ታምራት  ፕሌት እና ጄቦልት አቅራቢ

♧ ሁሉን በአንድ ቦታ ለሁሉም ቅርብ

📍ኢትዮጵያ ዉስጥ የትም እንልክሎታለን

♧ ይደውሉልን ያማክሩን

0904040477
0911016833

👉 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

🚧Beam Design

📌A reinforced concrete beam must be proportioned according to its span (L) so that it safely carries loads without excessive bending or shear.

👉The image shows general guidelines, not exact code rules — final sizes must be based on structural design.

1. Beam Depth (H)

H = L / 12

📌The depth (height) of the beam should be about 1/12 of the span length.

Example: If span L = 6 m,
→ H ≈ 6000 / 12 = 500 mm

📌This ensures the beam can resist bending moments.

2. Beam Width (B)

B = L / 24

📌The width of the beam is generally half of its depth.

Example: If L = 6 m,
→ B = 6000 / 24 = 250 mm

This proportion keeps the beam stable and avoids cracking.

3. Longitudinal Reinforcement (Main Bars)

📌The top image shows red lines representing the tension reinforcement.

📌For long spans, beams tend to lift upward near supports due to negative moments.

📌Additional bars called “swings” or extra top bars are placed over supports.

📌Purpose:

✔ Controls cracking
✔ Handles negative bending moment
✔ Strengthens beam over supports

4. L/4 Reinforcement Zones

The bottom image shows   L/4 zones at both ends.

📌Why L/4?

🔗Negative bending moments occur near supports.

🔗So extra top bars must extend:

🔗L/4 from the support into the span.

Example: If L = 6 m,
L/4 = 1.5 m
→ Extra top bars must extend 1.5 m from each support.

5. Main Idea

📌A beam must be:

🔗Deep enough to resist bending

🔗Wide enough to ensure stability

🔗Properly reinforced at mid-span and supports

🔗Extra top bars are required at ends (L/4 region)

6. Important Note

The images provide general proportions only.

📌Actual design depends on:

🔗Load

🔗Span

🔗Material strength

🔗Building code (ACI / IS / BNBC etc.)

🔗Structural calculations are always required.


@etconp

👉Bridge Design and Construction

💫1. Introduction

Bridge design and construction involve planning, analysis, and execution to create safe and durable structures that span obstacles such as rivers, roads, and valleys.

2. Types of Bridges

• Beam Bridge
• Arch Bridge
• Suspension Bridge
• Cable-Stayed Bridge
• Truss Bridge

3. Key Design Considerations

• Load Calculation (Dead, Live, Wind, Earthquake loads)
• Material Selection (Concrete, Steel,
Composite)
• Foundation Design (Pile, Well, Caisson)
• Environmental Factors & Durability
• Safety Standards and Codes

4. Construction Steps

• Site Investigation & Surveying
• Soil Testing & Foundation Preparation
• Substructure Construction (Piers,Abutments)
• Superstructure Construction (Girders, Decks, Cables)
• Finishing Works & Load Testing

5. Modern Technologies

• Precast Bridge Elements
• Segmental Construction
• Drone-Based Inspection
• BIM (Building Information Modeling)

6. Conclusion

Bridge construction requires precision, engineering knowledge, and technology to ensure long-term safety and structural performance Bridge Design and Construction

@etconp

👉There are Three Elements of Cost.

1. Material
2. Labour
3. Expenses

⏺So each element is Further divided into two categories,

📌Direct and Indirect.


@etconp

👉Rebar Cracks

📌Cause : visible defect is a crack running along the bar, most likely caused by internal stresses, poor manufacturing processes, or rolling defects during steel production.

🏷Effect : Using rebars with such cracks in construction can severely reduce the load-carrying capacity and pose a risk of premature failure under stress.Practical Implications

⭐️Preventive action: All reinforcement materials should be visually inspected for cracks, splits, or signs of corrosion before use to ensure construction quality and safety.

⏺Damaged or defective bars like the one shown must be rejected in quality control and not used in structural concrete work.

@etconp

👉NINE KEY FACTORS THAT AFFECT THE CONCRETE STRENGTH

🧱 1. Water-Cement Ratio (w/c ratio)

⏺Definition:Ratio of the weight of water to the weight of cement used in the mix.

