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♧ 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