The cheapest bridge in Rural area

Spend 10 USD to build a bridge by tree (印度橡樹)  for 1 decade?


By this web site

https://edition.cnn.com/style/article/living-bridges-india-scn/index.html?fbclid=IwAR0z1hyqXHeFDlBEIsAimpTKnycMGeboUrwN6gFqGxxfNfCfZyogBLHwbSI

3 年前的文章，關於common service channel

公共地下設施服務系統:

有一日，當我們的團隊設計一個排水渠的發掘工程並重舖路面時，我們需要去與不同的地底所屬
負責人合作。 當日，我們的團隊被要求安排其他負責人更換掉地下的水喉，以頗免爆喉時又要重
新發掘。 當時，水喉佬有一個意見 - 他們的水喉可不可以走我們的排水渠。當時，由於工程的設
計己被定好，改動需要的VO可能很大，又怕阻到我們的排水渠，所以沒有接受。

但其實，外國一早存在這些概念，被稱為Common Service Channel (CSC)。可否直接建造CSC是較
高級的工程司想的問題。但，作為低級工程人員，我覺得其實發掘時，只要再掘多一點，或再加
上一面牆隔開排水渠和地底設施的通道，那就可以為日後的安排地下設施省下很多工夫或省下不
必要的重新掘路。在人口密集的香港，其實很多時都需要裝排水渠，那為什麼做時不可以做大點
讓其他所屬公司通過呢? 這意見可用在新建渠工程和大型維修渠或甚至重舖地下設施時，作為日
後更好的安排。否則每次發掘時，都要掘出一堆泥，再按標準回一堆泥，又要冒險探地，裝
shoring system，這現像可能可改善。

One day, when our project team decide to excavate for a drainage channel and repave the concrete
road surface, we have to coordinate between different under utilities party. There is a comment that
we have to renew all the old fresh water pipe in this project when we make improvement to the
pavement and drainage. So that there is no need to break up the concrete carriage next time. Our
team consider this idea justify and during the coordination, the water supply party purposed to add
their pipe into our drainage system. At that time, we reject the suggestion. But, I would accept the
offer after I read through the idea that there can be common service tunnel in a city planning. As
there would just excavate for a bit larger but can let other party easier to connect their utilities and
fewer works is needed. Actually, in a high people dense city like Hong Kong, it is always necessary
to construct drainage system. So, why don’t we excavate & construct the drainage system larger so
that other utilities parties can use it? This idea can be used in new works and enlarge the existing
drainage channel when repair works is needed. But, at least, the design details of this idea would
proceed to study under the complaint raised by citizens and government would strive to make the
best development planning in the future project.

drainage條 margin冇左會唔會更好？

If adjacent to the drainage is concrete slab,  what is the purpose of the drainage margin?

While,  normally,  it would reduce the support width of drainage cover.

Would it be possible to make the adjacent concrete slab (say 100 width)  50mm thicker instead,  then,  it would keep the abate support width. 

如果adjacent 係路， 會唔會冇左條margin 更好？ 或者條margin應該做出渠邊， 即2旁的路做厚小小。

steel bar Lap and anchoragelength calculation by excel

https://drive.google.com/file/d/1UCCX-psjPu1lTWHOMoPXjyZrk-NnJYo9/view?usp=sharing


一直希望用漫長的學習人生去慢慢一個個structural calculation excel 整出來，整教學和公式的根據。 希望而家職位低微唔會令我放棄呢個興趣。

石矢lap length
取決因素:
steel bar strength
Under tension or compression
concrete strength


根據steel bar 和 石矢的接觸面愈大,黏力愈大
steel bar接觸面的formula 係: 2R*PI()*Length

有空打

Different types of pavilion roof

4個摺位因為太多鐵cross over, 所以好時會整條幼beam 比佢。

亦有一種傳統方法，但我冇mark低，因為D鐵較為密或難以3D表達。

但那種圍鐵方法可以容許roof 有curve 的存在。

畢竟只受風力，大概好多種設計都ok.