2. Reinforced Concrete Design-II
Detailing of RCC
By Dr. Attaullah Shah Swedish College of Engineering and Technology Wah Cantt.

3. What is an Engineer: Herbert Hoover-US president Engineer turned politician said:
The great liability of the engineer …compared to men of other professions……is that:
His works are out in the open where all can see them.
His acts …..step by step …are in hard substances.
He cannot bury his mistakes in the grave like the DOCTORS.
He cannot argue them into thin air…..or blame the judge…..like the LAWYERS.
He cannot, like the ARCHITECT, cover his figures with trees and vines.
He cannot, like the politicians, screen his shortcomings by blaming his opponents….and hope the people will forget. The ENGINEER simply cannot deny he did it.
If his works do not work……he is damned.

4. Details and Detailing of Concrete Reinforcement (ACI 315-99) Reported by ACI Committee 315
Increased use of computers has led to sophisticated techniques of structural analysis and has increased manufacturing and fabrication capabilities.
More complex structures being designed and built with structural members that have long spans, shallow depths, and contain a high percentage of reinforcing steel.
The Architect/Engineer (A/E) prepares the structural design to meet the requirements of the applicable building code and provides sufficient definition through the contract documents to convey all the requirements for detailing reinforcing steel.
It is then the detailer’s responsibility to develop all of the dimensions and quantities of the reinforcing steel to conform with the structural drawings and project specifications of the A/E.
As the complexity of design and construction increases, it is imperative that both the A/E and detailer understand their responsibilities clearly.

5. Drawing standards Commercial standards: 18 x 24 in. (457 x 610 mm)
Materials—The minimum standard media for production of structural drawings should be penciled on tracing paper. Other media providing improved reproducibility or durability, such as microfilm, electronic files, ink, tracing cloth, or polyester film, can also be used.
Drawing sizes:
Commercial standards:
18 x 24 in. (457 x 610 mm)
24 x 36 in. (610 x 914 mm)
27 x 36 in. (686 x 914 mm)
30 x 42 in. (762 x 1067 mm)
Direction—An arrow indicating the direction of North should be placed on every drawing that contains a plan view
Scales—The scales used should be indicated on all structural drawings, preferably under the title of each view. Drawings that can be enlarged or reduced in reproduction should show a graphic scale, as well as a descriptive one, to aid the user.

6. Lettering—All lettering must be clear and legible
Lettering—All lettering must be clear and legible. If reduced scale photographic prints are made for field use, lettering must be correspondingly larger and meet microfilming standards in accordance with the Association for Information and Image Management

7. Detailing principles
Prepare drawings properly & accurately if possible label each bar and show its shape
Cross section of retaining wall which collapsed immediately after placing of soil backfill because ¼” rather than 1-1/4” dia were used. Error occurred because correct rebar dia. Was covered by a dimension line for clarity.

8. 2. Prepare bar-bending schedule , if necessary. 3
2. Prepare bar-bending schedule , if necessary. 3. Indicate proper cover-clear cover, nominal cover or effective cover to reinforcement. 4. Decide detailed location of opening/hole and supply adequate details for reinforcements around the openings. 5. Use commonly available size of bars and spirals. For a single structural member the number of different sizes of bars shall be kept minimum. 6. The grade of the steel shall be clearly stated in the drawing. 7. Deformed bars need not have hooks at their ends. 8. Show enlarged details at corners, intersections of walls, beams and column joint and at similar situations.

9. 9. Congestion of bars should be avoided at points where members intersect and make certain that all rein. Can be properly placed. 10. In the case of bundled bars, lapped splice of bundled bars shall be made by splicing one bar at a time; such individual splices within the bundle shall be staggered. 11. Make sure that hooked and bent up bars can be placed and have adequate concrete protection. 12. Indicate all expansion, construction and contraction joints on plans and provide details for such joints. 13. The location of construction joints shall be at the point of minimum shear approximately at mid or near the mid points. It shall be formed vertically and not in a sloped manner.

10. DO’S – BEAMS & SLABS:
Where splices are provided in bars, they shall be , as far as possible, away from the sections of maximum stresses and shall be staggered.
2. Were the depth of beams exceeds 750mm in case of beams without torsion and 450mm with torsion provide face rein. As per ACI-318
3.Deflection in slabs/beams may be reduced by providing compression reinforcement.
4. Only closed stirrups shall be used for transverse rein. For members subjected to torsion and for members likely to be subjected to reversal of stresses as in Seismic forces.
5. Accommodate bottom bars, it is good practice to make secondary beams shallower than main beams, at least by 50mm.

11. Do’s –COLUMNS.
A reinforced column shall have at least six bars of longitudinal reinforcement for using in transverse helical reinforcement.-for CIRCULAR sections.
. A min four bars one at each corner of the column in the case of rectangular sections.
3. Keep outer dimensions of column constant, as far as possible , for reuse of forms.
4. Preferably avoid use of 2 grades of vertical bars in the same element.
DONOT’S-GENERAL:
1. Reinforcement shall not extend across an expansion joint and the break between the sections shall be complete.
2. Flexural reinforcement preferably shall not be terminated in a tension zone.

12. Bars larger than 36mm dia. Shall not be bundled.
4. Lap splices shall be not be used for bars larger than 36mm
dia. Except where welded.
5. Where dowels are provided, their diameter shall not exceed the diameter of the column bars by more than 3mm.
6. Where bent up bars are provided, their contribution towards shear resistance shall not be more than 50% of the total shear to be resisted.
USE OF SINGEL BENT UP BARS(CRANKED) ARE NOT ALLOWED IN THE CASE OF EARTHQUAKE RESISTANCE STRUCTURES.
Minimum and max reinforcement % in beams, slabs and columns as per codal provisions should be followed.

38. One way slabs

40. Beams

42. Joist Construction

44. Column and Splice details

46. Seismic Resisting details