BCCE CENTENERY SQUARE EXTENSION VICTORIA SQUARE …€¦ · The Services were performed by Fugro Aperio Limited exclusively for the purposes of the Client. Fugro Aperio Limited is

NON DESTRUCTIVE INVESTIGATION

FOR CENTRO

BCCE CENTENERY SQUARE EXTENSION VICTORIA SQUARE HOUSE (CHATEAU)

FUGRO APERIO PROJECT NO: 4158

FUGRO APERIO REPORT NO: 4158REP_002

VICTORIA SQUARE HOUSE (CHATEAU) NON DESTRUCTIVE INVESTIGATION

Fugro Aperio Project No. J4158 Fugro Aperio Limited

REPORT ISSUE STATUS

Issue Date Description Prepared Checked

001 7/11/14 Draft

S BROOK

Project Manager

002 11-

Nov-14 Draft

S BROOK

Project Manager


Project No. 4158 Fugro Aperio Limited

EXECUTIVE SUMMARY

This report documents a non-destructive investigation using ground penetrating radar (GPR)

of sections of Victoria Square House (Chateau).

The brief was to determine the as-built construction of the walls in preparation for fixings of

the OLE brackets.

The survey was carried out in September and October 2014 using a GSSI SIR3000 digital

GPR system coupled to an antenna operating at a centre frequency of 2 GHz.

The walls were found to be solid masonry and stone varying between 440mm and 500 mmm

thick. The stone was found to be 150 mm thick.


Project No. 4158 Fugro Aperio Limited

TABLE OF CONTENTS

1. INTRODUCTION ................................................................................................................... 1

1.1 General .................................................................................................................................. 1 1.2 The Brief ................................................................................................................................ 1 1.3 Terms of Reference ............................................................................................................... 1 1.4 Service Constraints ................................................................................................................ 1

2. BACKGROUND INFORMATION ........................................................................................... 2

2.1 General .................................................................................................................................. 2

3. DATA ACQUISITION ............................................................................................................. 3

3.1 General .................................................................................................................................. 3 3.2 Ground Penetrating Radar Profiling ....................................................................................... 3 3.3 Survey Methodology .............................................................................................................. 4 3.4 Calibration and Relocation ..................................................................................................... 4 3.5 Radar Data Processing .......................................................................................................... 5

4. FINDINGS .............................................................................................................................. 6

4.1 General .................................................................................................................................. 6 4.2 Location 1 .............................................................................................................................. 7 4.3 Location 2 .............................................................................................................................. 7 4.4 Location 3 .............................................................................................................................. 7

LIST OF APPENDICES

APPENDIX A - Service Constraints .............................................................................................. 8 APPENDIX B - GPR Processing ................................................................................................. 11 APPENDIX C – Drawings ........................................................................................................... 14

LIST OF DRAWINGS

Drawing No. 4158-01: Victoria Square House Chateau


Project No. 4158 Fugro Aperio Limited Page 1

1. INTRODUCTION

1.1 General

1.1.1 This report documents a non-destructive investigation using ground penetrating

radar (GPR) of Victoria Square House (Chateau), Birmingham.

1.2 The Brief

1.2.1 The brief was to determine the as-built construction at locations where overhead

cables are proposed to be fixed.

1.3 Terms of Reference

1.3.1 This report is based upon data acquired in September and October 2014.

1.3.2 This investigation involved the use of non-destructive methods and therefore the

majority of the findings presented here are the result of the measurement and

interpretation of electrical and electromagnetic signals. This report represents the

best professional opinion of the authors. Every effort has been made to ensure that

the results are accurate and reliable, including reference to material calibration data

from this and other sites. However, as with other indirect methods there is a

possibility of localised inconsistencies and inaccuracies within the results.

1.3.3 This final report supersedes any previous reports, whether written or oral and

completes the work currently commissioned by Centro.

