Ethio Construction Engineering

👉In road construction surveying, "As-Built" surveys and "Blue Top" surveys serve different purposes at different stages of the project.

💫Here’s the key difference:

🏷1. As-Built Survey

- Purpose: Documents the final constructed conditions of the road, verifying that the work matches the design plans. 
- When Performed: After construction is completed. 
- Details Recorded: 
  - Final elevations, alignments, and locations of road features (pavement, utilities, drainage, etc.). 
  - Any deviations from the original design. 
- Use: For legal records, future maintenance, and compliance verification. 

🏷2. Blue Top Survey

- Purpose: Provides precise grade control just before paving to ensure the final surface meets design elevations. 
- When Performed: After subgrade preparation but before placing the final pavement layer. 
- Details Marked: 
  - Surveyors set "blue tops" (stakes or marks with blue paint) indicating the exact elevation for the top of the upcoming pavement (usually asphalt or concrete). 
- Use: Guides contractors in achieving the correct road profile and smoothness. 

❇️Key Difference:

- Blue Top is a pre-paving control survey to guide construction. 
- As-Built is a post-construction verification survey to confirm accuracy. 

🎲Both are critical for quality control but serve different phases of road construction.

@etconp

💫PART 2

🏷Procedure for Sieve Analysis

1. Prepare Sample: Take a 500g – 1000g representative dry sample.

2. Arrange Sieves: Stack sieves in descending order, from largest to smallest, with a pan at the bottom.

3. Weigh Initial Sample: Record the total weight before sieving.

4. Sieve the Material: Shake for 10-15 minutes manually or mechanically.

5. Weigh Retained Material: Weigh the material retained on each sieve.

6. Calculate Percentage Retained:

Cumulative % retained = Sum of % retained on all previous sieves.

% Passing = 100 - Cumulative % Retained.

Interpretation & Acceptance Criteria

The particle size distribution should fall within the specified range as per IS 383 (for concrete aggregates) or ASTM C33.

⭐️Grading Zones (IS 383:2016):

Zone I: Coarse sand.

Zone II: Moderately coarse sand (most suitable for concrete).

Zone III: Moderately fine sand (used for plastering).

Zone IV: Fine sand (used for masonry and plastering).

📜Conclusion

⏺Understanding the details of sand aggregate sieve analysis is crucial for ensuring that the aggregates used in construction meet the required specifications.

⏺This analysis not only informs the quality control process but also guides adjustments in mix design, ultimately contributing to the performance and longevity of the constructed structure.

@etconp

👉What Is Sieve analysis

⚡️PART ONE

💫Sieve analysis is a key quality control procedure used in construction to determine the particle size distribution of sand and aggregate materials.

⏺Its purpose is to verify that the material meets the gradation requirements necessary for the intended construction application—whether that’s for concrete mixes, road bases, or asphalt—ensuring proper compaction, strength, and durability.

📜Process Overview

🎲Sample Collection and Preparation

⏺A representative sample is collected from the aggregate batch. The sample is then dried to remove moisture, as this could affect the weight distribution. Any large clumps are broken apart to ensure individual particles can pass through the sieves.

🎲Sieve Stack Setup

⏺A stack of sieves with different mesh sizes is arranged in descending order, with the largest openings at the top and the smallest at the bottom. A base pan is placed below the smallest sieve to collect the finest particles.

🎲Weighing the Sample

⏺The total weight of the dry sample is measured. This serves as the basis for determining the percentage of material that passes through or is retained on each sieve.

🎲Sieving Procedure

⏺The sample is placed on the top sieve and the entire stack is mechanically shaken for a predetermined time period. This shaking allows the particles to segregate based on size as they move through the stack.

🎲Weighing and Calculation

⏺After shaking, each sieve is removed, and the material retained on each is weighed. The weight retained on each sieve is expressed as a percentage of the total sample weight. This data is then used to plot a gradation curve, which provides a visual representation of the particle size distribution.

