Attachment_J.14_-_Geo-technical_Report.pdf

EHIP- Health Infrastructure Program FMOH - National Blood Transfusion Service Geotechnical Report (Final) (July 17, 2015)

This publication was produced for review by the United States Agency for International Development. It was prepared by Tetra Tech, Inc.

Geotechnical Investigation of B+G+3 Federal Ministry of Health

National Blood Transfusion Service Building

July, 2015

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TABLE OF CONTENT

LIST OF TABLES…………………………………………………………………………………………iii

ABBREVIATION………………………………………………………………………………………….iv

EXECUTIVE SUMMARY ............................................................................................................ v

1. INTRODUCTION

1.1. BACKGROUND

1.2. OBJECTIVES AND SCOPE OF THE WORK

1.3. SEISMICITY OF THE STUDY AREA

1.4. EXISTING CONDITION FOR THE BUILDING SITE

1.5. LOCATION OF PROJECT SITE

1.6. SITE GEOLOGY

1.6.1. Regional Geology

1.6.2. Local/Site Geology

2. METHODOLOGY

2.1. DRILLING

2.2. IN SITU TESTS AND SAMPLING

2.2.1. In Situ Tests

2.3. SAMPLING

2.4. LABORATORY TESTING

2.5. SUMMARY

3. GEOTECHNICAL CHARACTERISTICS OF SUB-SURFACE LAYERS

3.1. DESCRIPTION OF GEOTECHNICAL LAYER

3.1.1. Layer 1: Backfill material with cobble stone and grass covers (scoria at the top) 14

3.1.2. Layer 2: Light brown, medium stiff to stiff, medium to high plastic silty CLAY with some sand and gravel

3.1.3. Layer 3: Gray to light brown, medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt

3.1.4. Layer 4: Light brown to dark brown, medium grained, highly and completely weathered to moderately, soft to medium strong, vesicular Basalt

3.1.5. Layer 5: Gray, fine to medium grained, strong to very strong, jointed and vesicular at the top, slightly weathered to fresh Basaltic

3.2. GROUNDWATER OBSERVATION

4. FOUNDATION RECOMMENDATIONS

4.1. DETERMINATION OF FOUNDATION TYPE AND DEPTH

4.2. ISOLATED OR MAT ON MEDIUM GRAINED, MODERATELY TO HIGHLY AND COMPLETELY

WEATHERED, SOFT TO MEDIUM STRONG, VESICULAR BASALT WITH SIGNIFICANT SAND AROUND

ALL BOREHOLES EXCEPT AROUND BH4 ON MEDIUM GRAINED, SLIGHTLY TO MODERATELY

WEATHERED, MEDIUM STRONG TO STRONG, VESICULAR BASALT

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4.3. RECOMMENDATION FOR DESIGN AND CONSTRUCTION

4.4. EARTH WORK

4.5. SLAB CONSTRUCTION

4.6. LATERAL EARTH PRESSURE

4.7. SETTLEMENT ANALYSIS

5. CONCLUSIONS

6. APPENDICES………………………………………………………………………………..22

Appendix 1: Borehole Logs……………………………………………………………………...23

Appendix 2: Borehole Locations………………………………………………………………...33

Appendix 3: Plates of Core Boxes……………………………………………………………….35

Appendix 4: Laboratory Test Results……………………………………………………………46

Appendix 5: Stress &Settlement Analysis……………………………………………………….75

Appendix 6: Soil Profile and Elastic Property…………………………………………………...88

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LIST OF TABLES

Table 1-1 Bedrock acceleration ratio o

EBCS 8, 1995

Table 1-2 Co-ordinates of Boreholes Table 2-1 Standard Penetration Test Results Table 2-2 Laboratory test results of disturbed soil samples Table 2-3 Laboratory test results of Rock samples Table 2-4 Summary of the geotechnical investigations carried out Table 4-1 Presumptive Allowable Pressure for Different Foundation Condition

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ABBREVIATIONS

ASTM - American Society for Testing of Materials

BH - Boreholes

BS - British Standards

GWL - Ground water level kPa - Kilo-Pascal (kN/m

LL - Liquid limit m - Meters

SPT N-value- Number of blows for 300mm penetration

FMH - Federal Minster of Health

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EXECUTIVE SUMMARY

Location

The project site is located at The Minister of Health compound in Addis Ketema, sub-city, Addis

Ababa. Based on the area to be covered by the structure, five boreholes were selected for the investigation. The project site is generally characterized by flat topographical feature.

Site Geology and Subsurface Condition

Sub-surface geotechnical investigation was conducted for the building which included drilling borehole, in-situ and laboratory tests. From the investigation, five main geotechnical layers are identified. The layers are Backfill material with cobble stone cover (scoria at the top), Light brown, medium stiff to stiff, medium to high plastic silty CLAY with some sand and gravel , Gray to light brown, medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt, Light brown to dark brown, medium grained, highly to completely weathered, soft to medium strong, vesicular Basalt, Gray, fine to medium grained, strong to very strong, jointed and vesicular at the top, slightly weathered to fresh Basaltic rock. Groundwater was not encountered in all bore boles at the time of investigation.

Foundation Recommendation

Based on the visual identification, in-situ test, and laboratory test results isolated footing or mat foundation is proposed for supporting the building project. This foundation shall be safely placed at a depth of 4.50m to 5.0m and 4.0m to 4.50m from natural ground level and below for isolated and mat respectively, on the in-situ medium grained, highly to completely weathered, soft to medium strong, vesicular Basalt with significant sand around all boreholes except around BH-4 on medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt.

It is recommended to use an allowable bearing pressure 560kPa based on the anticipated superstructure load and 800Kpa around BH-4 only.

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1. INTRODUCTION

1.1. BACKGROUND

This geotechnical investigation works was conducted for Federal Ministry of Health National

Blood Transfusion Service Building. The building project is located at Federal Minister of

Health in Addis Ketema, Sub city, Addis Ababa. The proposed development consists of the construction of a ground plus three stories with basement (B+G+3) National Blood Transfusion

Service Building. This report presents the findings and results of geotechnical whose field work was carried out from August 25 to September 16, 2014.

The geotechnical investigation was carried out by core drilling, including in situ tests, such as

Standard Penetration Tests (SPT) to determine the strength of the various layers. Even though, in-situ tests could be conducted full penetration test results are not obtained due to weathered basaltic rock, and moderately weathered to fresh basaltic rock layer encountered. Moreover, it includes ground water monitoring.

