Different types of precast concrete products and their benefits

Beam and Block Floors: Beam and block is made of precast concrete and it is suitable for superior quality, cost-effective concrete floor construction.

Concrete beam and block floors are built up with prestressed concrete beams which provide support to standard concrete blocks stretching among ‘T’ beams. These come in different sizes to fit with several spans and loads. Individual concrete blocks are placed among the precast beams to build up an instant floor.

In prestressed concrete beams, beam spacing is modified to adapt probable loads.

Beam and Block Flooring

Manufacture: Long line prestressed production of concrete floor beams allows high performance beams to be formed economically.

ACP floor beams are wet cast from superior quality steel moulds with high strength engineering grade concrete, ensuring quality and performance.

Concrete Beams – Design: 150mm concrete beams are can be used for an extensive range of concrete floor construction like domestic house floors, flats, nursing homes and commercial developments.

225mm concrete beams can be used for floors depending on higher loads and larger unsupported extents.

Specification: ACP concrete floor beams are suitable for being applied with standard 440 x 215 x 100 concrete blocks in either 7.0N/mm2 or 3.5N/mm2 compressive strengths.

Closure blocks to adapt 530mm and 305mm concrete beam spacing to accelerate floor edge construction.

A dry grout system is applied to tie the beam and block floor jointly before setting up insulation and floor finishes.

A sand/cement screed is employed to the grouted beam and block system for a strong finished floor or base for ceramic floor finishes. Openings inside the floor for service ducts and pipes can be smoothly and inexpensively integrated in the scheme.

Specialist ceiling clips can be used to accelerate the ceiling installation process to the underside of the suspended concrete floor.

Benefits: Low cost concrete flooring is obtained with the ACP beam and block floor system.

It facilitates huge savings in both time and cost at ground floor level with regard to other flooring systems and also reduces groundworks. Beam and block flooring is also suitable for suspended flooring to consequent levels, even being effective to promote partition walling with double beam layouts.

The set up of beam and block floors is usually weather independent minimizing site delays and making sure that construction programme is retained.

The suspended beam and block floor system provides the scope to reduce excavations; of specific advantages where excavated material should be eliminated from site.

The high thermal mass inbuilt with precast concrete floor construction provides benefits for the finished buildings energy consumption. Precast concrete flooring also contains properties like exceptional noise reduction and fire resistance.

ACP precast floor beams are also suitable for the Tetris Thermal flooring system to attain even better insulation performance.

The concrete beam and block floor is ideal for underfloor heating systems with a high thermal mass.



Read more

~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~

How To Arrange Bar Bending Schedule For RCC Beams

This construction video tutorial is based on BAR BENDING SCHEDULE FOR RCC BEAM.

From bar bending schedule, one can get the reinforcement calculation for reinforced concrete beam. It gives us details of reinforcement cutting length, type of bends and bend length.

In this construction video, solution is given for two beams having spans of 6 meter. 1st layer of bottom bar of beam is 32 dia and 2nd layer that is called bottom extra is 25 dia.

1st layer of top bar of beam is 25 dia and US bar (extra cover support in second layer) is 25 dia.

Clear cover = 30 mm
Development length = 50 dia
Lapping = 50 dia

To have the complete calculation process, go through the following video

Video Credit : L & T - Learning Technology

~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~

Bar Bending Schedule-BBS Civil Engineering Estimation And Casting

Bar bending schedule offers the reinforcement calculation for reinforced concrete beam. It supplies details of reinforcement cutting length, type of bends and bend length.

Here we will take one example for reinforcement quantity calculations for a concrete beam.

Example of RCC Beam Reinforcement Calculation:

Assume a beam of clear length of 4m, 300mm wide by 450mm depth. It consists of 2-12 diameter bars at top, and 2-16 diameter and 1 – 12 diameter bars at the bottom. Diameter of stirrup is 8mm spaced at 180mm center to center. Clear cover to reinforcement provided is 40mm.

Now we will calculate the length of reinforcement on the basis of shapes of reinforcement mandatory for reinforced concrete beam in above example.

We will start with bottom reinforcement, B1.

