Subscribe to My You tube channel

Bar Bending schedule (BBS)

By -

 The bar bending schedule is a table that contains the details of reinforcement for a specific structural member such as footing, column, slab, and others. The bar bending schedule will contain the bars' dimensions to be used, the shape of the bars, the size of bars, bar mark, number of bars, and the weight of bars. BBS will be used to determine the weight of reinforcement required for a specific structural member. 

there are various advantages of bar bending schedule such as:

  1. estimating the quantity of reinforcement for each structural member. So we can estimate the amount of reinforcement required for a construction project. 
  2. BBS will help in reducing the losses of steel by procuring the precise quantity of different rebar diameter. 
  3. BBS will reduce the wastage of reinforcement by providing the engineers with the exact dimension and shape of rebars. Knowing the exact dimension and shape will reduce the time of cutting and bending rebars. 
  4. BBS will reduce the effort at the time of billing. Quantities of reinforcement will be calculated and shown in BBS. Therefore the billing of reinforcement for various members will be quick and simple.
  5. For big projects. The main contractor will not cut and bend the reinforcement. The cutting and bending will be done at the factory. The presence of BBS will reduce the effort and time of cutting and bending reinforcement at the factory.
  6. The bar marks can help the fabricators in placing the rebars in correct locations. The bar mark usually is shown in the shop drawing, and each bundle of bars will have a tag with a bar mark and detail.
The preparation of the bar bending schedule will be done for different bars in a reinforced member. First, we will identify an identical rebar group. From figure no:1, we can see a different type of rebar—for example, T32-125-B1. T23 is the bar diameter, and it will place at a space of 125 mm. B1 is the location of the bar. The legend of reinforcement drawing will explain the symbols such as B1, B2, T1, etc. after determining the identical group of bars such as T32-125-B1, we will give the group a unique id such as 1A1.
Figure 1

The next step is to determine the number of bars in each group. The number of bars can be determined by knowing the spacing between bars, length of the member, and the concrete cover. For our example: we have T32-125-B1. The C-C spacing between 32 bars is 125 mm, and the length is 9000 mm, as shown clearly in figure no:2. The concrete cover is 100 mm. 

number of bars=(9000-2*100)/125+1=71.4 so it is 72 bars. 
So now we have the mark for this group of bars(1A1), and we have the number of bars(72). 

Figure 2


After determining the bar mark and bar number, we need to determine the bar length. Bar length will depend on bar shape.usually, the designer will determine the bar shape. If we look at figure no:1 again. We will notice that the bar T25-150-B2 is a U shape as drawn by the designer. Similarly, T32-125-B1is a U shape, but it is not shown clearly in this section. Usually, the designer will provide a plan and a cross-section in each direction. We can also notice that the designer determined the shape of bar T32-250-FF, which is a dowel bar for the wall above the pile cap. The shape of this bar is L, the length of each shape can be determined from figure no:3. While calculating the bar's length, we should not forget the overlap length with other bars. for long members, it is impossible to use an individual bar from the start to end. Therefore, we use two or more bars, and we overlap it. Overlapping will be determined by the designer. The designer will usually provide the overlapping length and anchorage length, similar to what is shown in figure no:4.

Figure 3



Figure 4

The last step is to calculate the weight of each group of bars. the weight will be calculated using the following equation:
weight of bar group=(no of bars)*(length of the bar)*(Bar weight per meter)
bar weight per meter for various bar diameters shown in figure no:4. Figure no:5 showing a sample of the bar bending schedule.

Figure 5



Comments

  1. steel constructionJuly 15, 2023 at 4:03 AM

    Thnks for sharing this blog. If you know more about Bar Bending Schedule than Connected with Us.
    If you know more about Bar Bending Schedule services than visit Here :
    https://www.steelconstructiondetailing.com/bar-bending-schedule.html

    ReplyDelete
  2. ROBOTIC TECHNICAL SUPPORT SERVICESDecember 21, 2023 at 8:10 PM

    This comment has been removed by the author.