This report deals with the regional geology, site geology, the methodology employed, field and laboratory tests conducted to determine the engineering properties of the subsurface strata including analyses and interpretations of test results. Finally, the report provides recommendation on the bearing layer, foundation depth, allowable bearing pressure and appropriate foundation type.

1.2. OBJECTIVES AND SCOPE OF THE WORK

The scopes of the investigations include core drilling, in situ testing, collection of representative samples and subsequent laboratory tests to determine the engineering properties and ground water measurements.

The purposes of the investigation are:

a) Determine the type and extent of geological layers;

b) Investigate the presence of ground water and identify its level if encountered;

c) Determine the engineering properties of the geotechnical layers constituting the sub-surface geology of the site;

d) Develop engineering recommendations to guide design and construction of the project.

We accomplished these purposes by:

1. Borehole drilling to explore the subsurface soil and ground water conditions;

2. Reviewing available geologic literature and soil mapping information;

3. Analyzing the field and laboratory data to develop appropriate engineering recommendation, and

4. Preparing this geotechnical investigation report

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1.3. SEISMICITY OF THE STUDY AREA

The study of seismicity of a given area is an important consideration when constructing engineering structures since earthquake forces may cause significant damage and destruction on the engineering structure.

The project traverses an area of the country defined within Zone 2 of the seismic hazard map of Ethiopia. According to past arguments, for all design of civil structures within this area, ground acceleration for Zone 2 is considered. Ground acceleration of 0.05*g is considered as low seismicity zones.

The methods of assessing likely earthquake intensity and frequency at this project site as in any given site are complex, requiring reasonable judgment and collection of geological and seismic data.

Due to this complexity for the structures with lesser magnitude, the tendency is to rely upon seismic risk maps. The maps are often published in national or state building codes, which recommend the engineering precaution to be taken in each rank of hazard in the map.

Basic information has been taken from Ethiopian Building Code standard EBCS 8-1995.

Ethiopia is divided into zones of approximately equal seismic risks based on the known distribution of past damaging earthquakes. By definition, the hazard within each zone can be assumed to be constant (Refer Table 1.1 below).

From the seismic hazard map of Ethiopia, the project site falls under zone 2 with a corresponding of no hazardous zone (no damage). This map is based on the amplitudes to be expected during 100 years return period. Zone 2 with a ground acceleration 0.05*g are considered as low seismicity zones, for which reduced or simplified seismic design procedures for certain types or categories of structures may be used.

The parameter o , the ratio of the bedrock acceleration to the acceleration of gravity depends on the seismic zone (see the table 1-1 below).

Table 1-1 Bedrock acceleration ratio o

EBCS 8, 1995

Zone 4 3 2 1 o

0.10 0.07 0.05 0.03

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Figure 1-1 Seismic hazard map of Ethiopia for 100-year return period as per EBCS 8: 1995 (pp,

14) Project Location

A recent helpful compilation of worldwide seismicity is provided by the Global

Seismic Hazard Assessment Program (GSHAP), which was launched by the International

Lithosphere Program (ILP) with the support of the International Council of Scientific

Unions (ICSU), and endorsed as a demonstration program in the framework of the

United Nations International Decade for Natural Disaster Reduction (UN/IDNDR). It had the objective of mitigating the risk associated with the recurrence of earthquakes by promoting a regionally coordinated, homogeneous approach to seismic hazard evaluation.

The major output of the GSHAP is the global seismic hazard map for a 475-year return period. As noted above, this level of hazard has been widely accepted all over the world as a design-level earthquake and incorporated in US codes for more than three decades now. In contrast, the EBCS 8, 1995 employs a return period of just 100 years. Due to this reason the code is under revision.

According to recent argument, seismic hazard map for Ethiopia prepared by the revised code using the appropriate data is given in Fig. 1-2, in which five distinct seismic regions are identified with different ranges of PGA values as shown in the legend. Note that the ratio of the PGA to the gravitational acceleration, g, corresponds to α0 - the bedrock acceleration ratio in EBCS 8.

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Figure 1-2 The seismic hazard map of Ethiopia based on the GSHAP data for a return period of

475 years Project Location

Changes introduced in recent editions of international codes as a result of such evidences are presented.

According to the new map, Addis Ababa belongs to the second most seismic zone with PGA in the range of 0.1g to 0.16g.

Soil classification is the placing of soils which exhibit similar behavior into groups and subgroups. Classification of sub soil condition is done as per EBCS-8. According to EBCS-8, 1995 pp, 8 the soil this project soil fall for class A, and B.

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1.4. EXISTING CONDITION FOR THE BUILDING SITE

The project area of the proposed site for B+G+3 Blood Transfusion Service Building is generally characterized by flat topographical feature.

Picture 1-1 Partial View of the Project Site

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1.5. LOCATION OF PROJECT SITE

The project site is located at Federal minister of health in Addis Ketema Sub city, Addis Ababa.

Based on the area to be covered by the structure, five boreholes were selected for the investigation. The co-ordinates of the exploratory boreholes measured using Total Station and handheld GPS and the depth drilled are tabulated as follows:

Table 1-2 Co-ordinates of Boreholes

1.6. SITE GEOLOGY

1.6.1. Regional Geology

Addis Ababa city is situated in the western margin of the Main Ethiopian Rift and represents a transition zone between the Ethiopian Plateau and the rift with poorly defined escarpment.

The geology of Addis Ababa area is represented by four volcanic units dominated in the lower part by basaltic lava flows (Addis Ababa basalt), followed by a pyroclastic sequence, mainly formed by ignimbrites (Addis Ababa Ignimbrite), followed by central composite volcanoes

(Central Volcanoes unit), and finally small spatter cones and lava flows (Akaki unit).

Addis Ababa basalt extensively crops out along Akaki, Kebena, and Dukem rivers at the east to southeastern part of Addis Ababa, and represents the oldest unit of the area. It consists of essentially sub-horizontal lava flows with thickness ranging from few meters up to 20m.

Maximum exposed thickness was found east of Addis Ababa, along the Kebena River. Addis

Ababa basalt is predominantly constituted by alkaline and olivine basalts with three main textural attributes, that is, porphyritic, aphyric, and sub-aphyric.

