Structural Investigation Report for the Burnt One Storey ...

1

Date of Test: 4th – 5th June, 2020

Client: Karen Roses Joint Body

Structural Investigation Report for the Burnt One Storey Building

On Block/ Plot No 2/38 Nakuru/ Eldama-Ravine Highway

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Table of Contents

Executive Summary 4

1.0 Introduction 10

1.1 Study Objective 11

1.2 Methodology 11

2.0 Tests and Assessments 12

2.1 Visual Inspection of the Structure 12

2.2 Schmidt hammer test 17

2.2.1 Schmidt Hammer Test results 18 2.3 Ultrasonic Pulse Velocity Test 21

2.3.1 Ultrasonic Pulse Velocity Test Results 23

2.3.1.1 Direct test results 23

2.3.1.2 Indirect test results 26

2.4 Carbonation test 35

2.4.1 Visual Assessments of Concrete Cores for Carbonation test 36 2.4.2 Carbonation test results 38

2.5 Compressive Strength Test 40

2.5.1 Visual Assessments of Concrete Cores for compressive strength 41

2.5.2 Core Compressive Strength Test Results 43

2.6 Electromagnetic Ferroscan Test. 45

2.6.1 Electromagnetic Ferroscan Test Results 46 3.0 Conclusions and Recommendations 56

3.1 Schmidt hammers test results 56

3.2 Ultrasonic Pulse Velocity Test 56

3.3 Core compressive strength test results 56

3.4 Carbonation test results 57

3.5 Reinforcement Details 57

3.6 General conclusions 58

3.7 Recommendations 58

4.0 Appendices 66

4.1 Layout Plan 66

4.2 Photographs 68

4.2 References 75

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Executive Summary

i. Leeds Engineering Company Limited (L.E.C.L) was commissioned by the client to

carry out a detailed structural integrity audit for a Burnt one story building in Eldama

Ravine. This was necessitated after a fire incident on the building

ii. The structure under investigation has one suspended reinforced concrete slab plus

ground floor level. The structural frame of the building is comprised of reinforced

concrete slabs, typical reinforced concrete beams (450x200mm) and typical reinforced

concrete columns (200x200mm).

iii. Based on our visual inspections on the structure, it is evident that the structural

elements supporting the structure have been affected by the fire. The following

conditions were observed:

a) At the ground floor level, only the area between grid lines 1/5-A/D was affected

by the fire incident whereas at the first floor level the entire structure was

affected.

b) Cracks had developed on some of the walls in the first floor.

c) Plaster on some structural elements had completely de-bonded and peeled off;

the most affected areas are the sports bar and entire first floor.

d) Concrete had flaked off from some columns and beams an indication that fire

exposure has affected the integrity of concrete.

e) Most of the non-structural fittings such as non-load bearing walls, partitions, wall

linings, ceilings, windows, glazing, roofing, doors, tiles, timber floor, movable and

fixed furniture had been completely destroyed by the fire.

f) All elements above first floor level have been completely destroyed by the fire.

g) There were no major effects noted on external walls.

iv. Results obtained from Schmidt hammer test regime confirm that concrete on structural

members achieved an average compressive strength of 15 N/mm². This is below the

nominal concrete strength of C20 for that nature of a structure; an indication that the

concrete strength has been affected by the fire exposure.

v. Ultrasonic pulse velocity test was carried out on concrete elements to assess the

quality of concrete on these members. The test was also done on plastered elements

to assess whether the plaster has de-bonded.

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vi. Direct Ultrasonic Pulse Velocity test results showed that the concrete on structural

elements was ranging from doubtful quality to good quality. This is an indication

that surface concrete on some of the affected elements has developed voids, cracks

and internal cavities due to fire exposure.

vii. Results for Indirect Ultrasonic Pulse Velocity test on concrete elements gave largely

non-homogeneous concrete and some fairly homogenous concrete matrix. This is

a further indication that surface concrete has developed voids, cracks and internal

cavities due to the fire exposure. Indirect Ultrasonic Pulse Velocity test results on

plastered elements also confirm that plaster has de-bonded on most of the elements.

viii. Concrete strength assessed through Ultrasonic Pulse Velocity test gave an average of

16.9 N/mm². This is below the nominal concrete strength of C20 for that nature of a

structure; an indication that the concrete strength has been affected by the fire

exposure.

ix. Results obtained from core compressive strength tests confirm that concrete on

structural members achieved an average compressive strength of 15.4 N/mm2. This is

below the nominal concrete strength of C20 for that nature of a structure; an indication

that the concrete strength has been affected by the fire exposure.

x. Results obtained from carbonation test confirm that the carbonation depth was NIL for

some cores, and in the range of 15mm - 35mm for the other cores. Considering an

average concrete cover to reinforcement of around 25mm, the carbonation depth for

the affected elements is high. Thus, in general, carbonation front has reached the

vicinity of the surface of the Rebars for most of the affected elements. This increases

the risk of reinforcement corrosion in the elements thereby undermining their yield

strength.

xi. Consistencies of electromagnetic ferroscan results confirm that columns had 4No

12mm bars with 8mm links at a spacing of 200mm c/c.

xii. Beams were established to have 2No. 16mm bottom bars with 8mm links at a

spacing of 200mm c/c.

xiii. The slabs were established to have 10mm bars bottom 1 at a spacing of 200mm c/c

and 10mm bars bottom 2 at a spacing of 200mm.

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General conclusions

i. The concrete strength on structural elements is below the nominal concrete strength of

C20 for that nature of a structure. This gives an indication that the concrete strength

has been affected by the fire exposure

ii. Surface concrete has deteriorated as a result of fire exposure. It has developed voids,

cracks and internal cavities.

iii. Carbonation depth has reached the vicinity of the surface of the rebars. There is a high

risk of reinforcement corrosion considering that this is a time dependent process.

iv. Considering the low concrete strengths, it is our conclusion that the structural capacity

of the concrete members including first floor beams, first floor slab and ground floor

columns within grid lines 1/5-A/D has been compromised. As these members are still

intact, they can still be repaired and strengthened for them to achieve their full

structural potential.

v. The structural frame above the suspended slab is completely damaged and has been

weakened by the fire. This frame therefore cannot be salvaged.

Recommendations

Following the assessments carried out, the physical conditions observed and tests

carried out, the structure has been found to be adversely affected by the fire incident.

