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TCWA-02-10Monitoring revision Building permit design

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Tunnelconsult, SCP 27/04/2010 e-mail: [email protected]

LINE II OF WARSAW METRO

REPORT ON

BUILDING PERMIT DESIGN ELABORATIONS

- MONITORING DESIGN REVISION

Prepared for AGP METRO

Report number TCWA-02-10

Rev. Date Description Prepared by Verified by Approved by

0 27/04/10 Monitoring revision SBB NDV NDV

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INDEX1. Introduction.................................................................................................................................22. References..................................................................................................................................23. Comments ..................................................................................................................................24. Conclusion ..................................................................................................................................5

1. INTRODUCTIONIn the frame of the agreement between Tunnelconsult and AGP Metro, we have been requested to analyze andreport on the monitoring document prepared by ILF relevant to the buildings in the proximity of station C09within the context of Warsaw Underground Line II Project.The present report specifically analyses the document referenced as [6], relevant to the Building Permit DesignStructure of stations C09. Furthermore the revision has been made based on the available documents deliveredby AGP Metro and the information acquired during Mr. Della Valles visit in Warsaw (March 2010).We understand that document [6] is centered on TBM start shaft as part of C09 station.

2. REFERENCESThe following references have been used for the redaction of this report:

[1] Tender Document: Functional application programme BP METROPROJEKT and MetroWarszawskie - September 2008.

[2] Tender Document: Multidisciplinary concept design for design and construction of central sectionof II line of the underground in Warsaw from Rondo Daszyskiego to Dworzec Wileski (MN-L21-10-4670/II/01) BP METROPROJEKT and AMC ANDRZEJ M. CHODZYSKI CONSORTIUM OFLIMITED COMPANIES (SP.Z.O.O.) September 2008.

[3] Design criteria for monitoring design based on requirements of functional application programmerequirements & multi-disciplinary concept design requirements (E-ILF-B-000-MON-REP-0001_R00_EN-PL) ILF CONSULTING ENGINEERS March 2010.

[4] Description of monitoring design for station C09 Rondo Daszy

skiego (E-ILF-B-C09-MON-REP-0001_B00_EN) - ILF CONSULTING ENGINEERS March 2010.

[5] Tender Document: Summary geological-engineering documentation for the central part of the IIsubway line in Warsaw with changes from Nowy Swiat station to Dworzec Wilenski station andrelative geological profile GEOTEKO SGGW GEOPROJEKT - February 2007.

[6] Volume III chapter 02 of Building permit design structure, Prostra Street/Towarowa Street Daszynskiego Roundabout Area (E-ILF-B-C09-MON-SPC-0001_C00) - ILF CONSULTING ENGINEERS March 2010.

[7] Drawing C09.2 ILF- March 2010. [8] Our report TC-WA-01-10- April 2010.

3. COMMENTSFor easy reference and immediate appreciation we have prepared the below table where we show thecomments on chapter 2 of volume III of Building permit design structure, Prostra Street/Towarowa Street

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Daszynskiego Roundabout Area document [6]. It looks that [6] is a deepened and more structured version of[4].

Table 3.1 Comments to [6]

ILF [6] TC commentsChapter 1 The document concerns the first phase of construction of

station C9, which foresees the excavation between diaphragmswalls of a part of the zone where the entry shaft previously andC9 station next will be located, in the proximity of RondoDaszyskiego.A list of 22 referenced documents is presented, out of which wehave 3 available.

Chapter 2

Paragraph 2.1

Based on detailed calculations of grounddeformations that will be carried out later inthe design process, range of the zones aswell as the number of the affected

buildings, may decrease

Paragraph 2.2

Paragraph 2.3Monitoring design defines means of

measurements of vertical deformations ofthe buildings in impact zones

As there are no enough suitable places forfixing benchmarks on building Prosta 69,only 3 benchmarks will be installed. Due to

good technical condition of the building issatisfactory.

