All posts by Vinod Gopinath

geotechnical, pile foundation

Driven piles – Features, Types and advantages

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Driven piles support structures and transmit loads to underlying soil or rock, as they are a type of deep foundation used for this purpose. Contractors use driven piles, made of steel, concrete, or wood, to support structures and transmit loads to underlying soil or rock. They also call them displacement piles. The installation of driven piles involves driving them into the ground using impact hammers or vibratory drives until they reach a layer of rock or soil that can support the required loads.

If the soil is exceptionally dense, they may need to pre-drill to ensure the pile reaches the design depth. Construction projects commonly employ driven pile to provide stability and strength to the structure. Driven piles offer a cost-effective deep foundation solution and are commonly used to support buildings, tanks, towers, walls, and bridges.

  1. Why driven piles?
  2. Types of driven piles
    1. Steel Driven pile
    2. Pre-cast concrete Driven Piles
    3. Timber pile
    4. Composite driven pile
  3. Quality Control for Driven Piles
    1. Pile driving equipment for driven piles
    2. Pile inspection and testing
    3. Pile load testing for driven pile
    4. Pile driving records
  4. Advantages of driven piles
    1. High Capacity
    2. Ease of Installation of driven piles
    3. Cost-effective
    4. Minimal disturbance
    5. Versatility
  5. Disadvantages of driven piles
    1. Noise and vibration
    2. Limited depth
    3. Difficulty in driving through hard soil or rock
    4. Quality Control
    5. Limited environment suitability

Why driven piles?

Contractors often use driven piles, which are the most cost-effective deep foundation solution, to support buildings, tanks, towers, walls, and bridges. They are also suitable for embankments, retaining walls, bulkheads, anchorage structures, and cofferdams. Driven piles possess a high load-bearing capacity, durable, and contractors can install them quickly and effectively in various soil conditions. Engineers frequently use them in places with inadequate soil, where conventional shallow foundations would not be strong enough to sustain buildings.

In addition, contractors can install driven piles to support compression, tension, or lateral loads, with specifications determined by the structure’s needs, budget, and soil conditions, making them very versatile.

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Types of driven piles

Driven piles are broadly classified as follows

  • Steel Driven pile
  • Precast Concrete Driven pile
  • Timber pile
  • Composite driven pile

Steel Driven pile

Steel-driven piles support major structures such as buildings, bridges, roads, and industrial facilities in construction. Construction workers push them into the earth using specialized tools like hydraulic hammers or pile drivers until they reach a predetermined depth or a firm layer of rock or soil. Steel-driven piles are steel beams with broad flanges on both ends.

Steel Driven Pile

Steel-driven piles are typically made of high-strength steel with a round or square cross-section. They come in various lengths and widths and can be installed vertically or at an angle to meet foundation design requirements. An impact hammer is used to press the pile into the soil by delivering a forceful blow. For shorter depths, steel screw piles are supported by a cast iron helix and powered by rotary motors.

Because of their durability, strength, and capacity to support enormous loads, the steel-driven pile is a common choice for deep foundations. Steel-driven piles are a cost-effective and quick solution for many construction projects. However, their applicability will depend on factors such as soil characteristics, anticipated loads, and local construction building codes and regulations.

Pre-cast concrete Driven Piles

Precast concrete pile manufacturers deploy these piles in construction to support structures built on weak or compressible soils. They prefabricate these piles in a factory or casting yard before transporting them to the construction site. Based on the project’s unique needs, they can construct precast concrete piles in a vast range of dimensions, forms, and configurations. High-strength concrete, reinforced with steel rebar, is used to make these piles. They often use a vibratory hammer or hydraulic hammer to drive the piles into the earth until they reach the required depth or a solid layer of soil or rock.

Precast Concrete Driven Piles

Piles come in a variety of shapes, such as square, octagonal, cylindrical, or sheet. Percussion-driven piles are used in situations where bored piles would be ineffective due to running water or excessively loose soils. They have a load range of 300-1,200 kN and a maximum reach of 30 m. Precast concrete piles are constructed with great accuracy and quality control in a controlled environment, resulting in a consistent and uniform product that satisfies design requirements. They are durable and can withstand adverse weather conditions such as seawater or chemical exposure. Precast concrete piles can also be installed quickly and effectively, saving time.

  • Precast concrete piles are quick to install.
  • They can be used in various soil conditions.
  • Using precast concrete piles saves time and money in construction.
  • Precast concrete piles are durable and reliable.
  • They have high-quality control standards.
  • Precast concrete piles are a popular choice for deep foundation construction.

Timber pile

Timber-driven piles are used in construction to create a stable foundation for structures in weak or compressible soils. Contractors use hammers or pile drivers to create cylindrical or square wood piles from premium softwood species. This type of pile is particularly effective in areas with high water tables where other types of piles may not work as well. Timber-driven piles provide a stable foundation for structures in weak or compressible soils. This is achieved by hammering wooden piles into the ground, which compresses the wood and displaces the surrounding soil. The resulting tight fit helps to support the weight of the structure. Timber-driven piles have the advantages of being inexpensive and simple to install. Nonetheless, they may be susceptible to rot and pest infestation.

timber driven piles
timber-driven-pile

Composite driven pile

Engineers commonly use composite piles made of a combination of two or more materials, such as concrete, steel, or timber, when soil conditions require a combination of strength and flexibility. An example of a composite pile is a concrete pile with a steel section, as shown in the figure.