-  Effect:   Lower w/c ratio → higher strength.
-- Reason:   Excess water weakens the cement paste by increasing porosity

🪨 2. Quality of Cement

-  Effect:   The grade, freshness, and fineness of cement directly influence concrete strength.
-  Example:   Fresh cement with finer particles hydrates better, forming stronger bonds.

🧾 3. Type and Quality of Aggregates

-  Effect:   Strong, clean, and properly graded aggregates improve concrete strength.
-  Example:   Crushed angular aggregates bond better than rounded river gravel.

🧂 4. Mixing Method and Time

-  Effect:  Proper mixing ensures uniform distribution of materials.
-  Poor mixing leads to weak zones and lower compressive strength.

🧊 5. Compaction

-  Effect:  bProper vibration removes air voids.
-  Poor compaction causes honeycombing and reduces strength significantly.

🌡️ 6. Curing Conditions and Duration

-  Effect:   Adequate moisture and temperature during curing promote full hydration.
,-  Example:   Concrete cured for 7–28 days gains much higher strength than uncured concrete.

🧪 7. Age of Concrete

-   Effect:   Concrete gains strength with time as hydration continues.
-  Example:   Concrete typically reaches about 70% of its strength in 7 days and full strength at 28 days.

🌦️ 8. Temperature and Humidity During Setting

-  Effect:  vExtreme temperatures can speed up or slow down hydration.
-  Hot weather may cause cracking; cold weather may delay strength gain.

🧰 9. Use of Admixtures

-  Effect:   Chemical admixtures (like plasticizers, retarders, accelerators) modify strength and workability.
-  Example:   Superplasticizers allow lower water content without loosing workability, increasing strength .

@etconp

👉The Main Types Of Traffic Loads On A Highway

🚧1. Static Load

⏺This is the load from a vehicle when it is not moving or is moving very slowly.
🏷Example: a truck stopping on the road.
⏺It puts a constant pressure on the pavement.

🚧2. Dynamic Load

⏺This is the load from vehicles in motion.
⏺When a vehicle moves, the load increases because of acceleration, braking, bumps, and surface roughness.
⏺Dynamic load is higher than static load.

🚧3. Impact Load

⏺When a vehicle hits a bump, pothole, or uneven surface, an extra sudden force is applied on the pavement.
⏺This sudden force is called impact load and can damage weak pavement.

🚧4. Axle Load

⏺This is the load carried by each axle of a vehicle.
⏺Heavy trucks have multiple axles, and each axle transfers load to the pavement.
⏺High axle load = fast pavement damage.

🚧5. Wheel Load

⏺This is the load applied by each wheel of a vehicle.
⏺The pavement directly feels this wheel pressure on a small area.

🚧6. Repetitive Load (Load Repetition)

⏺Highways get millions of vehicles.
⏺Even if each load is small, repeated passing creates fatigue on the pavement.
⏺This is the main reason pavements crack over time.

🚧7. Braking and Acceleration Load

⏺When vehicles brake or accelerate, they apply horizontal (longitudinal) forces on the pavement.
⏺These forces can create rutting or surface skid marks.

🚧8. Lateral Load

⏺This occurs when vehicles turn or change lanes.
⏺Side forces act on the pavement and can cause pavement shoving or displacement.

🚧9. Environmental Load (Indirect Traffic Load)

⏺Temperature changes and moisture combined with traffic movement create extra stresses.
⏺Hot weather softens asphalt, and traffic loads cause rutting.

🚧10. Overload (Illegal Load)

⏺When trucks carry more weight than allowed, they create very high pavement stress.
⏺Even one overloaded truck can damage the pavement equal to thousands of normal cars.

@etconp

👉The Main properties of concrete, explained clearly and simply:

🚧1. Workability

⏺How easy it is to mix, place, compact, and finish concrete.
Depends on water content, aggregates, admixtures, and temperature.
⏺High workability = easy to pour. Low workability = stiff concrete.

🚧2. Strength
Concrete mainly has:

⏺a) Compressive Strength
The most important property.
Concrete is very strong in compression (20–50 MPa or more).
⏺b) Tensile Strength
Concrete is weak in tension.
That is why we add reinforcement bars (rebar).
⏺c) Flexural Strength
Ability to resist bending forces.

🚧3. Durability

⏺Ability to resist weathering, chemicals, and abrasion.
⏺Good concrete lasts many years without major damage.

