Steeped strip foundation

INTRODUCTION

Foundation provide support for structures and transfer their load to the layers of soil or rock that having sufficient bearing capacity and suitable settlement characteristics.

➪ መሰረት (foundation) ለሚሰራው ህንፃ ወይም ድልድይ ድጋፍ የሚሰጥ የመዋቅር ክፍል ነው። የህንፃ መሰረት ከላይ የሚመጣውን ክብደት በመቀበል ወደመሬት ያስተላልፋል።

➪ ሁል ጊዜም የህንፃ መሰረት መገንባት ያለበት የአፈር የመሸከም አቅሙ ለህንፃው በቂ በሆነበት ቦታ ነው ወይም የአፈር የመሸከም አቅሙን እና engineering property of soil የተለያዩ መንገዶች ማሻሻል እንችላለን።

👉🏿 ለምሳሌ የ ጥቁር አፈር የመሸከም አቅሙ ጥሩ ሚባል ነው ነገር ግን ውሃ ሲያገኝ expand ያደርጋል (volume ይጨምራል) እና ውሃ ሲያጣ ይሸማቃል (contract) ይህም በህንፃው ላይ ጉዳት ያደርሳል።

➪ በሚነፋበት (expand) እና በሚሸማቅበት (contract) ጊዜ ከ መሬት ጋር ቀጥተኛ ግንኙነት ያለውን ወለል ይሰነጠቃል (Ground support slab which has contact with the surface will crack) ይህ እንዳይሆን አፈሩን በደንብ መጠቅጠቅ (compact) አለበት።

STEEPED FOOTING

Strip foundation (or strip footing) are types of shallow foundation used to provide a continuous, level (or sometimes steeped) strip of support to linear structure such as wall or closely-spaced rows of columns built centrally above them.

Where the natural surface of ground is sloped the most economical may be stepped foundation.

In this case, the foundation takes the form of a series concrete horizontal steps following the slope of the ground.

This helps to minimize the amount of excavation and below ground wall construction that would otherwise be required. Steeped foundation can also be used to transition from deep foundation to shallow foundations, and at the corners and intersections. Regularly steeping foundations also avoids abrupt and excessive changes in level that could cause a weakness resulting in movement. Similarly, abrupt and excessive changes in foundation depths should be avoided at corners and intersections by the introduction of steeping.

Each step in foundation should be no higher than thickness of the foundation. The foundation at higher level should also overlap the lower foundation, typically by at least twice the height of the step, or by the thickness of the foundation, or by at least 300milimeters (whichever is greatest). Drainage must be carefully designed to eliminate the danger of instability due to accumulating water pressure.

የ እያንዳንዱ ደረጃ thickness ከ foundation’ሁ thickness መብለጥ የለበትም። የእያንዳንዱ የደረጃ ብረት ቀጣይ ካለው ብረት (reinforcement bar) ጋር መያያዝ አለበት። ይህም ማለት ላይ ያለው ቀጣይ እታች ካለው ጋር መያያዝ አለበት።

ይህን Foundation በምንሰራበት ጊዜ የብረት overlap በተለምዶ የደረጃውን ሁለት እጥፍ መሆን ያለበት ወይም የደረጃውን ከፈታ እኩል ወይም ደግሞ 300 ሚሊሜትር (ከነዚህ ከ3ቱ የበለጠው overlap length of bar for the steeps ተብሎ ይወሰዳል) ። ልክ ለ column 40d (40 times diameter of the bar) ብለን እንደምንወስደው።

የ Drainage ስራ ስንሰራ የተጠራቀመ የውሃ ግፊት (water pressure and pore water pressure) በከፋ ጉዳት እንዳያደርስ at design stage ቆም ብለን ማሰብ ይኖርብናል።

Source: - topper

               Foundation specialists

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