The load carrying capacity of the structural frame has therefore been undermined. It is

imperative that urgent corrective measures are undertaken on the damaged areas by

carrying out the following procedures;

i. Repair of all the concrete elements within the ground floor and first floor levels

that have developed surface defects by use of a structural repair mortar between

grid lines 1/5-A/D.

ii. To safeguard the existing ground floor columns, first floor slab and first floor

beams between grid lines 1/5-A/D against carbonation attack, we propose

demolition of columns and recasting with a suitable structural repair mortar before

containing them by use of carbon fibre wraps. The repair mortar shall be a mixture

of Master Flow 928 hydraulic cement-based mineral aggregate non-shrink grout

and 10mm aggregates to a ratio of 1:2. The first floor slab and first floor beams

shall be strengthened using epoxy bonded carbon fibre strips as specified below.

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iii. The existing reinforcement on ground floor columns, first floor beams and slab

that experienced the heat, were never checked for percentage (%) elongation

including tension, bending and re bending properties after the fire exposure. In

addition, we note that reinforcement in these elements may have been affected by

carbonation attack. It is therefore important we strengthen the these elements by

use of carbon fibre wraps and epoxy bonded carbon fibre strips as follows;

a) One (1) laminate plate of 50mm width should be fixed at the center of the

beam soffit covering the total length of the beam to increase flexural capacity

and one (1) shear strip should be fixed at either sides of the beam to

increase shear capacity.

b) Laminate plates of 50mm width should be fixed at the soffit of the first floor

slab in one direction at a spacing of 1500mm c/c to provide additional

flexural resistance.

c) Strengthening of ground floor columns between grid lines 1/5-A/D by

application of epoxy bonded unidirectional carbon fibre wrap placed around

the entire circumference of the columns.

iv. Demolishing and reconstruction of the entire structural frame above the first floor

slab.

v. Reconstruction of the entire roof structure.

vi. Redoing all non-structural elements such as non-load bearing walls, partitions,

wall linings, ceilings, flashings, windows, glazing, roofing, doors, tiles, movable

and fixed furniture

vii. Redoing all the electrical and mechanical services as detailed in the services

engineering report.

viii. All the structural repair work should be done under instructions and supervision of

a competent structural Engineer.

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Summary of Mechanical and Electrical Services

The table below gives a summary of the Mechanical and Electrical Services as

observed on site;

AREA OBSERVATIONS RECOMMENDATION

GF – Commercial

recreation centre

1. All electrical fitting and wiring

burnt, damaged beyond salvage.

1. Replace all electrical fitting

and wiring with new.

2. To reinstate fire alarm

detection devices and security

surveillance system

GF – ATS board

adjacent to staircase

1. The board not affected by

fire. The ATS and some

isolators observed intact

2. Some cut outs observed

disconnected.

1. To replace with an ATS

board that incorporates

latest switchgear that got

self-tripping mechanism in

case of a fault.

GF – KPLC meter

chamber

1. Observed in a standlone

chamber surrounded by

vegetation

2. 2. The chamber not accessible

and not secured by a padlock.

3. Cables poorly managed

4. Mounting height for the

switchgear too low against

working safely guidelines

5. Routing for cables from

transformer to metering chamber

to ATS board not traceable.

1. The meter chamber should

be easily accessible and

lockable.

2. Cables to be neatly

managed and labelled.

3. The mounting heights to

be raised to 1200mm

above finished floor level

4. Cable routing from the KPLC

transformer to metering

chamber to ATS board

should be in well-marked &

identifiable accessible ducts.

Ground floor – Diesel

powered Generator

1. 10kva 3phase diesel

powered generator observed

in a secure metal cage

behind the building.

2. Observed ok with no visible

effect of fire

3. Power and control cable

exposed on their entry to ATS

board at the staircase lobby

observed burnt.

1. Power and control cable from

Generator to ATS board to

be replaced with new.

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Ground floor –

External services

1. Some lights on the perimeter

column at the backside of the

plot observed burnt

2. The top most water tank

observed burnt on the side

3. The rear side rain water

gutters and drop pipes

observed burnt

1. Replace all the burnt items

with new

1st Floor – Staircase

lobby

1. The fitting on roof and wall all

burnt.

1.Replace all burnt fittings

1st Floor – Computer

room


burnt, damaged beyond

salvage.

2. 2no portable fire extinguisher

cylinders observed beyond

salvage

1. Replace all burnt fittings

2. Reinstate the fire detection

and extinguishing system in

this room as per building fire

code

1st Floor – Office

room(2no)



salvage.


2. Reinstate fire detection

& alarm system as per

building fire code

1st floor - Library 1. All electrical fitting and wiring


salvage.


2. Reinstate fire detection &

alarm system as per building

fire code

1st floor - WC 1. All electrical fitting and

wiring burnt, damaged

beyond salvage.

2. Sanitary fitting burnt

beyond salvage

3. Concealed plumbing pipe

work also observed burnt.


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1.0 Introduction

Leeds Engineering Company Limited (L.E.C.L) was commissioned by the client to carry

out a detailed structural integrity audit for a Burnt one story building in Eldama Ravine.

This was necessitated after a fire incident on the building. The fire incident was severe

in some parts of the structure, as evident in that most items were burnt down and very

few were salvaged. Both structural and non-structural members were also adversely

affected by the fire incident and this warranted the structural investigations to determine

the structural integrity of the building.

The Structural investigations entailed carrying out an assessment of physical conditions

of the structure including assessment of the in-situ concrete strengths and its

consistency throughout the structural elements, reinforcement mapping on the structural

members of the building and assessment of extent of damage caused by the fire. The

data obtained thereof would then be used to establish the structural robustness, stability

and remedial measures necessary to restore its structural capacity.

A team from Leeds Engineering Co. Ltd. visited the above mentioned site on 4th – 5th

June 2020 to carry out structural investigations that entailed both non-destructive and

destructive tests. Non-destructive tests included Schmidt Hammer Test and Ultrasonic

Pulse Velocity Test on structural members and a detailed study of reinforcement

mapping by use of Electromagnetic Ferro Scan. The destructive tests included sampling

and extraction of four (4) number concrete cores from structural members for

carbonation test and compressive strength tests. The cores were well labeled and

information was gathered and recorded for each core based on the visual inspection

and measurements done on site. The results of the investigation into each of the tests

are followed by a summary of the findings enclosed herein.

This report has been prepared based on the results obtained from the tests mentioned

above. Any conclusions made at the end of this report are based on the results obtained

thereof and firm’s experience in execution of similar exercises.

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1.1 Study Objective

The main objective of this study was;

1. In situ materials assessment on the existing building structure which included

determination of the quality of concrete in the structural elements.

