👉ጎተራ አካባቢ ሊፈርስ መሆኑ ተሰማ

በአዲስ አበባ ከተማ ንፋስ ስልክ ላፍቶ ክፍለ ከተማ ውስጥ የሚገኘውና በተለምዶ ጎተራ ተብሎ የሚጠራው ሰፈር ሊፈርስ መሆኑን ዘሪፖርተር እንግሊዘኛ ጋዜጣ ዛሬ ባቀረበው ዘገባ አስታውቋል፡፡

‹‹አዲስ ቱሞሮው›› በሚል ፕሮጀክት የከተማው አስተዳደር ለሚያስገነባው ልዩ የኢኮኖሚ መንደር አካባቢውን ለማፍረስ መታቀዱንም አስረድቷል፡፡

ፕሮጀክቱ በአዲስ አበባ ከንነቲባ አዳነች አቤቤና በጠቅላይ ሚኒስትር ፅህፈት ቤት የሚመራ እንደሆነ የጠቀሰው ዘገባው የከተማው አስተዳደር መንደሩን ለመገንባት ከቻይናው የኮሚኒኬሽንና ኮንትራክሽን ድርጅት ጋር ስምምነት መፈፀሙን አስታውቋል፡፡

መንደሩ የንግድ፣ የፋይናንስ፣ የትምህርት፣ የባህልና ሰማይ ጠቀስ የመኖሪያ ህንፃዎች እንደሚኖሩት መገለፁን ያስረዳው ዘገባው በመሆኑም በጎተራ አካባቢ በሚገኝ ሰፊ መሬት ላይ ለመስራት እንደታሰበ ጠቅሷል፡፡

የአዲስ ቱሞሮው መንደር ግንባታ በቢሊዮን የሚቆጠር ብር እንደሚፈጅ አስረድቶም ከዚህም በላይ በጎተራ አካባቢ የሚኖሩ በርካቶችን እንዲፈናቀሉ እንደሚያደርግ ገልጿል፡፡

በአሁኑ ወቅት በኮሪደር ልማትና በጫካ ፕሮጀክት ፕሮጀክቶች አማካኝነት በመቶ ሺ የሚቆጠሩ የአዲስ አበባ ነዋሪዎች ተፈናቅለው ወደተለያዩ አካባቢዎች እንዲሰፍሩ የተደረገ ሲሆን በዚህኛው ፕሮጀክትም በርካታ ነዋሪዎች ተመሳሳይ እጣ እንደሚገጥማቸውም አስታውቋል፡፡

@etconp

👉ቻይና ጨረቃ ላይ በ3ዲ ቴክኖሎጂ ጡቦች አምርታ ቤዝ ልትገነባ ነው

ቻይና ከጨረቃ ላይ ግብዓት በመውሰድ በጨረቃ ገጽ ቤዝ ለመገንባት ማቀዷን ይፋ አድርጋለች።

ማንኛውንም ነገር ወደ ጨረቃ መላክ እጅግ በጣም ውድ ስለሆነ፣ በጨረቃ ገጽ ላይ የሚገኙ ቁሳቁሶችን በመጠቀም ግንባታዎችን ለማከናወን ያቀደችው ቻይና፤ ወደ ጨረቃ መንኮራኩር በመላክ ስለጉዳዩ ሰፋ ያለ ዝግጅት ለማድረግ አቅዳለች።

ቻንግኤ 8 በ3D ህትመት ቴክኖሎጂ የጨረቃን ፍለጋ መልክ ለመቀየር የሚሞክረው በዚህ ረገድ ነው።

ቻንግኤ 8 (Chang'e) የተሰኘችውን መንኮራኩር እ.ኤ.አ. በ2028 አካባቢ ለማምጠቅ ከወዲሁ ዝግጅት እያደረገቸ ይገኛል።

የቻይና የጨረቃ ፍለጋ ፕሮግራም ዋና ዲዛይነር የሆኑት ው ዌይረን ለቻይና ማዕከላዊ ቴሌቪዥን (CCTV) እንደተናገሩት፣ "አሁን ከጨረቃ አፈር የተሰሩ ጡቦችን የሚያመርት በዓለም የመጀመሪያ የሆነውን መሳሪያ አዘጋጅተናል።

