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Binding wire for steel reinforcement

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  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 ...
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stress-strain diagram for aluminium alloy and rubber

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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...
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Concrete repair-selecting the repair method

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Repairing concrete structure passes through various stages. Selecting the correct repair method will depend on completing the previous steps, such as determining the cause of concrete damage, evaluate the extent of the damage, and assess the need for repair. The completion of these steps will define the type of conditions the repair must resist, the available repair construction time period, and when repairs must be accomplished. The data collected from performing these steps will help in selecting which of the 15 standard methods is suitable and durable for repairing the damaged concrete structure. Figure 1 In general, the old concrete surface should be prepared before beginning with the repairing process. It is essential to remove all unsound concrete before applying the repairing. Improper preparing of damaged concrete structure will result in unsatisfactory repair with low durability. The first step in preparing the old concrete surface is the saw cutting of repairin...
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Rebar Splicing and Overlapping — ACI 318-19 Requirements Explained

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Reinforcement splicing or overlapping is a fundamental requirement in reinforced concrete structures. Because reinforcement bars (rebars) are manufactured in limited standard lengths—typically 12 m —it becomes necessary to splice or overlap them to achieve the required continuity in structural members. The main purpose of a splice is to ensure smooth stress transfer between adjacent bars through the surrounding concrete. The overlap length, commonly known as the splice length , must be long enough to safely transfer the tensile stresses from steel to concrete without causing bond failure. It is recommended to avoid splicing in high-stress zones such as areas of maximum moment, and to stagger the splices to prevent congestion and reduce stress concentration. The ACI 318-19 providing the following recommendatin and requirement for the lap splicing: 1. Splice Limitation by Bar Size Lap splicing is not permitted for reinforcement bars larger than 36 mm in diameter. 2. Non-Contact L...
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Non-Working Pile Testing and Static Compression Load Test

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Purpose of Non-Working Piles Non-working piles are constructed at the beginning of the project to evaluate soil bearing capacity and determine the maximum settlement. These piles are loaded up to twice the working load. Based on the test results, the pile length may be adjusted. If the measured settlement exceeds the allowable limit, the pile length will be increased accordingly. construction management: concrete construction bridge construction:How to become a bridge engineer Static Compression Load Test The static compression load test provides insight into how the pile responds to loading. Settlement is measured at different load increments to determine the appropriate pile design length. The maximum applied load is typically twice the working load (2 × working load) or as specified by local standards. The following steps outline the testing procedure: A. Steel Cage Preparation The steel reinforcement cage is prepared in accordance with the approved shop drawings. ...
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Pile cap

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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...
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The reasons behind the trimming of pile head

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In general, the bored piles are casted to a level higher than the required pile cut-off level. Pile cut-off level is usually similar or a little bit higher than the blinding level of a pile cap. the process of constructing a cast-in-situ pile involves the following steps: installation of the temporary casing to prevent the soil collapse during the drilling process and to guide the drilling rig. Drilling the pile to the required level and diameter. Installation of a reinforcement cage. Reinforcement cage vertical bars will be extended above the pile cut-off level to improve the bonding with the pile cap. The casting of concrete usually done with a tremie pipe. Tremie pipe will be lowered to the bottom of the pile, and then the concrete will be poured. Once the casting is completed, the temporary casing will be removed. It is a common practice to cast the concrete above the cut-off level. the concrete casted then removed for the following reasons: during the casting pro...
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Tunnel lining systems-Ribbed system

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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 afte...
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Bridge Diaphragm

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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 ...
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Fiber Reinforced polymer for strengthening of reinforced concrete

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 Fiber-reinforced plastic (FRP) is a new technique to strengthen structures. Fiber-reinforced plastic has various types, such as a carbon-fiber-reinforced polymer (CFRP), glass fiber reinforced plastic (GFRP), and aramid fiber-reinforced polymer (AFRP).  The below table shows the mechanical properties of different fiber types.     Table 1 we can notice that carbon fiber reinforced polymer possesses better properties compared to other types. For example, the tensile strength of CFRP extra-high strength can reach 6200 MPA compared to a maximum tensile strength of 4135 MPA of other fiber types.   The FRP has various uses such as: Improved seismic performance of masonry walls Replacing missing steel reinforcement Increasing the strength and ductility of columns Increasing the loading capacity of structural elements Correcting structural design and/or construction defects Increasing resistance to seismic movement Improving service life and durability ...
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