👉What is Formwork in Building Construction?

💫Formwork is a temporary or permanent mold used in construction to shape and support fresh concrete until it hardens and gains enough strength to support itself.

🔰In simple words, formwork is the container into which concrete is poured to get the required shape, size, and position of structural elements.

🚧Purpose of Formwork in Building Construction

⏺Formwork plays a very important role in concrete construction.

⭐️Its main purposes are:

🚧1. To Give Shape and Size

⏺Formwork ensures concrete members like slabs, beams, columns, walls, and foundations are formed according to the design drawings.

🚧2. To Support Fresh Concrete

⏺Fresh concrete is heavy and fluid. Formwork holds the concrete in place until it hardens and becomes strong enough.

🚧3. To Maintain Alignment and Level

⏺It keeps structural elements straight, level, and properly aligned, avoiding deformation.

🚧4. To Achieve Good Surface Finish

⏺Proper formwork provides a smooth and neat surface, reducing plastering and finishing work.

🚧5. To Ensure Safety During Construction

⏺Strong and well-fixed formwork prevents collapse, protecting workers and materials.

🏷Common Materials Used for Formwork

⏺Timber/Wood – most common and easy to use
Plywood – smooth finish, reusable

⏺Steel – strong, durable, reusable many times

⏺Aluminum – lightweight, fast construction

⏺Plastic – reusable and water-resistant

📍Where Formwork Is Used

⏺Columns
⏺Beams
⏺Slabs
⏺Foundations
⏺Staircases
⏺Shear walls

@etconp

👉FIRST SAFETY

⚡️The first safety requirements on high-rise building construction are critical because work is done at great heights, with heavy materials, machinery, and many workers.

🚧These safety measures must be in place before and during construction to prevent serious accidents.

💫1. Site Safety Planning (Before Work Starts)
Prepare a Site Safety Plan (SSP)

⏺Conduct risk assessment for height work, lifting, fire, and electrical hazards
⏺Provide safety induction training for all workers
⏺Display safety signs, emergency contacts, and rules clearly on site

💫2. Personal Protective Equipment (PPE) – Mandatory

🏷Every worker must wear:

⏺Safety helmet (hard hat)
⏺High-visibility vest
⏺Safety boots (steel toe)
⏺Gloves
⏺Safety goggles
⏺Full body safety harness for work at height

💫3. Fall Protection Systems (Most Important)

⏺Guardrails at slab edges and openings
⏺Safety nets below work areas
⏺Lifelines and anchor points
Covered floor openings
⏺Strict rule: No work at height without fall protection

💫4. Scaffolding & Formwork Safety

⏺Scaffolding must be designed, erected, and inspected by competent persons
⏺Strong base and proper bracing
⏺Safe access ladders and platforms
⏺Formwork must be stable and checked before concreting

💫5. Lifting & Crane Safety

⏺Only certified crane operators
⏺Regular inspection of cranes, hoists, slings
⏺No lifting over workers
⏺Clear communication using signals or radios

💫6. Electrical Safety

⏺Proper grounding (earthing)
⏺Use insulated cables and tools
⏺Temporary power systems well protected
⏺No damaged wires or exposed connections

💫7. Fire Safety & Emergency Preparedness

⏺Fire extinguishers on every floor
⏺Safe storage of flammable materials
⏺Emergency evacuation routes
⏺First-aid kits and trained first-aiders
⏺Emergency drills

💫8. Housekeeping & Access Control

⏺Clean walkways and working areas
⏺Proper waste disposal
⏺Secure site fencing
⏺Restricted access for unauthorized persons

💫9. Safety Supervision & Monitoring

🎲Appoint a Safety Officer

⏺Daily safety inspections
⏺Toolbox meetings
⏺Immediate correction of unsafe acts

🔑 Key Rule:

Fall protection + PPE + supervision = life-saving combination in high-rise construction

@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

👉Sections of Beam (Based on Reinforcement)

💫Reinforced concrete beams are classified into Balanced, Under-Reinforced, and Over-Reinforced sections based on the amount of steel provided.

🚧1) Balanced Section

▶️A balanced section is one in which both concrete and steel reach their permissible stresses at the same time.

• Concrete reaches its maximum compressive strain
• Steel just reaches its yield stress
• Neutral axis depth = critical depth

▶️Failure nature:

• Sudden and brittle

📜Remarks:

• Ideal theoretical condition
• Rarely used in practice due to lack of warning before failure

🚧2) Under-Reinforced Section

▶️An under-reinforced section has less steel than required for a balanced section.