ይህ ሥርዓት የፀሐይ ብርሃንን በመጠቀም የፀሐይ ኃይልን ይሰበስባል፤ ከዚያም በፋይበር ኦፕቲክስ አማካኝነት ወደ ጨረቃ ያስተላልፋል" ብለዋል።

አክለውም "የፀሐይ ብርሃንን በማሰባሰብ ከ1400 እስከ 1500 ዲግሪ ሴልሺየስ የሚደርስ የሙቀት መጠን ማግኘት እንችላለን፤ ይህም የጨረቃን አፈር ለማቅለጥ በቂ ነው።

ከዚያም የእኛ መሳሪያ የቀለጠውን ቁስ በተለያዩ መስፈርቶች ) ወደሆኑ ጡቦች ለመቅረጽ የ3D ህትመት ቴክኖሎጂን እንጠቀማለን።

ይህ አካሄድ ውሃና ሌሎች ቁሳቁሶችን ከምድር ማጓጓዝ ሳያስፈልገን በጨረቃ ላይ የሚገኙ ሀብቶችን እንድንጠቀም ያስችለናል" ብለዋል።

የተሳካ ሙከራ ቻይና በጨረቃ ላይ ይበልጥ ትልልቅ የግንባታ ሥራዎችን እንድታቅድና እንድታከናውን እንዲያስችላት ትልቅ አስተዋጽኦ ያደርጋል።

@etconp

👉What Is A prime coat

🚧It is a thin layer of low-viscosity bituminous material applied to a non-bituminous granular base course (e.g., crushed stone or gravel) in road construction before laying the asphalt surface layer.

Its primary purpose is to prepare the base for better bonding with the asphalt layer, enhance durability, and protect the base course. Below are detailed aspects of a prime coat:

🏷Purpose of Prime Coat

1. Bonding: Ensures strong adhesion between the granular base and the asphalt layer, preventing slippage or delamination.
2. Waterproofing: Seals the base course to prevent water infiltration, which could weaken the base.
3. Base Protection: Protects the granular base from weather exposure and traffic damage before the asphalt layer is applied.
4. Dust Control: Reduces dust generation from the base course during construction.
5. Strengthening: Penetrates and binds loose particles in the base, improving its stability.

❇️Materials Used

- Cutback Asphalt: Most common, typically medium-curing (MC) grades like MC-30, MC-70, or MC-250.

⏺These are asphalt cement mixed with a solvent (e.g., kerosene) to reduce viscosity for easier application.
- Emulsified Asphalt: Less common but used in some cases (e.g., SS-1 or CSS-1).

⏺These are asphalt droplets suspended in water, environmentally friendlier due to lower solvent use.
- The choice depends on local climate, base material, and project specifications.

🚧Application Process

1. Base Preparation:
   - The base course (e.g., aggregate base) must be clean, dry, and free of loose material, dust, or debris.
   - Compact the base to the required density and ensure a smooth, even surface.
   - Correct any surface irregularities or weak spots.
2. Equipment:
   - A distributor truck with a spray bar is used to apply the prime coat uniformly.
   - Hand sprayers may be used for small or inaccessible areas.
3. Application Rate:
   - Typically ranges from 0.65 to 1.75 liters per square meter (0.15 to 0.4 gallons per square yard), depending on the base’s porosity and texture.
   - Coarse, porous bases require higher rates; denser bases need less.
4. Temperature:
   - The bituminous material is heated to the recommended temperature (e.g., 50–80°C for MC-70) for proper spraying viscosity.
   - Ambient temperature should generally be above 10°C (50°F) to ensure proper curing.
5. Curing:
   - The prime coat must penetrate the base and cure (solvent evaporates or emulsion breaks) before the asphalt layer is placed.
   - Curing typically takes 24–48 hours, depending on weather, material, and application rate.
   - Traffic should be kept off the surface during curing to avoid damage.
6. Blotting (if needed):
   - If excess prime coat pools on the surface, fine sand or aggregate is applied to absorb it and prevent tracking.