2. Reinforcement mapping to determine the actual size and number of rebars used

on site.

3. Carbonation tests on concrete core samples extracted on site.

4. Condition assessment of the structural elements with a view of modeling their

deterioration mechanism due to fire exposure.

5. Material analysis and risk assessment on the structural elements.

1.2 Methodology

The structural integrity assessment was carried out as follows:

i. Site visit(s) to carry out visual inspection to determine the condition of the

building and identify areas for testing.

ii. Carrying out a comprehensive material tests that included;

i. Non-destructive testing thus;

Schmidt Hammer test

Ultrasonic Pulse Velocity Test

Determination of reinforcement used on the structural

elements

II. Destructive testing that included;

Depth of carbonation test on concrete core samples

extracted on site.

Core compressive strength test

iii. Making conclusions based on the findings.

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2.0 Tests and Assessments

The following tests/inspections were carried out;

i) Condition assessment and Visual inspection of the building from an engineering

point of view.

ii) Schmidt Hammer Test to determine the quality and strength of concrete in

accordance with BS EN 12504:2-2012).

iii) Assessment of plaster debonding by Ultrasonic Pulse Velocity Analyzer in

accordance with BS EN 12504-4:2004

iv) Electromagnetic Ferro scan Test to determine reinforcement mapping in

accordance to BS 1881 – 204: 1988

v) Core extraction and crushing to determine the compressive strength of

concrete cores according to BS EN 12504-1:2009.

vi) Depth of Carbonation determination with accordance to BS 1881-210:2013 and

BS EN 14630:2006.

2.1 Visual Inspection of the Structure

The structure under investigation has one suspended reinforced concrete slab plus

ground floor level. The structural frame of the building is comprised of reinforced

concrete slabs, typical reinforced concrete beams (450x200mm) and typical reinforced

concrete columns (200x200mm).

Based on our visual inspections on the structure, it is evident that the structural

elements supporting the structure have been affected by the fire. The following

conditions were observed;

i. At the ground floor level, only the area between grid lines 1/5-A/D was affected

by the fire incident whereas at the first floor level the entire structure was

affected.

ii. Cracks had developed on some of the walls in the first floor.

iii. Plaster on some structural elements had completely de-bonded and peeled off;

the most affected areas are the sports bar and entire first floor.

iv. Concrete had flaked off from some columns and beams an indication that fire

exposure has affected the integrity of concrete.

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v. Most of the non-structural fittings such as non-load bearing walls, partitions, wall

linings, ceilings, windows, glazing, roofing, doors, tiles, timber floor, movable and

fixed furniture had been completely destroyed by the fire.

vi. All elements above first floor level have been completely destroyed by the fire.

vii. There were no major effects noted on external walls.

Structural members identified for testing were selected randomly depending on

accessibility, functions and damage observed. Tests on the structural elements were

carried out as planned in the preamble to this report. Information generated from the

inspection and deductions made are contained in this report.

The photographic records below show the condition of the structure as noted during

these investigations.

Plate 1: Cracks on an a wall element

Crack on

an internal

wall

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Plate 2: Debonded plaster which has peeled off on a wall element

Plate 3: Completely burnt roof structure

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Plate 4: Debonded and damaged floor tiles

Plate 5: Destroyed non-structural fittings

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Plate 6: Section of the structure not affected by the fire

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2.2 Schmidt hammer test

The rebound (Schmidt) hammer is one of the oldest known methods of non-destructive

methods of determining concrete strength in different parts of a structure. The rebound

hammer is a means of assessing variations in strength within a structure. It is not

concise but gives an indication of acceptable concrete strength and if not acceptable,

then a destructive method is employed by cutting concrete core for crushing strength

testing in the laboratory

Apparatus:

The Schmidt Hammer test involves various apparatus namely:

1. Rebound Hammer – calibrated before commencement of the test

2. Abrasive stone – used to smoothen the surface before the test is conducted

3. Chisel and mason hammer – used in hacking and leveling the test surface

4. Reference anvil – used to check the correct functioning of the rebound hammer.

Sufficient test readings at each test location were taken. Care was taken to keep the

Rebound hammer perpendicular to the surface which is tested to specifications BS EN

12504-2:2012 in managing any error.

Plate 7: Schmidt hammer test in progress

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2.2.1 Schmidt Hammer Test results

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Project:

Date:

Element Floor Level GridTest

Direction1 2 3 4 5 6 7 8 9 10 11 12

Average

Rebound

Value

Equivalent

Compressive

Strength(N/MM2)

Age of Concrete

Beam First Floor A/B - 1 Side 28 20 24 26 24 26 26 26 28 25 27 23 25 18 Over 28 days

Side 19 16 16 18 19 16 18 14 18 18 19 16 17 12 Over 28 days

Soffit 26 24 25 25 26 24 26 26 26 24 24 26 25 14 Over 28 days

Side 25 24 26 26 25 26 23 24 24 26 23 26 25 17 Over 28 days

Soffit 27 28 26 30 27 29 27 24 26 29 28 31 28 15 Over 28 days

Side 19 24 22 21 19 22 22 22 21 19 20 24 21 15 Over 28 days

Soffit 35 35 30 32 34 33 30 30 36 34 31 35 33 18 Over 28 days

Side 20 19 25 20 19 24 25 22 24 21 20 21 22 15 Over 28 days

Soffit 29 30 34 30 30 33 32 29 31 33 31 30 31 17 Over 28 days

Beam Roof 8 - B/C Soffit 26 27 30 25 29 24 26 24 26 26 29 24 26 14 Over 28 days

Beam Roof A/B - 5 Soffit 21 25 24 21 20 24 22 23 24 25 26 23 23 13 Over 28 days

N/B: Approximate Converted Strength(N/MM2)=Average Rebound x Correlation factor of 0.70 for horizontal orientation

and 0.55 for vertical orientation obtained from calibration of cube compressive strength.

Proper Surface preparation was done on site according to BS EN 12504-2:2012

Tested by:………………………………… Checked by:…………………………

Sign:…………………………………….

Date:………………………………………

Beam First Floor C/D - 4

Beam First Floor 5/6 - B

Beam First Floor 4/5 - C

STRUCTURAL CONCRETE ASSESSMENT FOR THE BURNT STRUCTURE IN ELDAMA RAVINE

04-06-20

Beam First Floor B - 4/5

Leeds Engineering Company LtdP.O. Box 64785, 00620Nairobi, KenyaParklands,Forest Road/Forest Court Mezzanine FloorOffice: +254 705186673/ +254 788316459Email: [email protected]

[email protected]

Leeds Engineering Company Ltd. P.O. Box 64785 - 00620, Nairobi, Kenya MOBILE : 0705 186673 / 0788 316459 Email: [email protected]

[email protected]

Date:………………………………….….