• Steel yields first before concrete crushes
• Neutral axis depth < critical depth

📜Failure nature:

• Ductile failure
• Large deflection and visible cracks before failure

🎲Advantages:

• Gives sufficient warning before collapse
• Safe and preferred in design

🔰Used in practice:

• YES (most commonly used in RCC design)

🚧3) Over-Reinforced Section

▶️An over-reinforced section has more steel than required for a balanced section.

• Concrete crushes before steel yields
• Neutral axis depth > critical depth

📜Failure nature:

• Brittle failure
• Sudden collapse without warning

🎲Disadvantages:

• Unsafe
• Not recommended in RCC design

🔰Used in practice:

• NO (avoided by design codes)

📍Comparison Summary

❇️Balanced section:

• Steel and concrete fail together
• Brittle failure

❇️Under-reinforced section:

• Steel fails first
• Ductile and safe

❇️Over-reinforced section:

• Concrete fails first
• Brittle and unsafe

@etconp

👉Design Requirements for Solid Slab Design (Building Construction)

🚧A solid slab is a reinforced concrete slab that transfers loads directly to beams, walls, or columns.

💫To ensure safety, serviceability, and economy, the following requirements must be satisfied.

🏷1. Applicable Design Codes

⏺Design must comply with recognized standards, for example:
EBCS
ACI 318 (USA)
Eurocode 2 (EN 1992)
BS 8110
IS 456
Local building codes (as applicable)

🏷2. Span & Support Conditions

📍Identify whether the slab is one-way or two-way:

▶️One-way slab: Longer span / shorter span ≥ 2
▶️Two-way slab: Longer span / shorter span < 2

⏺Define support type: simply supported, continuous, or cantilever.

🏷3. Loads to Be Considered

⏺All relevant loads must be included:
❇️Dead load: Self-weight of slab + floor finishes
❇️Live load: Occupancy load (residential, office, storage, etc.)
❇️Partition wall load (if any)
Environmental loads: seismic and wind (indirect effect on slabs)
❇️Apply load combinations as per the code.

🏷4. Slab Thickness (Depth)

⏺Minimum thickness to control deflection:

⏺Simply supported slab:
h ≥ L / 20
🎲Continuous slab:
h ≥ L / 26
⏺Cantilever slab:
h ≥ L / 10
(L = effective span)
⏺Also check deflection limits according to code.

🏷5. Material Requirements

⏺Concrete grade: Usually ≥ C25/30
⚡️Reinforcement steel:
⏺Yield strength (fy) = 415 MPa or 500 MPa
⏺Materials must meet durability and exposure conditions.

🏷6. Reinforcement Design
Main reinforcement: Along the direction of bending

❇️Distribution reinforcement: Perpendicular to main bars
❇️Minimum reinforcement:
Typically ≥ 0.12% of gross concrete area (for HYSD bars)
❇️Bar spacing:
⏺Main bars ≤ 3d or 300 mm
⏺Distribution bars ≤ 5d or 450 mm (d = effective depth)

🏷7. Bending Moment Check
Calculate design bending moments.

🚧Ensure: Mu ≤ φMn (or equivalent safety format per code)

🏷8. Shear Check

⏺Slab should resist one-way shear without shear reinforcement in most cases.

🚧Ensure:
Vu ≤ Vc
If Vu > Vc → increase slab thickness.

🏷9. Deflection Control

⏺Satisfy span-to-depth ratios.
Long-term deflection (creep + shrinkage) must be within limits.

🏷10. Crack Control

⏺Limit bar spacing and stress in steel.
⏺Proper curing is essential to minimize cracking.

🏷11. Cover to Reinforcement
Minimum clear cover (typical values):

⏺Interior slab: 20–25 mm
⏺Exposed or aggressive environment: 30–40 mm

🏷12. Construction & Detailing Requirements

⏺Proper formwork alignment
Correct bar placement and spacing Adequate compaction (vibration)
⏺Minimum curing period (7–14 days)

🏷13. Serviceability & Durability

⏺Control cracking and deflection Ensure fire resistance and long-term durability
⏺Consider waterproofing for roofs and wet areas

@etconp

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ታምራት ፕሌት እና ጄ ቦልት አቅራቢ

👉Design Requirements of Shear Walls according to EBCS (Ethiopian Building Code Standards)

🚧1. Purpose of Shear Wall

💫Shear walls are structural elements provided to:
⏺Resist lateral loads (earthquake & wind)
⏺Control story drift
Increase stiffness and strength of buildings
⏺Improve seismic performance, especially for mid- and high-rise buildings

