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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