Contractors use composite-driven piles consisting of a steel tube filled with concrete and reinforced with steel rebar because they can withstand heavy loads. They use in various construction projects, such as bridges, high-rise buildings, and marine structures. The steel tube provides structural support and protects the concrete from damage during installation, while the concrete and rebar provide additional strength and stability. Contractors can install composite piles using hydraulic hammers or vibratory drivers to reach depths of up to 60 meters. Due to their durability and corrosion resistance, composite piles are ideal for use in harsh environments.

composite pile

Quality Control for Driven Piles

The construction of driven piles requires high-quality materials and adherence to standards such as BS 8004:2015 and EC standards. It’s crucial to maintain the pile’s shape and avoid damage during installation and inspect them beforehand for quality assurance. The maximum load a pile can carry depends on soil or rock strata properties, pile dimensions and material, and installation method. Engineers perform load testing on representative samples to determine capacity and use monitoring instruments like inclinometers and settlement gauges to ensure the pile’s sufficient support. Effective quality control and testing are crucial for the safe and reliable performance of driven piles in construction projects.

driven piles

During installation, it is crucial to maintain the shape of driven piles and ensure they are not damaged by the installation of subsequent piles.

Quality control of driven piles is an important aspect of ensuring the stability, safety, and longevity of structures that rely on them for support. Here are some of the common quality control measures used for the driven piles.

Pile driving equipment for driven piles

To make sure that piles are installed correctly, trained personnel are required to maintain, calibrate, and operate pile driving equipment properly. Regular inspections are necessary to detect any damage or wear in the equipment, and repairs or replacements must be made promptly.

Pile inspection and testing

Inspect the piles for defects or damage before driving them into the ground. To ensure that the piles have been installed correctly and meet the specified requirements, non-destructive testing methods such as sonic testing or integrity testing should be used to test the piles after installation.

Pile load testing for driven pile

pile load test

One can conduct load testing of a sample of piles to ensure that they can support the required loads. This involves applying a controlled load to the pile and measuring the resulting deformation, which one can compare to the design specifications to ensure that the piles are safe and reliable.

Pile driving records

One should keep detailed records of the pile driving process, including the number of blows or vibrations required to drive the pile to the required depth, the penetration rate, and any other relevant information. These records are essential to monitor the quality of the installation and identify any issues that may arise during the construction process.

Regular inspections and testing are essential to identifying any issues early in the construction process and enabling prompt corrective action.

Advantages of driven piles

The main advantages are

  • Piles can be pre-fabricated off-site which allows for efficient installation once on-site.

High Capacity

Piles are driven deep into soil or rock. This provides high load-bearing capacity. It’s suitable for supporting heavy structures like buildings, bridges, and marine structures. The process increases the effective length of the pile, resulting in high capacity.

Ease of Installation of driven piles

Compared to other pile types like drilled shafts, the installation of a driven pile is quick and efficient. The installation process involves driving the piles into the ground using an impact hammer or a vibratory driver. This requires minimal excavation and soil removal.

Cost-effective

Other types of foundation systems can often be more expensive than driven piles, particularly when the soil conditions are favourable. The cost-effectiveness of driven piles is due to their relatively simple installation process and the availability of pre-manufactured piles, which can reduce the time and cost required for pile installation.

Minimal disturbance

The installation process of driven piles minimizes the disturbance to the surrounding area, making them suitable for use in urban or environmentally sensitive areas. The piles are driven into the ground, which reduces the amount of soil disturbance and the need for excavation.

Versatility

Driven piles are suitable for a variety of soil conditions, including soft soils, hard soils, and rock layers. They can also be made of different materials such as steel, concrete, and timber, providing a wide range of design options.

  • When driven into the ground, piles displace and compact the soil, resulting in increased bearing capacity. In contrast, other types of deep foundations may require soil removal, which can cause subsidence and structural problems.
  • Installation usually produces little spoil for removal and disposal.

Overall, driven piles offer several advantages in terms of high capacity, speed of installation, cost-effectiveness, minimal disturbance, and versatility, making them a popular choice for foundation systems in many construction projects.

However, the use of driven piles also has some disadvantages, including their relatively high cost compared to shallow foundations, the noise and vibration associated with their installation, and the potential for damage to nearby structures or utilities. Therefore, the selection of driven piles as a foundation type depends on a variety of factors, including soil conditions, load requirements, and site-specific constraints.

Disadvantages of driven piles

In the design and construction process, it is important to consider the disadvantages of driven piles, despite their many advantages. Some of the main disadvantages of driven piles are:

Noise and vibration

The installation of driven piles can generate high levels of noise and vibration. This can be a concern for nearby residents and sensitive structures. Pile driving can cause damage to nearby structures, particularly those with shallow foundations.

Limited depth

Other foundation types may be necessary if the capacity or depth required cannot be achieved with driven piles. This is because of the limitations imposed by soil or rock conditions and the driving equipment’s capacity.

Difficulty in driving through hard soil or rock

Driving piles in hard soil or rock layers can be difficult and time-consuming, which can lead to higher installation costs. Overcoming the hardness of the soil or rock may also require the use of specialized driving equipment or techniques.

