水草情迷

250kg/1平方米, 這個數據確實令不少魚友迷惑, 並且終日提心吊膽,

而師兄則獨排眾議, 提出新數據2.5噸/1平方米(not 250kg!!!),
如然則確實令人振奮, 而且可以放下心頭大石,

請問師兄這項珍貴數據資料從何得知, 可否分享一下?

Wa, 咁舊

[quote="mitac"]Design live load好明顯唔係2.5Ton, 係250kg/m2啦 (2.5kPa = 2500Pa = 2500N/m2 = 250kg/m2, with g~10), 不過唔洗驚, 因為lee個design loading係講成塊樓板(slab)

(no pen input at home... hee...hee...)

Yes, you are right in general. And do remember that there are safety factors such as 1.6 for the design live load... no need to worry about that at all.

However, if you still afraid of that, you may better obtain the structural framing plan of your premises and I may help...

Hi mitac,
I have a different understanding of the regulation with you, the total imposed load of the floor shall be distributed evenly on the slab, in this case, the area to stand for the tank is 72" x 36" = 1.8m x 0.9m = say 1.8 sq. m and the permitted imposed load shall be 1.8 x 2.5 kPa = 4.5 kPa = 450kg approx. only. In order to place the tank, the loading shall be evenly spreaded to an area of 15kN/2.5kPa = 6sq. m.
Therefore, it is danger to simply tell 穗香 it is ok to place such tank and also it is not a good suggestion to use the safety factor in the first instance because there will be a risk that the slab will become overloaded if there are some more loading imposed on that slab afterward without the checking of remaining permitted imposed loading.
Pl. let me know if I'm wrong.

_________________
鯛來也鯛去、鯛風教人掉．．．．＄＄＄

just a little remind~
most furniture in the house are not heavier than the tank,right?
IF 穗香's theory is right(i.e. the total loading of the floor can be >10000KG),
it's impossible to have collapse just because of one tank~
I know this is not funny to have a hole broken on the floor, but the force to make a hole is related to the breakage of the strength between concrete particle.TO break those force need even more times power than only a tank to give ,right?

pls correct~

三位師兄均具精闢見解, 真知灼見, 多謝, 多謝!

請教mitac兄
以我15呎平方單位計, 兩對邊為落地牆, 兩對邊為丁方1呎橫樑, 樑底係門與窗,
則靠牆邊還是靠樑邊承載力較大?

但我仍有疑惑, 以下列兩式看, 明顯地陣距愈大, 承載力愈大:
3m x 1m x 2.5 = 7.5kN = 750kg.
5m x 5m x 2.5 = 62.5kN =6250kg.

但以我淺薄愚見感覺, 假如以一個3m x 1m 大魚缸
直接放置於3m x 1m樓面上, 是否反而安全些?

有煩師兄賜教, 再次多謝

Yes, you are right in terms of concept and calculation.
However, my point is that when you consider the whole slab panel (which spaning between 2 beams for 1-way span or 4 beams for 2-way span), the total loading on that particular slab panel shall not be overloaded easily as you have to access the tank from at least 2 sides. Taking to the account of the space required for access, the overall loading on that slab panel will normally not be overloaded except a very large tank.

Some examples of overloading (locally) in domestic:
- 6 men sitting on a 6'x3' sofa ~> 600kg (370kg/m2)
- a 8' (H) x 6' (W) x 3' (D) storing cabinet ~> 600~700kg (432kg/m2)

No one will calculate and make beams to support these furnitures, why? The same principle...

I would rather remind people to consider the strength of tank itself and the supporting cabinet/rack for such a large tank.

唔好客氣. 但我唔係好明, 可否劃張圖看看?



Wa... 3m x 1m 泳池? (hee..hee.. 講笑)
其實要睇埋水深及附近放了幾多傢俱, 樓宇本身結構如何, 正如樓上師兄所講. 不過我講一般放在家庭的魚缸應該無問題係因為一般放在屋入面的合理(合比例)魚缸大極有限, 加上要有位置去觀賞及整理魚缸, 一般唔係大問題. 魚缸與屋大小不合比例另計.

其實好多魚友家裹都有大魚缸, 你也可以問

另行pm 師兄請教

我的疑惑是: 舉一個膚淺的例子,

一個人站在一條長1m陣距的木橋上,
是否應該較站在一條長10m陣距的木橋上,

來得安全些?

雖然唔識,但可以用另一個角度解釋,除了要看板面承托力,亦要看橫樑既接觸面長度所受既重力, 先假設板面承托力大於負重,即係板面唔會有承托唔到穿洞可能,相同面積的板面唔同長闊既面板,橫樑每尺接觸板面所受既重力都唔同。
假設樓面面板總重量 = 100kg, 面板有兩面有橫樑承托。
(1) 10尺 x 10尺 兩面橫樑既接觸面有20尺,每尺橫樑所受重力 = 100kg(樓面面板總重量)/20尺 = 橫樑每尺承受5kg的重量
(2) 5尺 x 20尺 兩面橫樑既接觸面在20尺的一面, 所以兩面總和有20尺x 2 = 40尺的接觸面,每尺所受重力 = 100kg(樓面面板總重量)/40尺 = 橫樑每尺承受2.5kg的重量

我相信大家都應該知道 2 的負重比會好過 1 了。實際應用,數據我就沒有,但印刷機這類重形機器的組裝要求就經常需要在原有樓面上加建石屎地台,因為樓層板面的負重量與機身重量要去到一定的比例,而加建的地台面積,使受力的樓面面積及橫樑接觸面積加大, 有時甚至要將地台建於橫跨兩條橫樑, 去分散樓面的負重。

唔係咩數據,祗是工作關係接觸得知!

_________________
"一起推動水族設景潮流, 集思廣益, 雅俗共賞。"
Life is to enjoy.....

Yes, provided that the section size, material & structural form are all the same for both bridges.

Hee... 我其實唔係好明你第1段所講, 但你在第2段所提及的確是真實的. 因為當要放真正重型機器時, 我們要check

1. 一個人站在一條長1m陣距的木橋上,
應該較站在一條長10m陣距的木橋上,
來得安全些, (陣距愈小, 承載力愈大= 安全些)

2. 以下列兩式看, 明顯地陣距愈大, 承載力愈大:
3m x 1m x 2.5 = 7.5kN = 750kg.
5m x 5m x 2.5 = 62.5kN =6250kg.

1.與2. 是否存在有矛盾呢?

問題有錯請指正