Addis Ababa Ignimbrite is exposed close to Addis Ababa along the Akaki and Kebena rivers. It overlies the Addis Ababa basalt and locally covers the products of the composite central

Borehole ID Easting Northing Elevation

(m)

Drilled depth (m) Remark

BH-1 472021.942 996456.135 2384.725 30.0

BH-2 472046.103 996453.613 2384.943 20.0

BH-3 472044.778 996413.246 2383.676 19.0

BH-4 472011.204 996417.131 2383.229 13.30

BH-5’ 472028.727 996432.377 2384.076 3.5

Drilling suspended after we intercepted the septic tank

BH-5 472025.835 996433.927 2384.079 10.20 GPS – accuracy 3.0m

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Central volcanoes unit includes the Yerer volcano and the product of the two composite volcanoes wechecha and Furi west and southeast of Addis Ababa, respectively. Wechecha and

Furi volcanoes are two large edifices composed by predominant trachyte with minor pyroclastics. Yerer represents the largest volcanic edifice in the region, with a relief of 1000m from the plain and 14km wide along east-west direction. Products mainly consist of trachytes, even if pyroclastics are widespread mainly in the central part eastern sector. The highest part of

Yerer volcano was affected by a more recent volcanic activity that produces spatter cones and associated basalt.

Akaki unit crops out east of Addis Ababa and consists of scoria and spatter cones with associated tabular lava flows and phreato-magmatic deposits. Alluvial deposits covering these units consists of regolith, reddish brown soils, talus and alluvium with maximum thickness of about two meters.

Figure 1 3 Geological map of Addis Ababa by Asseged Getahun, Mulugeta H/Mariam and Kifle Mariam Gashaw (2007)

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1.6.2. Local/Site Geology

Backfill material with cobble stone cover (scoria at the top) and grass root layer covers the top part of the project area around all bore holes. This soil layer extends to a maximum depth of

0.70m, 1.0m, 0.65m,0.80m,0.40m,0.40m in BH-1, BH-2, BH-3, BH-4, BH-5’ and BH-5 respectively.

Light brown, medium stiff to stiff, medium to high plastic silty CLAY with some sand and gravel layer is found underlying the top layer of the project area around all bore holes. This soil layer extends from depth of in 0.70m to 2.0m, 1.0m to 2.20m , 0.65m to 4.0m , 0.80m to 2.0m, 0.40m to 1.60m and 0.40m to 3.0m in BH-1,BH-2,BH-3,BH-4,BH-5’,and BH-5 respectively.

Gray to light brown, medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt found underling the top layers of project area around some of the bore holes. This fractured rock layer extends from depth of 2.0m to 4.0m, 9.30m to 13.35m and

17.60m to 19.0m in BH-1, 8.90m to 11.20m and 15.30m to 19.0m in BH-3, 4.0m to 5.0m and

8.70m to 13.0m in BH-4, 1.60m to 3.50m in BH 5’, and from 5.30m to 10.20m in BH-5.

Light brown to dark brown, medium grained, moderately to highly and completely weathered, soft to medium strong, vesicular Basalt is also encountered around all bore holes. This soil layer extends from depth of 4.0m to 9.30m, 13.35m to 17.60 and 19.0m to 27.30m in BH-1, 2.20m to

17.0m in BH-2, 4.0m to 8.90m and 11.20m to 15.30 in BH-3, 5.0m to 8.70m in BH-4, and from

3.0m to 5.30m in BH-5.

Gray, fine to medium grained, strong to very strong, jointed and vesicular at the top, slightly weathered to fresh Basaltic rock is encountered around some of the bore holes. This rock layer extends from depth of 28.75m and 17.0m all the way to the bottom in BH-1 and BH-2 respectively.

The detailed geological strata are presented in the borehole logs attached with this report

(Appendix 1).

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2. METHODOLOGY

2.1. DRILLING

The site investigation was conducted by deploying one Spindle type China made XYT-200 core drilling rig having the capacity to perform boring operations to the required standard and quality.

Dry drilling method was carried out in soil formations using single core barrels fitted with appropriate size tungsten carbide bits at the bottom. This will enable the drilling to achieve good quality core recovery. In rocky section, double core barrel fitted with diamond bit was utilized.

Water was pumped down to the bit through hollow drill rods to lubricate the bit and flushing the cuttings up the borehole.

Equipment to conduct in situ tests and sampling such as SPT apparatus including split spoon sampler, Shelby tubes, water pump, rods, casings and a wide range of heavy-duty tools were used during the drilling operations.

2.2. IN SITU TESTS AND SAMPLING

2.2.1. In Situ Tests

Even though, the test results indicated refusal; few standard Penetration Test (SPT) were conducted inside boreholes using a standard hammer, weighing 63.5kg falling freely from a height of 760mm along a frictionless guide rod in accordance with test procedure mentioned in test No. 19 of BS 1377; 1975. Blow counts for a total penetration depth of 450mm from the bottom of a cleaned borehole were not obtained due to geological formation (weathered rock).

Counts for the first 150mm penetration were discarded since the ground is considered to be disturbed during drilling activity prior to the test. SPT N-values for the last 300mm penetration were taken.

In situ field testing was carried starting from 3.0m depth from natural ground level. The SPT test results are summarized and presented in the following Table.

Table 2-1 Standard Penetration Test Results

BH-ID Depth (m) SPT Site Record

SPT N value for

100mm penetration

BH-1

5.00 R 50*

7.00 R 50*

9.00 R 50*

BH-2

3.00 R 50*

5.00 R 50*

7.00 R 50*

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BH-ID Depth (m) SPT Site Record

SPT N value for

100mm penetration

9.00 R 50*

BH-3

3.0 R 50*

5.00 R 50*

7.00 R 50*

9.00 R 50*

BH-4

3.0 R 50*

5.00 R 50*

7.00 R 50*

9.00 R 50*

BH-5 5.0 R 50*

* Refusal values (SPT N > 50)

The values obtained from field tests are equivalent with the assumed SPT N values for fractured rock layer (according to Handbook of Geotechnical Investigation and Design Tables, 2007, By

Burt G. Look, Table 6.4, pp. 67).

2.3. SAMPLING

A total of thirteen disturbed representative soil and four Rock samples were collected (in accordance with ASTM D 4220) from the five boreholes sunk to determine the geotechnical properties.

2.4. LABORATORY TESTING

Representative soil samples collected from the boreholes were taken to EDGE/ZEHA Soil and

Construction Materials Laboratory and subjected to different kind of quantitative and qualitative tests. The method of packing, storing and transportation was in accordance with the technical specifications ASTM to ensure minimum damage and disturbance. However, samples from BH-

4 and BH-5 at the top layer are not collected because the foundation material is dominantly rock layer.