Sign:………………………………….….

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Project:

Date:


Direction1 2 3 4 5 6 7 8 9 10 11 12

Average

Rebound

Value

Equivalent

Compressive

Strength(N/MM2)

Age of Concrete

Column Ground Floor 8 - C Side 20 16 19 18 19 16 16 17 16 17 16 17 17 12 Over 28 days

Column Ground Floor 4 - B Side 19 15 21 19 18 18 16 19 19 21 18 17 18 13 Over 28 days

Column First Floor 4 - D Side 20 22 24 26 23 26 24 24 22 24 24 26 24 17 Over 28 days

Column First Floor 5 - B Side 22 27 23 24 21 22 26 22 21 26 24 23 23 16 Over 28 days

Column First Floor 8" - D Side 24 26 26 22 23 28 24 25 27 24 26 27 25 18 Over 28 days

Slab First Floor 4/5 - A/B Soffit 27 27 23 24 27 26 23 29 26 24 25 27 26 14 Over 28 days

Slab First Floor C/D - 4/5 Soffit 27 29 31 30 33 29 34 32 31 34 29 32 31 17 Over 28 days

N/B: Approximate Converted Strength(N/MM2)=Average Rebound x Correlation factor of 0.70 for horizontal orientation

and 0.55 for vertical orientation obtained from calibration of cube compressive strength.

Proper Surface preparation was done on site according to BS EN 12504-2:2012

Tested by:………………………………… Checked by:…………………………

Sign:…………………………………….

Date:………………………………………


04-06-20


[email protected]

Leeds Engineering Company Ltd. P.O. Box 64785 - 00620, Nairobi, Kenya MOBILE : 0705 186673 / 0788 316459

Email: [email protected]

[email protected]

Date:………………………………….….

Sign:………………………………….….

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2.3 Ultrasonic Pulse Velocity Test

This test was carried out on structural elements with accordance to BS EN 12504-

4:2004 to determine the concrete quality and plaster De-bonding. The test

equipment has provisions for generating ultrasonic pulse, transmitting it to concrete,

receiving and amplifying the pulse and measuring and displaying the pulse travel

time. Good acoustic coupling between the transducers and concrete is established

for correct measurement of the speed.

Couplant is applied on the locations where the transducers are placed. Care is taken

not to move the transducers while reading is being taken, as this can generate noise

signals and errors in measurements. The transducers are held onto the surface of

the material until a consistent reading appears on the display. This is the time in

microsecond for the ultrasonic pulse to travel the test distance.

By this technique one can assess the quality of concrete such as presence of any

hollow sections, voids as well as cracks.

When an ultrasonic pulse travelling through concrete meets a concrete-air interface,

there is negligible transmission of energy across this interface. Thus, any air-filled

crack or void lying immediately between two transducers will obstruct the direct

ultrasonic beam when the projected length of the void is greater than the width of the

transducers and the wavelength of sound used. When this happens, the first pulse to

arrive at the receiving transducer will have been diffracted around the periphery of

the defect and the transit time will be longer than in similar concrete with no defect.

The following arrangements of the transducers were used during the tests to achieve

different test results:

a. Direct Transmission: - During this arrangement the transducers were placed

in opposite faces of the element.

b. Indirect Transmission: - During this arrangement the transducers were place

on the same face of the test area. This was mainly used where only one face

of the element sample area was accessible.

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Plate 8: Ultrasonic pulse velocity test in progress

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2.3.1 Ultrasonic Pulse Velocity Test Results

2.3.1.1 Direct test results

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PROJECT:

DATE:


Location

Average

Transit Time

(µ Sec)

Average

Distance

(mm)

Transit

Velocity

(km/s)

Concrete Quality

(IS Code 13311 Part

1-1992) Table 2

Compressive

Strength

(N/MM2)

Column Ground Floor 4 - C Middle 182 334.00 2.20 Doubtful Quality 14.09

Column Ground Floor 4 - B Middle 134.2 318.00 2.84 Doubtful Quality 18.20

Column Ground Floor 5 - C Middle 45.2 141.42 3.75 Good Quality 24.03

Column Ground Floor 8 - C Middle 44.3 141.42 3.83 Good Quality 24.52

Column Ground Floor 9 - D Middle 46.6 141.42 3.64 Good Quality 23.31

Column First Floor 6 - B Middle 125.0 240.00 2.30 Doubtful Quality 14.75

Column First Floor 4" - D Middle 46.2 141.42 3.67 Good Quality 23.51

Column First Floor 8" - D Middle 96.3 141.42 1.76 Doubtful Quality 11.28

Checked by……………………………………..

LEGEND:

Signature…………………………………

N/B: Compressive Strength(N/MM2)= Corrected Transit Velocity (km/s) x Correlation factor of 6.4 obtained from

calibration of cube compressive strength.

Test

Regime


05-06--2020

DIRECT ULTRASONIC PULSE ANALYZER TEST (BS 12504-4:2004, IS 13311-1:1992)

Tested by:……………………………………………….

Date:……………………………………………………

Direct

Direct

Semi Direct

Semi Direct

Semi Direct

Direct

Semi Direct

Semi Direct


[email protected]



[email protected]

Date:………………………………….….

Sign:………………………………….….

25

PROJECT:

DATE:


Location

Average

Transit Time

(µ Sec)

Average

Distance

(mm)

Transit

Velocity

(km/s)

Concrete Quality

(IS Code 13311 Part

1-1992) Table 2

Compressive

Strength

(N/MM2)

Beam First Floor 4/5 - C Midspan 119.2 240.00 2.42 Doubtful Quality 15.46

Beam First Floor 4/5 - B Midspan 101.5 255.00 3.01 Medium Quality 19.29

Beam First Floor C/D - 4 Midspan 155.2 270.00 2.09 Doubtful Quality 13.36

Beam First Floor 4 - A/B Midspan 116.3 141.42 1.46 Doubtful Quality 9.34

Beam First Floor 5/8 - C Midspan 89.1 250.00 3.37 Medium Quality 21.55

Beam First Floor 8/9 - C Midspan 82.4 240.00 3.50 Medium Quality 22.37

Beam First Floor 5/6 - B Midspan 35.6 141.42 4.77 Excellent 30.51

Beam Roof 8 - B/C Midspan 177.1 141.42 0.96 Doubtful Quality 6.13

Beam Roof 5/6 - B Midspan 324.7 270.00 1.00 Doubtful Quality 6.39

Beam Roof C/B - 4 Midspan 443.2 250.00 0.68 Doubtful Quality 4.33

Checked by……………………………………..