🚧4. Density

⏺Normal concrete density ≈ 2400 kg/m³.
⏺Depends on aggregates and mix design.
⏺Higher density improves strength.

🚧5. Permeability

⏺How easily water and chemicals pass through concrete.
⏺Good concrete should have low permeability to avoid corrosion of steel.

🚧6. Setting Time

⏺Time taken for concrete to start hardening.
⏺Initial setting: ~30 minutes–2 hours.
⏺Final setting: ~6–10 hours (varies with temperature & admixtures).

🚧7. Shrinkage

⏺Concrete shrinks when drying.
Leads to cracks if not controlled.
⏺Using proper curing reduces shrinkage.

🚧8. Creep

⏺Long-term deformation under continuous load.
⏺Concrete slowly bends or compresses over months/years.

🚧9. Thermal Expansion

⏺Concrete expands and contracts with temperature.
⏺Important when designing joints.

🚧10. Hardness

⏺Concrete becomes very hard after curing.
⏺Good resistance to wear on floors, pavements, and roads.

🚧11. Fire Resistance

⏺Concrete is non-combustible.
⏺Offers good fire protection due to slow heat transmission.

🚧12. Modulus of Elasticity

⏺Shows stiffness of concrete.
⏺Higher strength concrete = higher elasticity.

@etconp

👉Here are the advantages and disadvantages of concrete in construction structures

🚧Advantages of Concrete

❇️1. High Compressive Strength

⏺Concrete is very strong in compression, making it ideal for foundations, columns, beams, slabs, dams, and bridges.

❇️2. Durable and Long-Lasting
Concrete can resist

⏺weathering, chemicals, fire, and abrasion. Well-designed concrete structures can last 50–100 years or more.

❇️3. Easily Molded Into Any Shape

⏺Concrete is fluid when fresh, so it can be cast into any shape using formwork—complex structures become easy to build.

❇️4. Fire Resistant

⏺Concrete does not burn and protects reinforcement bars from fire, giving high fire resistance.

❇️5. Low Maintenance

⏺After construction, concrete requires very little maintenance compared to steel or timber.

❇️6. Locally Available Materials

⏺Concrete ingredients (cement, sand, aggregates, water) are usually available everywhere, making it economical.

❇️7. Good Thermal Mass

⏺Concrete absorbs and slowly releases heat, helping stabilize indoor temperature.

🚧Disadvantages of Concrete

🏷1. Low Tensile Strength

⏺Concrete is weak in tension. It cracks easily unless reinforced with steel bars (reinforcement).

🏷2. Heavy Weight

⏺Concrete is dense and heavy, increasing dead load on structures.

🏷3. Shrinkage and Cracking

⏺During curing and drying, concrete can shrink and crack if not properly mixed, cured, or placed.

🏷4. Requires Formwork

⏺Most concrete members need formwork and skilled labor, which adds cost and time.

🏷5. Long Curing Time

⏺Concrete requires 7–28 days to reach desired strength. Construction can be slow.

🏷6. Environmental Impact

⏺Cement production releases large amounts of CO₂, making concrete less eco-friendly.

🏷7. Difficult to Repair

⏺Once hardened, concrete can be difficult to modify or repair without special equipment.

@etconp

ታምራት  ፕሌት እና ጄቦልት አቅራቢ

♧ ሁሉን በአንድ ቦታ ለሁሉም ቅርብ

📍ኢትዮጵያ ዉስጥ የትም እንልክሎታለን

♧ ይደውሉልን ያማክሩን

0904040477
0911016833

👉Possible Reasons for Removing Column Formwork at 8 Hours

💫1. Rapid-Hardening (High Early Strength) Concrete Was Used

⏺If the contractor used rapid-hardening cement (RHC) or an accelerator admixture, the concrete can gain enough strength in 6–8 hours to allow formwork removal.

🏷Example:

⏺Quick setting concrete
⏺Concrete with calcium nitrate/calcium chloride accelerators
⏺Special high-early-strength mix

💫2. Very High Temperature Curing Conditions

⏺In hot climates, concrete gains strength faster.
⏺If the temperature is 30–35°C+, the surface concrete may harden quicker, sometimes allowing earlier removal.

💫3. Contractor Working Under Time Pressure or Poor Planning

⏺Sometimes the contractor removes formwork early to:

*reuse formwork
*push schedule
*continue work above

⏺This is not a valid technical reason and is risky.