The laboratory testing for disturbed soil samples include sieve analyses and Atterberg Limits.

The procedures followed for each type of test is mentioned in the respective tests results provided in Appendix-4 (i.e., laboratory test results).

Summary of laboratory test results on disturbed samples and rock samples are presented in Table

2-2 and 2-3 and details in Appendix-4.

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Table 2-2 Laboratory test results of disturbed soil samples

BH-ID Depth (m) Sieve Analysis Atterberg Limit Soil Type as

Unified Soil

Classification

Description

4.75 2.00 0.425 0.075 LL PI

BH 1-1 4.50-5.00 77.09 73.54 60.88 44.53 57 25 SC

S u b su rf a ce s a m p le s o b ta in ed d u ri n g t h e si te i n v e st ig a ti o n w er e w ea th er e d b ed ro ck

A ft er g ra d a ti o n a n d A tt er b er g

L im it s ev a lu a ti o n s o f th e d is tu rb ed w e a th er e d b ed ro ck sa m p le s, t h e sa m p le s a re c la ss if ie d fo r th e m o st p a rt a s S il ty

/c la y ey

S a n d a n d g ra v el s

BH 1-2 6.50-7.00 49.44 41.81 29.40 18.60 58 27 GC

BH 1-3 13.25-13.60 74.90 66.57 43.53 28.88 51 22 SC

BH 1-4 15.00-15.50 86.15 79.62 58.32 41.13 64.5 30 SC

BH 1-5 22.00-22.50 99.07 89.92 53.03 22.59 88 38 SC

BH 2-1 3.00-3.50 97.97 88.95 73.85 51.10 60.5 29 MH

BH 2-2 6.00-6.50 99.99 94.76 73.09 53.41 78 78 MH

BH 2-3 8.50-9.00 99.95 98.84 84.19 68.06 85 85 MH

BH 2-4 10.00-10.50 99.96 99.48 83.76 63.53 73 73 MH

BH 3-1 2.50-3.00 99.13 95.18 74.36 48.46 64 26 SC

BH 3-2 4.50-5.00 96.86 94.22 77.46 53.97 55 21 MH

BH 3-3 13.00-13.50 78.02 71.40 56.36 42.31 52.5 20 SC

BH 4-1 2.00-2.50 50.07 45.72 40.24 33.42 55.3 29 GC

Figure 2-1 Plasticity Chart for Soil Classification Based on USCS

0 20 40 60 80 100 120

P I

LL (%)

Soil classification based on the USCS

Series1

Black Cotton Soils

LL

CH

CL

OH

or

OL

or

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Table 2-3 Laboratory test results of Rock samples

Sr.

NO

Borehole

ID

Sample depth [m]

Area of

Sample

(m²)

Compressive

Strength

(KN)

Compressive

Strength

(MPa)

Unit

Weight

(g/cm3)

1 BH-1-1 11.10-11.50 0.000464953 48.39 104.07 2.26

2 BH-1-2 17.80-19.00 0.000464953 162.94 350.44 2.71

3 BH-3-1 18.50-19.00 0.000464953 133.11 286.29 2.66

4 BH-5-1 5.30-5.70 0.000464953 148.03 318.38 2.69

2.5. SUMMARY

The following table summarizes the in-situ tests and laboratory test conducted on the site while the geotechnical investigation was being carried out.

Table 2-4 Summary of the geotechnical investigations carried out

Geotechnical investigations carried out Quantity

Drilling to a maximum 10.0m depth below the ground level 50.0m

Drilling in all formation 10– 20 33.50m

Drilling in all formation 20 – 30 10.0m

Standard Penetration Test(Gravel and sand all Refusal with boulder) 16

Laboratory tests/analyses

Atterberg Limits 13

Grain size analysis 13

Natural Moisture Content 20

Unconfined compression 4

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3. GEOTECHNICAL CHARACTERISTICS OF SUB-SURFACE

LAYERS

3.1. DESCRIPTION OF GEOTECHNICAL LAYER

Descriptive analysis is made on the soil and rock layers identified from the five bore holes sunk.

Visual description of core sample and in-situ tests results of representative sample reveal the occurrence of the following geotechnical layers. Details on type and extent of the geotechnical layers are given in Appendix 1 (Borehole logs).

3.1.1. Layer 1: Backfill material with cobble stone and grass covers (scoria at the top)

Backfill material with cobble stone cover (scoria at the top) and grass root layer covers the top part of the project area around all bore holes. This soil layer extends to a maximum depth of

0.70m, 1.0m, 0.65m,0.80m,0.40m,0.40m in BH-1, BH-2, BH-3, BH-4, BH-5’ and BH-5 respectively.

3.1.2. Layer 2: Light brown, medium stiff to stiff, medium to high plastic silty CLAY with some sand and gravel

Light brown, medium stiff to stiff, medium to high plastic silty CLAY with some sand and gravel layer is found underlying the top layer of the project area around all bore holes. This soil layer extends from depth of in 0.70m to 2.0m, 1.0m to 2.20m , 0.65m to 4.0m , 0.80m to 2.0m, 0.40m to 1.60m and 0.40m to 3.0m in BH-1,BH-2,BH-3,BH-4,BH-5’,and BH-5 respectively.

3.1.3. Layer 3: Gray to light brown, medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt

Gray to light brown, medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt found underling the top layers of project area around some of the bore holes. This fractured rock layer extends from depth of 2.0m to 4.0m, 9.30m to 13.35 and 17.60m to 19.0m in BH-1, 8.90m to 11.20m and 15.30m to 19.0m in BH-3, 4.0m to 5.0m and 8.70m to

13.0m in BH-4, 1.60m to 3.50m in BH 5’, and from 5.30m to 10.20m in BH-5.

3.1.4. Layer 4: Light brown to dark brown, medium grained, highly and completely weathered to moderately, soft to medium strong, vesicular Basalt

Light brown to dark brown, medium grained, highly and completely weathered to moderately, soft to medium strong, vesicular Basalt is also encountered around all bore holes. This soil layer extends from depth of 4.0m to 9.30m, 13.35m to 17.60 and 19.0m to 27.30m in BH-1, 2.20m to

17.0m in BH-2, 4.0m to 8.90m and 11.20m to 15.30 in BH-3, 5.0m to 8.70m in BH-4, and from

3.0m to 5.30m in BH-5.