Quality Control

The installation of a driven pile requires critical quality control. Poor installation can cause issues such as pile damage, pile movement, or insufficient load capacity. To ensure that the piles are installed correctly and meet the required standards, regular inspection, and testing are required. Moreover, monitoring is necessary during pile installation.

Limited environment suitability

Driven piles may have limited suitability in environmentally sensitive areas. This includes wetlands or areas with a high water table. This is due to the potential soil disturbance caused by the driving process. Moreover, the use of chemicals for the preservation or treatment of piles can have negative impacts on the environment. It is important to consider these factors and explore alternative foundation options in such areas.

Roads, TRANSPORTATION ENGINEERING

Camber in roads – Types of Road Cambers

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Camber in roads is the slope or angle built into the road surface. It is typically seen on curved or sloped sections of the road. This slope is designed to provide several benefits, including improved drainage, enhanced vehicle stability, and better driver visibility. The purpose of camber on roads is to ensure safe and comfortable driving conditions for motorists.

A cambered road has a slight slope from the center to the edges. This design allows water to drain off the surface efficiently. The road camber helps prevent water from accumulating, which otherwise damage the pavement and make driving hazardous. Camber in roads improves safety and extends the lifespan of the road. There are different types of cambers, including straight, parabolic, and composite cambers, each suited for specific conditions. The camber of road design is essential for maintaining road quality, particularly in areas with heavy rainfall.

This article explains cambered road designs, road camber benefits, camber in roads, and the types of cambers. You’ll also learn how the camber of road surfaces improves drainage and road safety.

  1. Significance of camber of the roads
  2. Types of Camber in roads
    1. Positive camber in roads
    2. Negative camber in roads
    3. Zero camber
    4. Composite camber
    5. Sloped camber/straight camber
    6. Two straight-line camber
    7. Barrel camber/Parabolic camber
  3. Significance of road camber
  4. Advantages of Camber on Roads
  5. Recommended Values of Camber in Road For Different Types of Road surface by IRC: 
  6. Disadvantages of excessive road camber

Significance of camber of the roads

The camber of road is crucial for effective water drainage, preventing accumulation and reducing the risk of skidding. A cambered road ensures water flows off the surface, maintaining road durability and safety. Road camber also improves vehicle handling, especially in wet conditions. Different types of cambers are designed to suit various environments and traffic needs. Proper camber in roads helps reduce maintenance costs and keeps the road safe for drivers year-round.

Road Camber

The slope can be positive, negative, or zero. This depends on the specific requirements of the road and the expected traffic flow. The appropriate camber for a road depends on various factors. These include the type of road, its location, and the expected speed and volume of traffic. Proper design and construction of road camber can significantly improve road safety. It reduces the risk of accidents. It also increases the lifespan of the road surface.

Types of Camber in roads

Camber in roads, or road camber, is the slope built into the road surface. It is typically seen on curved or sloped sections. The road’s camber is usually indicated by the ratio 1:n or as a percentage. Proper camber design and construction are crucial to improve road safety, reduce accidents, and ensure adequate drainage and vehicle stability.

Here’s a list of the types of camber used in road design and construction:

  • Positive camber
  • Negative camber
  • Zero camber
  • Composite camber
  • Sloped or straight camber
  • Two straight-line camber
  • Barrel camber

Positive camber in roads

Positive camber is the angle of a vehicle’s wheels. The top of the tire tilts outward from the centre of the vehicle. This can provide improved stability and handle in certain driving situations, such as high-speed cornering. However, excessive positive camber can lead to uneven tire wear and decreased handling performance.

Positive camber
Positive Camber - Camber of roads

Negative camber in roads

Negative refers to the angle of a vehicle’s wheels where the top of the tire tilts inward towards the centre of the vehicle. This can provide improved grip and handling during cornering, as the tire maintains more contact with the road. However, excessive negative camber can lead to uneven tire wear and reduced straight-line stability.

Negative Camber
Negative Camber

Zero camber

Zero camber refers to the angle of a vehicle’s wheels where the tire is perpendicular to the ground and the wheel is vertical. This is considered the ideal angle for tire wear and handling, providing a balance between straight-line stability and cornering grip. Many production vehicles are designed with zero camber for optimal performance and safety.

Zero camber

Composite camber

Composite camber refers to a combination of positive and negative camber on a vehicle’s wheels. In order to achieve optimal handling and performance in specific driving situations, one can adjust the angle of each wheel independently to create a custom setup. This allows for a personalized approach to handling and can be achieved through the use of composite camber. Composite camber is a technique commonly utilized in high-performance vehicles and motorsports to attain maximum grip and control.

Composite Camber
Composite Camber

Sloped camber/straight camber

Sloped camber refers to a wheel angle where the tire leans towards the inside or outside of the vehicle, creating a slope. Straight camber refers to a wheel angle where the tire is vertical and perpendicular to the ground. Sloped camber is often used in motorsports to improve cornering performance, while straight camber is more common in street vehicles for better tire wear and handling.

Straight line/ sloped
Straight Line Camber

Two straight-line camber

Two straight-line camber refers to a setup where the camber angle is set to zero for both front and rear wheels. This provides a balanced setup that promotes even tire wear and stable handling. “People commonly use two straight-line camber in street vehicles, SUVs, and pickup trucks, prioritizing comfort, safety, and longevity over high-speed cornering performance.”