LEGEND:

Signature…………………………………

N/B: Compressive Strength(N/MM2)= Corrected Transit Velocity (km/s) x Correlation factor of 6.4 obtained from

calibration of cube compressive strength.

Semi Direct


05-06--2020

DIRECT ULTRASONIC PULSE ANALYZER TEST (BS 12504-4:2004, IS 13311-1:1992)

Test

Regime

Direct

Direct

Direct

Semi Direct

Direct

Direct

Semi Direct

Tested by:……………………………………………….

Date:……………………………………………………

Direct

Direct


[email protected]


[email protected]

Date:………………………………….….

Sign:………………………………….….

26

2.3.1.2 Indirect test results

27

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR SLAB (A/B-4/5) FIRST FLOOR

Distance (mm) Transit time(µsec)

50 53.2

100 72.4

150 124.0

200 160.1

250 180.1

Remarks: Non Homogeneous concrete matrix; plaster has debonded

Tested by:……………….. Checked by:…………………

Sign:……….……..…….

Date:……………………

PROJECT: STRUCTURAL CONCRETE ASSESSMENT FOR THE BURNT

STRUCTURE IN ELDAMA RAVINE

05-06-20

y = 0.7676x

0.0

50.0

100.0

150.0

200.0

250.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve

Leeds Engineering Company LtdP.O. Box 64785, 00620Nairobi, Kenya

Parklands,Forest Road/Forest Court,Mezzanine FloorOffice : +254705186673/ 0788316459

Email: [email protected] [email protected]



[email protected]

Date:………………………………….….

Sign:………………………………….….

28

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR SLAB (C/D - 4/5) FIRST FLOOR


50 22.9

100 42.1

150 71.2

200 105.2

250 135.4

Remarks: Fairly Homogeneous concrete matrix; plaster has debonded


Sign:……….……..…….

Date:……………………



05-06-20

y = 0.5158x

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve






[email protected]

Date:………………………………….….

Sign:………………………………….….

29

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR SLAB (B/C - 5/8) FIRST FLOOR


50 25.3

100 44.7

150 66.9

200 84.7

250 99.2



Sign:……….……..…….

Date:……………………



05-06-20

y = 0.4183x

0.0

20.0

40.0

60.0

80.0

100.0

120.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve





[email protected]

Date:………………………………….….

Sign:………………………………….….

30

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR COLUMN (9-B) GROUND FLOOR


50 23.6

100 48.5

150 66.3

200 106.8

250 125.7



Sign:……….……..…….

Date:……………………



05-06-20

y = 0.5001x

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve






[email protected]

Date:………………………………….….

Sign:………………………………….….

31

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR WALL (C/D - 4) FIRST FLOOR


50 28.4

100 48.3

150 78.5

200 115.5

250 137.2



Sign:……….……..…….

Date:……………………



05-06-20

y = 0.5485x

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve





[email protected]

Date:………………………………….….

Sign:………………………………….….

32

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR WALL (5 - C/B) FIRST FLOOR


50 39.3

100 125.4

150 236.2

200 426.6

250 545.4



Sign:……….……..…….

Date:……………………



05-06-20

y = 1.9753x

0.0

100.0

200.0

300.0

400.0

500.0

600.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve






[email protected]

Date:………………………………….….

Sign:………………………………….….

33

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR WALL (9 - B/C) FIRST FLOOR


50 56.6

100 92.2

150 185.7

200 221.5

250 288.3



Sign:……….……..…….

Date:……………………



05-06-20

y = 1.1366x

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve






[email protected]

Date:………………………………….….

Sign:………………………………….….

34

DATE:

ULTRASONIC PULSE ANALYZER TEST FOR WALL (A/B - 8) FIRST FLOOR


50 66.3

100 122.4

150 141.2

200 170.2

250 201.1



Sign:……….……..…….

Date:……………………



05-06-20

y = 0.8804x

0.0

50.0

100.0

150.0

200.0

250.0

0 100 200 300

Tim

e (µ

sec)

Distance ( mm)

Homogeneity curve






[email protected]

Date:………………………………….….

Sign:………………………………….….

35

2.4 Carbonation test

This test was conducted in accordance to BS 1881-210:2013 and BS EN

14630:2006.

Carbonation of concrete by attack from atmospheric carbon dioxide will result in a

reduction in alkalinity of the concrete, and increase the risk of reinforcement

corrosion. This will normally be restricted to a surface layer of only a few millimeters

thickness, in good quality concrete but can be much deeper in poor quality concrete,

with results as high as 30 mm being not uncommon. The extent of Carbonation can

be easily assessed by treating with phenolphthalein indicator the freshly exposed

surfaces of a piece of concrete which has been broken from a member to give

surfaces roughly perpendicular to the external face.

Plate 9: Showing extraction of concrete a core for carbonation test

36

2.4.1 Visual Assessments of Concrete Cores for Carbonation test

Visual assessment was carried out on all the concrete cores extracted for

carbonation both after sampling and after treating the cores with phenolphthalein

indicator.

The figure below shows the general condition of the concrete cores extracted from

the beams.

Figures 1- 4 show the general condition of concrete cores as noted:

Longitudinal Profile Cross-Section Comments

At Sample Location

Core Length= 165mm

Diameter= 100mm

The concrete has angular

aggregates with maximum

aggregate size of 20mm

The percentage of voids is

<0.5%

2 No. Rebars present

Carbonation depth = 15mm

Figure 1: Core extracted from first floor Slab C/D – 4/5

At Sample Location

Core Length= 140mm

Diameter= 100mm





<0.5%


Carbonation depth = 35mm

Figure 2: Core extracted from first floor slab B/C – 4/5

37


At Sample Location

Core Length=180mm

Diameter= 100mm





<0.5%


Carbonation depth = NIL

Figure 3: Core extracted from first floor slab 5/8 – B/C


At Sample Location

Core Length=145mm

Diameter= 100mm





<0.5%


Carbonation depth = NIL

Figure 4: Core extracted from first floor slab 8/9 – C/D

38

2.4.2 Carbonation test results

39

Project: DEPTH OF CARBONATION TEST FOR THE BURNT BUILDING IN ELDAMA RAVINE

Date: 04.06.2020

First Slab C/D - 4/5 100 165 VERTICAL 15

First Slab B/C - 4/5 100 140 VERTICAL 35

First Slab 5/8 - B/C 100 180 VERTICAL NIL

First Slab 8/9 - C/D 100 145 VERTICAL NIL

Tested by:…………………………………….. Checked by:………………………………

Sign:……………...…………………………….