1.4 Service Constraints

1.4.1 Appendix A (Service Constraints) outlines the limitations of this report in terms of a

range of considerations including, but not limited to, its purpose, its scope, the data

on which it is based, its use by Third Parties, possible future changes in design

procedures and possible changes in the conditions at the site with time. Appendix A

represents a clear exposition of the constraints, which apply to all reports issued by

Fugro Aperio Limited. It should be noted that the Service Constraints do not in any

way supersede the terms and conditions of the contract between Fugro Aperio

Limited and the Client.



2. BACKGROUND INFORMATION

2.1 General

2.1.1 Overhead cables are proposed to be attached to the building as part of the

Birmingham City Centre extension of the tram system.

2.1.2 Victoria Square House is a Grade II listed property built on the south side of Victoria

Square between 1889 and 1891.

2.1.3 Drawings obtained showing the existing building construction from the Building

Management team do not positively identify the structural floor construction although

there are indications on the drawing that concrete has been used.

2.1.4 Visual inspections of the external walls of the property appear to show that

loadbearing brickwork has been used with a stone veneer in the external face.



3. DATA ACQUISITION

3.1 General

3.1.1 The survey was carried out in September and October 2014 using a GSSI SIR3000

digital GPR system coupled to an antenna operating at centre frequency of 2 GHz.

3.2 Ground Penetrating Radar Profiling

3.2.1 GPR is an echo sounding method where a transducer (transmitter/receiver) is

passed over the surface at a controlled speed. Short duration pulses of radio energy

are transmitted into the subject and reflections from material boundaries and

embedded features such as metalwork or voids are detected by the receiver.

Sampling is so rapid that the collected data are effectively a continuous cross

section, enabling rapid assessment of thickness and condition over large areas. By

assessing the strength, phase and the scatter of signals it is often possible to find

changes in structure or material type.

3.2.2 GPR involves the collection of a large body of information - not all of which is of

engineering significance. Analysis involves identifying the main elements of the

structure under investigation and establishing the characteristics of its base

condition. Variations in construction and condition can then be identified and

compared with other similar structures investigated elsewhere enabling significant

features to be mapped.

3.2.3 The arrangement and condition of structural components can be identified by

analysing a combination of three main variables in the GPR data:

the amplitude, phase and velocity of the signals from within the material and

from the material boundaries which give an idea of material type

the continuity of the signal which gives an idea of the shape of the

component

the travel time of radio pulses though the material gives an indication of the

layer thickness or depth to embedded features



3.3 Survey Methodology

3.3.1 For each element investigated a series of orthogonal profiles were surveyed

wherever access would allow. Due to the physical size of the GPR antenna and

combined survey wheel, access to parts of some elements was severely restricted

and survey profile lengths were often very short.

3.3.2 The GPR data were collected in survey wheel control mode to ensure consistent

sampling despite variations in profile speed and to aid relocation of detected

features in real time. The survey wheel was calibrated over a 2 m length at the start

of the survey. The radar equipment was operated at 200 scans per metre to provide

a suitable level of data density over short survey lengths.

3.3.3 Data were collected internally and externally.

3.3.4 GPR data were also recorded to hard disk for later processing and analysis.

3.4 Calibration and Relocation

3.4.1 The measurement of thickness or depth from GPR data relies on multiplying the

measured two-way travel time by the velocity of the radio signals passing through

the materials under investigation.

3.4.2 No accurate direct calibration of velocity within the elements was possible at this site

and therefore for the purposes of this investigation a typical velocity for GPR pulses

within masonry has been used. Some of the derived thickness measurements have

been compared to the expected thickness of various parts of the structure and have

been found to provide a good correlation.

3.4.3 This velocity has been used to calculate the thickness of materials and the depths to

located features relative to the surveyed surface. A velocity value of 0.13 m/ns has

been used for all calculations.



3.4.4 No allowance has been made for variations in included moisture content or void ratio

and therefore depth values in this report are likely to be accurate to within ±10% of

the quoted value for depths greater than 50 mm and to ±5 mm for depths less than

50 mm.

3.4.5 With the methodology described above it is likely that relocation of any detected

features can be expected to be accurate to 50 mm or better.