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3.1.5. Layer 5: Gray, fine to medium grained, strong to very strong, jointed and vesicular at the top, slightly weathered to fresh Basaltic

Gray, fine to medium grained, strong to very strong, jointed and vesicular at the top, slightly weathered to fresh Basaltic rock is encountered around some of the bore holes. This rock layer extends from depth of 28.75m in BH-1 and from 17.0m in BH-2 and extends to maximum drilling.

The result of the grain size analysis, Atterberg limits, and free swell could be referred in Table 2-

2; the rock compressive strength could be referred in Table 2-3 and Appendix-4 of this report.

The results are not summarized under each layer due to the descriptiveness of the layer naming.

3.2. GROUNDWATER OBSERVATION

During the course of the drilling, groundwater was not encountered in all boreholes. However, variation in the location of the long-term water table may occur as a result of changes in precipitation, evaporation, seepage and other factors not immediately apparent at the time of this exploration. If water is encountered, Pumping from sumps or other dewatering means may be utilized to control water within excavations.

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4. FOUNDATION RECOMMENDATIONS

Foundation recommendation refers to the determination of the bearing layer and depth, allowable pressure on the bearing layer and type of foundation that could be adopted safely and economically. This process requires both site investigation works and desktop studies.

The geotechnical investigation work included bore hole drilling, in-situ and laboratory tests, identification and sampling of soils, ground water measurements and collection of other relevant data. On the other hand, the desk study encompassed referring materials related to the specific site condition and project. The previous sections gave detail discussion regarding the geotechnical investigations.

The laboratory test results and field observation around BH-2 and BH-3 (but thickness below proposed depth is very thin) shows that the foundation layer may not undergo volume change upon wetting and drying, as we observed from free swell result (less than 50%).

4.1. DETERMINATION OF FOUNDATION TYPE AND DEPTH

Even though, in situ tests could be conducted, full test penetration depth couldn’t be obtained due to the prevailing geological conditions below the proposed depth, consequently allowable bearing pressures for the selected foundation layers shall be discussed based on the presumptive bearing pressures values recommended by different codes and design manuals, for different type of foundation materials and consistency.

As it can be observed from the detailed geotechnical logging, the subsurface formation of the project site which comprises of dominantly weathered vesicular basalt and when tested for their gradation and Atterberg Limits characteristics, and the results were similar to soils that classify as Silty/clayey Sand and gravels underlain by Gray, fresh to slightly weathered and closely jointed Basalt Rock material that is grouped into different geotechnical layers based on visual description and lab results.

An isolated footing or Mat foundation on an in-situ medium grained, highly to completely weathered, soft to medium strong, vesicular Basaltic with significant sand (around all boreholes except BH-4) and medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt (only around BH-4) are considered for analysis and selected to support the proposed structure. Placing the foundation at least 4.50m to 5.0m and 4.0m to 4.50m depth from the lowest natural ground level for isolated and mat foundations respectively, is required to accommodate the need for basement construction.

EDGE Consult Enterprise 17 National Blood Transfusion Service Building

4.2. ISOLATED OR MAT ON MEDIUM GRAINED, MODERATELY TO HIGHLY AND COMPLETELY

WEATHERED, SOFT TO MEDIUM STRONG, VESICULAR BASALT WITH SIGNIFICANT SAND

AROUND ALL BOREHOLES EXCEPT AROUND BH4 ON MEDIUM GRAINED, SLIGHTLY TO

MODERATELY WEATHERED, MEDIUM STRONG TO STRONG, VESICULAR BASALT

The upper layers of the project site are made up of Light brown, medium stiff to stiff, medium to high plastic silty CLAY with some sand and gravel layers up to 2.20m depth. The top layer up to

4.50m or 4.0 depths based on type of foundation should be excavated since the layer is needed for basement construction. The foundation system can be placed at an average depth of 4.0m below the lowest natural ground level on the medium grained, moderately to highly and completely weathered, soft to medium strong, vesicular Basaltic with significant sand.

Table 4-1 Presumptive Allowable Pressure for Different Foundation Condition

* Depth of ground water is assumed to be not less than B below the base of foundation, where B is width of foundation.

According to Ethiopian Building Code of Standard for Foundations (EBCS 7 1995), for medium grained, moderately to highly and completely weathered, soft to medium strong, vesicular

Basaltic with significant sand and medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt, a minimum presumed design bearing resistance of 560kPa and

1400kPa respectively, is allowed. According to Naval Facilities Engineering Command

(NAVFAC) Design Manual 7.02, 1986, a presumed design bearing resistance of 600kPa and

800kPa can be taken for spread footing.

Type of Bearing Material Consistency in place

Recommended Allowable

Bearing Pressure (kPa)

ORN 9 EBCS 7 NAVFAC

Massive igneous and metamorphic rock (basalt, granite, gneiss)

Hard and sound 10,000 5,600 7,600

Foliated metamorphic rock and sedimentary rocks (un-weathered)

Medium hard and sound 4,000 2,800 3,300

Weathered or broken bed rock of any kind

Soft rock 1,500 1,400 800

Gravel, gravel-sand mixtures, boulder gravel mixtures, and sand with little gravel

[Non-cohesive Soils]

-Dense/very compact

-Medium dense

- Loose

Clay

[Cohesive Soils]

Silt

-Hard

-Stiff

-Hard

-Stiff

EDGE Consult Enterprise 18 National Blood Transfusion Service Building

Thus, the lower allowable bearing value of 560kPa around all boreholes except around BH4 which is 800kPa shall be taken as allowable bearing capacity for the proposed building at foundation depth of 4.50m to 5.0m or 4.0m to 4.50m below the natural ground level for isolated or mat foundation respectively.

4.3. RECOMMENDATION FOR DESIGN AND CONSTRUCTION

4.4. EARTH WORK

All topsoil, debris, organics, and other deleterious materials should be removed from the areas of proposed structures, fills, pavements, and slab areas. Exposed surfaces should be free of mounds and depressions which could prevent uniform compaction. If unexpected fills or underground facilities are encountered during site clearing, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction. All excavations should be observed by the geotechnical engineer prior to fill placement. Stripped materials consisting of vegetation and organic materials should be wasted from the site or used to revegetate landscape areas after completion of grading operations. Exposed subgrade areas which will support fill, floor slabs and/or pavement, once properly cleared, should be scarified to a minimum depth of 20cm, conditioned to near optimum moisture content and properly compacted since this fill used where rock stratum is encountered in this site.