Bar shape of B1 is as shown below:

RCC Beam Bar Bending Shape

Length of B1 = clear distance between walls + 2 x width of walls – 2 x bar cover + 2 x bend length

Bend length = 6 x 16 = 96 consider as 100mm

Bend length is calculated as 6 x diameter of bar for reinforcement conforming to IS: 1786-1961

Length of B1 = 4000 + 2 x 230 – 2 x 40 + 2 x100 = 4580mm

Length of bar B2 is calculated on the basis of the shape of this bar. This bar bends up closer to the support as shown below:

RCC Beam Bar Bending Shape

Length of bar B2: A + B + C = 4000 + 2 x 230 – 2 x 40 + (1.414xH – H)

H = 450 – 2 x 40 – 2 x 12 – 2 x 12/2 = 334mm

B2 = 4000 + 2 x 230 – 2 x 40 + (1.414×334 – 334) = 4518.3 = 4520mm

Length of Bar T1 = 4000 + 2 x 230 -2 x 40 = 4380mm

Length of Stirrups S1:

RCC Beam Stirrups Length Calculation

Stirrups are spaced at 180mm center to center. Stirrups are provided between walls or support for a beam.

No. of stirrups required for given beam = No. of Stirrups

Length a = 450 – 2 x40 – 8 = 362mm

Length b = 300 – 2 x 40 – 8 = 212mm

Therefore length of 1 stirrup S1 = 2 x (212 + 362 + 90) = 1328 mm

Where 90mm is the minimum hook length as per IS 2502 – Table – II.

~~~~~~~~~~~~~~~~~~~~~

Published By

Rajib Dey

www.constructioncost.co

~~~~~~~~~~~~~~~~~~~~~

How to design and detail the RCC Beams

RCC beams structural elements are formed to bear transverse external loads that produce bending moment, shear forces and in some cases torsion over their length. Concrete performs well in compression but feeble in tension. The role of Steel reinforcement is to combat tensile stresses in reinforced concrete beams.

Now-a-days deformed and twisted bars are extensively used in RCC work. Deformed or High yield strength deformed bars (HYSD) contains ribs on the surface. It improves the stability of bond by minimum 40% with regards to that of mild steel bar.

Fine detailing of reinforcements with exact drawings is necessary at the job site to optimize the construction procedure. Usually, there is a bar bending schedule contained with these drawing. The bar bending schedule defines the length and number, position and the shape of the bar.

The detailing of beams generally involves the followings :

i) Size and number (or spacing) of bars,

ii) Lap and curtailment (or bending) of bars,

iii) Development length of bars,

iv) Clear cover to the reinforcement and

v) Spacer and chair bars

Anchorage in steel bars is demonstrated with bends and hooks. Hooks do not include Twisted steel bars or deformed steel bars. The anchorage value of bend of bar is captured as 4 times the diameter of bar for each 450 bend that depends on maximum of 16 times the diameter of bar. To expand the length of bars, bars are lapped over one another. Lowest lap length is identical to development length. Development length for bars in various concrete mix is provided in tables 4.2 to 4.4 of SP34.

The value of K given above is subjected to type of steel applied that is provided below :-

The beams are categorized as:

• Based on shape: Rectangular, T, L, Circular etc.
• Based on supporting conditions: Simply supported, fixed, continuous and cantilever beams
• Based on reinforcement: Singly reinforced and doubly reinforced

Depth of the beam is obtained on the basis of flexural strength and satisfying the deflection criteria. Usually the ratio of span to depth ratio is retained as 10 to 15 and the depth to width ratio of rectangular is maintained in the range of 1.5 to 2.

Lowest cover in beams should be 25 mm or not below the larger diameter of bar for all steel reinforcement together with links. Minimal cover provided in Table 16 and 16A of IS456-2000 should be applied to meet the stability criteria.

To read the complete article, go through the following link theconstructor.org

~~~~~~~~~~~~~~~~~~~~~

Published By

Rajib Dey

www.constructioncost.co

~~~~~~~~~~~~~~~~~~~~~

An Exclusive Construction Demo On Finite Element Modeling Of RC Beams

This construction video is extracted from an exclusive presentation by Raafat El-Hacha, Associate Professor, University of Calgary, Calgary, AB, Canada, that focused on the tolerable performance of concrete bridges as well as their components when based on rigorous environmental conditions.

The session covers a range of technical features like strength of concrete members, techniques for checking performance, appraisal methodologies, damage appraisement, and structural restoration supported with both experimental and analytical examinations. The session highlighted current research outcomes as well as offers the scope to talk about existing confrontations and technical issues. The session is ideal for the professionals who play a vital role in tomorrow’s bridge design and construction, along with practicing engineers, government officials, and academics to obtain crucial information.

~~~~~~~~~~~~~~~~~~~~~

Published By

Rajib Dey

www.constructioncost.co

~~~~~~~~~~~~~~~~~~~~~

How to compute the design moment strength of a singly reinforced concrete beam

This construction video is made on Reinforced Concrete Design and it narrates the method for creating the estimate of the design moment strength concerning a singly reinforced concrete beam following the ACI Code.

