የኦሮሚያ ክልል ግዥ አዋጅ
በኦሮሚያ ክልላዊ መንግስት በስራ ላይ ያለው የግዥ አዋጅ አያይዘንላችኋል

https://t.me/ETCONpWORK

@etconp

👉In building construction, a roof structure is made up of several key components that work together to support loads, protect the building, and drain rainwater.

🚧The main components are:

💫1. Structural Members (Load-Bearing Parts)

These carry the weight of the roof and transfer loads to walls or columns.

Roof Truss – A triangular framework (wood or steel) that supports the roof over large spans
Rafters – Sloping members that support the roof covering
Beams / Purlins – Horizontal members that support rafters or roof sheets
Tie Beams / Ceiling Joists – Prevent the roof from spreading and may support ceilings

💫2. Roof Decking / Sheathing
Roof Slab (in RCC roofs) –

Reinforced concrete slab forming the roof

Decking / Boards / Sheets – Base layer fixed on rafters or purlins (wood, metal, or concrete)

💫3. Roof Covering (Weather Protection)

This protects the building from rain, sun, and wind.

Corrugated metal sheets
Clay or concrete tiles
Shingles

Roofing membranes (for flat roofs)

💫4. Insulation Layer

Reduces heat transfer and improves comfort
Common materials: foam boards, fiberglass, mineral wool

💫5. Waterproofing Layer

Prevents water leakage
Includes membranes, bitumen layers, or coatings (especially in flat roofs)

💫6. Drainage Components

Gutters – Collect rainwater
Downpipes – Carry water to the ground or drainage system
Roof slope – Directs water flow

💫7. Roof Finishing & Accessories

Fascia board – Covers rafter ends
Eaves & Overhangs – Protect walls from rain
Flashing – Seals joints and edges
Ridge & Hip caps – Cover roof intersections

💫8. Ceiling (Optional but Common)

Fixed below the roof structure for aesthetics and insulation
Made of gypsum board, PVC, or wood panels

@etconp

👉የሥራ ተቋራጭ (Contractor) የሕግ ተጠያቂነት

🚧በኮንስትራክሽን ውል ሁለት አይነት የግንባታ ስራ ርክክቦች ያሉ ሲሆን እነሱም  ግዚያዊ ርክክብ እና የመጨረሻ ርክክብ በመባል ይታወቃሉ፡፡

🏷1/ ግዚያዊ ርክክብ

⏺ግዜአዊ ርክክብ በተለይ በኮንስትራክሽን ውል የተመለከቱ የግንባታ ስራዎች ተከናውነው ካበቁ በኋላ ወዲያውኑ ሁለቱ ወገኖች ማለትም አሰሪውና ተቋራጩ ባሉበት በስራው ላይ የሚደረግ የምርመራ ማረጋገጫ ነው:: (የፍትሀብሄር ህግ አንቀጽ 3274(1)):: ይሄውም አሰሪው በትክክል የተገነባውን ግንባታ በእጁ አግብቶ መያዙን ጭምር ያረጋግጣል፡፡
⏺ስለዚህ ጊዜአዊ ርክክብ በዋናነት የተሰራውን የግንባታ ስራ አሰሪው መብቱን ጠብቆ በመጀመሪያ የሚረከብበት ሂደት ነው፡፡  በስራው ላይ ምርመራ መደረጉንም የሚያረጋግጥ ነው፡፡

⏺እንግዲህ ስራው ከተመረመረ በኋላ አሰሪው ያላመነበትን ግንባታ ፈርሶ እንደገና እንዲሰራ ወይም እንዲጠገን ተደርጐ የጥራት ደረጃውን ባሟላ ሁኔታ እንዲከናወን ለማዘዝ እንደሚችል ፒፒኤ ክሎስ 85 ይፈቅድለታል:: በዚህም መሰረት ግንባታው የስራ ምርመራውን ካለፈ አሰሪው ግንባታውን የሚረከበው ይሆናል፡፡