Date:…………………………………………….

Carbonation Depth test results( Tests carried out according to BS EN 14630-2006)

SITE SPECIMEN SAMPLING FORMS

Length

(mm)GridFloor Level

Element

Extracted

Depth of Carbonation

(mm)

Diameter

(mm)

Direction of

Extraction






[email protected]

Date:………………………………….….

Sign:………………………………….….

40

2.5 Compressive Strength Test

Cores of 100mm diameter were used for compressive strength tests. The test

specimens were centrally positioned between the compressive test machine platens

and a load was then applied at a uniform rate, approximating the rate of stress of

about 15MPa/min, until the test specimen failed. The load at failure was recorded in

KN and the compressive strength was calculated to the nearest 0.1 MPa by dividing

the load at failure, in N, by the area of the contact face, in mm2. Correction factors

were then applied to derive the equivalent cube strength in accordance to BS 12504-

1.

Plate 10: Showing Core crushing in progress

41

2.5.1 Visual Assessments of Concrete Cores for compressive strength

Visual assessment was carried out on all the concrete cores both at the sample

location and after core preparations.

Figures 1- 4 shows the general condition of concrete cores as noted:


At Sample Location

Length=165mm

Diameter= 100mm


aggregates with

maximum aggregate size

of 20mm

The percentage of voids

is <0.5%

2No. Rebar present

Trimming and capping

done at the top and

bottom to achieve parallel

surfaces.

Figure 1: Core for First floor slab grid C/D – 4/5


At Sample Location

Length=140mm

Diameter= 100mm


aggregates with


of 20mm


is <0.5%

1No. Rebars present


done at the top and

bottom to achieve parallel

surfaces.

Figure 2: Core for First floor slab grid B/C – 4/5

42


At Sample Location

Length=180mm

Diameter= 100mm


aggregates with


of 20mm


is <0.5%

2No. Rebars present


done at the top and

bottom to achieve

parallel surfaces.

Figure 3: Core for First floor slab grid 5/8 – B/C


At Sample Location

Length=145mm

Diameter= 100mm


aggregates with


of 20mm


is <0.5%

1No. Rebars present


done at the top and

bottom to achieve

parallel surfaces.

Figure 4: Core for First floor slab grid 8/9 – C/D

43

2.5.2 Core Compressive Strength Test Results

44

COMPRESSIVE STRENGTH OF CONCRETE CORES

BS EN 12504-1:2009, BS EN 13791:2007, BS 6089:2010

DATE SAMPLED 05th June 2020

DATE TESTED 8th June 2020

CLIENT

ELEMENT GRID FLOOR VOIDS HEIGHT CORE HEIGHT/ BULK COMPRESSIVE

LEVEL (mm) DIAMETER DIAMETER DENSITY STRENGTH

(mm) RATIO (kg/cu.m) (N/mm2)

Slab C/D - 4/5 Firs t Floor 0.5% 110 100 1.10 2273 125.6 16.0

Slab B/C - 4/5 Firs t Floor 0.5% 110 100 1.10 2265 119.8 15.3

Slab B/C - 5/8 Firs t Floor 0.5% 115 100 1.15 2265 112.5 14.3

Slab C/D - 8/9 Firs t Floor 0.5% 110 100 1.10 2265 105.1 13.4

TESTED BY: REPORTED BY: CHECKED BY:

PROJECTCONCRETE ASSESSMENT FOR THE

BURNT BUILDING IN ELDAMA RAVINELOCATION:

ELDAMA

RAVINEELEMENT:

15.8

13.9

15.1

KAREN ROSES JOINT BODY

FAILURE

LOAD (KN)

SLABS

EQVLT. CUBE STRENGTH

(BS EN 12504-1:09)

(N/mm2)

16.6


Parklands,Forest Road/Forest Court,Mezzanine FloorOffice : +254705186673/ +254788316459




[email protected]

Date:………………………………….….

Sign:………………………………….….

45

2.6 Electromagnetic Ferroscan Test.

The electromagnetic test is conducted in accordance of BS 1881 – 204: 1988

A PS200 Ferroscan cover meter is used. A 600mm square template is fixed to the

structure and the area in question is scanned in two directions at right angles to each

other, in a series of sweeps. A calibrated wheel on the search head records where

the search head is at all times. Using electromagnetic principles and an on-board

computer analysis, an image of the underlying reinforcement is shown on a screen.

This is downloaded to a PC and analysed in detail to give readout of bar sizes. The

data can also be saved to a Microsoft Excel file.

When conducting these tests we made sure that the surface was uniform and level

as possible since bumps and unevenness would cause variation from the correct

readings.

Plate 11: Showing Electromagnetic Ferroscan test in progress

46

2.6.1 Electromagnetic Ferroscan Test Results

47

Project: STRUCTURAL CONCRETE ASSESSMENT FOR THE BURNT STRUCTURE

IN ELDAMA RAVINE

Date: 04.06.2020

Location: First floor

Element: Beam B - 4/5

Beam Size: 300 X 240

Electromagnetic Ferro Scan

Side Soffit

Main bars Links Main bars Links

1No. 16mm bottom bar 8mm @ 200mm c/c 2 No. 16 mm bottom bars 8mm @ 200mm c/c

Remarks: 2 No. 16mm bottom bars with 8mm links @ 200mmc/c

Cover to reinforcement = 25mm

Tested by:………………………………… Checked by:………………………………

Sign:…………………………………….

Date:………………………………………





[email protected]

Date:………………………………….….

Sign:………………………………….….

48


IN ELDAMA RAVINE

Date: 04.06.2020


Element: Beam C/D - 4



Side Soffit






Sign:…………………………………….

Date:………………………………………






[email protected]

Date:………………………………….….

Sign:………………………………….….

49


IN ELDAMA RAVINE

Date: 04.06.2020


Element: Beam C - 5/8



Side Soffit






Sign:…………………………………….

Date:………………………………………






[email protected]

Date:………………………………….….

Sign:………………………………….….

50


IN ELDAMA RAVINE

Date: 04.06.2020


Element: Beam 8/9 - C

Beam Size: 310


Soffit

Main bars Links

2No. 16mm bottom bar 8mm @ 200mm c/c




Sign:…………………………………….