🏷Importance in Construction
Strength and Durability: The gradation of sand aggregates affects the packing density in a mix. Well-graded aggregates tend to pack more tightly, reducing voids and leading to higher strength and durability in concrete or asphalt.

🔰Workability: In concrete, a well-graded aggregate mix improves workability and reduces the amount of cement paste needed, leading to cost efficiency.

🔰Consistency: Regular sieve analysis ensures consistency in material quality, helping to maintain uniform performance across different batches of construction material.

📜Standards and Guidelines
Many construction projects adhere to standards such as ASTM C33 for concrete aggregates or ASTM C136 for sieve analysis procedures.

⏺These standards specify the methodology, sieve sizes, and acceptable gradation limits for different construction applications.

❇️Interpretation of Results
Gradation Curve: The plotted curve (often a cumulative percentage passing vs. sieve size) helps engineers identify if the aggregate mix falls within the desired gradation range. A curve that is too steep may indicate a uniform size distribution, which might not be ideal, while a well-graded mix shows a smooth transition across sieve sizes.

⏹Quality Control: Any deviation from the specified gradation can lead to adjustments in the mix design. For example, too many fine particles might lead to higher water demand and shrinkage issues, whereas too many coarse particles could result in weak bonding and lower strength.

🚧Equipment Required:

1. Sieves: Standard sieves as per IS:460 or ASTM E11.

2. Weighing Balance: Accuracy of 0.1g or 1g depending on the sample weight.

3. Mechanical Sieve Shaker (optional): For consistent and efficient sieving.

4. Brush: To clean sieve meshes.

5. Sample Splitter: For obtaining representative samples.

Standard Sieve Sizes for Fine Aggregate (Sand)

📍Part 2 Will Continue

@etconp

👉What Is Slab

💫Slabs are structural elements used in buildings to provide flat surfaces like floors and roofs.

🚧They are typically made of reinforced concrete and can be categorized based on their support conditions, shape, and construction method.

📜Here are the main types of slabs:

🎲1. Based on Support Conditions

🔰a) One-Way Slab

Supported on two opposite sides.

Load is transferred in one direction.

Used for small spans.

🔰b) Two-Way Slab

Supported on all four sides.

Load is distributed in two directions.

Used for larger spans.

🎲2. Based on Shape & Design

❇️a) Flat Slab

Directly supported by columns without beams.

Often has drop panels or column capitals.

Used in commercial buildings and parking structures.

❇️b) Ribbed Slab (Waffle Slab)

Has ribs or grid-like reinforcement to reduce weight.

Suitable for large spans with heavy loads.

❇️c) Hollow Core Slab

Prefabricated with hollow sections to reduce weight.

Common in high-rise buildings and bridges.

❇️d) Solid Slab

Fully cast-in-place, providing strength and durability.

Used in residential and commercial buildings.

🎲3. Based on Construction Method

⏺a) Cast-in-Situ Slab

Constructed on-site using formwork.

Takes longer to build but allows flexibility in design.

⏺b) Precast Slab

Manufactured in factories and transported to the site.

Faster construction with better quality control.

⏺c) Post-Tensioned Slab

Uses high-strength steel tendons to improve load capacity.

Ideal for long spans and minimizing slab thickness.

@etconp

👉Concrete Admixtures

💫In concrete mix design, Superplasticizers, Accelerators, and Retarders are key admixtures that modify the properties of fresh and hardened concrete.

⭐️Here’s a breakdown of each:

⚡️1. Superplasticizer (High-Range Waters Reducer)

⏺Purpose:

Increases workability without adding extra water.

Reduces the water-cement ratio, enhancing strength and durability.

Helps in producing self-consolidating concrete (SCC).

⏺Types:

Sulfonated Melamine Formaldehyde (SMF)

Sulfonated Naphthalene Formaldehyde (SNF)

Polycarboxylate Ether (PCE) – Most advanced, high efficiency

⏺Dosage: Typically 0.1–2% by weight of cement.