⚡️Key Considerations

- Environmental Conditions: Avoid application during rain, high humidity, or cold weather, as these can hinder curing or penetration.
- Material Selection: Match the prime coat material to the base type and climate (e.g., MC-70 for warmer climates, MC-30 for cooler ones).
- Safety: Handle bituminous materials carefully due to flammability and fumes. Use proper protective equipment.
- Environmental Impact: Cutback asphalts release volatile organic compounds (VOCs). Some regions prefer emulsified asphalts for lower environmental impact.
- Testing: Conduct field tests (e.g., penetration test or visual inspection) to ensure adequate penetration and curing before overlaying asphalt.

⭐️Advantages

- Enhances pavement longevity by improving base-asphalt bonding.
- Protects the base from moisture and construction traffic.
- Cost-effective way to stabilize the base course.

⭐️Disadvantages

- Requires curing time, which may delay construction.
- Improper application (e.g., excess material) can lead to bleeding or poor bonding.

@etconp

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👉The base course layer in flexible pavement (typically asphalt pavement) plays a critical role in providing structural support, distributing loads, and ensuring long-term durability.

💫Flexible pavements are designed to bend and flex under traffic loads, and the base course is a key component in this system.

🚧Below are detailed insights specific to the base course layer in flexible pavement:

🏷Role of the Base Course in Flexible Pavement

- Load Distribution: Spreads traffic loads from the asphalt surface layer to the subgrade, reducing stress on the weaker underlying soil.
- Stability: Provides a stable platform for the asphalt layer, preventing deformation like rutting or cracking.
- Drainage: Facilitates water removal to prevent moisture-related damage, which is critical in flexible pavements as they are more susceptible to water infiltration.
- Frost Protection: In cold climates, it minimizes frost heave by insulating the subgrade.

🏷Materials for Base Course in Flexible Pavement

⏹1. Unbound Granular Materials:

   - Crushed Stone or Gravel: Most common, offering high strength through particle interlocking.
   - Well-Graded Aggregates: Ensures proper compaction and load-bearing capacity (e.g., meeting AASHTO M 147 gradation standards).
   - Recycled Materials: Crushed concrete or reclaimed asphalt pavement (RAP) may be used for sustainability.

⏹2. Bound/Stabilized Materials:

   - Asphalt-Treated Base (ATB): Aggregates mixed with asphalt binder for enhanced strength and moisture resistance.
   - Cement-Treated Base (CTB): Aggregates stabilized with cement for high stiffness, though less flexible.
   - Lime-Stabilized Base: Used in clay-rich subgrades to improve workability and strength.
⏹3. Quality Requirements:

   - Aggregates must be durable, angular, and free of organic matter.
   - Typical tests include Los Angeles Abrasion (for durability) and California Bearing Ratio (CBR, typically 50–100 for base course).

🏷Design Considerations

▶️1. Thickness:

   - Varies based on traffic volume, subgrade strength, and climate (typically 4–12 inches for light to moderate traffic, thicker for highways).
   - Determined using design methods like AASHTO 1993 or Mechanistic-Empirical Pavement Design Guide (MEPDG).
   - Example: A highway with heavy truck traffic and weak subgrade (CBR < 5) may require a 10–14 inch base course.

▶️2. Compaction:

   - Achieves 95–100% of maximum dry density (per Proctor test, ASTM D698/D1557).
   - Compacted in lifts (4–6 inches) to ensure uniformity.

▶️3. Drainage:

   - Base course materials are designed for permeability to prevent water accumulation.
   - Often paired with a drainage layer or edge drains in high-rainfall areas.

▶️4. Gradation:

   - Well-graded aggregates (mix of coarse and fine particles) ensure dense packing and stability.
   - Example gradation: 100% passing 2-inch sieve, 30–60% passing No. 4 sieve.

⭐️Construction Process

⏺1. Subgrade Preparation:

   - Subgrade is compacted and leveled to a specified CBR or modulus.
   - Weak subgrade may require stabilization (e.g., lime or geotextiles).

⏺2. Material Placement:

   - Base course material is spread using graders or pavers in controlled lifts.
   - Moisture content is optimized (typically near optimum moisture content from Proctor tests).

⏺3. Compaction:

   - Vibratory rollers compact each lift to the required density.
   - Field tests (e.g., nuclear density gauge) verify compaction.