    ReplyDelete

Post a Comment

Popular posts from this blog

Binding wire for steel reinforcement

By -
Image
  Binding wires are used to tie steel bars together. These wires are playing a significant role in maintaining the reinforcement stability and rigidity. Wires are used to tie the steel bars at intersections points. By tying the steel bars together, we ensure that the steel bars will not move from their locations during construction or during the time of concreting. In slabs, binding wires are used to tie longitudinal and transverse bars together. In columns, it is used to tie vertical bars with stirrups.   Figure 1 There are various types of binding wires such as  Black annealed baling wire, Stainless Steel Binding Wire, and PVC coated binding wires.  Black annealed baling wire used to tie black steel. The popular size for black wire ranges from 16 to 22 gauges. Stainless steel binding wires are used to bind stainless steel reinforcement. Stainless steel reinforcement is used in a harsh environment where the black steel gets rusted quickly. Therefore, stainless steel reinforcement is u
Read more

stress-strain diagram for aluminium alloy and rubber

By -
Image
figure no:1 showing the stress-strain diagram for aluminum alloy. we can notice from the stress-stress diagram that aluminum has a considerable ductility. despite the absence of explicit yield point as in structural steel . the initial portion of the stress-strain curve is linear with a recognizable proportional limit. the proportional limit for aluminum alloy ranges from 70 to 410 Mpa (10 to 60 Ksi). aluminum alloy undergoes large strain before failure. ultimate stress ranges from 140 to 550 Mpa (20 to 80 Ksi). construction management: concrete construction bridge construction:How to become a bridge engineer Figure-1 Yield stress for aluminum alloy can be determined by drawing offset line parrel to the linear portion of the stress-strain curve. the straight line offset by a standard strain such as 0.002. the intersection point with the stress-strain curve is the point of yield stress. figure no:2 illustrates the concept of offset method. yield stress acquire
Read more

Repairing of concrete bulging

By -
Image
Improper designing and installation of formwork for a concrete member can result in concrete Bulging. During the placing and compacting of concrete, forms may deflect largely in the weak areas. The deflection of forms will cause concrete to expand at this location, and this known as concrete Bulging. Concrete Bulging will spoil the appearance of a concrete member. Therefore we should always ensure that the forms are appropriately installed, and it is sufficiently supported to resist the concrete during placing and compacting. Bulging should be repaired in case we couldn't avoid it. The solution of concrete Bulging, offset, or surface irregularities are surface grinding. However, excessive surface grinding can weaken the concrete.  Figure 1 If the bulging or surface irregularities are small, grinding of concrete surface will be sufficient to remove surface irregularities. If the Bulging of concrete is significant, then the concrete should be chipped, and the surface
Read more

Pile cap

By -
Image
Pile cap used to transfer the loads from superstructure to the piling. The pile cap is thick concrete mat rests on piles. It is part of the foundation and used to distribute the loads over the piles. Piles used when the soil bearing is not enough to carry loads of the structure. Figure 1  construction management: concrete construction bridge construction:How to become a bridge engineer Pile cap construction procedure Excavation around piles: After 7 days of the casting of the pile the concrete will gain approximately, 70% of it is compressive strength. The soil around piles will be removed to the required levels and dimension that allows construction of the pile cap. A step shall be made if the excavation is more than 1.5 m to prevent soil collapse. Figure 2 Pile head cutting: Concrete will be removed up to cut off level. If concrete under the cut off level is unsound. It shall be removed, and the pile will be repaired. Pi
Read more

Bridge Diaphragm

By -
Image
The main function of diaphragms is to provide a stiffening effect to deck slab in case bridge webs are not situated directly on top of bearings. Therefore, diaphragms may not be necessary in case bridge bearings are placed directly under the webs because loads in bridge decks can be directly transferred to the bearings.On the other hand, diaphragms also help to improve the load-sharing characteristics of bridges. Diaphragms also contribute to the provision of torsional restraint to the bridge deck. Diaphragm will be used also to resist stresses that occurs during the post-tensioning process. Post-tensioning hardware are casted inside the diaphragm. Figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer Types of diaphragm: Diaphragm at the span end: this type of diaphragms will be located between two bridge spans or at the bridge abutments. Expansion joints will be used to connect bridge spans. This
Read more