📍Advantages:

Improves slump without compromising strength.

Reduces segregation and bleeding.

Enhances durability and resistance to sulfate/chloride attack.

⚡️2. Accelerator

⏺Purpose:

Speeds up the setting time and early strength development.

Useful in cold weather concreting.

Helps in rapid repairs and early formwork removal.

⏺Types:

Calcium Chloride (CaCl₂) – Common but not recommended for reinforced concrete due to corrosion risk.

Non-chloride accelerators (Calcium Nitrate, Calcium Formate, Sodium Thiocyanate, etc.) – Safer for reinforced concrete.

⏺Dosage: 1–3% by weight of cement.

📍Advantages:

Faster setting and early strength gain.

Reduces bleeding and shrinkage cracking.

Increases freeze-thaw resistance in cold climates.

⚡️3. Retarder

⏺Purpose:

Delays setting time to prevent premature hardening.

Useful in hot weather to avoid rapid hydration.

Helps in large pours or long transportation times.

⏺Types:

Lignosulfonates

Hydroxycarboxylic acids (e.g., tartaric acid, citric acid)

Sugars (like glucose-based compounds in small amounts)

⏺Dosage: 0.1–1.5% by weight of cement.

📍Advantages:

Extends workability time.

Reduces heat of hydration in mass concreting.

Improves surface finishing by preventing cold joints.

Choosing the Right Admixture

For high-strength concrete → Use superplasticizer (PCE preferred).

For cold weather → Use a non-chloride accelerator.

For hot weather or long transport → Use a retarder.

@etconp

👉Steel is one of the most essential materials in construction due to its strength, durability, and versatility.

💫Here are the key details construction workers need to know about steel:

🚧1. Types of Steel Used in Construction

⏺Mild Steel (MS) – Most commonly used, offers good strength and flexibility.

⏺Reinforced Steel (Rebar) – Used in concrete reinforcement to improve tensile strength.

⏺Structural Steel – Includes beams, columns, and plates used in frameworks.

⏺Stainless Steel – Resistant to corrosion, used in special structures or exposed environments.

⏺High-Strength Low-Alloy Steel (HSLA) – Lighter and stronger, used in high-rise buildings and bridges.

🚧2. Common Steel Shapes and Uses

⏺Rebars (Reinforcing Bars) – Strengthen concrete structures.

⏺I-Beams (H-Beams) – Used in structural frameworks.

⏺Angle Bars – Provide support in construction joints.

⏺Steel Plates – Used for floors, walls, and load-bearing surfaces.

⏺Pipes & Tubes – Used in plumbing, scaffolding, and structural support.

🚧3. Advantages of Steel in Construction

⏺High Strength – Can support heavy loads and resist deformation.

⏺Durability – Long-lasting and withstands extreme weather conditions.

⏺Flexibility – Can be molded into various shapes for different construction needs.

⏺Recyclability – Environmentally friendly as it can be reused.

⏺Fire Resistance – With proper treatment, it can withstand high temperatures.

🚧4. Common Applications in Construction

⏺Buildings & Skyscrapers – Frameworks, reinforcements, and load-bearing structures.

⏺Bridges – Structural supports and reinforcements.

⏺Roads & Highways – Reinforced concrete and guardrails.

⏺Industrial Structures – Warehouses, factories, and power plants.

🚧5. Handling & Safety Precautions

⏺Wear Protective Gear – Gloves, helmets, and boots to prevent injuries.

⏺Proper Lifting Techniques – Use cranes or multiple workers for heavy loads.

⏺Welding Safety – Use protective eyewear and ventilation when working with steel.

⏺Rust Prevention – Store steel in dry places and apply coatings if needed.

