Rebar

What is rebar and where is it used?

Rebar is a ribbed steel bar cast into reinforced concrete to carry the tensile stresses that concrete on its own resists poorly. The transverse and longitudinal projections on the surface, the ribs, lock the bar into the concrete and stop it slipping, which is what creates bond; a plain round bar simply cannot do the same job.

It goes into foundations, shear walls, columns, beams, slabs, stairs, retaining walls, ground slabs and every kind of precast work. The bar we sell is black, that is, uncoated, and is priced by the kilogram. We sell the product and ship it from our Ostim base across Turkey; bar bending and tying labour on site is not part of what we offer. You can add formwork consumables such as construction nails to the same order.

Ribbed bar has a second job: crack control. Concrete inevitably cracks, and the reinforcement is not there to prevent cracking altogether but to keep the width limited and keep load transferring across it. That is why bar spacing and cover matter at least as much as diameter. Cover is the thickness of concrete protecting the steel from the environment and from heat in a fire; once you drop below the value given on the drawings, increasing the diameter achieves nothing.

Diameters in stock and technical data

We hold three diameters. The weights per metre given in the table are theoretical values, produced with the calculation the whole trade shares.

Steel grade and batch details are confirmed when the order is placed. On jobs that have drawings, always check which grade the structural calculation assumes; even with the right diameter, a difference in grade changes the load capacity.

How do you work out weight per metre from diameter?

The formula is simple and every site knows it by heart: kg/m = diameter² / 162. Take the diameter in millimetres, square it and divide by 162. It comes from the density of steel, 7,850 kg/m³; multiplied by the area of a circular section that gives a coefficient of 0.006165, and the inverse of that is roughly 162.

Applied to our sizes: for Ø8, 64 / 162 = 0.395 kg/m. For Ø10, 100 / 162 = 0.617 kg/m. For Ø12, 144 / 162 = 0.888 kg/m. The ribs are covered by this figure, because theoretical weight is defined on the nominal diameter. Small deviations on the scale are normal; expect a point or two of difference between the weighbridge ticket and the theoretical calculation.

The formula has one more use. When bar arrives on site you can accept the delivery by comparing the weighbridge ticket with the theoretical figure and see whether the tonnage is short. Measure the length of a few bars from the batch and multiply by the number delivered, then multiply those running meters by the weight per metre to reach the theoretical weight. A gap outside a reasonable tolerance is the first sign that diameter or length does not match.

Converting tonnes to metres, with a worked order

Rebar is sold by the kilo but the drawings come out in metres. To convert, multiply the total running meters by the weight per metre. Example: if a slab schedules 620 metres of Ø10 and 340 metres of Ø12, then 620 x 0.617 = 383 kg and 340 x 0.888 = 302 kg, so the order placed is 685 kilograms.

Reading it the other way round is just as useful: 1 tonne of Ø10 is 1000 / 0.617 = approximately 1,620 metres, or about 135 bars in 12 metre lengths. One tonne of Ø8 works out at roughly 2,530 metres. Adding 5-8% to the running meters for cutting waste and lap lengths is sound practice; laps build up serious tonnage, particularly at Ø12.

The length you order also moves the tonnage. Ordering long bars and cutting them on site can leave short pieces accumulating as dead waste; ordering short bars, on the other hand, increases the number of laps and pushes the total kilos up. The soundest approach is to identify the element length that repeats most often and plan the order around it. Where a slab takes hundreds of cuts at the same length, waste can be brought down to almost nothing.

Stirrup and lap length calculations

Ø8 bar is used mostly for stirrups, and stirrup quantities are the ones most often taken off short. The cut length of a stirrup is the net perimeter of the column plus an allowance for the hooks. Example: for a stirrup sitting on 25x45 centimetres once cover has been deducted, the perimeter is 2 x (25 + 45) = 140 centimetres, with roughly 16 centimetres more for the hooks at the two ends; the total cut length comes to 156 centimetres.

With stirrups at 15 centimetre centers up the column, a 3 metre column takes 21 of them. 21 x 1.56 = 32.8 metres, and that means 32.8 x 0.395 = approximately 13 kilograms of Ø8 bar. Do not forget the laps on the longitudinal bars either; lap length is typically in the order of tens of bar diameters and is stated on the drawings.

Stirrup spacing is not constant up the column. Close to the beam connections, in the confinement zones, stirrups are closed up, while the spacing opens out in the middle region. Taking the quantities off with one average spacing for the whole column is the most common reason for under-ordering; work out the confinement zone lengths on the drawings separately. Since the inside radius stretches when the bar is bent, make the first stirrup as a template and try it in the section.

Black surface, rust and acceptance on site

The bar we sell is black; there is no protective coating on the surface. A thin film of surface rust on bar left standing outdoors does not count as a defect, and light rust does no harm to the bond with concrete. What cannot be accepted is flaky, laminated rust that comes away in sheets when rubbed by hand; that means loss of section.

Do not lay bar straight onto the ground on site. Stack it on blocks or box section, a few centimetres clear of the ground, in bundles kept separate by diameter. Bar carrying oil, grease or mud will not key into the concrete; check that the surface is clean before the pour.

Cover any stack that will stand for a long time, but do not let the tarpaulin hang to the ground; moisture trapped underneath speeds the rusting up. Covering it so that air can move through is the right way to do it. Lifting a bundle from a single point in the middle bows it as well, permanently deforming bars that need to stay straight; lift from two points with a proper sling.

Site deliveries and stacking discipline

The problem that comes up most often on rebar deliveries is that nobody planned the unloading. Settle in advance where the vehicle will pull up, whether there is a crane or forklift available and what the ground is like in the stacking area; a one tonne bundle of bar cannot be shifted by hand.

Separate the stack by diameter and label it. Ø10 and Ø12 are not always distinguishable by eye on site, and a caliper is the safest way to be sure. To secure the ground around the works, a temporary enclosure of construction safety barriers reduces both material losses and third-party risk.

One more detail on the safety side is the ends of bars standing vertically. Fitting plastic caps to starter bars, or bending the ends over, prevents serious injury if someone falls. Do not let offcuts collect in a corner either; short pieces are a hazard in the walkways and tend to go missing when they could have been recovered as scrap.

What determines the price of rebar?

Price is driven almost entirely by raw material: the tonne price on the billet and wire rod side, the scrap market, energy costs and the exchange rate. Rebar is one of the product groups with the thinnest margin, so movements in raw material feed through to the price almost one for one and can shift within the day.

Secondary factors are diameter, order tonnage, length choice and delivery distance. Unit cost rises on small diameters because the production cycle runs longer. All our prices include VAT and exclude carriage. Current figures are in the price table on this page; we quote no figures in the text, because they are out of date the moment they are written.

Ordering, site survey and delivery terms

To order, it is enough to tell us the total kilograms with a breakdown by diameter. If all you hold is the running meters, we can work the tonnage out with you using the conversion above. The site survey is free within Ankara; seeing the unloading conditions and the stacking area in person removes the surprises that otherwise appear on delivery day.

Delivery is always charged. Carriage is added to the order separately, deliveries inside Ankara included; it is never built into the product price on any consignment, and the amount is confirmed in advance according to tonnage and distance. Installation and bar fixing are not a standard service of ours; our teams attend site only on perimeter projects of approximately 1000 metres and above.