Three different influence zones are defined, taking into account

the instructions proposed by the Building Research Institute(ITB) of Warsaw (2002) and already contained in [2] and [4].As we have stated in [8], we deem that the adopted zones areconservatives, i.e. larger enough to cover station excavationinfluence zone.

Computing the expected settlements by FEM analysis would bethe appropriate method to verify the expected extension of theabove mentioned influence zones. Finite elements numericalmodels will allow to estimate the extension of the influence zonewithin which settlements are expected and their amount.

We have verified that the list of the buildings located in theinfluence zones coincides with the one that appears inparagraph 5.4.2.2.3 of [2].We have notice that buildings in Hrubieszowska 5/3/1 have notbeen included respect the list contained in [2], reasons shouldbe indicated in the report.

It is stated that a survey of existent damages and assessment oftechnical conditions of the buildings have been carried out, but

they have not been included in the document.

As we have already pointed out in [8], horizontal deformationsshould also be checked. It is important to recall that horizontaldeformations are likely to damage buildings much more than thevertical ones, since they are likely to produce tension.

Observing the geometrical location of the mentioned threebenchmarks on building Prosta 69 [7], we deem that thisconfiguration will hardly allow the possibility to check buildingrotation. We notice that on building Hrubieszowska 11 only onebenchmark is proposed and in Hrubieszowska 9 benchmarkshave been all positioned on the northern side of the building.Benchmarks shall be located in rows at corners to checkdifferential settlements and structure rotations.

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Take the zero measurement at least 5days prior to commencement ofconstruction works

Critical settlement values

If the differential settlements reach 60% ofthe limiting values it is necessary to startdirect observation of the affected building

We stress that this period is too short. We recommend take thereference measurement as early as possible and practicable. Wenotice that the captioned period of 5 days is even smaller than

the one proposed in [4] that was equal to 10 days.

Critical settlement values are indicated for serviceability limitstate (11-9mm) and for ultimate limit state (35-25mm), having

taken into account ITB instructions.

We agree with this procedure, pointing out that the limitingvalues should be referred to ultimate limit state.

As general observation we recall that Monitoring Design should

contemplate the use of other measuring devices, like opticalprisms and clinometers on building walls.

Chapter 3

It is envisaged to use existing piezometersprovided their technical condition issatisfactory.

The piezometers are to be installed atleast two weeks prior to excavation works

for construction of the retaining structure

It would be necessary to specify the kind of piezometers to beemployed (open piezometers or pressure cells). It is not clear ifpiezometers have been already installed.

We recommend install the piezometers network as soon aspracticable in order to record the seasonal water level oscillation

previous to the works start.

Observing Drawing 3, we agree with the proposed piezometerslocation. In Drawing 4 we detect the lack of the geologicallegend and the structure geometry. For sake of clarity, it wouldbe necessary include this information in the drawing.

Chapter 4

Zero measurement should be carried out,at least 3 days prior to commencement ofconstruction works of the diaphragm walls

We recommend carrying out the reference measurement assoon as practicable. We deem that three days is a too shortperiod.

Observing Drawing 5, we deem that ground benchmarks shallbe placed at regular interval (20meters) around the structure.

Chapter 5 Deformation limits should be given by D-walls designer, at leastfor the inclinometers at the stations. Moreover the stationstructural design shall specify expected vertical and horizontaldeformations in the stated building influence areas and check

them against building conditions.The location of the benchmarks is not included in the analyseddocument.

Chapter 6 Direct observation will be carried out on all the trees present in

the proximity of the excavation area.

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Figure 3.1 Daszynskiego Roundabout Area

4. CONCLUSIONOur conclusions are similar to the ones contained in our previous report [8]. We strongly recommend start

monitoring measurements as soon as practicable in order to recognize building deformation behaviours whichare independent from the works execution. Furthermore we highlight the necessity of more detailedspecifications on the instrumentations location, for instance with some example on an existing building.

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