Read the Full Blog to know what is Site benchmark in surveying & a Temporary bar is and why this is important before building houses complete practical knowledge from the site benchmark.
14 Dec 2021
Do you know about Site Benchmark - In the Picture below, you can see-Written there 301.300 Hospital Plinth Level. Meaning, Whatever we construct in the Excavation site, Everything, Including these (Excavation, building height, Road, Drain), will be taken from this Reference only.
Because Site Benchmark is made concerning the Road Level and transferred to this, you'll know how the site construction works starts from zero. You'll find the surveying team has set this kind of Benchmark. they take these becnchmark with respect to the mean see level. with the help of this benchmark, every building components contruct. And this is distributed all over the site boundary.
These BMs served as local reference of precisely measured elevation and They were often on stone posts, milestones, stone embedded into culvert walls, bridges, Railway Platform, temple/church. These indicate current day survey of India Topo Maps.
In every 100 Km Distance, you'll find a permanent benchmark taken concerning the mean sea level.
A temporary benchmark (TBM) is a point with a known elevation used for level control during drainage construction works of houses and surveys. For example, nails on road level or marks on drainage channels are use as temporary benchmarks.
Your House drainage pipes must be drop at somewhere in the main drain line, and the position of your house drainage pipe (Inside) must be above the main drain line.
For that, you have to establish TBM (Temporary benchmark) concerning that Drain Line (House drain). Below you can see the Temporary benchmark taken from the site benchmark.
A temporary benchmark (TBM) is a point with a known elevation used for level control during drainage construction works of houses and surveys. For example, nails on road level or marks on drainage channels use as temporary benchmarks.
Your House drainage pipes must be drop at somewhere in the main drain line, and the position of your house drainage pipe (Inside) must be above the main drain line. also to maintaing the slope of the drain line.
For all these, you have to establish TBM (Temporary benchmark).
A temporary benchmark (TBM) is a fixed point with a known elevation used for level.
Road Level as the TBM- Most of the time, Even Road level also matters for the TBM Benchmark.
You have to see the present road level and consider that one-day road level will be high.
In the future, the road level would go up, your House might be down, and water will flow to your House.
You have seen this with many Houses.
TBM should not take from the Neighbour’s House- You have to take TBM according to the final destinations.
The Site Benchmark should not take from the Neighbours because you don’t know if they have taken the measures correctly or not. Otherwise, If the person’s House is drowning, your House will drown too.
These 3 methods are considered as the TBM for your House Drainage system.
1. Water Level Pipe
2. Auto Level
3. Total Station
Plumbing Code- These are all according to the Plumbing Code specification-
1. For Open-drain Line- Where, for 1 m distance, 20.8 mm Slope is considered.
2. For Closed-drain-Line- For 1 m Distance, A 10.4 mm slope is considered.Even a Little slope is sufficient to free the water flow from the house 5mm to 10 mm per meter.
So till now, you have understood what is Benchmark in surveying and Temporary benchmark. So if you want to know such amazing Practical things- Click Here!
Also, Read- How to Center Line Layout Done at site
Read the practical training- What is- Evening Planning/ Morning distribution sheet?