Two straight line Camber
Two straight line camber

Barrel camber/Parabolic camber

“In drifting and racing applications, people commonly use barrel camber to promote tire grip . This in turn improves cornering performance by adjusting the camber angle and toe settings on each wheel independently. Barrel camber is a wheel angle where the center of the tire is lower than the edges, creating a barrel-like shape.”

Barrel Camber or parabolic camber
Parabolic Camber

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Significance of road camber

Road engineers provide camber to promote safe and efficient driving. They use positive camber on curves and turns to offer better stability and prevent vehicles from sliding off the road. On the other hand, they use negative camber on straight sections to enhance tire traction and lower the risk of hydroplaning in wet conditions.

Advantages of Camber on Roads

Camber provides several advantages for road safety and efficiency. “Moreover,” positive camber assists vehicles in remaining centered on the road while turning. This in turn results in decreased skidding and improved stability. Negative camber improves tire contact with the road on straight sections, increasing traction and reducing hydroplaning risk. Camber also helps to reduce tire wear by distributing the load evenly across the tire surface, promoting longer tire life. Overall, camber is a key design feature in road engineering. This helps to promote safe, efficient, and sustainable transportation for all.

Road
Importance of camber on road
Image credit : Rick Muscoplat

The Indian Road Congress (IRC) provides recommended values for camber in road design, based on the type of road surface. These values are as follows:

  1. Flexible Pavement on Earth Embankment
  • Straight: 1.5%
  • Crossfall: 2.5%
  1. Flexible Pavement on Soft Soil
  • Straight: 2%
  • Crossfall: 3.5%
  1. Rigid Pavement on Earth Embankment
  • Straight: 2%
  • Crossfall: 3%
  1. Rigid Pavement on Soft Soil
  • Straight: 2.5%
  • Crossfall: 4%
  1. Bituminous Wearing Course
  • Straight: 1.5%
  • Crossfall: 2.5%

“These values provide general guidance only and depend on local conditions, traffic volume, and other factors. It is important to note that.”

Disadvantages of excessive road camber

Providing excessive road camber height can have several disadvantages. These include:

  • Uneven tyre wear: Excessive camber height can cause the tire to wear unevenly, leading to reduced tire life and increased maintenance costs.
  • Increased fuel consumption: High camber angles can increase rolling resistance and reduce fuel efficiency, leading to higher fuel consumption and greenhouse gas emissions.
  • Reduced braking performance: Excessive camber can reduce the contact area between the tire and the road surface, reducing braking performance and increasing stopping distances.
  • Reduced stability: High camber angles can reduce vehicle stability, especially at high speeds, making the vehicle more difficult to control and increasing the risk of accidents.
  • Uncomfortable ride: Excessive camber can cause the vehicle to ride harshly, transmitting more shocks and vibrations to the occupants, leading to discomfort and fatigue during long journeys.
civil engineering, REINFORCEMENT STEEL

Development length formula as per IS 456 & ACI 318-19

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Development length is an essential concept in civil engineering that refers to the length of reinforcement required to transfer the force from the steel reinforcement to the surrounding concrete. It is crucial in ensuring that the reinforcement is effectively bonded to the concrete to resist the applied forces. “The development length depends on several factors, including the diameter of the bar and the strength of the concrete. “Another factor that affects the development length is the bond strength between the steel reinforcement and the surrounding concrete.”

Properly understanding development length is essential for designing reinforced concrete structures to ensure their safety and stability. Engineers calculate the development length to ensure that the reinforcement will provide the intended strength and reinforcement to the structure. “Insufficient development length can cause the reinforcement to fail to transfer forces to the concrete effectively. This can ultimately lead to structural failure.”

  1. What is the development length?
  2. Significance and functions of Development length.
    1. Transfer of applied forces
    2. Prevents structural failure
    3. Important for design
    4. Structural safety and stability
  3. Factors determining Development strength
  4. Development length as per IS 456
  5. Development length as per IS 456 for columns, footings and beams
  6. Typical section beam-column junction
  7. Development length as per codes
    1. ACI 318-19 (American Concrete Institute)
    2. BS 8110-1:1997 (British Standard)

What is the development length?

To develop the full tensile strength of the reinforcement, one must embed the reinforcement in concrete for a minimum length known as the development length. This is necessary to ensure that the reinforcement can resist the applied loads. This should happen without pulling out of the concrete or causing concrete failure.

Either pull-out or splitting failure modes typically control the length. In pull-out failure, the force applied to the reinforcement exceeds the pull-out strength of the concrete. This generally causes the reinforcement to pull out of the concrete. In splitting failure, the force applied to the reinforcement causes the concrete to crack and split. This can lead to the failure of the reinforcement.

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Significance and functions of Development length.

This is a critical concept in reinforced concrete structures that ensures the effective transfer of forces and prevents premature failure. It is important for the safety and stability of structures and is a crucial factor in their design and construction. The main function is as follows.

Transfer of applied forces

Ensuring effective bonding of the steel reinforcement to the surrounding concrete is the purpose of the Development length in reinforced concrete structures. This allows it to transfer the applied forces to the concrete.

Prevents structural failure

Basically, the proper bonding of the reinforcement to the concrete prevents premature failure of the structure. This could otherwise result in catastrophic consequences.

