FDRE-Procurement-Manual-Final-2018-NBGMS-1221-3.pdf
2.9 MB
የፌደራል መንግሥት ግዢና ንብረት ባለስልጣን አሻሽሎ ያወጣው 192 ገጽ ያለው የፌደራል መንግሥት ግዢ አፈፃፀም ማኑዋል
https://t.me/ETCONpWORK
@etconp
https://t.me/ETCONpWORK
@etconp
❤4🕊2
👉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
🚧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
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👉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
🚧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
❤9👍7
👉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
💫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
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👉 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
● 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
❤2👍1
👉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
🚧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
👍11❤6👏3
👉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
🚧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
❤14🥰3👍1
Ethio Construction Engineering
👉Do you Know About Curtain wall 💫Curtain walls are non-structural cladding systems for building exteriors — they resist weather and wind loads but do not carry floor or roof loads. ⏺They are usually made of aluminum frames with glass, metal panels, or thin…
👉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
💫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
❤17👍6
👉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
🚧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
❤11👍9