鋼筋會埋藏在石屎裡有幾深?

鋼筋會埋藏在石屎裡有幾深?
In according to the BS 8110, the concrete cover should fulfill the following requirements:
1. should not less than the main bar or equivalent cross section area if in bundles or less than the nominal maximum size of aggregate..
2. protect the steel against corrosion.
3. protect the steel against fire
4. allow for surface treatments.
上面的意思是說，要根據主鋼筋的直徑和石屎中的最大石仔直徑，取其大者。
(另外在 bundles 裡，要計橫切面積，這點我不清楚。)
例如：main bar Y40, concrete mix 35/20 即 concrete cover 40mm。若 main bar Y10, concrete mix 35/20, 即 concrete cover 20mm.
但在懸臂式結構，BD 有要求 concrete cover 要至少 40mm (見下)
http://www.bd.gov.hk/english/documents/pnap/Pnap173.pdf ( 5(c), p2)
水,電,煤,喉管的路徑怎樣走?有否規格?
這點不清楚，一般來說水和電的路徑是根據樓宇結構設計，沒有太大要求。煤氣管進入樓宇時是有例規管，但是我不清楚。
其實，石屎 和 水電煤 是兩個不同專業，建議您最好分開兩條問題問。

圖片參考：http://i175.photobucket.com/albums/w130/bjoechan2003/My%20Cat/DSC00002.jpg?t=1170197548

good ans.

鋼筋會埋藏在石屎裡有幾深?

Concrete Cover

In according to the BS 8110, the concrete cover should fulfill the following requirements:
1. should not less than the main bar or equivalent cross section area if in bundles or less than the nominal maximum size of aggregate..
2. protect the steel against corrosion.
3. protect the steel against fire
4. allow for surface treatments.

The following different types of spacer is used in provided adequacy concrete cover to the reinforcement:

Large diameter concrete cover for bored pile Fixing of concrete cover on the bored pile Plastic wheel spacers for the vertical side of the walls/Columns Plastic wheel spacers

Concrete Block used in ground slab/foundation to provide 50-75 mm concrete cover Plastic chair for slab bottom bar Plastic chair Steel chair for slab top bar

Steel chair Steel chair for heavy slab top bar Top view of the steel chair Plastic spacer for beams

Spacing 應最少為maximum aggregate size +5至20不等,可參閱bs8110。或5400,如果做橋的話。用minimum spacing的原因為要肯定石屎可以容易通過鐵和鐵之間的空隙,如果太少的話,石屎就不夠過了。


水,電,煤,喉管的路徑怎樣走?有否規格?