How to calculate the self weight of the different structural elements

A building load belongs to a force that should be confronted by the house frame. The frame should be designed in an efficient manner to resist eight of these loads ranging from wind, earth, and snow devoid of catastrophic stress on the structure.

Given below, the detail calculation method of self weight for the structural components:

a. Beam: It is applicable to different types of shapes like rectangular/square/tee/trapezoid for measuring the weight.
Weight of member = cross section area of member x length of member x RCC density
Suppose, the width is taken as 0.3 m and depth is taken as 0.45 m for the beam section with 5 m clear length & material density = 25 kn/m3 (for RCC), the weight should be as follow :-
Weight of beam = (0.3 x 0.45) x 5 x 25 = 16.875 Kn
The above calculated weight of 16.875 Kn stands for the total weight that should be transformed into Uniformly Distributed Load (UDL) by dividing the total weight with member length.
UDL = 16.875/5 = 3.375 Kn/m

b. Column: While measuring the self-weight of a column, the terminology of member length should be converted to member height & the weight of column should be computed as point load only its conversion in UDL is not necessary.

c. Slab: For RCC slabs, the weight of roof slabs is employed as invariable pressure in Kn/m2. For making analysis, a 1 m x 1 m square section is taken into consideration & the volume of the RCC is measured & then the same is multiplied with the density for derivation of pressure in kn/m2.

Weight of slab = (1 x 1 x slab thickness) x RCC density

In the above formula as (1 x 1) doesn’t impact the estimate thus it can be further clarified as follow :-
Weight of slab = slab thickness x RCC density

If the thickness of the slab is 0.15 m, then the estimate is done as follows :-
Weight of slab = 0.15 x 25 = 3.75 Kn/m2

In the above estimate of RCC slab weight further supplementary load resulting from floor finishes should be generally taken into consideration for stone/cement floorings as 0.75 kn/m2 to 1.5 kn/m2.

The U-value unit is the inverse those of R-value:

Disposition of slab load on supporting beams: Based on the placement of the beams (square or rectangular) triangular or trapezoidal shape distribution is performed. As for instance, for a rectangular slab of 6 m x 4 m the longer side beams distancing among A-B & D-C will bear the load of related trapezoidal portion while the shorter span beams distancing among A-D & B-C will support weight of roof slab arise out of the related triangular region.

Load on 6 m span = area of trapezoid x thickness of slab x density
Load on 6 m span = 8 x 0.15 x 25 = 30 Kn = 30 / member length = 30/6 = 5 Kn/m
The above estimated load of 30 Kn can be again transformed to UDL of 5 kn/m by dividing it with member length.
Load on 4 m span = area of triangle x thickness of slab x density
Load on 4 m span = 4 x 0.15 x 25 = 15 Kn = 15 / member length = 15/4 = 3.75 Kn/m

To get more details, go through the following article civilengineeronline99.blogspot.com

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Published By
Rajib Dey
www.constructioncost.co
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Methods to save sun shade for life long

Sun is the source of our energy; in the construction energy this sun plays a vital role as it helps to dry the site, helps to get the moisture far away from the materials etc.

But it is also true that shade is important in construction process as it plays as a protection shield for rest of the things like doors, window and inner sides of building form the scorching hot sun light and rain water. So if the sun shade is not placed and finished successfully, many problem will come one after another; major failure will be seen in the buildings also.

A sunshade is basically a metal shutter which is installed horizontally over a window and/or vertically in front of a window to stop the insertion of solar heat or glare while allowing daylight views.

Originally metal sunshades were known as “eyebrows” and simply added an extra dimension to a relatively flat surface. They were known as more of a building’s aesthetic feature than a functional one and also one of the first things to execute of the building to decrease owner’s cost.

This article is strongly dedicated to know about the right method of placing and finishing a sun shade through some easy steps.

Placing a Sunshade concrete in perfect way:

• Reinforcement placing and leaving correct clear covers are the two most important factors in sun shade. 
• In Sunshade, Main rod should be on top of the concrete to make the balance of the negative bending movement.
• The development length of sun shade should be followed and inserted to lintel beam as without development length of a rod for sunshade may lead to failure.

