# Author: Practical Civil Concepts In my Pocket

# Setting out Right angles method by 3-4-5 method

**3-4-5 method is commonly used for setting out the right angle by using the tape which gives pretty accurate right angle and is widely used in day to day practice.**

**Person 1:** holds the zero mark & 12m mark of tape

**Person 2:** holds the 3 meter mark of the tape

**Person 3:** holds the 8 meter mark of the tape

When all the sides are stretched, a triangle is formed and the angle near position or person1 is a right angle.

We can either use: 3-4-5 m

Or other multiplies too, depending upon the situation, say

6-8-10 m

9-12-15 m

12-16-20 m

# Why use 150mm size cube for testing ?

- Maximum construction site have the cube testing machine of capacity 100 ton/ 1000 KN. We calculate the compressive strength as Load / Area i.e. N/mm².

- If we increase the loading area, the load for crushing or the load at which it fails also increases.

- If you are checking M30 grade concrete and you require minimum compressive strength of 33 N/mm² and the size of cube is 150 mm, then the load required to get this much strength is 742.5 KN.

⇒ Compressive Strength = Load / Area

⇒ Load = 33 x ( 150 x 150 ) = 742.5 KN

- If you use cube of size 300 mm, the load required becomes 2970 KN which is practically not possible because to crush the respective cube we require 3000 KN/ 300 ton capacity machine.

- When the applied load is much more, the additional safety factor needs to be increased because when the cube fails under such loads, it may hit anything in room with bullet speed.

- Also, casting of this size cube and handling is not easy.

- For feasibility, safety and ease of work therefore we prefer the 150mm size cubes.

- If you have a machine with less capacity and load to crush the cube is more than the capacity of machine; you can further reduce the size of cube to 100 mm preferably.

# Theoretical Weights of Material:

**Cement 1440 kg/m3****Steel 7850 kg/m3****Bricks 1600 – 1900 kg/m3****20 mm gravel 1750 kg/m3****R.C.C. 2500 kg/m3****P.C.C. 2400 kg/m3**

**Aluminium 2710 kg/m3****Brass 8525 kg/m3****Copper 8920 kg/m3****Stainless Steel 7900 kg/m3****Wood (Oak) 600 – 700 kg/m3****Water 1000 kg/m3****Ice 920 kg/m3**

# AutoCad 2D & 3D Basics

**“Everything in this world is easy unless you take the first step.”**

The** best way to learn the AutoCad for the beginners who have not taken any courses for learning the same and also for those who have zero knowledge of its operation, is to install the AutoCad in your comp and try operating every command as per my tuts everyday. It does not matter which upgraded version of AutoCad software you use as long as you know the shortcut keys of the command. I assure you; within no time you will boost your confidence level in learning the software. **

- AutoCad is a software program which has been used in various industries for many years. This software can help architects, designers, engineers, etc…

- This particular product is used for the engineering of new bridges, buildings, stadiums, homes, electrical and so much more.

- This software is actually very helpful for engineering students, especially those that wish to have an impact on their engineering course.

- This software is so easy to use and offers the ease of cut, copy and paste, saving time, energy and making it easy to use once you know how.

- Hundreds of people attend AutoCad classes every year to add to their growing resume, making them more appealing to prospective employers and increasing their chances of being accepted for promotion.

**I will be sharing my notes of AutoCad that I had prepared during my engineering days in the form of pictorial representation. Hope it would be beneficial to all my upcoming civil engineering friends. Any feedbacks and comments are appreciated. Also don’t forget to like my post if you find it worthy. Have a nice day !!! God bless you all.**

AutoCad tutorial comprising of 22 pages. Hope it would be easy and simple for you to understand. Lets begin…

*Good day, pals !!! *

# Reconciliation of steel

- Length of one rod from each diameter is to be measured and written in Stock Register.

- Weight of rods vary from the standard weight.

- Calculating the weight of steel based on the sample unit weight is necessary to avoid manipulation by the Supplier.

- This actual weight of steel is required for the periodical Reconciliation of Steel.

**Say, for example**

**100 MT of 16mm Ø bars of Fe500 grade are required to procure. Assume the weight of bar received is 1.63 kg/Rm.**

**⇒ Total Weight of Steel received = 100,000 kg**

**⇒ Standard Weight of Steel = 1.58 kg/m**

**⇒ ∴ Length of Steel received = 100,000 / 1.63 = 61,349.693 m**

**⇒ But the length of Steel as per Standard weight = 100,000 / 1.58 = 63,291.139 m**

**⇒ Loss of Weight = ( 1.63 – 1.58 ) / 1.58 = 3.16 %**

**This is the Rolling Margin in Reinforcement Steel.**

**The Allowable deviation in Rolling Margin in R/f Steel ( IS 1786 ) :**

**8 mm to 10 mm : ± 7.0 %**

**12 mm to 16 mm : ± 5.0 %**

**20 mm & above : ± 3.0 %**

**⇒ Weight computed by measurement & Standard weight**

** = 61,349.693 x 1.58 = 96,932.50 kg**

**⇒ Loss of Weight = 100,000 – 96,932.50 = 3067.50 kg**

# For easy remembrance of the Conversions-

*There is an equal importance to both English and metric systems in our path.*

*I have come across many times to an situation where most civil engineering students find it very difficult to work with the British Systems of measurement as they are use to metric systems only.*

*These conversions are for those fellow friends who are confused and find it bit tough to convert the respective units. Hey pals, its time to play with these conversion factors without any hesitation….*

** Conversion of Approx Conversion Accurate Conversion for easy remembrance**

**m to ft****x 3**x 3.278**ft to m****x 0.3**x 0.305**sq.m to sq.ft****x 10**x 10.76**sq.ft to sq.m****x 0.09**x 0.0929**cum to cub.ft****x 35**x 35.315**cub ft to cum****x 0.028**x 0.0283

**Foot-Inch Conversion :**

**1 foot = 12 inches**

To Convert, ft to inches → Multiply by 12

Inches to ft → Divide by 12

**Consider an example: We got to add………7′ 10″ + 8’5″**

- Just add foot with foot & inches with inches

= ( 7′ + 8′ ) + ( 10″ + 5″ )

= 15′ + 15″

Now divide by 12 to convert inches to ft

= 15′ + ( 15 / 12 )’

= 15′ + 1.25′

= 16.25′

**To convert this 0.25 into iches, x by 12**

i.e. 0.25 x 12 = 3″

Thus we would have 16′ 3″.

*Have a nice day civil engineering fellas !!! Its an pretty easy concept but have due importance at every stage of civil engineering work. Hope you enjoy it.*