Curious Civil Engineer

First, we should know that steel rebar comes in standard length such as 12m. using very long reinforcement is impractical because it will result in difficulties in handling reinforcement by steel fabricators. Also, longer rebar is heavier and difficult to lift and move. So for a long structure such as a slab, we require a reinforcement length that is more than the standard reinforcement. We can't use a single piece of rebar for a specific length for such a structure, so we use two or more steel rebars to cover the entire length of the structure. Figure no:1 The zone of overlapping between reinforcement will be considered as a weak zone. Therefore, it is a good practice to stagger the reinforcement overlapping. Staggering is done by overlapping the reinforcement at a different location. Staggering reinforcement overlapping will reduce the number of rebars overlapped at the same point, which will be beneficial in two ways. Firstly, it will reduce the discontinuity of rebar at the s

 First, we should know that steel rebar comes in standard length such as 12m. using very long reinforcement is impractical because it will result in difficulties in handling reinforcement by steel fabricators. Also, longer rebar is heavier and difficult to lift and move. So for a long structure such as a slab, we require a reinforcement length that is more than the standard reinforcement. We can't use a single piece of rebar for a specific length for such a structure, so we use two or more steel rebars to cover the entire length of the structure. Clearly, the point of joining these rebars is critical and weak. So, for this reason, and to prevent structure failure at this point, we overlap the reinforcement to ensure that there is sufficient length to transfer stresses at this point, which prevent: tension, pull-out, and shear failure at the location of joining the rebars. Figure no:1

 The use of adhesives for fixing anchors such as bolts, steel dowels increased recently. We can see many adhesive anchors in the market. However, not all products are suitable for the various adhesive anchoring applications. The anchoring of adhesive can be horizontally, downward, upward and inclined in terms of orientation. In terms of working environment, the adhesive anchors can be used in dry conditions, water-saturated and submerged conditions. Therefore, the selection of adhesive products should consider all these factors to ensure the durability and safety of used anchors.  Figure no:1 The adhesive anchoring system consists of adhesive material, anchors such as dowel reinforcing bars, drilling equipment, and the equipment used for cleaning such as wire brush and air compressor.  There is a various methods used for drilling the holes for adhesive anchors. the hammer drilling machine can be used to drill the hole. it is preferred to use the hammer drilling machine because it is pr

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

 Ductility is an important property of steel reinforcement. Ductility is the ability of the material to undergo plastic deformation before failure. The ductility of reinforcement is related to the elongation property. The ductility of reinforcement ensures safer and durable structures. Material that undergoes little or no plastic deformation is known as a brittle material. Brittle reinforcement can cause sudden structure failure because it doesn't undergo any plastic deformation before failure.  Figure 1 The ductility factor for reinforcement can be computed using the following equation: µ=ϵu/ϵy where, µ is the ductility factor ϵu is the ultimate strain ϵy is the yield strain In figure no:1-a, we can see the stress-strain curve for mild steel. The mild steel has well-defined yield stress and strain, as shown in the stress-strain curve. The reinforcing bar can recover all the elongation if the applied stress is lesser than the yield stress. This portion of the curve is known as the

 Construction management: Road construction course This course is designed to expand your practical side of engineering knowledge. This course is concentrating on the construction of roads. Here you will learn how the road is constructed. The construction stages such as protection of existing services, clearing the area, future utilities, preparing the road subgrade, then placing different pavement layers such as sub-base, base course, and asphaltic courses. We will also discuss the types of asphaltic course and the common defects of asphaltic pavement, such as permanent deformation, fatigue cracking, and low-temperature cracking. Also, I will show a typical cross-section of road and road profiles and many other subjects. Enroll from here  Pile foundation design This course will discuss the design of pile foundations. We will learn the methods of calculating the pile bearing capacity. The bearing capacity for a pile consists of skin and end bearing resistance. Here you will understand

 Corrosion of steel reinforcement is problematic and posing a threat to reinforced concrete structures. Severe corrosion of reinforcement can result in concrete spalling and damaging structure integrity. Various factors can affect the rate of reinforcement corrosions. The environment is one of these factors. For example, the rate of reinforcement corrosion will accelerate for structures submerged in seawater compared to structures built above the ground—concrete properties playing an important role in reducing the rate of reinforcement corrosion. Concrete with low permeability will reduce the ingress of chemicals that cause the corrosion of reinforcement, which can effectively slow the corrosion of reinforcement. The concrete cover is another factor that can effectively slow reinforcement corrosion. Usually, a higher concrete cover is used for members of the structure in contact with groundwater or soil. Figure 1 In a severe environment, galvanized reinforcement can be used to reduce

  Foundations are an essential part of any structure. Structures will not be able to withstand imposed loads, and it will fail in case of using the wrong foundation type or foundation with a smaller size. Determining the type of foundations will be based on a soil investigation study. Soil investigation will determine the soil bearing capacity and the other characteristics of the soil. Loads transferred from the structure is playing an important role in determining the type and size of foundations. For small structures, shallow foundations will be sufficient to transfer the load to the soil. On the other hand, huge structures required deep foundations to transfer the loads to the soil without causing large settlement or structure failure.  Figure 1 The method of construction and the mechanism of distributing the loads are different in shallow and deep foundations. Shallow foundations are composed mainly of footing. The shape of the footing can vary. It can be the square, rectangular, o

  Cofferdams are temporary structures used as a barrier to keep out the water and soil during the construction of a permanent structure such as a foundation in a maritime environment. The loads imposed on cofferdams structure includes hydrostatic forces of the water and dynamic forces due to waves and currents. The construction of cofferdams is a tough job since it is usually constructed offshore and in severe weather conditions. Therefore, the tolerance of construction may deviate from the design due to construction conditions, and cofferdams elements may deform significantly during cofferdam construction.  Figure 1 For a typical cofferdam, the construction sequence will be as follow. The construction of the cofferdam will begin with the preparation of the cofferdam area. The soil and sediments will be removed, and the area will be leveled.  The temporary support piles will be driven, and temporary supporting frames will be erected on support piles.   Figure 2 Drive the sheet pile to

  Concrete bonding agent used for bonding fresh concrete to existing hardened concrete. the bonding agents can be used for existing horizontal or vertical concrete surfaces where the fresh concrete will be supported by formworks. the bonding agent can be used at construction joint locations to ensure better adhesion between old and new concrete. in large structures such as bridge deck. the casting of the whole deck at one time is difficult and not practical. therefore, the deck divided into areas and each area casted separately.  Figure 1 before applying the bonding agent, the existing concrete surface should be cleaned properly. all grease, loose concrete, plaster, oil, or any other dirt should be removed. furthermore, the surface of the concrete should be roughened by scrabbling or grit blasting. The mixing and applying of bonding should be as per the manufacturer. the component of the bonding agent should be mixed properly. the bonding agent should be applied thoroughly on the exist

High-strain dynamic test performed by dropping a heavyweight that will cause a high strain on the pile foundation and measuring the velocity and force response of the pile foundation. This test can be used to evaluate the pile integrity, and the maximum compressive and tensile stresses occur on the pile due to impact. The dynamic test results can be used to assess the pile axial static capacity if sufficient movement occurs during the impact of heavyweight. The estimated axial static capacity may be affected by the following factors: Pile installation equipment and procedure. Elapsed time since the installation. Pile material properties and dimensions. Type, density, strength, stratification, and saturation of the soil, or rock, or both adjacent to and beneath the pile. Quality of dynamic test data. Foundation settlement. Engineering experience and judgment.   Figure 1 The dynamic test can be conducted for driven and cast-in-situ piles. Piles made from concrete should be allowed to gai