It is anticipated that excavations into the in-situ soil can be accomplished with conventional earthmoving equipment. The excavations around BH-1 and BH-4 and BH-5 above the foundation level need to penetrate into the bedrock, and ripping may be required. Jack-hammering may be needed to advance the excavation, particularly if hard fresh Vesicular basalt is encountered.

For slopes in these areas, recommended maximum slope angles of 2:1 (horizontal to vertical) for in-situ materials are recommended. The foundation material is good and the depth of excavation is very shallow, thus the slope cut ratio provided is to remove construction uncertainty but it is also possible to cut vertical slopes.

4.5. SLAB CONSTRUCTION

Since medium to high plastic clayey SAND/GRAVEL (weathered vesicular basaltic rock) is present in this project, it is recommended to place 20cm thick low plastic engineering fill

(selected fill) beneath slab on grade floor.

Slab-on-grade foundations will be placed on selected structural fill/on the in situ material with a subgrade support modulus ks =40*F.S*qa

Where, F.S factor of safety for bearing capacity let us assume 3.0 qa allowable bearing pressure of soil=560kPa

EDGE Consult Enterprise 19 National Blood Transfusion Service Building

Then ks=40*F.S*qa =40*3*560=67200kN/m

4.6. LATERAL EARTH PRESSURE

It is common to define the active earth pressure loading in terms of equivalent fluid pressure such as 40 pcf for ease of calculation. Many design codes define minimum equivalent fluid pressures as a means for establishing a simple retaining wall design criteria without site specific analysis. Since an active earth pressure calculation without considering surcharges or complex loadings yields a simple triangular earth pressure distribution, the similarity to a fluid pressure analysis at some equivalent weight is reasonable. An allowable coefficient of sliding friction (for concrete cast against soil) of 0.35 can be used for design. An active earth pressure (based on level backfill) of 45 pcf is recommended as an equivalent fluid unit weight and assuming the use of the on-site lean clay soils. An at-rest earth pressure (based on level backfill) of 60 pcf is recommended. A passive earth pressure (based on level backfill) of 225 pcf is recommended.

Lateral wall movements or rotation of at least 0.5% of the wall height are typically required to develop the full active case, while lateral movement of at least 1% of the wall height is normally required to establish the full passive case for granular backfill. Suitable factors of safety should be included in the design to limit the strain which will occur at the ultimate strength, particularly for passive resistance. The lateral earth pressures presented herein are not applicable for submerged soils.medium to high plastic clayey SAND/GRAVEL (weathered vesicular basaltic rock) is present in this project, it is recommended to place 20cm thick low plastic engineering fill

(selected fill) beneath slab on grade floor.

4.7. SETTLEMENT ANALYSIS

Settlement is another criterion for evaluating the performance of structure because excessive settlements will result in poor performance of the structure. Different codes set the limiting settlement for the type of the structure and foundations. The proposed foundation shall meet this criterion.

Different kinds of settlements occur under structure in which the major ones are immediate and consolidation settlements. These settlements depend on a number of parameters as well as type of soils.

Even though material is clayey SAND/clayey SILT we can’t retrieve undisturbed sample because the soil is found intermingled with boulders and is cohesion-less as the major constituent is SAND/SILT [Subsurface samples obtained during the site investigation were weathered bedrock. After gradation and Atterberg Limits evaluations of the disturbed weathered bedrock samples, the samples classified, for the most part, as Silty Sands]. Under such soil profiles, it is clear that immediate settlement is governing and we carried out analysis for immediate settlement however this doesn’t mean that there is no long term consolidation but it means that it is insignificant.

EDGE Consult Enterprise 20 National Blood Transfusion Service Building

Due to this reason settlement check for the project is done by considering the clayey

SILT/Clayey SAND (weathered vesicular basalt) soil layer beneath the foundation. This layer extends up to a maximum depth drilled around BH 2. For the soil type under consideration, settlement contributed by immediate settlement is considered.

The immediate settlement according to (Bowles, 1997)

Where qo = intensity of contact pressure in units of Es

B' = least lateral dimension of contributing base area in units of

∆H

Ii = influence factors, which depend on L'/B', thickness of stratum H, Poisson's ratio µ, and base embedment depth D see

Tables and chart on (Bowles, 1997)

ES, µ = elastic soil parameters—see Tables on (Bowles, 1997)

According to Bowles (1997) for Silts, sandy silt, or clayey Silt

Es = 300(24 + 6)

= 9000kPa

Where N is the corrected SPT blow count taken as 24 (average value computed from allowable bearing capacity for mat and isolated as stated on Appendix-5) µ = 0.3 is taken for the clayey SAND/SILT soil.

The detail calculation for settlement and the data used for calculating are attached in Appendix-5 of this report. The actual loads are considered in the analysis.

Total Load under ULS=105813kN

Maximum column load=3026kN

For isolated footings, a total settlement of 50 mm is allowable in EBCS-7 (1995) code. Bowles

(1997) gives a margin up to 75 mm while U.S. Army Corps of Engineers (1990) recommends

100 mm allowable settlement. The immediate settlements computed are in the range of the values provided in the prevailing codes.

For mat footings, Bowles (1997) gives a margin up to 125 mm while U.S. Army Corps of

Engineers (1990) recommends 100 mm allowable settlement. The immediate settlements computed are in the range of the values provided in the prevailing codes.

July, 2015

EDGE Consult Enterprise 21 National Blood Transfusion Service Building

5. CONCLUSIONS

Sub-surface geotechnical investigation for a ground plus three with basement (B+G+3) Federal

Ministry of Health National Blood Transfusion Service Building was conducted using rotary core drilling. Visual identification and logging were conducted. From the investigation, the following geotechnical layers are identified in the different layers.

Backfill material with cobble stone cover (scoria at the top);

Light brown, medium stiff to stiff, medium to high plastic silty CLAY with some sand and gravel;

Gray to light brown, medium grained, slightly to moderately weathered, medium strong to strong, vesicular Basalt with significant sand;

Light brown to dark brown, medium grained, highly to completely weathered, soft to medium strong, vesicular Basalt, and

Gray, fine to medium grained, strong to very strong, jointed and vesicular at the top, slightly weathered to fresh Basaltic rock

Two options of shallow foundation systems are considered to support the proposed structure.

Only shear strength criteria are used to evaluate the recommended allowable bearing capacity and corresponding values are given in section 4 above. The foundation designer can use any of the recommended options depending on the superstructure loads.

The Geotechnical Engineer in charge shall conduct intermittent supervision of the foundation excavation works during construction to verify/check the actual subsurface conditions, and shall make adjustments to the foundation recommendation given in this report, where actual site conditions warrant such changes.