⏺4. Surface Finishing:

   - Base course is smoothed to ensure a uniform platform for the asphalt layer.
   - Checked for proper cross-slope (typically 2–3%) to aid drainage.

📜Standards and Specifications

- AASHTO: M 147 (material specs), T 180 (compaction), and pavement design guidelines.
- ASTM: D2940 (granular base specs), D1241 (material gradation).
- Local DOT Standards: Most regions have specific requirements for base course materials and thickness (e.g., FHWA or state DOT manuals).
- CBR Requirement: Typically 50–80 for unbound granular base, higher for treated bases.

@etconp

ታምራት  ፕሌት እና ጄቦልት አቅራቢ

📌ፕሌትና ጄቦልት በፈለጉት አይነት የተዘጋጀ አለን

♧ ሁሉን በአንድ ቦታ ለሁሉም ቅርብ

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📍ኢትዮጵያ ዉስጥ የትም እንልክሎታለን

♧ ይደውሉልን ያማክሩን

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👉Methods of Analysis of Loss and Expense

The analysis of loss and expense is a critical component of construction contracts. It involves identifying, quantifying, and valuing the losses incurred by the contractor due to various events or circumstances.

*Prolongation of Preliminaries*
Prolongation of preliminaries refers to the extension of the initial costs incurred by the contractor to set up the site, including site accommodation, lighting, and power. To correctly ascertain the loss and expense for preliminaries, it is essential to subdivide them into their constituent parts.

The following are the key components of preliminaries:

* Site set-up costs are admissible where additional plant is properly brought onto the site. However, if plant is already on-site, setting-up costs would rarely be admissible unless setting up has been delayed by a relevant matter and inflation has occurred which is not reimbursable under the fluctuations clauses.
* Removal costs are admissible in the same way as setting-up costs.
* Additional hire charges are generally reimbursable if the item is required to be kept on-site longer than otherwise would have been the case due to the relevant matter.
* Running charges: Additional running charges would be reimbursable if, due to a relevant matter, the particular item is required for a longer period than otherwise would have been the case.

Calculation Method:

Prolongation Costs = (Daily Site Establishment Costs x Number of Days of Delay) + (Additional Preliminaries Costs x Number of Days of Delay)

Where:

* Daily Site Establishment Costs = (Site Establishment Costs / Contract Period)
* Site Establishment Costs = Preliminaries costs, including site accommodation, lighting, and power
* Number of Days of Delay = Delay caused by the employer or other parties
* Additional Preliminaries Costs = Additional costs incurred due to the delay, such as additional hire charges and running charges

*Disruption (of Labour)*
Disruption to labour is a common issue in construction projects. The ascertainment of the cost of disruption to labour is invariably a difficult and wide-reaching process.

The following are key considerations when analysing disruption to labour:

* Avoid applying an overall percentage: It would be unusual that the whole project labour costs on a major scheme, for example, are disrupted.
* Keep contemporary records: Request that contemporary records be kept, noting the output achieved in practice by the particular labour resource that is being affected and hence disrupted.
* Consider the nature of the delay: Be cognisant as to whether any delay comprises a multitude of fragmented or smaller delays or, in the alternative, a major delay.
* Recognise the ‘learning curve’: There can be a ‘learning curve’ in most or if not all activities. The advantage of this can be lost if new resource is requested to undertake tasks that have become familiar to others.

Calculation Method:

Disruption Costs = (Total Labour Costs x Disruption Percentage) + (Total Plant Costs x Disruption Percentage)

Where:

* Total Labour Costs = Total labour costs incurred during the project
* Disruption Percentage = Percentage of labour costs disrupted due to the delay or disruption
* Total Plant Costs = Total plant costs incurred during the project

*Additional (Extra Waste) and Abortive Material Purchase*
Additional waste and abortive material purchase can result in significant losses for the contractor.

The following are key considerations when analysing additional waste and abortive material purchase:

* Relevance: Providing the contractor has not been at fault and they can prove as such, this cost will properly form part of any ascertainment.
* Contemporaneous records: Keep records of the materials purchased and the waste generated to support the claim.

@etconp