Date:………………………………………





[email protected]

Date:………………………………….….

Sign:………………………………….….

51

Project: STRUCTURAL CONCRETE ASSESSMENT FOR THE BURNT BUILDING

IN ELDAMA RAVINE

Date: 04.06.2020

Location: First Floor

Element: Column 4 - D

Column Size: 220mm


SIDE

Main bars Links

2No. 12mm bars

Remarks: 2No. 12mm bars with 8mm links @ 200c/c (single face scanned)



Sign:…………………………………….

Date:………………………………………

8mm bars @ 200c/c






[email protected]

Date:………………………………….….

Sign:………………………………….….

52


IN ELDAMA RAVINE

Date: 04.06.2020

Location: Ground Floor

Element: Column 6 - B

Column Size: FWW


SIDE

Main bars Links

2No. 12mm bars




Sign:…………………………………….

Date:………………………………………

8mm bars @ 200c/c






[email protected]

Date:………………………………….….

Sign:………………………………….….

53


IN ELDAMA RAVINE

Date: 04.06.2020

Location: First Floor

Element: Column 9" - D

Column Size: FWW


SIDE

Main bars Links

2No. 12mm bars




Sign:…………………………………….

Date:………………………………………

8mm bars @ 200c/c






[email protected]

Date:………………………………….….

Sign:………………………………….….

54


IN ELDAMA RAVINE

Date: 04-06-20


Element: Slab 4/5 - A/B


Bottom 1 Bottom 2

10mm bars @ 200c/c 10mm bars @ 200c/c

Remarks: Bottom 1: 10mm bars @ 200c/c

Bottom 2: 10mm bars @ 200c/c


Tested by:…………………………………….. Checked by:…………………………

Sign:…………………………………….

Date:…………………………………………….


[email protected]



[email protected]

Date:………………………………….….

Sign:………………………………….….

55


IN ELDAMA RAVINE

Date: 04-06-20


Element: Slab 8/9 - A/B


Bottom 1 Bottom 2

10mm bars @ 200c/c 10mm bars @ 200c/c

Remarks: Bottom 1: 10mm bars @ 200c/c

Bottom 2: 10mm bars @ 200c/c


Tested by:…………………………………….. Checked by:…………………………

Sign:…………………………………….

Date:…………………………………………….


[email protected]



[email protected]

Date:………………………………….….

Sign:………………………………….….

56

3.0 Conclusions and Recommendations

3.1 Schmidt hammers test results

The tests were carried out in accordance to BS EN 12504:2-2012.

Results obtained from this test regime confirm that concrete on structural members

achieved an average compressive strength of 15 N/mm². This is below the nominal

concrete strength of C20 for that nature of a structure; an indication that the concrete

strength has been affected by the fire exposure.

3.2 Ultrasonic Pulse Velocity Test

The tests were carried out in accordance to BS EN 12504:2-2012.

Ultrasonic pulse velocity test was carried out on concrete elements to assess the

quality of concrete on these members. The test was also done on plastered

elements to assess whether the plaster has de-bonded.

Direct Ultrasonic Pulse Velocity test results showed that the concrete on structural

elements was ranging from doubtful quality to good quality. This is an indication

that surface concrete on most of the affected elements has developed voids, cracks

and internal cavities due to fire exposure.

Results for Indirect Ultrasonic Pulse Velocity test on concrete elements gave largely

non-homogeneous concrete and some fairly homogenous concrete matrix. This is

a further indication that surface concrete has developed voids, cracks and internal

cavities due to the fire exposure. Indirect Ultrasonic Pulse Velocity test results on

plastered elements also confirm that plaster has de-bonded on most of the elements.

Concrete strength assessed through Ultrasonic Pulse Velocity test gave an average

of 16.9 N/mm². This is below the nominal concrete strength of C20 for that nature of

a structure; an indication that the concrete strength has been affected by the fire

exposure.

3.3 Core compressive strength test results

The tests were carried out in accordance to BS EN 12504:1-2009, BS EN 13791-

2007 and BS 6089:2010.

Results obtained from this test regime confirm that concrete on structural members

achieved an average compressive strength of 15.4 N/mm2. This is below the nominal

concrete strength of C20 for that nature of a structure; an indication that the concrete

strength has been affected by the fire exposure.

57

3.4 Carbonation test results

This test was carried out in accordance to BS 1881-210:2013 and BS EN

14630:2006.

Results obtained from carbonation test confirm that the carbonation depth was NIL

for some cores, and in the range of 15mm - 35mm for the other cores. Considering

an average concrete cover to reinforcement of around 25mm, the carbonation depth

for the affected elements is high. Thus, in general, carbonation front has reached the

vicinity of the surface of the Rebars for most of the affected elements. This increases

the risk of reinforcement corrosion in the elements thereby undermining their yield

strength.

3.5 Reinforcement Details

The tests were carried out in accordance to BS 1881 – 204: 1988.

The columns were established to have 4No 12mm bars with 8mm links at a


Beams were established to have 2No. 16mm bottom bars with 8mm links at a


The slabs were established to have 10mm bars bottom 1 at a spacing of 200mm c/c

and 10mm bars bottom 2 at a spacing of 200mm.

58

3.6 General conclusions

i. The concrete strength on structural elements is below the nominal concrete

strength of C20 for that nature of a structure. This gives an indication that the

concrete strength has been affected by the fire exposure

ii. Surface concrete has deteriorated as a result of fire exposure. It has developed

voids, cracks and internal cavities.

iii. Carbonation depth has reached the vicinity of the surface of the rebars. There is a

high risk of reinforcement corrosion considering that this is a time dependent

process.

iv. Considering the low concrete strengths, it is our conclusion that the structural

capacity of the concrete members including first floor beams, first floor slab and

ground floor columns within grid lines 1/5-A/D has been compromised. As these

members are still intact, they can still be repaired and strengthened for them to

achieve their full structural potential.

v. The structural frame above the suspended slab is completely damaged and has

been weakened by the fire. This frame therefore cannot be salvaged.

3.7 Recommendations

Following the assessments carried out, the physical conditions observed and tests

carried out, the structure has been found to be adversely affected by the fire incident.

