settlement calculation for footing

properties of channels , angles, ismb members

30m steel tower design and analysis

4000 ton crane ( world heaviest crane)

types of trusses for bridges

CONCRETE FLOOR SLAB CONSTRUCTION

As general guide-lines the following items are important for successful execution of the concrete ground floor slab

The specification should give clear and precise requirement.

The floor shall be designed to carry specified loading with adequate factor of safety.

The selected contractor shall be experienced with good track records and with available resources to tackle the execution of the job.

Design, drawings and materials specified will be important. The type of concrete and the floor with
joints and isolation details or not to be defined clearly.

Study of sub-soil condition and water proofing requirement to be ensured.

Preparation of well compacted sub-grade and the built-up sub-base layers is important. The layer
underlying the concrete slab should have provision to reduce frictional resistance to concrete slab.

Shrinkage reducing admixture may be required.

The amount of fibres should be minimized to control water demand and cement content and
subsequently shrinkage.

Control on concrete mix design and proper supervision will be very important.

Effects of microfibres on concrete properties

Effects of microfibres on concrete properties

1. Increases homogeneity of the mix, stabilizing the movement of solid particles and blocking bleed

water channels.

2. Helps controlling plastic settlement of concrete.

3. Will increase the early age tensile strain capacity of plastic concrete and will restrict the development of plastic shrinkage and drying shrinkage cracks.

4.Will enhance the bahaviour of joints within the concrete.

5.Will improve the surface layer of concrete and thus improves abrasion resistance.

6.Will be effective in distributing impact stresses and delays deterioration.

sequence of construction of bridge in sea (

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correction in IS800 2007

steel frame errection

list of corrections in is800-2007

soil compaction

settlement limits

steel connections

good vedio i got in net just iam sharing.

crack width for slabs as per is 456

HABITS OF HIGHLY SUCCESSFUL PEOPLE

STEEL REINFORCEMENT FOR CRACK WIDTH CONTROL

For over 65 years, steel reinforcement has been used in the construction of concrete
pavements in an effort to control the opening of concrete cracks. To achieve
approximately uniform opening at all cracks, sufficient steel reinforcement must be used
to prevent the steel yielding at cracks, as the pavement’s concrete shrinks. If the steel
yields, the joint will open excessively. Calculation of the reinforcement required to
prevent the steel yielding, involves consideration of the following variables:
• Length of pavement with continuous reinforcement
• Subgrade friction
• Magnitude of thermal shrinkage
• Magnitude of drying shrinkage
• Required crack width
• Required crack spacing
• Use of stress concentrators (e.g. sawcuts)
• Pavement thickness
• Concrete’s tensile strength
• Diameter of steel reinforcement
• Yield stress of steel reinforcement
In the case of continuously reinforced concrete pavements constructed on a concrete
sub-base, steel reinforcement equal to between 0.6% and 0.7% of the pavement’s cross
sectional area is typically specified. This quantity of reinforcement is capable of
producing maximum crack widths of between 0.5 and 0.6mm, at an average spacing of
1.2 metre centres. Such continuously reinforced concrete pavements can extend for
kilometres without a termination point.
For buildings, minimum reinforcement of 0.14% is recommended (i.e. SL82 mesh in a
150mm thick pavement) for concrete pour lengths of up to 25 metres (Cement Concrete
& Aggregates Australia, 2009). With the increasing use of laser screeds, it is not
uncommon to have single concrete pours over 50 metres long, in which case
significantly more than minimum reinforcement will be required.

punching reinforcement for flat slabs