Important for design

Properly understanding Develop length is critical for designing reinforced concrete structures. Engineers must calculate the length to ensure that the reinforcement provides the intended strength and reinforcement to the structure.

Basically, an insufficient development length can lead to the reinforcement not being able to transfer the forces to the concrete effectively. However, this results in premature failure and instability.

Structural safety and stability

Generally, this is crucial for the safety and stability of reinforced concrete structures. The failure to effectively bond the reinforcement to the concrete would result in the inability to transfer the applied forces. However, this can lead to structural failure.

Factors determining Development strength

Several factors influence the required development length to fully develop the tensile strength of reinforcement in concrete, including

  • Reinforcement properties: The strength and diameter of the reinforcement significantly impact the required development length. Generally, high-strength reinforcement with a larger diameter will require a longer D length to develop its full strength.
  • Concrete properties: The strength, stiffness, and thickness of the concrete member where we place the reinforcement are crucial factors. However, a higher concrete strength requires a longer d length, while a thicker concrete section may require a shorter length.
  • Bond strength: The bond strength between the reinforcement and concrete is critical in determining the development length. However, the bond strength depends on various factors. This includes the surface condition of the reinforcement, the degree of deformation, and the quality of the concrete surface.
  • Environmental conditions: Environmental factors such as humidity, temperature, and exposure to corrosive agents can affect the bond strength between the reinforcement and concrete. In such cases, we may require a more extended development length.
  • Load conditions: The type, magnitude, and direction of the load applied to the reinforcement significantly influence the development length required. Generally, Higher loads require a longer D length to prevent the reinforcement from pulling out of the concrete.
  • Design codes and standards: Design codes and standards typically provide guidelines for determining the minimum development length required for different types of reinforcement and loading conditions. However, these guidelines may vary depending on the specific code or standard used.

Development length as per IS 456

Basically, Clause 26.2.1 of the Indian code for the design of reinforced concrete structures (IS 456:2000) provides the formula. The formula is used to calculate the development length of reinforcement bars in tension. We require the length of the reinforcement bar to transfer the stresses between the reinforcement and the surrounding concrete.

The formula for calculating the length (Ld) of a reinforcement bar with a diameter of D, embedded in concrete with a grade of M, and subject to tension, is as follows:

Ld = (0.87 fy A / 4τ_bd) + (0.2 √fc) …Equation 1

where:

  • fy is the characteristic strength of the reinforcement in N/mm²
  • A is the area of the reinforcement in mm²
  • τ_bd is the bond stress between the reinforcement and the surrounding concrete in N/mm²
  • fc is the characteristic compressive strength of concrete in N/mm²

The first term in Equation 1 represents the basic development length. This is the minimum length required for the reinforcement to fully develop its strength. The second term represents the additional development length due to the curvature of the bar.

It is worth noting that the code also provides alternative methods for calculation, such as the empirical equations given in Table 5 of the code. However, Equation 1 is the most widely used method for calculating the development length in India.

It is important to note that these calculations are based on certain assumptions and simplifications. The actual development length required may vary based on the specific design requirements and site conditions.

Development length as per IS 456 for columns, footings and beams

The development length of rebars is the minimum length required. This ensures the effective transfer of forces from the steel reinforcement to the surrounding concrete. However this ensures that the reinforcement is properly bonded to the concrete, preventing premature failure of the structure.

Typical section beam-column junction

Development length of a beam column junction
Development length of a beam column junction

Development length as per codes

The development length of a reinforcing bar, or rebar, is the minimum length that must be embedded or overlapped with concrete. This ensures proper transfer of stresses between the concrete and steel. This is a critical design parameter, and it is determined based on various factors such as the strength of the rebar, the strength of the concrete, and the design requirements of the structure.

Here are the formulas as per some commonly used codes:

ACI 318-19 (American Concrete Institute)

Ld = [(φ x Fy x As) / (4 x Fc’^(0.5))] x (1.3 for deformed bars, 1.7 for plain bars)

where: Ld = development length in inches

φ = strength reduction factor (0.7 for deformed bars, 0.8 for plain bars)

Fy = yield strength of rebar in ksi

As = area of rebar in square inches

Fc’ = specified compressive strength of concrete in psi

BS 8110-1:1997 (British Standard)

Ld = [(1.2 x σst x As) / (0.87 x Fy x (1 + (200/d))^(0.5))] x (1.4 for deformed bars, 1.7 for plain bars)

where: Ld = development length in mm

σst = stress in rebar at yield in N/mm2

As = area of rebar in mm2 Fy = characteristic yield strength of rebar in N/mm2 d = diameter of rebar in mm

IS 456:2000 (Indian Standard)Ld = [(0.87 x fy x As) / (4 x τbd x fck^(0.5))] x (1.2 for deformed bars, 1.6 for plain bars)

where: Ld = development length in mm

fy = characteristic strength of rebar in N/mm2

As = area of rebar in mm2 τbd = design bond stress in N/mm2

fck = characteristic compressive strength of concrete in N/mm2

It is important to note that the development length calculation may vary based on the specific requirements of the structure, and it is recommended to consult the appropriate code for accurate and up-to-date information.

civil engineering

All cement price list today 2023 – Cement Price per bag today

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All cement price list today is the most important update every construction engineer and civil engineering construction firm should be familiar with. Cement is the most significant and widely used construction material which forms an integral part of any structure. Cement is the major ingredient of concrete and mortar and the structural stability and life of a structure or building depend on the cement quality.