@etconp

👉ለግንባታው ዘርፍ መሳለጥ ሚና የሚጫወት የፕላስቲክ ፎርምወርክ ምርት ላይ የግንዛቤ ማስጨበጫ ተካሄደ

🚧በግንባታው ዘርፍ ጥራትን በማስጠበቅ፣ ወጭን በመቀነስ፣ ጊዜን በመቆጠብ እና ለአካባቢ ደህንነት መጠበቅ ጉልህ ሚና መጫወት የሚችል የፕላስቲክ ፎርምወርክ ምርት ላይ ለባለድርሻ አካላት የግንዛቤ ማስጨበጫ መርሃ ግብር መጋቢት 27/2017 ዓ.ም በስካይላይት ሆቴል ተካሂዷል፡፡

⏺የኢትዮጵያ ኮንስትራክሽን ባለስልጣን ከኤች ኬ ቢዝነስ ግሩፕ ኃ/የ/የግል ማህበር ጋር በመተባበር በምርቱ ላይ ግንዛቤ ለመፍጠር በተዘጋጀው ስነስርዓት ላይ የባለስልጣን ተቋሙ ም/ዋና ዳይሬክተር ዶ/ር ሙዓዝ በድሩ በክብር እንግድነት ባደረጉት የመክፈቻ ንግግር ኤች ኬ ቢዝነስ ግሩፕ ለሀገራዊ የኮንስትራክሽን ኢንዱስትሪው እና  ለማንፋክቸሪንግ ዘርፍ ትልቅ ብስራትን ይዞ መጥቷል ብለዋል፡፡

⏺ተቋሙ ለግንባታ ግብአት ይዞት የመጣው የፕላስቲክ ፎርምወርክ ቴክኖሎጅ ምቹ ፣ ቀላል፣ ወጭ ቆጣቢ እና ከአካባቢ ጋር ስምም ስለመሆኑና በዚህ ረገድ ፈር ቀዳጅ ፋብሪካነቱን ዶ/ር ሙዓዝ በድሩ ገልፀዋል፡፡

⏺በተጨማሪም የተቋሙ ምርት ገቢ ምርትን በሀገር ውስጥ አቅም በመተካትና የውጭ ምንዛሪን በማስቀረት፣ የስራ ዕድልን በመፍጠር፣ በረሃማነትን በመከላከል፣ የቴክኖሎጂ ሽግግርን ዕውን በማድረግ ረገድ ሚናው የጎላ መሆኑን ገልፀዋል፡፡

🏷የኢትዮጵያ ኮንስትራክሽን ባለስልጣን በመንግስት ከተሰጡት ተልዕኮዎች ውስጥ የግንባታ ፕሮጀክቶችን ጥራትን ማስጠበቅ፣ የጊዜና የግብአት ብክነትን መከላከል አንዱ ዓላማው መሆኑን ያወሱት ም/ዋና ዳይሬክተሩ በዚህ ረገድ ሚና ከሚጫወቱ የግል አልሚዎች ጋር ባለስልጣን ተቋሙ በአጋርነት መስራትን አጠናክሮ እንደሚቀጥልም አስገንዘበዋል፡፡

⏺መንግስት የግሉ ዘርፍ በኢትዮጵያ ዕድገት ላይ ድርሻ እንዳለው ሙሉ እምነት ያለው በመሆኑ የኮንስትራክሽን ኢንዱስትሪውን በማሳለጥ ረገድ ሰፊ ሚና እንደሚጠበቅባቸውም አስምረውበታል፡፡ 

⏺የኢትዮጵያ ኮንስትራክሽን ባለስልጣን በተሰጠው ተልዕኮ አንፃር ዘርፉን ለማዘመንና ኢትዮጵያን ለማልማት ከሚተጉ አካላት ጋር በአጋርነት፣ በትብብር እና በአብሮነት እንደሚተጋም አረጋግጠዋል፡፡

