Why do we calculate deflection?

Why do we calculate deflection?

Deflection gives us value (distance) to which the beam will deflect after the application of load. So the reason behind calculating slope and deflection is to know how the beam will bend and to which extent.

What are the importance of checking the deflection being experienced by a prestressed concrete element?

Therefore, in order to check the performance of rcc member or structure it is advised to check deflections of beams at working load condition to ensure the performance of the member or structure and not at ultimate load level.

Why is it important to evaluate the deflection of a structure?

The deflections of structures are important for ensuring that the designed structure is not excessively flexible. The large deformations in the structures can cause damage or cracking of non-structural elements. The deflection in beams is dependent on the acting bending moments and its flexural stiffness.

What are the major factors that affect deflection explain?

Shrinkage depends on the water/cement ratio, relative humidity and the size and shape of the member. The effect of shrinkage in an asymmetrically reinforced section is to induce a curvature that can lead to significant deflection in shallow members. This effect should be considered in the deflection calculations.

Why is it necessary to keep the deflection as small as possible?

Apart from being unsightly and giving an impression of insecurity, excessive deflection can cause cracking of plaster ceilings and partitions. For steel beams, the deflection should not exceed 1/360 of its span and for timber it is .

Why it is important to study the deflection of beams?

Deflection is a crucial consideration in the design of a structure and failure to apply due attention to it can be catastrophic. Different types of load can cause deflections. These include point loads, uniformly distributed loads, wind loads, shear loads as well as ground pressure and earthquakes, to name but a few.

What are the factors affecting deflection of a PSC beam?

There are various factors that affect creep and shrinkage such as age of loading, minimum thickness, relative humidity, volume to surface ratio, cement content, slump, aggregates, air content, ambient temperature, and admixtures.

Why is it sometimes important to know about the deflection of beams?

If we know the deflection of the beam that may occur under specific conditions then we may easily judge if it seems safe or not (for example if a 1 m long beam deflects by 10 cm then it’s not good). We can also find out if the deflection is high enough to cause any interference with other parts of the structure.

What does not affect deflection?

Which of the following does not affect deflection? The correct answer is C – Shear force. Shear force does not affect deflection of a beam.

Why is deflection control necessary in beam?

Deflection control ensures serviceability. If the deflection value is very large then it leads to cracking of doors, windows, supported and partition walls, drainage in roof slab and misalignment of sensitive machinery that cause excessive vibration. This demands the control on deflection.

Why is it necessary to limit deflection in reinforced concrete flexural members?

Why is computed deflection greater than actual deflection in ACI code?

The ACI Code value is conservative, so computed deflection is greater than actual deflection. Moreover, in the case where premature cracks due to construction loads are not permitted, it is advised to use effective moment of inertia at all loading stages based on cracking amount of that stage.

What are the sources of errors in the deflection calculation?

Utilization of factored loads or moments unintentionally rather than actual service loads or moments in calculation of deflection is another source of errors in the deflection calculation of beams and slabs (flexural members).

How to reduce the deflection of a reinforced concrete member?

Consider redundancy; for instance when reinforced concrete element transverses to the main span may some loads, consequently the moment is decreased which in return the deflection of the member under consideration is reduced.

How to assess the deflection variation of reinforced concrete beams and slabs?

Moreover, the potential deflection variation of reinforced concrete beams and slabs can be assessed by calculating deflections employing realistic maximum and minimum values for parameters. In this article the most important and influential factors are discussed.