3.5 Radar Data Processing

3.5.1 To assist in analysis of the recorded data, the digital radar data were processed in

the following stages:

Declipping

Start-time correction

Dynamic correction

3.5.2 For a more detailed description of these processing stages see Appendix B.



4. FINDINGS

4.1 General

4.1.1 Our findings from the survey are presented on Drawing 4158-01 and are discussed

in detail below.

4.1.1 The dashed red line is 6 m above street level

4.1.2 In general the locations investigated were found to be solid masonry walls.

4.1.3 It was not possible to investigate the floors at the locations suggested due to raised

floors above and false ceilings below covering and preventing access to the

structural floor.



4.2 Location 1

4.2.1 The wall was found to be consistently between 500mm and 440mm thick with the

thicker walls on the lower floors. The outer stone was found to be between 100 and

150 mm thick.

4.2.2 No voids were found to be present in the wall

4.3 Location 2

4.3.1 The wall was found to be consistently between 500mm and 440mm thick with the

thicker walls on the lower floors. The outer stone was found to be between 100 and

150 mm thick.

4.3.2 No voids were found to be present in the wall

4.4 Location 3

4.4.1 The wall in the location varied in thickness mainly due to the curvature of the The

wall was found to be consistently approximately 500 mm and. The outer stone was

found to be between 100 and 150 mm thick.

No voids were found to be present in the wall.



APPENDIX A - SERVICE CONSTRAINTS



Appendix A – Service Constraints

1. This report and the assessment carried out in connection with the report (together the “Services”) were compiled and carried out by Fugro Aperio Limited for CENTRO (the “Client”) in accordance with the terms of a contract between Fugro Aperio Limited and the Client. The Services were performed by Fugro Aperio Limited with the skill and care ordinarily exercised by a reasonable specialist at the time the Services were performed. Further, and in particular, the Services were performed by Fugro Aperio Limited taking into account the limits of the scope of works required by the Client, the time scale involved and the resources, including financial and manpower resources, agreed between Fugro Aperio Limited and the Client.

2. Other than that expressly contained in paragraph 1 above, Fugro Aperio Limited provides no other

representation or warranty whether express or implied, in relation to the Services.

3. The Services were performed by Fugro Aperio Limited exclusively for the purposes of the Client.

Fugro Aperio Limited is not aware of any interest of or reliance by any party other than the Client in or on the Services. Unless expressly provided in writing, Fugro Aperio Limited does not authorise, consent or condone any party other than the Client relying upon the Services. Should this report or any part of this report, or otherwise details of the Services or any part of the Services be made known to any such party, and such party relies thereon that party does so wholly at its own and sole risk and Fugro Aperio Limited disclaims any liability to such party. Any such party would be advised to seek independent advice from a competent specialist and / or lawyer.

4. It is Fugro Aperio Limited’s understanding that this report is to be used for the purpose described in

Section 1 - “Introduction” of this report. That purpose was a significant factor in determining the scope and level of the Services. Should the purpose for which the report is used, and/or should the Client’s proposed development or use of the site change (including in particular any change in any design and/or specification relating to the proposed use or development of the site), this report may no longer be valid or appropriate and any further use of or reliance upon the report in those circumstances by the Client without Fugro Aperio Limited’s review and advice shall be at the Client’s sole and own risk. Should Fugro Aperio Limited be requested, and Fugro Aperio Limited agree, to review the report after the date hereof, Fugro Aperio Limited shall be entitled to additional payment at the then existing rates or such other terms as may be agreed between Fugro Aperio Limited and the Client.

5. The passage of time may result in changes (whether man-made or otherwise) in site conditions and

changes in regulatory or other legal provisions, technology, methods of analysis, or economic conditions which could render the report inaccurate or unreliable. The information, recommendations and conclusions contained in this report should not be relied upon if any such changes have taken place or after a period of 2 years from the date of this report or such other period as maybe expressly stated in the report, without the written agreement of Fugro Aperio Limited. In the absence of such written agreement of Fugro Aperio Limited, reliance on the report after any such changes have occurred or after the period of 2 years has expired shall be at the Client’s own and sole risk. Should Fugro Aperio Limited agree to review the report after the period of 2 years has expired, Fugro Aperio Limited shall be entitled to additional payment at the then existing rates or such other terms as may be agreed between Fugro Aperio Limited and the Client.