💫4. Very Light Formwork (Only Side Panels)

⏺For columns, removing only the side panels earlier is possible because the column carries no load from above at this stage.

⏺But 8 hours is still too early unless concrete strength is verified.

❌ Why It Is Usually NOT Allowed

⏺Removing formwork at 8 hours may cause:

*surface damage / honeycombing
*corners chipping
*loss of shape
*structural weakness if strength is too low

⏺Concrete normally needs: 5–7 MPa minimum strength before column formwork removal
⏺Usually achieved at 24 hours, not 8.

✅ Correct Professional Answer

🚧Formwork removal at 8 hours is only acceptable if the concrete is high-early-strength or contains an accelerator and if strength has been verified.

⏺Otherwise, it is not recommended and can damage the column.

@etconp

ደረጃቸውን የጠበቁ እብነበረድ እና ግራናይቶች!

ለቤትዎ ወይም ለንግድ ተቋምዎ ግንባታ ተስማሚ የሆኑ፣ ከፍተኛ ጥራት ያላቸውን እና ጠንካራ የእብነበረድ እና ግራናይት ውጤቶችን እናቀርባለን።

Lime stone
Babile Granite
Axum Granite

👉 አዳዲስ የገቡ ምርቶችን፣ ወቅታዊ መረጃዎችን እና ልዩ ቅናሾችን ለማግኘት የቴሌግራም ቻናላችንን ይቀላቀሉ!

@wollegastones
@wollegastones

👉If Ready-Mix Concrete (RMC) has already started to set while pouring, you must be very careful.

💫The correct action depends on how far setting has progressed.

✅ If concrete is only losing workability (early stiffening)

🚧You can add a compatibility-approved chemical admixture such as:

⭐️1. Superplasticizer / High Range Water Reducer (HRWR)

⏺Restores workability without adding water
⏺Maintains strength and durability

🏷Common types:

*Polycarboxylate Ether (PCE)
*Naphthalene-based

✅ This is the best and safest option when setting has just started.

💫2. Retarding Admixture (only if approved by mix designer)

⏺Slows down further setting
⏺Useful in hot weather or long transport time

❌ What NOT to do

⏺Do NOT add water indiscriminately → reduces strength & causes segregation
⏺Do NOT remix concrete that has begun hard setting or initial set
⏺Do NOT add cement on site

🚨 If concrete has reached initial set

⏺DO NOT try to re-temper
⏺Reject the batch
⏺Remove and replace

✅ Practical Site Action Steps

⏺1. Check concrete temperature & slump
⏺2. If slump is low but still plastic → add approved superplasticizer as per supplier dosage
⏺3. Remix truck for 30–60 revolutions
⏺4. Re-test slump before placing

📍Typical Dosage (Guide only)

⏺Super plasticizer: 0.8 – 1.5% of cement weight (Exact dosage must follow supplier data sheet)

@etconp

👉What is HVAC in Electrical instalation?

💫HVAC = Heating, Ventilation and Air Conditioning.

🚧HVAC Services include:

🏷1. Heating systems

⏺Design and installation of boilers / heat pumps
⏺Installation of radiators, fan coil units
⏺Operation & maintenance of heating system
⏺Troubleshooting heat loss, balancing

🏷2. Ventilation systems

⏺Fresh air duct design and installation
⏺Exhaust systems (kitchen, toilet, basements, car parks)
⏺Smoke control ventilation (stair pressurization, smoke extraction)
⏺Air filtration systems
⏺Periodic cleaning of ducts & filters

🏷3. Air conditioning systems

⏺Split AC installation, testing and commissioning
⏺VRF/VRV system supply & installation
⏺Chilled water system installation (chillers, AHUs, FCUs)
⏺Cooling tower checking and servicing

🏷4. Controls & automation

⏺BMS integration for HVAC
⏺Thermostat installation
⏺Sensors and actuators calibration

🏷5. Preventive maintenance services

⏺Gas leak detection
⏺Filter cleaning and replacement
⏺Coil and duct cleaning
⏺Refrigerant charge checking
⏺Electrical connection tightening

🏷6. Energy efficiency improvement

⏺Energy audit and energy saving recommendations
⏺Optimization of equipment operation
⏺Upgrading equipment to high efficiency systems

@etconp