The video highlights the following :-

The video highlights the following :-

i) How to draw the strain and stress profile at ultimate

ii) Force equilibrium to estimate neutral axis depth

iii) Examine assumptions (i.e. verifying steel yield) and decide phi

iv) Compute nominal moment and design moment

Go through this supportive article to learn more

~~~~~~~~~~~~~~~~~~~~~

Published By

Rajib Dey

www.constructioncost.co

~~~~~~~~~~~~~~~~~~~~~

How to model a Reinforced Concrete Beam with Ansys Workbench

Ansys, a USA based Computer-aided engineering software developer, presents an exclusive construction tutorial on modeling a Reinforced Concrete Beam with ANSYS Workbench. ANSYS Workbench is the most recognized platform to resolve any issue associated with engineering field. Here static static structural analysis method is followed for the modeling purpose.

PLCRACK command is applied to demonstrate failed elements or cracked or crushed elements. Deformation of the Rebar can also be exported. This is a four point bending test of concrete.

Click on this link to download command files

~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~

How to design a singly reinforcement concrete beam with RCM

This construction video shows the functionalities of RCM, a handy software for designing singly reinforcement concrete beam.

RCM is an adaptable and widely recognized tool for the structural engineers to create the design of various types of reinforced concrete members based on ACI318M-11 Code and other ACI Standards like ACI350M-06, ACI244R-01, CRSI-2008 etc.

The RCM can be used for providing complete through design reports containing full formulas and exemplifying figures just close to manual calculation.

The complete detailed reports transform RCM design engine to an open book, so the engineer can smoothly certify and authorize them. RCM reports allow the engineers to learn ACI Code thoroughly.

~~~~~~~~~~~~~~~~~~~~~

Published By

Rajib Dey

www.quantity-takeoff.com

~~~~~~~~~~~~~~~~~~~~~

Strength of Doubly Reinforced Concrete Beam (compression steel not yielding)

Some useful construction tips to calculate the nominal flexural strength Mn concerning the reinforced concreterectangular section. It is illustrated in figure 9-3(a).

The provided section is reinforced twice with steel in tension and compression zone of the section. The guidelines of ACI-318 is followed for calculating the nominal flexural strength Mn. The highest value of applicable strain at the utmost concrete fiber is supposed to be 0.003.

For fc' grerater than 4000 psi the value of ß1 is calculated as given below;

ß1 = 0.85 - 0.05 {( fc' -4000)/1000} = 0.8

Assume that the compression steel has yielded when the strength is reached (strain in concrete is 0.003).

Given that tension steel consists of 4 bars of #10 (dia 1.27 in.).

Area of one bar of #10 = 1.27 in2.

As = 4-#10 bars. = 4 (1.27) = 5.08 in2.

Area of compression steel , As' = 2-#7 = 2(0.6) = 1.2 in2. The internal forces acting on the section shown in figure 9-3(c) are calculated as given below;

Cc = 0.85 fc' ba = 0.85 (5) (14) a = 59.5 a 

Cs = (fs' - 0.85 fc') As' = (60 - 0.85*5) 1.2 = 66.9 kips

T = As fy = (5.08) (60) = 304.8 kips

Applying static equilibrium, we get Cc + Cs = T;

59.5 a + 66.9 = 304.8

therefore depth of stress block, a = (304.8- 66.9)/59.5 = 3.998 in Depth of neutral axis x = a / ß1 = 3.998/0.8 = 4.997 in

Read More: civilengineer.webinfolist.com/

~~~~~~~~~~~~~~~~~~~~~~

Published By

Rajib Dey

www.quantity-takeoff.com

~~~~~~~~~~~~~~~~~~~~~~

How to design a single reinforced concrete beam

This construction video will be very helpful for Civil Engineering Students to learn how to create the design concerning a singly reinforced concrete beam through step-by-step processes.

Reinforced concrete belongs to one of the primary building materials applied in engineered structures and it provides the following benefits :-

• Reinforced concrete contains superior compressive strength with regards to most other materials utilized in construction.

• Good fire resistance capability as compared to steel. It can defend against fire for a long period. It is also weather resistant.

• It is endurable and offers low maintenance cost.

• To some specific sorts of structures like dams, piers and footings, it can be the most cost effective structural material.

• It can be cast to accommodate with the desired shape and extensively applied in pre-cast structural components.

• It complies with unyielding members through least apparent deflection.

• Yield strength of steel is about 15 times the compressive strength of structural concrete and well over 100 times its tensile strength.

• Formability.

~~~~~~~~~~~~~~~~~~~~~

Published By

Rajib Dey

www.constructioncost.co

~~~~~~~~~~~~~~~~~~~~~