  1. Significance of knowing the price of cement today
  2. Factors affecting the cement prices
  3. Uses of Cement
  4. Top cement companies of India with the latest price list
  5. Conclusion

Significance of knowing the price of cement today

Cement is widely available on the market. Therefore, one needs to be aware of cement’s pricing before purchasing. Cement accounts for almost 20% of total construction costs. Cement is therefore one of the most expensive construction materials. One must therefore be familiar with the most recent cement price list rates that are offered on the market. Generally, cement is utilised for everything from a building’s foundation to its final touches. Because cement prices play such a significant effect on construction costs, it is necessary to consider them when making purchases.

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Factors affecting the cement prices

Also, the price of each cement varies according to its quality. Yet, different types of cement are utilised in different locations. The following variables influence cement pricing:

All cement price list today
  • Costs of Raw Materials: The basic raw materials for cement manufacture are limestone and clay, and their prices might fluctuate based on supply and demand situations in their respective markets.
  • Energy Costs: The cost of energy, such as the price of fuel and electricity, can impact cement’s cost.
  • Transportation Costs: The expense involved in transporting raw materials to the manufacturing plant, as well as the cost of delivering the final product to market, can influence cement prices.
  • Production Costs: The cost of production can be influenced by factors such as the cost of labour, the efficiency of the manufacturing process, and the level of competition in the market.
  • Government Regulations: Government rules, such as taxes, import duties, and environmental regulations, can also have an impact on the price of cement.
  • Economic Factors: Generally, economic factors such as inflation, exchange rates, and overall economic growth can all have an impact on cement prices.
  • Market Demand: The level of demand for cement in a particular market can also impact its price. However, during periods of high demand, prices may be higher, while during periods of low demand, prices may be lower.
  • Competition: The level of competition in the cement market can also influence prices. If there is a high level of competition, companies may be pressured to lower their prices in order to remain competitive.
Best Cement of India || Top Cement Companies in India -2021

Uses of Cement

Cement is an essential element in the construction industry. It is needed to make concrete and mortar. Cement is manufactured by heating a mixture of limestone and clay to form a powder. The powder, when mixed with water, makes a paste that sets and hardens. Some of the most common applications for cement are:

  • Cement is used in the manufacture of concrete. Concrete is the major building material for foundations, walls, bridges, and roadways.
  • Masonry work: For laying bricks and stone, cement is used as binding material
  • Plastering: Cement is widely used in the production of plaster. Plaster is used to coat the interior and exterior walls and ceilings of buildings.
  • Cement can be used as a base material in the manufacture of floor screeds, terrazzo, and other flooring products.
  • Dams: It is used in the production of concrete for dams, which are structures designed to retain water.
  • Pipelines: Other subsurface constructions, including pipelines, are made of cement.

In summary, cement is an essential material in the construction industry and is used for a wide range of purposes, from building construction to flooring, and from masonry work to making pipes.

Top cement companies of India with the latest price list

Here is a list of the top cement companies in India along with their latest price list:

  1. UltraTech Cement Ltd. – UltraTech Cement is the largest manufacturer of cement in India and one of the world’s leading suppliers of cement and clinker. As of February 2023, the latest price of UltraTech Cement is Rs. 350 – 400 per bag
  2. Ambuja Cements Ltd. – Ambuja Cements is one of the leading cement companies in India. Ambuja cement is best known for its sustainable practices and use of advanced technology. As of February 2023, the latest price of Ambuja Cement is Rs. 330 -400 per bag
  3. ACC Ltd. – ACC is one of the largest cement companies in India. ACC has a strong presence in the country’s western and southern regions. As of February 2023, the latest price of ACC Cement is Rs. 330 to 450 kg bag.
  4. Shree Cement Ltd. – Shree Cement is a leading cement company in India. We know that Shree cement is known for its high-quality products and innovative business practices. As of February 2023, the latest price of Shree Cement is Rs. 300 – 375 per 50 kg bag.

Please note that these prices may vary based on location and market conditions.

Conclusion

Cement prices play an important part in the cost of every structure. Everyone related to the civil engineering and the construction industry should be familiar with cement prices. Hence it is required to be updated with cement prices regularly. Top brands are available in almost every part of the country.

civil engineering

Unit weight of steel bars – How to calculate?

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Calculating the unit weight of steel bars with various diameters is crucial when creating a schedule for bar bending. The total weight of steel bars/TMT bars weight required for the project’s construction can be calculated once we know the unit weight of steel.

Understanding the unit weight of steel bars is crucial in construction projects for accurate material estimation and structural integrity. The unit weight of steel bars is often referred to as steel unit wt. This unit weight determines the amount of steel required for reinforcement. It affects both cost and structural stability.

Steel bars play a pivotal role in reinforcing concrete structures, enhancing their strength and durability. By knowing the steel bars unit weight, engineers can guarantee proper quantity calculations. They can also avoid potential overuse or shortages of materials. Precise knowledge of the unit wt of steel bars helps streamline project planning. It also ensures the structural stability of the finished construction.

