Attention must be given to detailing to facilitate convenient and easy fabrication and hence efficient construction, which gives an overall economical design. Verity must be kept to a reasonable level as far as possible. A design may consist of many beams of the same geometrical nature each having slight variations in loading. To consider each as one individual design would result in many different sections or details. The work entailed in designing, drafting and fabricating the many varieties would certainly not result in an economical structure. The use of complicated details or built up steel sections not easily fabricated or obtainable may result in an expensive form of construction even though the proposed design suggests that the minimum amount of material required to resist the load have been used.

The 3 types of steel reinforcement to be used for reinforced concrete structures are hot rolled plain round mild steel bars and deformed high yield bars, both to BS 449 and welded fabric reinforcement to BS 4483. Steel bars are manufactured in lengths of 12 m long welded fabric are in rolls of 2.4 m wide and cut to required size in the factory. As steel bars do not generally exhibit a definite yield point an arbitrary equivalent yield stress, the 0.2 % proof stress, the stress at which the bar increases in length by not more than 0.2 % of its original length, is used. High yield steel should be used as major reinforcement in beams, columns, large span and heavily designed slabs whereas mild steel should be used for nominal reinforcement, stirrups, links, ties, distribution bars and as main reinforcement in light designed slabs, parapets, walls and water retaining structures. Fabric steel should be used for slabs, parapets or walls where there is a high degree of repetitiveness in fabrication and the speed and low cot of fixing would provide the overall economy even though it will not be possible to curtail alternate bars.

Bars of as few different sizes as possible should be used. The size of bars used depends on several factors such as convenient spacing in the concrete, the required cover, the bond stress, each of handling, etc. But for a given cross-sectional area of steel, a small number of large bars will generally be cheaper than a larger number of smaller bars. Where bars over 25 mm diameter are used, the concrete cover may have to be increased. Anchorage and local bond considerations may force the designer to use the smaller sizes. Bars for slabs will normally be chosen from size 10 mm to 16 mm. Bars of beams and columns will normally be chosen from 13 mm to 25 mm. For stirrups in a beam, one size of bar should be chosen and the pitch varied as necessary. 6 mm bars should be avoided wherever possible, except where they are used as beam stirrups or column links. It will get trodden on when placed horizontally in slabs, and the links produced can never be eradicated. When placed in walls it will be found too weak to hold up the other reinforcement. Bars required for tying other bars on to, for example, to bars in the center of a beam for hanging stirrups on should be at least 13 mm diameter. Hooks should be eliminated if they can be replaced by the corresponding length of straight bar. Stirrups or links should be used as shear reinforcement in beams rather than using bent-up bars, except in the case of heavy shear stresses.

The area of cross wires of C-series fabric reinforcement does not satisfy the 0.12 % of sectional are of slab as recommended and additional bars are usually laid on the fabric to supplement the cross wire to comply with the recommendation. Such steel is important however when substantial temperature stresses are liable to occur, like roof slabs, corridors, etc. or when the slabs is of substantial length (or width) in the direction of the cross wire. When such additional bars are required they should be placed within the tension zone at the slab bottom. Using additional bar in the direction of the cross-wire and spanning the longer direction should also use c-series fabric in 2 way slabs. Where there is no fabrication difficulty, bent fabric should also be used. A-series fabric should be used as temperature steel in walls and unsuspended ground floor slabs. Where they are used in 2 way spanning slabs, tension laps must be provided and detailed. B-series fabric may also be used for 1 way spanning slabs if the area of across-wires matches closely the area required in the transverse direction if not it tend to be uneconomical. Special fabrics can be manufactured in accordance with the designers requirement as to the sizes and spacing of bars in both directions, but they must be in sufficient quantity to enable an economical price possible.

Plans, elevations and sections should be clearly defined. Section through plans should always be taken looking to the left (or upwards) and through elevations, to the left (or downwards). Dimension lines of structural units, where no general arrangement drawing is provided, should always be taken outside the member considered and should be clear but in thinner line form than the outline of the member to avoid confusion. As far as possible general arrangement drawing (key plans) should be provided in which case the reinforcement drawing will not show unit dimensions.

Reinforcement should be in heavy line form since it is the most important item on drawing. An indication of the reinforcement with one (or two if alternate) typical bar only in full should be drawn on plans and elevations. The bar should also be fully located either on plan or section. Cover or slab thickness should be indicated on the section where it varies from one unit to another on a drawing. Where it is constant it can be called up in the notes.

The standard abbreviations foe bar types should be used:-

     50, 75, 100, 125, 150, 175, 200, 250, 300, 350.