In this article today I am going to show you the important notes for structural drawing. which is too much important for civil engineers. Here in this article we will learn about materials, standard bar cut length, Standard hook’s and general notes about civil engineering. After reading this article you will be able to know all bout civil engineering important points.
Important Notes for Structural Engineering
1: Concrete of min. 28 days cylinder crushing strength of 3000 psi (Shall confirm to the relevant item in specifications provided with these drawings) Shall be used in construction of all the structural members including foundation Footing, foundation beams, floor slabs, beams, columns, stairs, slab etc.
2:Reinforcing bars used in structural members shall be of min. Yield strength of 40,000 psi Confirming to astm a-615.
Standard bar cut off points:
1:Standard bar cut off point for the negative reinforcement bars
shall be at distance of one third of the clear span length
(between the supports)from face of the support (l/3).
1:Hooks used for longitudinal tensile steel reinforcement bars shall be of 90 degree (right hook)
with an extension of at least 12 bar diameter at the free end of the bar and with a min.
diameter of bend of 6 bars diameter as shown in the figure below.
2:For all stirrups and tie bars 90 degree hooks shall be used with an
extension of at least 6 bar diameter at the free end of the bar and
with a min. Diameter of bend of 6 bar diameter shown in the figure below.
Standard bar splices
1:Lap splices in tension (used in all members and must in columns)
- For nos. (#) 3, 4 & 5 bars splice length = 12 inches.
Ii. For no. 6 bars splice length = 22 inches.
Iii. For no. 8 bars splice length = 40 inches.
1:Compression splices (used in all members except columns)
1:For nos. (#) 3, 4 & 5 bars splice length = 12 inches.
2. For no. 6 bars splice length = 15 inches.
3. For no. 8 bars splice length = 20 inches.
- Spacer bars of min. 1.0″ diameter or concrete
Spacer of 1″ thickness shall be used between the reinforcement
Layers to allow the placement of concrete between the reinforcement bars.
- Clear cover for slab = 0.75″
- Clear cover for beam = 1.5″
- Clear cover for column = 1.5″
- Clear cover for foundation = 2.5″
- All the positive (bottom) reinforcement is shown as solid lines.
- All the negative (top) reinforcement shown as dashed (broken) line.
- All the positive (bottom) reinforcement shall be extended a minimum of 6″ into the supports (beams)
- All the negative (top) reinforcement shall be cut off at l/3 from face of the support (beam)
Where l is the clear length between the supports (beams).
- In the edge slab panels the negative (top) steel shall be extended downward into the beams in the
Form of hooks. Minimum hook length for #4 bars is 6″.
- Concrete used shall have a minimum 28 days cylinder crushing strength of 3000 psi.
- Steel used shall conform to astm specifications of a615 with a minimum yield strength of 40,000 psi.
Note: The above notes are too much important, and these notes are using at site for all about construction and design data therefore you keep all these points in apply for any project to improve your knowledge and make your own design of any project construction