Steel is the most commonly used structural material. Steel’s basic components include metallic iron, non-metallic carbon, and minor amounts of nickel, silicon, manganese, chromium, and copper, among others. High tensile strength makes it a popular construction material for civil engineering projects. Steel reinforcement bars, often known as rebar, are placed in concrete members to enhance their tensile strength. As we all know, steel is utilized to construct structural members such as columns, beams, footings, foundations, and building slabs. Steel bars of various sizes are supplied by the manufacturer, with lengths of 12 meters or 40 feet.

  1. Why Unit Weight of steel bars Calculation is Important?
  2. How to calculate the steel bar weight/ TMT bars weight?
  3. Calculation of weight of steel bars per Running Meter
    1. Weight of steel per Meter
    2. Weight of steel per foot
    3. Weight of steel bars/TMT bars weight per meter

Why Unit Weight of steel bars Calculation is Important?

It is essential to comprehend the weight of steel bars. We estimate them as 100 meters 20 mm bar, 100 feet 16mm bar, and so on. (is the sign for diameter). Steel bar manufacturers, on the other hand, will not interpret this notation and will measure the steel bars in weight. So we have to order them in kilograms, quintals, or tonnes. This article will go through how to use the steel weight formula to determine the steel bar’s weight.

How to calculate the steel bar weight/ TMT bars weight?

Steel bar unit weight is the weight of steel per unit volume. Its SI unit is kg/m3. The unit weight of steel is typically measured as follows

  • Kilogrammes per cubic meter (7850 kg/m3),
  • Kilo Newton per cubic meter (78.5 kN/m3),
  • Grams per cubic centimeter (7.85 g/cm3).
Unit weight of steel
Unit weight of steel bars

Calculation of weight of steel bars per Running Meter

Let’s start with a 12 mm diameter.

The length of the rod L = 1 meter.

Steel has a density of 7850 kg/m3.

Let us see how the formula calculates the weight of steel bars.

Area of steel rod (Circular shape) = πr2 or πD2/4

Hence the wt of steel bar formula

= Area of steel x Density of steel x Length of steel

Where

Area of steel = πD2/4

The density of steel = 7850 kg / m3

Length of steel = 1 mtr

Diameter of steel = D mm

Weight of steel per Meter

= πD2/4 x 7850 x 1m = 3.14 x (D2 / 4) x 7850 x 1m

In this equation,

the Diameter is in mm and the Density (Unit Weight) is in m3

Let us convert the Diameter in mm2 to m as below

1 mm = 1/1000 m , 1 mm2 = 1/(1000)2 mm2

= 3.14 x (D2 /4 ) X 1/(1000) 2 X 7850 X 1

Weight of steel bars formula= D2 x 6162.5 x 1/(1000)2

= D2 x 1/(0.006162)-1

= D2 / 162.28

For calculation purposes, we used to take D2/162

Weight of steel rod per Running meter = D2/162 where D is the diameter of steel rod in mm

For a 12 mm dia rod,

D = 12 mm

Weight per meter = 12 x 12 /162 = 0.889 kg per rmt or meter length or unit length

If you want to know the steel weight per foot. 1 metre = 3.281 ft. Just multiply the same.

Weight of steel per foot

1 metre = 3.281 ft. Just multiply the same.

= D2/162 x 3.281 = D2 / 533

Weight of steel bars/TMT bars weight per meter

Let us have an idea about the unit weight of common diameters of reinforcement steel used in civil engineering construction.

Weight of steel bars/TMT bars weight per meter
architectural finishes, Doors

Types of doors – Top 7 door types explained

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Types of doors commonly used in residential, commercial, and industrial construction depend on the application area, durability required, the purpose of the door, etc.

What is a door?

A door is a movable barrier or mechanism for opening and closing an entranceway or a building/room. The purpose of the door in this urban environment is security and privacy. Apart from security, safety, and privacy, an aspect of art, beauty, and elegance is associated with it. The entrance door acts as a warm welcome to the areas inside.

This article is about the types of doors popularly used in civil construction.

  1. Classification of doors in Civil Engineering
    1. Types of doors in civil engineering– location based
      1. Exterior door
      2. Interior door
    2. Types of Doors – Based on Materials
      1. Wooden Door/Timber Door
        1. Demerits of wooden doors
      2. Glass Doors
      3. Metal Doors
      4. Types of Doors – Flush Doors
      5. PVC Doors
      6. Types of Doors – UPVC Doors
      7. Types of Door – Aluminium doors
  2. Conclusion

Classification of doors in Civil Engineering

Doors come in a number of types. The selection of a door type, on the other hand, is determined by the location, purpose, aesthetic needs, material availability, security, and privacy. Doors types are typically classified as follows.

  • Location based
  • Based on material
  • Based on operation mechanism

Types of doors in civil engineering– location based

The doors types are classified as follows

  • Exterior Doors
  • Interior Doors

Exterior door

An outside door is one that allows entry to a building/house. An outside door’s main function is to safeguard the building as well as the security and privacy of the occupants of the building. While selecting an exterior door, style, colours, finishes, and aesthetic looks to match the architectural theme must be considered.

Interior door

Interior doors provide access to interior spaces like bed, kitchen, special functional rooms, toilets, etc. However, choice of material and type depends on the nature of privacy, security, and purpose of the room. Interior doors used to be lighter than exterior doors.

Types of Doors – Based on Materials

The door choice is confirmed based on the material to be used. For that, we should have a better idea of the readily available, durable, and aesthetically matching materials. Following are the popular choices of doors based on materials used in construction nowadays.