July, 2015

EDGE Consult Enterprise National Blood Transfusion Service Building

APPENDICES

July, 2015

EDGE Consult Enterprise National Blood Transfusion Service Building

Appendix 1:

Borehole Logs

EDGE CONSULT ENTERPRISE

CONSULTING ARCHITECTS & ENGINEERS

Yonas Typewriter

Yonas Typewriter R=Refusal (50/100mm)

Yonas Typewriter

Yonas Typewriter

Yonas Typewriter

Yonas Typewriter

Yonas Typewriter R=Refusal (50/100mm)

Yonas

Yonas Typewriter Light brown to dark brown, medium grained, highly and completely weathered to moderately, soft to medium strong, vesicular Basalt

Yonas

R=Refusal (50/100mm)

Rad Typewritten text

Yonas

July, 2015

EDGE Consult Enterprise National Blood Transfusion Service Building

Appendix 2:

Borehole Locations

July, 2015

EDGE Consult Enterprise National Blood Transfusion Service Building

Appendix 3:

Plates of Core Boxes

Geotechnical Investigation of B+G+3 National Blood Transfusion Service Building

October, 2014

EDGE Consult Enterprise 1 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 1: BH-1, Depth: 0.00 – 5.00m, Box: 1 of 6

Plate 2: BH-1, Depth: 5.00-10.00m, Box: 2 of 6

October, 2014

EDGE Consult Enterprise 2 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 3: BH-1, Depth: 10.0 - 15.00m, Box: 3 of 6

Plate 4: BH-1, Depth: 15.00 - 20.00m, Box: 4 of 6

October, 2014

EDGE Consult Enterprise 3 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 5: BH-1, Depth: 20.00 - 26.0m, Box: 5 of 6

Plate 6: BH-2, Depth: 26.00 – 30.00m, Box: 6 of 6

October, 2014

EDGE Consult Enterprise 4 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 7: BH-2, Depth: 0.00 - 5.00m, Box: 1 of 4

Plate 8: BH-2, Depth: 5.00 - 10.00m, Box: 2 of 4

October, 2014

EDGE Consult Enterprise 5 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 9: BH-2, Depth: 10.00 - 15.00m, Box: 3 of 4

Plate 10: BH-2, Depth: 15.00 – 20.00m, Box: 4 of 4

October, 2014

EDGE Consult Enterprise 6 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 11: BH-3, Depth: 0.00 - 5.00m, Box: 1 of 4

Plate 12: BH-3, Depth: 5.00 - 10.00m, Box: 2 of 4

October, 2014

EDGE Consult Enterprise 7 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 13: BH-3, Depth: 10.00 - 16.00m, Box: 3 of 4

Plate 14: BH-3, Depth: 16.00 – 19.00m, Box: 4 of 4

October, 2014

EDGE Consult Enterprise 8 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 15: BH-4, Depth: 0.00 - 5.00m, Box: 1 of 3

Plate 16: BH-4, Depth: 5.00 – 10.00m, Box: 2 of 3

October, 2014

EDGE Consult Enterprise 9 of 10 National Blood Transfusion Service Building _Plate Photos

Plate 16: BH-4, Depth: 10.00 - 13.30m, Box: 3 of 3

Plate 17: BH-5, Depth: 0.00 – 4.80m, Box: 1 of 2

October, 2014

10 of 10 National Blood Transfusion Service Building_Plate PhotosEDGE Consult Enterprise

Plate 18: BH-5, Depth: 4.80 - 10.00m, Box: 2 of 2

Plate 19: BH-5’, Depth: 0.00 – 3.50m, Box: 1 of 1

July, 2015

EDGE Consult Enterprise National Blood Transfusion Service Building

Appendix 4:

Laboratory Test Results

Sr. FS

No. 50 37.5 25.0 19.0 12.5 9.5 4.75 2.0 0.425 0.075 LL PI

(mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (%) (%) (%)

1 BH 1-1 4.50-5.00 _ 100.00 92.49 85.64 82.45 80.49 77.09 73.54 60.88 44.53 57 25 SC 22.9 32.6 44.5 _

2 BH 1-2 6.50-7.00 100.00 86.59 69.48 62.79 62.22 56.72 49.44 41.81 29.40 18.60 58 27 GC 50.6 30.8 18.6 _

3 BH 1-3 13.25-13.60 _ 100.00 84.83 82.81 81.94 79.28 74.90 66.57 43.53 28.88 51 22 SC 25.1 46.0 28.9 _

4 BH 1-4 15.00-15.50 _ 100.00 93.72 90.99 90.17 89.52 86.15 79.62 58.32 41.13 64.5 30 SC 13.8 45.0 41.1 _

5 BH 1-5 22.00-22.50 _ _ _ _ _ 100.00 99.07 89.92 53.03 22.59 88 38 SC 0.9 76.5 22.6 _

6 BH 2-1 3.00-3.50 _ _ _ _ _ 100.00 97.97 88.95 73.85 51.10 60.5 29 MH 2.0 46.9 51.1 30

7 BH 2-2 6.00-6.50 _ _ _ _ _ 100.00 99.99 94.76 73.09 53.41 78 78 MH 0.0 46.6 53.4 _

8 BH 2-3 8.50-9.00 _ _ _ _ _ 100.00 99.95 98.84 84.19 68.06 85 85 MH 0.0 31.9 68.1 20

9 BH 2-4 10.00-10.50 _ _ _ _ _ 100.00 99.96 99.48 83.76 63.53 73 73 MH 0.0 36.4 63.5 _

10 BH 3-1 2.50-3.00 _ _ _ _ _ 100.00 99.13 95.18 74.36 48.46 64 26 SC 0.9 50.7 48.5 _

11 BH 3-2 4.50-5.00 _ _ _ 100.00 97.39 97.02 96.86 94.22 77.46 53.97 55 21 MH 3.1 42.9 54.0 _

12 BH 3-3 13.00-13.50 _ 100.00 90.79 89.54 87.81 84.39 78.02 71.40 56.36 42.31 52.5 20 SC 22.0 35.7 42.3 _

13 BH 4-1 2.00-2.50 78.94 78.94 62.93 60.89 58.98 55.66 50.07 45.72 40.24 33.42 55.3 29 GC 49.9 16.6 33.4 _

REPORTED BY APPROVED BY:

CLIENT TETRA TECH EM,INC.