The load carrying capacity of the structural frame has therefore been undermined. It

is imperative that urgent corrective measures are undertaken on the damaged areas

by carrying out the following procedures;

i. Repair of all the concrete elements within the ground floor and first floor levels

that have developed surface defects by use of a structural repair mortar

between grid lines 1/5-A/D.

ii. To safeguard the existing ground floor columns, first floor slab and first floor

beams between grid lines 1/5-A/D against carbonation attack, we propose

demolition of columns and recasting with a suitable structural repair mortar

before containing them by use of carbon fibre wraps. The repair mortar shall

be a mixture of Master Flow 928 hydraulic cement-based mineral aggregate

non-shrink grout and 10mm aggregates to a ratio of 1:2. The first floor slab and

first floor beams shall be strengthened using epoxy bonded carbon fibre strips

as specified below.

59

iii. The existing reinforcement on ground floor columns, first floor beams and slab

that experienced the heat, were never checked for percentage (%) elongation

including tension, bending and re bending properties after the fire exposure. In

addition, we note that reinforcement in these elements may have been affected

by carbonation attack. It is therefore important we strengthen the these

elements by use of carbon fibre wraps and epoxy bonded carbon fibre strips as

follows;

d) One (1) laminate plate of 50mm width should be fixed at the center of the

beam soffit covering the total length of the beam to increase flexural

capacity and one (1) shear strip should be fixed at either sides of the

beam to increase shear capacity.

e) Laminate plates of 50mm width should be fixed at the soffit of the first

floor slab in one direction at a spacing of 1500mm c/c to provide

additional flexural resistance.

f) Strengthening of ground floor columns between grid lines 1/5-A/D by

application of epoxy bonded unidirectional carbon fibre wrap placed

around the entire circumference of the columns.

iv. Demolishing and reconstruction of the entire structural frame above the first

floor slab.

v. Reconstruction of the entire roof structure.

vi. Redoing all non-structural elements such as non-load bearing walls, partitions,

wall linings, ceilings, flashings, windows, glazing, roofing, doors, tiles, movable

and fixed furniture

vii. Redoing all the services buried in walls, concrete elements or on the surfaces

such electrical and mechanical services and fittings.

viii. All the structural repair work should be done under instructions and supervision

of a competent structural Engineer.

60

3.8 Mechanical & Electrical Services

61

ITEM AREA OBSERVATIONS RECOMMENDATION PHOTOS 1 GF – Commercial

recreation centre

1. All electrical fitting and


beyond salvage.

3. Replace all electrical

fitting and wiring with new.

4. To reinstate fire alarm

detection devices and

security surveillance

system

2 GF – ATS board

adjacent to staircase

3. The board not

affected by fire. The

ATS and some

isolators observed

intact

4. Some cut outs

observed

disconnected.

1. To replace with an ATS

board that incorporates

latest switchgear that

got self tripping

mechanism incase of a

fault.

62

3 GF – KPLC meter

chamber

6. Observed in a standlone

chamber surrounded by

vegetation

7. 2. The chamber not

accessible and not secured

by a padlock.

8. Cables poorly managed

9. Mounting height for the

switchgear too low against

working safely guidelines

10. Routing for cables from

transformer to metering

chamber to ATS board not

traceable.

5. The meter chamber

should be easily

accessible and lockable.

6. Cables to be neatly

managed and labelled.

7. The mounting heights

to be raised to

1200mm above

finished floor level

8. Cable routing from the

KPLC transformer to

metering chamber to ATS

board should be in well-

marked & identifiable

accessible ducts.

63

ITEM AREA OBSERVATIONS RECOMMENDATION PHOTOS 4 Ground floor – Diesel

powered Generator

4. 10kva 3phase diesel powered generator observed in a secure metal cage behind the building.

5. Observed ok with no visible effect of fire

6. Power and control cable exposed on their entry to ATS board at the staircase lobby observed burnt.

1. Power and control cable

from Generator to ATS

board to be replaced with

new.

5.0

Ground floor – External services

4. Some lights on the

perimeter column at the

backside of the plot

observed burnt

5. The top most water tank

observed burnt on the

side

6. The rear side rain

water gutters and drop

pipes observed burnt

1. Replace all the burnt items with new

64

ITEM AREA OBSERVATIONS RECOMMENDATION PHOTOS

6.0

1st Floor –

Staircase lobby

1. The fitting on roof and wall all burnt.

1.Replace all burnt fittings

7.0

1st Floor –

Computer room



beyond salvage.

4. 2no portable fire

extinguisher cylinders

observed beyond

salvage


4. Reinstate the fire

detection and

extinguishing system in

this room as per building

fire code

8.0 1st Floor –

Office

room(2no)


wiring burnt,

damaged beyond

salvage.

3. Replace all burnt

fittings

4. Reinstate fire

detection & alarm

system as per

building fire code

65

ITEM AREA OBSERVATIONS RECOMMENDATION PHOTOS

9.0 1st floor - Library 1. All electrical fitting and


beyond salvage.


4. Reinstate fire detection &

alarm system as per

building fire code

10. 1st floor - WC 4. All electrical fitting

and wiring burnt,

damaged beyond

salvage.

5. Sanitary fitting

burnt beyond

salvage

6. Concealed

plumbing pipe work

also observed

burnt.


66

4.0 Appendices

4.1 Layout Plan

68

4.2 Photographs

75

4.2 References

1. BS EN 12504:2-2012)– Recommendations for surface hardness testing by

rebound hammer

2. BS 1881 – 204: 1988 – Recommendations for conducting electromagnetic

tests using a cover meter and Ferrouscan

3. BS EN 12504-1:2009, Cored specimens-Taking, examining and testing in

compression

4. Determination of Ultrasonic Pulse Velocity – BS12504:Part 4 : 2004

5. BS 1881-210:2013 - Testing hardened concrete. Determination of the

potential carbonation resistance of concrete. Accelerated carbonation

method

6. BS EN 14630:2006 - Products and systems for the protection and repair of

concrete structures. Test methods. Determination of carbonation depth in

hardened concrete by the phenolphthalein method

7. BS 4449:2005+A3:2016 - Steel for the reinforcement of concrete.

8. ISO 6892-1:2019(en) - Metallic materials — Tensile testing — Part 1:

Method of test at room temperature

9. Non – destructive methods of test for concrete - BS4408:Part 5 : 1974

10. J H Bungey, S G Millard, M G Grantham, Testing of concrete in structures, 4

ed. Taylor & Francis, 2006.

11. M Goueygou, O Abrahan, J-F Lataste, “A comparative study of two non-

destructive testing methods to assess near-surface mechanical damage in

concrete structures,” NDT&E International. 41, 2008.

76

Disclaimer The content of this report reflect the views that is (are) responsible for the fact and the accuracy of the data presented herein. This report does not constitute a standard specification or regulation and shall not be reproduced in part or in full without the written approval of Leeds Engineering Company Ltd

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