🏷2/ የመጨረሻ ርክክብ
የመጨረሻ ርክክብ/Final Acceptance/

⏺በተለይ የድህንነት ጊዜ ካለቀ በኋላ እና ተቋራጩ ጠቅላላ ግዴታዎቹን በደህና ሁኔታ የፈጸመ መሆኑን አሰሪው ሲያረጋግጥ ግንባታውን ሙሉ በሙሉ በእጁ የሚያደርግበት ስለመሆኑ የፍትሀብሄር ህግ አንቀጽ 3279 ይደነግጋል፡፡

⏺የመጨረሻ ርክክብ አሰሪውና ተቋራጩ ባሉበት በጽሁፍ መደረግ እንዳለበት በአስገዳጅ ሁኔታ በፍትሀብሄር ህግ አንቀጽ 3279(2) ላይ ተደንግጓል፡፡ 

⏺በፍትሀብሄር ህግ አንቀጽ 3282 ላይ እንደተቀመጠው ከመጨረሻ ርክክብ በኋላ ተቋራጩ እስከ 10 አመት ድረስ ስለስራው አሰራር ጉድለት ተቋራጩ ሀላፊነት አለበት ፣ ለስራው ጥራት መድህን ሆኖም ይቀጥላል፡፡ ስለሆነም በሀዋሳ ዩኒቨርሲቲ የተደረመሰውን ድልድይ የገነባው ሥራ ተቋራጭ ለደረሰው ጉዳት በሕግ ተጠያቂ የሚሆንበት አግባብ ሊኖር ይችላል:: ይሁን እንጂ በመጨረሻ ርክክብ ወቅት የሚታዩ ለነበሩ የጥራት ጉድለቶች ተቋራጩ ሀላፊነት የለበትም፡፡

@etconp

👉Soil Bearing Capacity

💫1. Bearing Capacity

⏺Bearing capacity is the ability of soil to support the loads coming from a foundation without shear failure or excessive settlement.

💫2. Ultimate Bearing Capacity (qu)

⏺Ultimate bearing capacity is the maximum pressure that soil can withstand just before failure occurs.

⏺Terzaghi’s equation (for strip footing):
qu = cNc + γDfNq + 0.5γBNγ

💫3. Safe Bearing Capacity (qs)

⏺Safe bearing capacity is the allowable pressure on soil obtained by dividing the ultimate bearing capacity by a factorof safety.

qs = qu / FOS

@etconp

👉 INTERCON Construction Chemicals 

● Concrete Admixtures
● Bonding Agents
● Waterproofings
● Wall Putty, Prime Coat
● Concrete Repair Mortar
● Floor hardener, Epoxy
● Grout, Self-level mortar
● Quartz paint, Contextra
● Tile Adhesive & Tile Joint Fillers 
● Geotextiles and other construction chemicals and materials

☎️ Tel: 0961955555

🔹 Address 1: Signal road, around
      Dinberwa Hospital

🔹 Addres 2: Wellosefer, Infront of
     Dani Plaza

ታምራት  ፕሌት እና ጄቦልት አቅራቢ

📌ፕሌትና ጄቦልት በፈለጉት አይነት የተዘጋጀ አለን

♧ ሁሉን በአንድ ቦታ ለሁሉም ቅርብ

📍ኢትዮጵያ ዉስጥ የትም እንልክሎታለን

♧ ይደውሉልን ያማክሩን

0904040477
0911016833

👉FIDIC Books Explained — The Colors of Construction Contracts

🚧In the world of construction and engineering, contracts are not about mistrust — they’re about mutual understanding.
FIDIC’s “rainbow” of contract books helps align responsibilities, risks, and expectations across projects worldwide.

🔴 Red Book – Construction (Employer-Designed)
Employer designs, Contractor builds. Best for roads, bridges, and fixed-design infrastructure. Risk: Employer-heavy.

🟡 Yellow Book – Plant & Design-Build
Contractor designs & builds. Ideal for MEP-heavy and industrial projects. Risk: Contractor-heavy (design).

⚙️ Silver Book – EPC / Turnkey
Contractor delivers ready-to-operate projects. Fixed price, fixed time. Risk: Contractor-heavy.

✨ Gold Book – Design, Build & Operate (DBO)
Contractor designs, builds, and operates long-term. Perfect for PPPs and water treatment plants. Risk: Shared lifecycle.

