor-layout - BRIMOS- Recorder and two ETNA-Recorder 12 th of December 08 Fig. 8: Sensor layout - BRIMOS sensor grid - 12 th of December 08 Iris Demonstration Report Annex A page 18 of 24

19 Saturday Weather observation: Temperature: C, light snowfall during the night, snow is lying on the bridge, high fog, no wind Damage test intersecting tendons: 08:20 The third tendon is cut through. The strands shortened as expected. No noises or other indications of changing conditions. No cracks or other damage indication arised at the visual inspection. 08:33 In the signal of the laser a shifting is visible. The middle of the structure has declined for just a few millimetres (structural rearrangement). That s why it is decided to stop doing more severe damages. To control the values of the levelling it was repeated. The output is consistent with the day before. The cracks at the eastern pier have not changed since the day before. This means that there was no torsional movement. 10:15 another levelling was done 10:30 Revealing of the fourth strand and removing of the cement injection. Slight flash rust on the wires (probably due to the installation); afterwards 5 wires are intersected. The concerned wires shortened. Six more wires are intersected. After that the progressive damage test is stopped. 10:50 Start of removing the measurement equipment. Iris Demonstration Report Annex A page 19 of 24

20 The visual inspection does not indicate any addidional changes. Another levelling is done the result does not differ from the one before. Demolition of the bridge 19:00 embargo of the motorway and preparing of the demolition 20:00 the bridge is cut through in midspan. As expected that doesn t cause a structural collapse. 21:00 The southern part of the bridge was removed with a demolition shear and two hydraulic breakers. The structure offered a lot of resistance. The tendons got exposed to a great extent, the wires were visible. There were no obvious damages or rust at the prestressing. The reinforcement worked as intended and kept all parts together well. A try to cause a collapse of the southern part of the bridge failed due to the high redundancy of the bridge. The concrete quality was equally good at all parts of the bridge. The south-eastern column was broken off but it did not collapse before most of the concrete was removed. After the demolition the condition of several parts of the bridge was documented. Iris Demonstration Report Annex A page 20 of 24

21 Measuring system Additionally to the dense BRIMOS sensor grid the following measurement equipment was installed at the structure during the day: The BRIMOS-Recorder above the north-western column (the one to be cut & lowered) started at approx. 7:50 am. The laser-displacement unit in the middle of the bridge s main span above the western main girder. One Etna-Recorder in the middle of the bridge s main span at the western footpath (started at approx. 08:00 am), one on the eastern one (started at approx. 8:10 am). Iris Demonstration Report Annex A page 21 of 24

22 Fig. 9: Sensor layout overview - 13 th of December in 2008 The sensor-layout of the BRIMOS- and ETNA-Recorders as well as the one of the BRIMOS sensor grid is identical to the one the day before. Fig. 10: Sensor layout - BRIMOS- Recorder and two ETNA-Recorder 13 th of December 08 Fig. 11: Sensor layout - BRIMOS sensor grid - 13 th of December 08 Iris Demonstration Report Annex A page 22 of 24

23 Conclusions: Prestressing, concrete quality and reinforcement were in faultless condition The system showed an extraordinary redundancy. Even though one column was removed completely hardly any changes were noticeable. The structure showed a great persistence and an excellent behaviour concerning rearrangement. To sum up, sudden failure without any previous indication at a similar structure of the same quality can be excluded. The progressive damage campaign established essential knowledge concerning the assessment of prestressed structures. The structure s behaviour was better than it was estimated due to the numerical analysis at all times. First impression into the measurements indicate, that already very slight artificial damage, induced into the bridge can be identified and assessed very clearly. Doubts, generally raised with regard to internally prestressed concrete structures, are unjustifiable in the present case. Iris Demonstration Report Annex A page 23 of 24

24 Structuring of the recorded data Due to the huge amount of data they were subdivided into several partial measurements. Those of the Brimos sensor grid were separated according to the various damage states characterised in the measurement description - whereas the MAINSPAN-measurements in each case contain all the data recorded by one particular Recorder placed on a precise position of the bridge. Data gaps in the MAINSPANmeasurements result from the fact that the Recorders were removed during the nights unlike the Brimos sensor grid which was constantly measuring from the 10 th Dec 08 05:16 PM to the 13 th Dec 08 11:14 AM. measurement Start End measurements with the Brimos sensor grid measurement descripition S101REIT_081210A_DECK :16 PM :13 AM undamaged structure S101REIT_081211A_DECK :13 AM :21 AM the north-western column was cut through S101REIT_081211B_DECK :21 AM :49 AM first step of lowering the column (1cm) S101REIT_081211C_DECK :49 AM :39 PM second step of lowering the column (2cm) S101REIT_081211D_DECK :39 PM :45 PM third step of lowering the column (3cm) S101REIT_081211E_DECK :45 PM :52 AM compensating plates are inserted S101REIT_081212A_DECK :04 AM :12 PM column returned in original position S101REIT_081212B_DECK :12 PM :03 PM first tendon intersected S101REIT_081212C_DECK :03 PM :44 AM second tendon intersected S101REIT_081213A_DECK :44 AM :08 AM third tendon intersected S101REIT_081213B_DECK :08 AM :14 AM single wires of the fourth tendon intersected measurements with the Brimos- and Etna-Recorders S101REIT_081210A_MAINSPAN :00 PM :02 PM Brimos-Recorder placed in the middle of the main span S101REIT_081211A_MAINSPAN :35 AM :50 AM Brimos-Recorder placed above the northwestern column S101REIT_081211B_MAINSPAN Etna-Recorder placed in the middle of the main :17 AM :50 AM span at the western footpath S101REIT_081211C_MAINSPAN Etna-Recorder placed in the middle of the main :35 AM :56 AM span at the eastern footpath Tab. 5: List of all measurements recorded during the progressive damage test from the 10 th to the 13 th of Dec 08 As the sensors E1, E2, E3, E4, E5 and E6 were recorded by an additional secondary measurement system which is not equipped with a hardware filter an additional preconditioning of these data is necessary by means of an introductive bandpassfiltering. Iris Demonstration Report Annex A page 24 of 24