🚧2. Location & Layout Requirements

💫According to EBCS-8: Shear walls shall be:
⏺Continuous from foundation to roof
⏺Uniformly distributed in plan to avoid torsion
⏺Preferably placed:
At building cores (stairs, elevators)
⏺Symmetrically in both X and Y directions
⏺Avoid: Sudden termination of walls and Large offsets or irregular wall alignment

🚧3. Thickness Requirements
As per EBCS-2:

💫Minimum wall thickness:
⏺150 mm for low-rise buildings
⏺200 mm or more for multi-storey buildings

⚡️Thickness must satisfy:Slenderness limits,Fire resistance,Durability requirements

🚧4. Material Requirements
Concrete

⏺Minimum concrete grade:
C25 (fck ≥ 25 MPa) for seismic areas
⏺Good compaction and curing are mandatory

⚡️Reinforcement Steel
⏺Deformed bars with:
fy = 300–500 Mpa

🚧5. Reinforcement Requirements (Very Important)

🏷5.1 Vertical Reinforcement
Minimum vertical steel ratio:
ρv ≥ 0.0025 (0.25%)
Bars: Uniformly distributed
⏺Minimum bar diameter: Ø10 mm
⏺Spacing: ≤ 300 mm

🏷5.2 Horizontal Reinforcement
⏺Minimum horizontal steel ratio: ρh ≥ 0.0025
⏺Spacing: ≤ 300 mm

📍Purpose:
⏺Control cracking
⏺Improve ductility

🚧6. Boundary Elements (Seismic Requirement)

⏺According to EBCS-8: Boundary elements are mandatory when:

🔰Wall is heavily stressed High axial force exists
🎲Requirements:

⏺Confined reinforcement (ties/stirrups)
⏺Tie spacing: ≤ 100 mm near ends
⏺Boundary zone width: ≥ max( wall thickness, 300 mm )

🚧7. Openings in Shear Walls

💫Openings (doors/windows) must:
⏺Be limited in size
⏺Be properly reinforced around edges
⏺Lintels and coupling beams:
Must be designed for shear + bending
⏺Require diagonal reinforcement in seismic zones

🚧8. Seismic Design Provisions (EBCS-8)

💫Shear walls must be designed for:
⏺Design base shear
⏺Overstrength factor
⏺Ductile detailing is compulsory:
⏺Proper anchorage
⏺Lap splices away from critical zones
⏺Drift limits must be checked:
Inter-story drift ≤ allowable limit

🚧9. Foundation Connection

💫Shear walls must be:

⏺Rigidly connected to foundation
⏺Proper dowel bars and development length provided
⚡️Foundation must resist:
⏺Overturning
⏺Sliding

🚧10. Construction & Quality Control

💫Accurate bar placement
Proper cover:

⏺≥ 25–40 mm depending on exposure
⏺Continuous supervision is required

📜Conclusion

💫According to EBCS, a shear wall must be:

⏺Properly located
⏺Adequately thick
⏺Correctly reinforced
⏺Detailed for ductility and seismic resistance
⏺Fully integrated with foundation and slabs

@etconp

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https://t.me/ETCONpWORK

👉Diagonal Reinforcement Bar in Open-Down Building Structures

💫Diagonal reinforcement bars are steel bars placed at an inclined (diagonal) angle in structural elements.

🚧In open-down structures (such as buildings with open ground floors, soft storey, large openings, or stilt parking), these bars are very important for stability and earthquake resistance.

❇️What is an Open-Down Structure?

⏺An open-down (soft storey) building has: Open ground floor (parking, shops, halls)
Fewer walls or columns at the lower level Reduced stiffness compared to upper floors
This makes the structure vulnerable to lateral loads (earthquake & wind).

📍Purpose of Diagonal Reinforcement Bars

⏺Diagonal bars are mainly used to: Resist shear forces
Prevent diagonal cracking due to lateral loads
⏺Improve seismic performance:-Act like a bracing system during earthquakes
⏺Control cracking:-Especially around openings (doors, windows, soft storey)
⏺Increase ductility:-Helps structure deform safely without sudden failure

🏷Where Diagonal Bars Are Commonly Used

⏺Shear walls Masonry walls (around openings)
⏺Soft storey / open ground floor
⏺Beam-column joints Infill walls for seismic zones

🏷How They Work (Simple Explanation)

⚡️When an earthquake pushes a building sideways:
⏺One diagonal bar works in tension
⏺The opposite diagonal resists compression
⏺This action distributes forces safely to the foundation

🔰Typical Arrangement

⏺Placed at 45°–60° angle
Anchored properly into beams, columns, or boundary elements
⏺Used in X-shape or single diagonal pattern
⏺According to Codes (General) Required in seismic design codes (EBCS, IS, Eurocode, ACI)
⏺Mandatory for soft storey mitigation
⏺Bar diameter and spacing depend on structural design

📜Simple Summary

Diagonal reinforcement bars strengthen open-down buildings by resisting shear, improving earthquake safety, and preventing sudden collapse.

