Quantity Take Off or QTO is a well known project estimating company serving to the contractors, home builders, architects, design- build firms and sub contractor trade. We are providing estimating service since 2002 with a great chronicle of success.
While analyzing the rate of brickwork, it is essential to ascertain the quantities of materials (bricks and mortar) and labors. There are different types of ratios for mortar which range from 1:2, 1:4, 1:6, 1:8 etc. Go through the following like to determine the quantity of mortar.
Estimating the quantity of bricks is necessary for the rate analysis.
Quantity Estimation for Brick Masonry - To analyze the rate of brick masonry, 1m3 of brick masonry is taken:
1. Number of bricks for 1 cubic meter of brick masonry: For 1m3 of brick masonry, the number of typical size of bricks must be 494.
2. Quantity of mortar for 1m3 of brick masonry:
For 1m3 of brickwork, the quantity of the mortar should be 25 – 30%, i.e. 0.25m3 – 0.3m3 of cement masonry. For this purpose, cement mortar is selected as 0.3m3 .
Labor Estimation for Brick Masonry: Labors which are essential for brick masonry belong to mason for brick work, labours for transmitting materials (sand, cement, bricks, and water), mixing and transporting mortar.
The quantity of labor is provided as requirement of labour in longer period for 1m3 of brick masonry.
1. Mason: The quantity of mason necessary for 1m3 of brickwork is provided as 0.94 days. 2. Labor: The quantity of labor for different types of works like carriage of materials, blending of mortar, carrying of mortar etc. are amassed. The labour necessary for 1m3 of brick masonry is for 1.57 days.
For a site engineer, it is essential to work out the cutting length of bars based on the slab dimensions and provided instructions to the bar benders.
If the construction work is intended for the small area, the reinforcement detailing can be transferred to the bar benders. They will deal with the cutting length. But be careful that it may not be perfect as they do not consider the bends and cranks. They may provide some additional inches to the bars for the bends which are fully imperfect. Therefore, to get rid of this issue, a site engineer should try to compute calculate the cutting length independently.
In this article, detailed explanation is given for working out the length for reinforcement bars of slab.
The calculation is made on the following dimensions :-
Diameter of the bar = 12 mm Clear Cover = 25 mm Clear Span (L) = 8000 Slab Thickness = 200 mm Development Length(Ld) = 40d
Process for computation
Cutting Length = Clear Span of Slab + (2 x Development Length) + (2 x inclined length) – (45° bend x 4) – (90° bend x 2) Inclined length = D/(sin 45°) – dD/ (tan 45°) = (D/0.7071) – (D/1)= (1D – 0.7071D)/0.7071= 0.42 D There exist four 45°bends at the inner side (1,2,3 & 4) and two 90° bends ( a,b ). 45 ° = 1d; 90 ° = 2d Cutting Length = Clear Span of Slab + (2 X Ld) +(2 x 0.42D) – (1d x 4) – (2d x 2) [BBS Shape Codes]
The following method are useful for working out various building quantities like earth work, foundation concrete, brickwork in plinth and super structure etc.
a) Long wall – short wall method b) Centre line method. c) Partly centre line and short wall method.
a) Long wall-short wall method: Under this method, the wall along the length of room is treated as long wall whereas the wall that is situated vertically to long wall is called short wall. To find out the length of long wall or short wall, initially compute the length of centre line for separate walls. Then compute the length of long wall, (out to out) once half breadth at each end is added to its centre line length. Therefore, the length of short wall is calculated into in and is built by subtracting half breadth from its centre line length at each end. The length of long wall normally declines from earth work to brick work in super structure whereas the short wall enlarges. In order to obtain quantities, multiply these lengths with breadth and depth.
This construction video briefly describes how to create the design of t-beam with the use of limit state method.
A T-beam (or tee beam) is applied in construction extensively. It is a structural element developed with reinforced concrete, wood or metal. It contains a t-shaped cross section that is formed by a stem and a flange of reinforced concrete or rolled metal.
The top of the t-shaped cross section acts as a flange or compression member in withstanding compressive stresses. The web (vertical section) of the beam underneath the compression flange contributes to withstand shear stress and offer better separation for the coupled forces of bending.
A T-beam has the capacity to tolerate large loads by providing resistance in the beam or by internal reinforcements. It operates similar to singly reinforced beam.
In order to enhance the structural strength of a T-beam, just utilize an inverted T-beam together with a floor slab or bridge deck linking the tops of the beams. If it is accomplished perfectly, the slab performs as the compression flange.
Definition of Segregation of Concrete? Major components of concrete are cement, sand, aggregate, and water. Normally, a coating is made to concrete aggregate with cement and sand for developing the consistent mass disjointing of these constituent materials of concrete from each other. It is known as segregation of concrete.
Type of segregation:
1. Partition of course aggregate from the paste. 2. Partition of course agreement paste from the concrete. 3. Partition of water from the cement mix which is also known as bleeding.
The segregation contains unwanted properties in the hardened concrete. It also leads to honeycombing in concrete. Segregation also adversely impacts on stability, compressive strength and all other characteristics of concrete. It also results in forming cavities in the concrete surface.
Reasons for segregation:
The segregation mainly occurs due to the variation in specific gravity and size of its constituent material. Specific gravity of water is 1. Specific gravity of cement is approx 3.15 whereas that of aggregate is 2.6 to 2.7. Because of the variation in specific gravity, lighter particle goes upwards and heavier particle goes downwards and consequently the segregation of concrete occurs.
Other reasons range from greater water cement ratio in concrete. Besides, when excessive water is added at the time of mixing concrete, it results in segregation. Improper vibration for a long period on wet mix of concrete also causes heavy material to setting down and lighter cement sand paste to move upwards. Imperfectly proportioned mix and inappropriate placing on site may also lead to segregation.