⏺የዘርፉ ባለድርሻ አካላትም ኤች ኬ ቢዝነስ ግሩፕ አዲስ ያስተዋወቀውን የፕላስቲክ ፎርምወርክ ምርት በማስተዋቅና ግንዛቤ በመፍጠር እንዲሁም ምርቱን በመጠቀም ረገድ የጋራ ርብርብ እንዲያደርጉ ዶ/ር ሙዓዝ በድሩ ጥሪ አስተላልፈዋል፡፡

⏺በስነስርአቱ ላይ የተለያዩ መንግስታዊ ተቋማት የስራ ኃላፊዎች ፣ የዘርፉ ልዩ ልዩ ሙያ ማህበራት ተወካዮች፣ የስራ ተቋራጮች፣ የሪልስቴት አልሚዎች እና ሌሎች ባለድርሻ አካላት ተሳትፈዋል፡፡

@etconp

👉DEFINITIONS

💫The following terms shall have the meanings ascribed to them in this Section, wherever
they appear in the A Specifications.

🚧1. Bill of Quantities: The document forming part of the Bid and containing an itemized
breakdown of the works to be carried out in a unit price contract, indicating a
quantity for each item and the corresponding unit price.

🚧2. Contract Documents: The documents listed in the GCC, including all attachments,
appendices, and all documents incorporated by reference therein, and shall include
any amendments thereto.

🚧3. Contract Price: The accepted Contract amount stated in the Procuring Entity's Letter of Acceptance.

The amount represents the initial estimate payable for the execution of the Works or such other sum as ascertained by the final statement of account as due to the Contractor under the Contract.

🚧4. Contract: The binding Contract Agreement entered into between the Procuring
Entity and the Contractor, comprising Contract Documents referred to therein,
including all attachments, appendices, and all documents incorporated by reference
therein.

🚧5. Contractor: A natural or juridical person under contract with a Procuring Entity to
supply Works.

🚧6. Day-works: Varied work inputs subject to payment on an hourly basis for the
Contractor's employees and equipment, in addition to payment for associated
materials and plants.

🚧7. Defect: Any part of the Works not completed in accordance with the Contract.

🚧8. Drawings: The drawings of the Works, as included in the Contract, and any additional and modified drawings issued by (or on behalf of) the Procuring Entity in accordance with the Contract, include calculations and other information provided or approved by the Engineer for the carrying out of the works.

🚧9. Engineer: A person named in the Special Conditions of Contract or appointed as such by the Procuring Entity and notified in writing to the Contractor to act as the representative of the Procuring Entity to supervise and inspect works and to test and examine the materials employed and the quality of workmanship, including any authorized representative of such person.

🚧10. Equipment: The Contractor's machinery, vehicles, apparatus, components and any
other articles brought temporarily to the Site to construct the Works.

🚧11. Final Acceptance Certificate: Certificate(s) issued by the Engineer to the Contractor at the end of the Defects Liability Period stating that the Contractor has completed its obligations to construct, complete, and maintain the Works concerned.

🚧12. General Conditions of Contract: The general contractual provisions setting out the administrative, financial, legal and technical clauses governing the execution of the
Contract, except where amended by the SCC or Contract Agreement.

🚧13. Materials: All supplies, including consumables, used by the Contractor for incorporation in the Works.

🚧14. Procuring Entity: Public body, which is partly or wholly financed by the Federal Government Budget, higher education institutions, and public institutions of like
nature which has the powers and duties to conclude a Contract for the supply of
Works, as specified in the SCC.

🚧15. Site: The places provided by the Procuring Entity where the Works are to be carried
out, and other places stated in the Contract as forming part of the site.

🚧16. Special Conditions of Contract: The conditions attached to the Contract Agreement,which shall govern the Contract and shall prevail over these General Conditions of Contract.

🚧17. Sub-Contractor: Any natural person, private or government entity, or a combination of the above, including its legal successors or permitted assigns who has a Contract with the Contractor to carry out a part of the Work in the Contract, which includes
work on the Site.

@etconp