🟢 Green Book – Short Form
Simplified for small, fast projects. Risk: Balanced.

🔵 Blue Book – Dredging & Reclamation
Tailored for marine and hydraulic works. Risk: Environmental/geotechnical shared.

⚪ White Book – Client–Consultant Agreement
Defines consultant scope, fees, and liability. Risk: Professional liability.

💗 Pink Book – MDB Edition
Adapted Red Book for projects funded by multilateral banks. Risk: Balanced with compliance.

@etconp

👉Short Column Vs Long Column

🚧Short Column

⏺1.Slenderness ratio (L/r) < 12.

⏺2.Failure occurs due to crushing (compression).

⏺3.High load-carrying capacity.

⏺4.Common in low-rise buildings.

⏺5.Strength mainly depends on material strength (concrete/steel).

🚧Long Column

▶️1.Slenderness ratio (L/r) > 12.

▶️2.Failure occurs due to buckling (instability).

▶️3.Lower load-carrying capacity compared to short columns.

▶️4.Common in tall structures.

▶️5.Strength mainly depends on slenderness ratio and buckling effect.

📜Summary:

💫Short column → Crushing failure

💫Long column → Buckling failure

@etconp

👉what type of glass used for curtain walls and why?

💫Curtain walls primarily use insulated glass units (IGUs), especially with low-emissivity (Low-E) coatings, for their thermal performance and energy efficiency.

⏺Other common types include tempered glass and laminated glass for safety and durability.

⏺The specific glass is chosen based on performance needs like energy conservation, glare reduction, safety, and sound insulation. 

🚧Insulated Glass Units (IGUs): Also called double or triple glazing, these units have at least two panes of glass with a sealed space between them filled with air or an inert gas.

▶️Why: This design provides excellent thermal insulation, reducing heating and cooling costs, and offers sound dampening.

🚧Tempered Glass: This is glass that has been heat-treated to increase its strength.

🏷Why: It is much stronger than regular glass and, when it does break, it shatters into small, relatively harmless pieces, making it a crucial safety feature.

🚧Laminated Glass: This is made of two or more layers of glass with a plastic interlayer, such as polyvinyl butyral (PVB), sandwiched between them.

⏺Why: It offers enhanced security and impact resistance, as the interlayer holds the glass fragments together if it breaks, and also provides better sound insulation.

🚧Low-E Coatings: These are microscopically thin, transparent coatings applied to one or more glass surfaces, usually within an IGU.

⏺Why: Low-emissivity (Low-E) coatings reflect infrared light, which keeps heat inside during the winter and outside during the summer.

⏺This significantly improves a building's energy efficiency and thermal performance.

@etconp

👉Tension zone and compression zone of a beam

🚧When a beam bends under load its cross-sectional fibers (top to bottom) stretch or shorten.

🏷That creates two zones:

⭐️Tension zone

⏺The part of the section where fibers are being stretched (pulled).
⏺Stretched fibers develop tensile stress.

⏺In reinforced concrete beams the steel reinforcement is placed in the tension zone because concrete is weak in tension but steel is strong in tension.
⏺Tension causes cracks (in concrete) when tensile stress exceeds tensile capacity.

⭐️Compression zone

⏺The part of the section where fibers are being shortened (squeezed).
⏺Fibers develop compressive stress.

⏺Concrete handles compression well, so the compression zone is mainly resisted by the concrete (and sometimes by compression reinforcement).
⏺Failure in compression shows as crushing of concrete if overload occurs.

⭐️Neutral axis

⏺The horizontal line inside the cross section that separates the two zones.

⏺Fibers on the neutral axis neither stretch nor shorten (zero strain/stress).
⏺Distance from neutral axis to extreme fiber is used in stress calculations.

❇️How it appears in common cases

⏺A simply supported beam loaded downward (sagging): top fibers → compression, bottom fibers → tension.
⏺A cantilever or overhanging span under certain loads (hogging): top may be in tension and bottom in compression — depends on bending moment sign.