Flakiness Index and Elongation Index of Coarse Aggregates

By -
Image
Flaky and elongated aggregates can adversely affect concrete. Flaky and elongated aggregates are difficult to compact. Therefore using flaky and elongated aggregates will reduce concrete workability, which required more amount of water to produce a workable mix. Increasing water content will reduce concrete strength and durability. Moreover, these aggregates are not robust, which leads to lowering concrete strength. Figure 1 construction management: concrete construction bridge construction:How to become a bridge engineer The Flakiness Index of aggregates is the percentage by weight of particles whose least dimension (thickness) is less than three- fifths (0.6times) of their mean dimension. This test does not apply to sizes smaller than 6.3mm. The Elongation index of an aggregate is the percentage by weight of particles whose greatest dimension (length) is greater than nine-fifths (1.8times) their mean dimension. Flakiness and elongation tests ar
Read more

Nominal maximum size of coarse aggregate

By -
Image
Concrete is a widely used material. Reinforced concrete structures can be found everywhere. The main reason behind the popularity of reinforced concrete structure is the high strength and the long life span of these structures. Concrete and steel are combined to produce reinforced concrete. Concrete is good at compression while steel good at tension. Concrete and steel form a perfect combination to resist loads imposed on the structure. Concrete is a composite material composed of cement, coarse aggregate, fine aggregate, and water. Admixtures can be used to enhance concrete properties. A concrete mix consists of almost 65% aggregates. Aggregates are classified into fine and coarse aggregates. Since the aggregates form the majority of a concrete mix. The quality of aggregates can greatly affect the strength and durability of concrete. Aggregates can be natural or crushed aggregates. Used aggregates should be strong, hard, and should not contain a large amount of organic matter or harmf
Read more

Tunnel lining systems-Ribbed system

By -
Image
Ribbed supporting system has been used for many years to support tunnels. The ribbed supporting system is based on steel ribs supporting tunnels. The implementation of this system involves the installation of rolled steel sections around the circumference at specified spaces. The formation of gaps between the steel ribs and the ground is very common. These gaps should be suitably wedged to avoid excessive deformation of the ground. It is essential to ensure that the loads are distributed evenly by the steel support around the tunnel profile. Subjecting of steel support to point load will significantly reduce their ultimate capacity.  Figure 1 The steel ribs can be combined with shotcrete concrete. The shotcrete concrete will be applied before the erecting of ribs. The applying of a layer of shotcrete concrete will reduce the problems of gaps between ribs and surrounding ground, which minimize the wedging problems. Then another layer of shotcrete can be applied after th
Read more

Prestressing stands debonding

By -
Image
  Prestressing bridge concrete beams contributes to resisting the tensile stresses caused by the traffic loads and the beam's weight. Stressing concrete has various benefits, such as increasing concrete members' capacity, reducing the concrete member section, and increasing the span lengths for structures such as bridges and buildings. However,  The stressing of bridge beam ends can result in unwanted cracks. Therefore AASHTO calling for debonding a specific portion of strands at the beam end to minimize the stresses and reduce cracks. Figure 1 Debonding is achieved by wrapping the strands at the end of the beam with plastic. Wrapping the strand with plastic wrapping will prevent the strands from bonding with concrete, thus avoid transferring unwanted stress to the beam end. As a result, the unwanted cracks will be prevented by reducing the stress levels at the end of the beam.  
Read more
My photo
Mohammad
My name is Mohammad Hamdan, and I am a Civil/bridge Engineer with extensive professional background and experience in the field of construction. I have 10+ years of experience in the construction field. During my professional career, my emphasis has been placed on structural projects, mainly bridges, infrastructure and roads. Reading and practicing the design of structures is my passion.i was lucky to be a part of a big team that executed major highway interchanges. I believe in spreading the knowledge, thus, i compose these courses to share my experience and knowledge. My course focuses on the practical side of construction field. On other word, i am sharing some of what new engineers need to know about construction field. Beside working on construction field, i love writing some articles on my website ( curious civil engineer) Moreover, i wrote some engineering papers, you can check them  by searching my name on Google (Mohammad mamon Hamdan)