@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

👉Foundation masonry work

💫it is masonry construction (stone, brick, or block) built below or just above ground level as part of the building foundation system.

🚧Its main purpose is to safely transfer building loads to the soil and protect the structure.

⭐️Purpose of Foundation Masonry Work

🎲1. Load Transfer to Soil

⏺Foundation masonry:
Receives loads from columns, walls, and beams Distributes these loads evenly to the footing and soil This prevents uneven settlement and structural cracks.

🎲2. Raises Structure Above Ground Level

⏺Masonry foundation walls or plinth walls: Lift the superstructure above natural ground Protect the building from surface water, moisture, and flooding

🎲3. Protection Against Moisture & Soil Contact

⏺Foundation masonry:Acts as a barrier between soil and upper structure Reduces dampness, termites, and soil chemicals from affecting walls
Often combined with DPC (Damp Proof Course) at plinth level.

🎲4. Provides a Level & Strong Base

⏺It creates: A firm, level base for RCC columns or load-bearing walls
⏺Proper alignment and stability for the superstructure

🎲5. Improves Durability & Strength

⏺Stone or block masonry foundations: Are durable and economical
⏺Resist compression forces very well
⏺Extend the building’s service life

🎲6. Cost Efficiency (Especially Low-rise Buildings)

⏺For: Low-rise buildings Load-bearing structures
Masonry foundations are often cheaper than full RCC foundations.

🏷Common Types of Foundation Masonry

❇️Stone masonry foundation
❇️Brick masonry foundation
❇️Block masonry foundation

📜Summary

📍Foundation masonry work is essential to:

⏺Transfer loads safely
⏺Protect against moisture and soil effects
⏺Provide a strong, durable, and level base
⏺Improve structural safety and building life

@etconp

👉CALCULATION – Field Density Test (FDT)

📜Example

⚖️ Weight of sand used

= Weight of sand + cylinder before test − Weight of sand + cylinder after test
= 8373 − 2524
= 5849 g

🕳️ Weight of sand in hole

= Weight of sand used − Weight of sand in cone
= 5849 − 1610
= 4239 g

📦 Volume of hole

= Weight of sand in hole ÷ Bulk density of sand
= 4239 ÷ 1.344
= 3154 cc

🪨 Weight of soil passing 19 mm sieve

= Weight of wet material − Weight retained on 19 mm sieve
= 7263 − 1350
= 5913 g

⚙️ Bulk density of soil

= Weight of soil ÷ Volume of hole
= 5913 ÷ 3154
= 1.875 g/cc

💧 Moisture content (Speedy Moisture Tester)

= 7.8 %

📊 Field dry density

= Bulk density ÷ (1 + Moisture content ÷ 100)
= 1.875 ÷ (1 + 7.8 ÷ 100)
= 1.875 ÷ 1.078
= 1.74 g/cc

📈 Percentage of compaction

= Field dry density ÷ Laboratory MDD × 100
= 1.74 ÷ 2.144 × 100
= 96.3 %

✅ RESULT

📌 Field Dry Density = 1.74 g/cc
📌 Laboratory MDD = 2.144 g/cc
📌 Compaction Achieved = 96.3 %

🫵For More Subscribe👇

https://t.me/ETCONpWORK

@etconp

👉በጨረታ ሂደት ውስጥ አንድ ብቻ ተጫራች ከተሳተፈ አሸናፊ ማድረግ ይቻላል?