Finishing a Sunshade concrete in perfect way: A sunshade must be finished with water proofing where Flat tile should be on top and projected for half inch around three sides. Sunshade ceiling should have a water blocking border on its edge; at joint of the wall and sunshade the flat tile would be inserted to plastering to prevent the water.

To get details, go through the following link youtoobuild.blogspot.com



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Published By
Rajib Dey
www.constructioncost.co
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The causes affecting the Degree of Earthquake damages to buildings

High rising buildings generally fall when the earthquake hits them and cause utmost destruction or damage with a loss of lives and the fall depends on several reasons.

Earthquake is really a destructive natural destroyer that is destroying some towns and cities continuously over the centuries and damaging them. This destruction for earthquakes can happen upon some conditions of ground or construction based mostly on sediments in flood plains, converted land or former landfill grows the effect of the vibrations though the harder rocks prevent the shaking amount. The result of the effect can be seen in a huge devastated way like damaging of lives and buildings and animals etc. in some cases the land may even dissolve like quicksand and make buildings sink.

Poor construction can make buildings more vulnerable for the earthquake damage and where the bricks have been held in place with the right mortar will survive long. Besides the construction, there are various other factors that are responsible for the damage of building for earthquake and they are breakable columns, stiffness elements, expandable ground floor, short columns, shapes, sizes, numbers of storeys, kind of foundation, location of the buildings, structural layouts etc.

Here all the above cause of damages is being discussed to give a clear overview of the problems and damages and the factors are also stated those can improve the degree of earthquake that damages the buildings. The factors are:

Difference between design and actual response range

Wrong measurement of excepted earthquake characteristics are used in the earthquake design of the form is both popular and difficult reason for the damage of the buildings.

Breakable columns

Most of the structures have been failed in earthquake as per the failure of column and the column may fail for decline of concrete that made cyclic loading and less number of ties fixed in the column at the important locations.

Irregular arrangement of hardness element in plan

Cores in structures are the main stiffness element and its location as building would influence the behavior of the structures when earthquake affects and make damage.

Adjustable ground floor

If the stiffness is decreased heavily of a structure then the stress falls on the structural elements of increased story may increase and fail.

Short columns

This reason is not very much familiar in comparison of ordinary column failure yet short column may fail in cutting in heavy manner and also make the structure fall.

Shape of the floor plan

It is said that the square shaped floor plan is the best insecure behavior than other shapes so the extent of building insecure damage is made by the floor shape plan.

Shape of the building in height

The normal upper storey have most insecure response capered with buildings which have upper storyes in the form.

Slabs support columns without beams

Flat slab system is the weakest structural system which does not have any good resistance against seismic effects and those system is very flexible and has low flexibility

Damages happen by previous earthquake

There are many buildings that have faced earthquakes previously and can face earthquakes again and will fail if the repairing had not done well. It is also seen that repairing a long ago can cause same damage though the methods have improved and the effects are also.

Strong concrete building with a frame structural system

this system is actually a base of weakness in buildings as it goes through many inter-storey drift by seismic excitation which needed more cost to repair.

Number of storyes

When the storeys number increases the chance of affected by earthquake gets high, high rises buildings’ storeys don’t have the strength to bear the capacity of the building.

Foundation types

The types of foundation raises the degree of earthquake damages in two forms – direct and indirect; for direct effect of foundation form it clear itself in number of characteristics and the failure of foundation member is rarely happening but leaves effect. On the other hand, the indirect one has out of plane movements of individual columns based in the case of isolated foundations.

Place of the connected buildings in the block

The location of the connected buildings on block affects on the structure and increases the fail of the buildings.

Slab levels of near structure

The impulse loading from adjacent buildings have a significant influence on the increment of the damages ; the increase of damages in structures with various floor level slabs are significantly greater than buildings with the same floor slab level.

Bad structural layout

The poor adjustment between architectural engineer and structural engineer at conceptual design phase can make bad structural layout.

Source: www.theconstructor.org/




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Published By
Rajib Dey
www.constructioncost.co
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