🚧Basic formula (bending stress sign)

⏺Bending stress formula:
sigma = (M * y) / I
Where
sigma = bending stress
M = bending moment
y = distance from neutral axis
I = moment of inertia
Tension and compression rule:
If sigma is positive →

⚡️TENSION

⏺If sigma is negative → COMPRESSION
▶️(Note: sign depends on bending direction)

❇️Neutral axis condition:
stress at neutral axis = 0
y = 0
❇️Maximum bending stress:
sigma_max = (M * y_max) / I

🔰For rectangular beam section: Moment of inertia:
I = (b * h^3) / 12

Where
b = width of beam
h = total depth of beam
Stress at extreme fibers:
Top fiber stress: sigma_top = (M * h/2) / I

🎲Bottom fiber stress: sigma_bottom = (M * h/2) / I
(Sign decides tension or compression)

🚧Reinforced concrete design concept (basic):

▶️Compression force in concrete: C = 0.36 * fck * b * x
▶️Tension force in steel: T = 0.87 * fy * Ast
▶️Equilibrium condition: C = T


⏺Positive means tension (convention depends on sign choices), negative means compression — importantly the sign changes across the neutral axis.

📜Design insight (reinforced concrete)

⏺Put main steel where tension occurs (to carry tensile forces and control cracking).

▶️Depth of compression zone controls the beam’s capacity; designers check that compression concrete and tension steel balance properly.

@etconp

👉What is Lean Construction?

💫Lean Construction is a modern approach to managing construction projects that focuses on maximizing value while minimizing waste.

⏺It applies principles from Lean Manufacturing (originally from Toyota Production System) to the construction industry.

✅ Key Principles of Lean Construction:

1. Value Definition – Define what the client truly needs and focus all efforts on delivering that.
2. Eliminate Waste – Reduce anything that doesn’t add value: waiting, overproduction, rework, excess inventory, unnecessary transport, etc.
3. Flow Efficiency – Ensure smooth workflow among trades and construction phases.
4. Pull Planning – Tasks are only done when the next process needs it (vs. pushing work regardless of readiness).
5. Continuous Improvement (Kaizen) – Constantly look for small, ongoing improvements.
6. Collaboration and Transparency – Strong coordination among all parties: clients, consultants, contractors, suppliers.

🛠️ Lean Tools Used in Construction:
• Last Planner System (LPS) – Collaborative planning system that improves scheduling and commitment tracking.
• 5S – Sort, Set in order, Shine, Standardize, Sustain – for clean and efficient job sites.
• Value Stream Mapping – Identifies waste across workflows.
• Just-In-Time (JIT) delivery – Materials arrive exactly when needed.
• Visual Management – Use of charts, boards, and visuals to communicate progress.

🇪🇹 Lean Construction in Ethiopia – Current Practice

🟡 Status: Very Limited but Growing Awareness

Lean construction is not yet widely practiced in Ethiopia, but the concept is gradually gaining attention among leading contractors, engineers, and construction managers.

🚧 Challenges in Ethiopia:

1. ❌ Low Awareness – Many professionals are not familiar with Lean Construction principles.
2. ❌ Fragmented Industry – Poor communication and siloed practices hinder collaborative planning.
3. ❌ Traditional Contract Models – Competitive, claim-based contracting discourages team collaboration.
4. ❌ Weak Planning Culture – Poor baseline schedules, unreliable procurement systems.
5. ❌ Short-term Thinking – Focus on lowest bid instead of long-term project performance.

✅ Positive Signs:
• Increasing interest in cost control, time management, and construction productivity is creating demand for lean tools.
• Some local firms and professionals are exploring lean principles to improve performance, especially on delayed projects.
• Performance-based pay schemes, which you’re working on, are aligned with lean thinking by encouraging efficiency and accountability.

🧭 How to Promote Lean in Ethiopia:

1. 📚 Introduce Lean Training to professionals (engineers, site managers, planners).
2. 🏗️ Pilot Lean Planning Tools like the Last Planner System on active sites.
3. 🧑‍🏫 Collaborate with universities and professional bodies to integrate lean into education.
4. 📊 Track and share performance metrics (cost savings, time reduction).
5. ⚙️ Promote integrated project delivery (IPD) or Design-Build models for better collaboration.