✅አንድ ተጫራች ብቻ ከሆነ አሸናፊ ማድረግ በህግ ሊቻል ይችላል፣
✅ ነገር ግን ይህ የሚከናወነው የጨረታ ሂደቱ በሙሉ በግልጽነት እና በህግ መሠረት ከተካሄደ እና የቀረበው የዋጋ ስሌት
     ➣ተመራጭ፣
     ➣ብቁ እና
      ➣በተገቢው የገበያ ዋጋ ክልል ውስጥ ከሆነ ብቻ ነው።

⭐️ይህንን ለመረዳት የሚከተሉትን ነጥቦች ማስተዋል አስፈላጊ ነው፡

📍1. የጨረታው ህጋዊ እና ሥርዓታዊ መሠረት

⏺የማንኛውም ጨረታ ዋና ዓላማ ተጫማሪ ውድድርን ማምጣት እና ለግምገማ ብቁ የሆኑ ብዙ ተጫራቾችን ማሰባሰብ ነው።
⏺ "የማይመለከታቸው ጨረታዎች" ወይም "ሙሉ በሙሉ ያልተሳኩ ጨረታዎች" በብዙ የግዥ ስርዓቶች ውስጥ እንደ አንድ ጉዳይ ተደርጎ ይቆጠራል። አንድ ተጫራች ብቻ መኖሩ ይህንን ሁኔታ ያስከትላል።

📍2. አንድ ተጫራች ብቻ ሲኖር የጨረታውን ሂደት ለመቀጠል የሚከተሉት መሟላት አለባቸው፡-

❇️የጨረታው ማስታወቂያ (Bid Invitation) በቂ ጊዜ እና በተገቢው መንገድ መወጣቱ፡
❇️ጨረታው በሕዝብ ተደራሽ የሆኑ መገናኛዎች (ማለትም ጋዜጦች፣ ድረገጾች) ላይ በተገቢው ጊዜ እንደተለጠፈ ማረጋገጥ አለበት።
❇️ይህ ለሁሉም አመቺ የሆኑ ተጫራቾች የመሳተፍ እድል እንዳላቸው ለማረጋገጥ ነው።
❇️የአንድ ተጫራች ዋጋ ስሌት (Bid) ተመራጭ እና ኢኮኖሚያዊ መሆኑ፡ የቀረበው ዋጋ በጨረታው ሰነድ ውስጥ በተገለጸው በጀት ወይም በገበያ ዋጋ ማለት ይቻላል በሚገመት የዋጋ ክልል ውስጥ መሆን አለበት።

🔰ከመጠን በላይ ከፍ ያለ ዋጋ መጠየቅ ችግር ሊፈጥር ይችላል።
🔰የተጫራቹ የብቃት ማረጋገጫ (Responsiveness and Responsibility)፡ አንድ ብቁ ተጫራች መሆኑን ማለትም ሁሉንም የጨረታ መስፈርቶች እንደሚያሟላ እና ሥራውን ለማከናወን የሚያስፈልገውን ቴክኒካል፣ ፋይናንሻል እና ህጋዊ አቅም እንዳለው ማረጋገጥ አለበት።
🔰የግዢው ኮሚቴ/አካል ውሳኔ፡ በመጨረሻ ላይ፣ ጨረታውን የሚያስተዳድረው ኮሚቴ ወይም አካል አንድ ተጫራች ብቻ ሆኖ የቀረበውን የዋጋ ስሌት የመቀበል ወይም የመግባባት ውሳኔ ማሳለጥ አለበት።
🔰ይህ ውሳኔ ብዙውን ጊዜ ከላይ ከተጠቀሱት መስፈርቶች ጋር በማገናኘት ይወሰዳል።

📍3. የሚከተሉት ሁኔታዎች ሊኖሩ ይችላሉ

⏺ጨረታው መዝጋት እና እንደገና መቅረብ፡ የግዢው አካል አንድ ተጫራች ብቻ ስላለ ወይም የቀረበው ዋጋ ከመጠን በላይ ከፍ ብሎ ስላገኘ ጨረታውን ሙሉ በሙሉ እንደማይመለከት ሊወስን ይችላል።
⏺በዚህ ሁኔታ ጨረታው ይታጠፍና  እና እንደገና በተሻለ ማስተዋወቂያ እና በማሳሰቢያ ሊቀርብ ይችላል።
⏺ከአንድ ተጫራች ጋር በቀጥታ ድርድር (Direct Negotiation)፡ በአንዳንድ ስርዓቶች፣ አንድ ተጫራች ብቻ ከቀረበ በኋላ፣ የግዢው አካል ከዚያ ተጫራች ጋር በቀጥታ ለመድርስ ውሳኔ ሊሰጥ ይችላል።
⏺ይህ ሂደት ግን በጣም ጥብቅ የሆኑ ህጎች ውስጥ ነው እና በግልጽነት መሠረት መከናወን አለበት።

🏷ለስራ ቅጥር እና ጨረታዎች👇

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