6. The observations, recommendations and conclusions in this report are based solely upon the

Services, which were provided pursuant to the contract between the Client and Fugro Aperio Limited. Fugro Aperio Limited has not performed any observations, investigations, studies or testing not specifically set out or required by the contract between the Client and Fugro Aperio Limited. Fugro Aperio Limited is not liable for the existence of any condition, the discovery of which would require performance of services not otherwise contained in the Services.

7. Where the Services have involved Fugro Aperio Limited’s interpretation and/or other use of any

information (including documentation or materials, analysis, recommendations and conclusions)



provided by third parties (including independent testing and/or information services or laboratories) or the Client and upon which Fugro Aperio Limited was reasonably entitled to rely or involved Fugro Aperio Limited’s observations of existing physical conditions of any site involved in the Services, then the Services clearly are limited by the accuracy of such information and the observations which were reasonably possible of the said site. Unless otherwise stated, Fugro Aperio Limited was not authorised and did not attempt to independently verify the accuracy or completeness of such information, received from the Client or third parties during the performance of the Services. Fugro Aperio Limited is not liable for any inaccuracies (including any incompleteness) in the said information, the discovery of which inaccuracies required the doing of any act including the gathering of any information which it was not reasonably possible for Fugro Aperio Limited to do including the doing of any independent investigation of the information provided to Fugro Aperio Limited save as otherwise provided in the terms of the contract between the Client and Fugro Aperio Limited.



APPENDIX B - GPR PROCESSING



Data examples shown are from various sources

Processing Explanation & Example Stages

1 Start -time Correction. The effect of the transmitter elevated above the road surface and small variations in surface moisture are corrected.

2 De-clipping. Keeping the signal amplitude the same for each survey line is essential for comparative reasons, but this means that some signals are too large to be recorded (for example steel in PQC). This correction reshapes the over-gained signals to allow it to fall within workable thresholds.

3 Dynamic Correction. The effect of the separation between transmitter and receiver is corrected.

4 Noise Removal. System noise is removed.

Before

After



5 Migration. Migration shifts dipping data to its true position below the transducer. In the case of hyperbolic signals such as reinforcement, migration collapses the signal to give an accurate point location for each feature.

Before

After

6 Pick Straight Correct.

When analysis of the amplitude and/or nature of reflected GPR signals from a specific boundary is required (such as the base of a slab), the data is adjusted such that the signal from this boundary becomes flat. This enables only data from the selected interface to be analysed without introducing spurious signals/noise into the analysis window.

Before

After



APPENDIX C – DRAWINGS

Drawing No. 4158-01: Victoria Square House Chateau

1

5

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1

9

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1

5

0

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9

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Date

Client

Title

Project

Checked Approved

Technical

Support

Project

Engineer

Issue

Ref.

Fugro Aperio Limited

Part of the Fugro Group of companies with offices worldwide

Fugro Aperio

Scale

@A3

BCCE CENTENARY SQUARE

EXTENSION

CENTRO

VICTORIA SQUARE HOUSE

CHATEAU

OCT 2014

**

SB

4158-01

A

SB

Drawing

No.

Issue Ref. Changes Date

A

Initial for client approval

Oct 14

The information shown on this drawing has been derived from

an investigation carried out using ground penetrating radar

(GPR). This drawing should be read in conjunction with Fugro

Aperio Report number 4158. All dimensions on this drawing

have the following accuracies:

▪ ± 100 mm in plan

▪ ± 10% in depth/thickness.

Please see the associated report for a more detailed

description of the accuracies.

LOCATION 1

LOCATION 2

LOCATION3

LOCATION 3

LOCATION 1

LOCATION 2

External

Internal

Internal

Internal

External

External

Documents

BCCE CENTENERY SQUARE EXTENSION VICTORIA SQUARE …€¦ · The Services were performed by Fugro Aperio Limited exclusively for the purposes of the Client. Fugro Aperio Limited is