PROJECT

LAB. NO. TP-ZE/ED/514/14

REPORTED ON 25/09/2014

GEOTECHNICAL ENGINEERING SERVICE

Tel: +251-913 543357/ +251-11-8504653/54;

E-mail: edgeconsult93@gmail.com or edulgg@yahoo.com, P. O. Box 40782; Addis Ababa, Ethiopia

B+G+3 Federal Ministry of Health National Blood Transfusion Service Building

High plastic clayey SAND with some gravel

High plastic clayey SAND with trace of gravel

High plastic gravely clayey

SAND

High plastic clayey GRAVEL with some sand

High plastic clayey SAND with trace of gravel

High plastic clayey sandy SILT with trace of gravel

%SAND %FINE

High plastic clayey sandy SILT with trace of gravel

High plastic clayey sandy SILT

High plastic clayey sandy SILT

High plastic clayey sandy SILT

Classifi cation

%GRAVEL

High plastic clayey sandy

GRAVEL

High plastic gravely clayey

SAND

ASTM D 4318

USCS

High plastic gravely clayey

SAND

SUMMARY OF LABORATORY TEST RESULTS

BH Depth Soil Description

Grain Size Analysis ASTM D 422 Atterberg Limits

UCS

Sr. NO Borehole ID SAMPLE

DEPTH [M]

Area of Sample (m²)

Compressive Strength (KN)

Compressive Strength (MPa)

Unit Weight (g/cm3)

1 BH-1-1 11.10-11.50 0.000464953 48.39 104.07 2.26

2 BH-1-2 17.80-19.00 0.000464953 162.94 350.44 2.71

3 BH-3-1 18.50-19.00 0.000464953 133.11 286.29 2.66

4 BH-5-1 5.30-5.70 0.000464953 148.03 318.38 2.69

REMARKE :

REPORTED BY: APPROVED BY:

CLIENT :

PROJECT :

TEST OBJECT :

GEOTECHNICAL ENGINEERING SERVICELAB. NO : SPT-ZE/ED/514/14

SAMPLE SOURCE : BH-1,BH-3 & BH-5

SAMPLE DEPTH[M] _

TEST FOR : UCS

REPORTED ON : 25/09/2014

Tel: +251-913-543357/ +251-11-8504653/54;

E-mail: edgeconsult93@gmail.com or edulgg@yahoo.com, P. O. Box

40782; Addis Ababa, Ethiopia

TEST RESULT OF UNCONFINED COMPRESSIVE STRENGTH

TETRA TECH EM,INC.

2B+G+4 National Blood Transfusion Office Complex Building

CONSULTING ARCHITECTS &

Tetra Tech Em,N_Lab Result

No. Blows 34 36 19 Wt. wet soil (g.) 19.36 22.54 19.95 2.00 1.83 Wt. dry soil (g.) 12.48 14.35 12.62 1.51 1.40 Moisture content (%) 55.13 57.07 58.05 32.45 30.71

AV. PL (%) 31.6

2mm 0.425mm 0.075mm 74 61 45

REPORTED BY APROVED BY

CLIENT : TETRA TECH EM,INC.

PROJECT :

TEST OBJECT : Disturbed soil

LAB. NO. : SPT-ZE/ED/514/14

SAMPLE SOURCE : BH-1-1

SAMPLE DEPTH : 4.50-5.00

TEST FOR : Atterberg Limits Analysis

REPORTED ON : 25/09/2014

57.00 32 25

GEOTECHNICAL ENGINEERING SERVICE

Tel: +251-913-543357/ +251-11- 8504653/54;

E-mail: edgeconsult93@gmail.com or edulgg@yahoo.com, P. O. Box 40782;

Addis Ababa, Ethiopia

Liquid Limit Plastic Limit Plasticity Index

B+G+3 Federal Ministry of Health National Biood Transfusion Service Building

WET SEIVE ANALYSIS, % PASS

LL(%) PL(%) PI

LIQUID AND PLASTIC LIMITS TEST REPORT

ASTM D 4318

LIQUID LIMIT PLASTIC LIMIT

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

M O

IS

TU

RE

C

ON

TE

NT

NO. OF BLOWS

Series1

Series2

Series3

ASTM D 422

SIEVE SIZE % Soil Description

(MM.) PASSED

9.50 100.00

4.75 77.09

2.000 74 Atterberg Limit

0.425 61 LL 57

0.075 45 PI 25

Classification

USCS SM

AASHTO A-7-5(3)

REPORTED BY APROVED BY

CLIENT : TETRA TECH EM,INC.

PROJECT :

TEST OBJECT : Disturbed soil

GEOTECHNICAL ENGINEERING SERVICE LAB. NO : SPT-ZE/ED/514/14

SAMPLE SOURCE : BH-1-1

SAMPLE DEPTH [M] : 4.50-5.00

TEST FOR : Sieve Analysis

REPORTED ON : 25/09/2014

Tel: +251-913-543357/ +251-11-8504653/54;

E-mail: edgeconsult93@gmail.com or edulgg@yahoo.com, P. O. Box 40782; Addis Ababa, Ethiopia

% COBBLE % GRAVEL % SAND % FINE

- 3.40 29.01 44.53

B+G+3 Federal Ministry of Health National Biood Transfusion Service Building

Low plastic Sandy SILT with trace of gravel

PARTICLE SIZE DISTRIBUTION REPORT

0.00

20.00

40.00

60.00

80.00

100.00

0.010.101.0010.00

P A S

PARTICLE SIZE IN mm

PARTICLE SIZE DISTRIBUTION CURVE

EDGE CONSULT ENTERPRISE

ENGINEERS

No. Blows 31 24 19 Wt. wet soil (g.) 19.78 20.98 19.04 1.96 1.95 Wt. dry soil (g.) 12.58 13.20 11.91 1.51 1.47 Moisture content (%) 57.23 58.94 59.87 29.80 32.65

AV. PL (%) 31.2

2mm 0.425mm 0.075mm 42 29 19

REPORTED BY APROVED BY

CLIENT : TETRA TECH EM,INC.

PROJECT :

TEST OBJECT : Disturbed soil

LAB. NO. : SPT-ZE/ED/514/14

SAMPLE SOURCE : BH-1-2

SAMPLE DEPTH : 6.50-7.00

TEST FOR : Atterberg Limits Analysis

REPORTED ON : 25/09/2014

58.00 31 27

GEOTECHNICAL ENGINEERING SERVICE

Tel: +251-913-543357/ +251-11- 8504653/54;

E-mail:…