  • Wooden Doors
  • Glass Door
  • Metal Door
  • Flush Door
  • PVC door
  • Aluminium Door
  • UPVC door

Wooden Door/Timber Door

Wooden doors types are the most common and premium choice for both external and internal doors. They are the preferred choice due to their classy and elegant looks, high durability, and ability to match any architecture theme. Moreover, they are aesthetically pleasing and are widely available on a reasonable budget. Wooden doors can be custom-made for any functional requirements and design. They are the oldest material used and never lose their sheen even after long years.

wooden door
wooden door
  • Easily available
  • Easy working
  • Best material for front doors due to its high durability.
  • Used for any functional requirement.
  • Wooden doors are mostly polished rather than painted for exposing the natural grain looks.
  • Simple and easy installation.
  • Carving works are easily done on wooden doors.
  • Wooden doors are soundproof, got high thermal insulation capabilities and are strong.
Demerits of wooden doors

Even though wooden doors are superior materials they have their demerits also. However, needs periodic maintenance to retain the sheen and looks.

  • Needs periodic maintenance to retain the sheen and looks.
  • Wooden doors on long exposure to moisture may deteriorate.
  • Prone to termite attacks.
  • May sags

Glass Doors

Glass doors are for areas where the availability of natural light and open feeling is the main functional requirement. They are mainly used in areas where privacy is not a prime factor-like back yard, balcony doors, cabin doors, etc.

Glass doors are elegant and give an enhanced look to the house. However, the main problem with glass doors is the safety and privacy factor and the possibility of glass breaking. The glass breaking problem is managed by using small glass pieces for front doors. The glass should be safety glass or toughened glass.

Metal Doors

Steel is one of the preferred and favorite alternatives to wood for both external and internal doors. Mild steel or Galvanized steel is used for the manufacturing of doors. These doors are manufactured in solid and hollow types and are a safer, durable, and stronger option when compared to wooden doors.

metal door
metal door

Steel door frames are usually combined with wooden, PVC, steel, and flush door shutters. Steel door frames are manufactured by pressing steel sheets, angles, channels, etc. Holdfasts and hinges are welded to the steel frames.
Steel frames are popular and are used for residences, factories, industrial buildings, etc. They are economical than conventional wooden frames.

Metal door shutters are manufactured from high-quality cold-rolled Mild Steel (MS) sheets, with a steel face and rock wool or foam insulation. Steel is a more economical and stronger option compared to other materials even though steel may not look as attractive as wooden or glass doors.
Metal doors are available in different tones and shades. They are durable, have minimal maintenance, and provide excellent security.

Types of Doors – Flush Doors

The flush door is made of a timber frame covered with plywood from both sides. However, the hollow core is filled with rectangular blocks of softwood just like block boards. Flush door surface finished with decorative finish by fixing veneers. The flush door is usually laminated or veneered to match the architectural themes. These doors are usually hinged type and have one side opening only. The frame can be of wooden, PVC, or steel.
Flush doors got a seamless look and are economical, look elegant, and are easily available in the market.

flush door
flush door

While providing these doors for toilets, baths; the inner face of the door should be covered with aluminum sheets to protect against water.

PVC Doors

PVC or polyvinyl chloride doors are a very popular choice for doors. They are available in a range of colors and styles. Furthermore these doors have high resilience, are anti-destructive, termite-proof, moisture-resistant, lightweight, etc. As a result they are best suited for areas with moisture chances like bathroom areas.
Polyvinyl doors come in a variety of designs types. colors, style and looks beautiful. Similarly these doors do not corrode like steel or disintegrate like wood and do not need much maintenance.
They are very simple and easy to install and are scratch-proof. These doors are not preferred for front doors due to their lightweight characters and inability to resist environmental conditions. These doors are cost-effective when compared to wooden and metal doors.

Types of Doors – UPVC Doors

uPVC stands for Unplasticised Polyvinyl Chloride. It is a form of plastic that is hard and inflexible, also known as rigid PVC. UPVC doors are a preferred choice of architects and home owners due to the superior qualities they offer when compared to other door materials like wood, metal , PVC etc

  • Easy to clean and maintain – UPVC doors can be cleaned by simply wiping with a soft cloth soaked with mild detergents even though they may not peel or cracks after years of usage.
  • UPVC Profiles are manufactured to accommodate double glass units (DGU) in fact provides excellent thermal and acoustic insulations. Furthermore glass panes can be substituted with reflective glass to reflect sunlight and keep the rooms cooler in summers.
  • Durability – UPVC is a highly durable material, in addition to that allows for the construction of doors and windows that are long-lasting. In addition to all above they are dust-proof, termite-proof, moisture, and weather-resistant.
  • Ease of installation – Similarly UPVC doors are very fast and easy to install.
UPVC doors
UPVC doors

Types of Door – Aluminium doors

Aluminium doors due to their excellent and durable qualities are the most preferred option for designers and architects. They are durable, strong and maintenance free material. The fabrication and installation is very easy and got the choice of using as member for DGU units for thermal insulation applications. Aluminium is expensive, however considering the superior qualities aluminium is preferred in most of the areas.

Conclusion

Apart from the types described above there are a lot of doors varieties available in the market to cater each and every situation and applications. However, these door type selection has to be in line with the requirements.