@etconp

👉In building construction, a spacer (also called cover block or concrete spacer) is a small component used to maintain the correct distance between reinforcement bars and the formwork in columns, beams, and slabs.

🚧Meaning of Spacer

🏷A spacer ensures the required concrete cover around steel reinforcement so that steel does not touch the shuttering or ground.

⭐️Why Spacers Are Important
Spacers are used to:

⏺Maintain specified concrete cover
⏺Protect steel from corrosion
Ensure proper bonding between concrete and steel
Improve durability and strength of the structure
⏺Maintain correct bar position during concreting

🔰Spacer in Different Structural Elements

1️⃣ Spacer in Column
Keeps vertical bars away from column formwork
Ensures uniform cover on all sides
Common cover: 25–40 mm (depends on design)

2️⃣ Spacer in Beam
Maintains bottom and side cover of beam reinforcement
Prevents steel from touching shuttering
Common cover:
Bottom: 25 mm
Side: 20–25 mm

3️⃣ Spacer in Slab
Supports bottom reinforcement mesh
Maintains cover from slab shuttering
Common cover: 15–25 mm

🏷Types of Spacers

⏺Concrete spacers (most common, durable)
⏺Plastic spacers (easy to use, light)
⏺Stone or brick pieces (not recommended)

📜Simple Definition

Spacer: A small block used in RCC works to maintain required concrete cover between reinforcement bars and formwork in columns, beams, and slabs.

@etconp

👉 INTERCON Construction Chemicals 

● Concrete Admixtures
● Bonding Agents
● Waterproofings
● Wall Putty, Prime Coat
● Concrete Repair Mortar
● Floor hardener, Epoxy
● Grout, Self-level mortar
● Quartz paint, Contextra
● Tile Adhesive & Tile Joint Fillers 
● Geotextiles and other construction chemicals and materials

☎️ Tel: 0961955555

🔹 Address 1: Signal road, around
      Dinberwa Hospital

🔹 Addres 2: Wellosefer, Infront of
     Dani Plaza

👉practical site checklist for a reinforced concrete column before concreting (casting)

🚧COLUMN CHECKLIST
Before Concrete Casting

1. Drawings & Setting Out

✅ Latest approved structural drawings available on site
✅ Column location, size, and orientation checked as per drawing
✅ Column grid lines and centerlines marked correctly
✅ Column position verified using total station / tape / plumb

2. Reinforcement (Rebar) Inspection

✅ Main bar diameter and quantity as per drawing
✅ Bar spacing correct
✅ Stirrups / ties size and spacing as per drawing
✅ Hooks and bends properly formed (135° for seismic areas)
✅ Lapping length as per code and drawing
✅ Lap location approved (not at critical stress zone)
✅ Bars are clean (free from mud, oil, loose rust)
✅ Cover blocks / spacers fixed properly
✅ Minimum concrete cover maintained (usually 25 mm)

3. Formwork (Shuttering)

✅ Formwork dimension checked (width, depth, height)
✅ Formwork is strong, rigid, and tight
✅ No gaps or openings for leakage of cement slurry
✅ Formwork properly aligned and plumb (vertical)
✅ Proper support and bracing provided
✅ Inner surface cleaned
✅ Form oil applied evenly (not excessive)

4. Embedded Items & Inserts

✅ Starter bars from footing / beam properly fixed
✅ Anchor bolts, sleeves, conduits placed correctly (if any)
✅ Openings and inserts approved and secured

5. Level & Height

✅ Column bottom level verified
✅ Column top level / cutoff level marked
✅ Reference level clearly visible

6. Concreting Preparation

✅ Approved concrete mix design available
✅ Slump requirement confirmed
✅ Concrete mixer / batching plant ready
✅ Vibrator available and working
✅ Sufficient labor and supervision arranged
✅ Weather condition suitable (no heavy rain)

7. Safety & Quality Control

✅ Safe access provided for workers
✅ PPE available (helmet, gloves, boots)
✅ Cube mold ready for concrete strength test
✅ Site engineer / consultant approval obtained

8. Final Approval

✅ Column inspected and approved for concreting
✍Inspection record signed by: Site Engineer Consultant / Client Representative

@etconp