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Showing posts with label Building Design Structural. Show all posts
Showing posts with label Building Design Structural. Show all posts

Wednesday, May 9, 2018

Various types of supports for loads

Roller Supports: Roller Support Example in a CraneRoller supports can be revolved freely as well as translated over the surface upon which the roller is situated.

The surface may come in different forms like horizontal, vertical or slopped at any angle. Roller supports are generally situated at one end of long bridges in the sort of bearing pads. This support facilitates bridge structure to stretch and contract as per modifications of temperature and devoid of this expansion the forces can rupture the supports at the banks.

This support does not have the capacity to withstand the lateral forces. Roller support is also utilized in frame cranes in heavy industries, the support can pass on toward left, right and rotate by withstanding vertical loads. In this way, a heavy load can be transmitted from one place to another horizontally.
Hinge Supports: With the hinge support, it is possible to withstand forces which operate in any direction of the plane. This support does not have any resistance capacity against rotation. The horizontal and vertical component of reaction is found with equation of equilibrium. Hinge support is also applied in three hinged arched bridges at the banks supports even as at the center internal hinge is introduced. It is also employed in doors to create only rotation in a door. Hinge support minimizes sensitivity to earthquake.
FIXED SUPPORT: Fixed support has the strength to withstand vertical and horizontal forces as well as moment as they prevent both rotation and translation. They are also called rigid support. To maintain longevity of a structure, a fixed support should exist.
A flagpole at concrete base is the instance of fixed support. In RCC structures, the steel reinforcement of a beam is implanted in a column to create a fixed support. The instances of fixed supports are all the riveted and welded joints in steel structure.
PINNED SUPPORTS: Pinned Supports - A pinned support has the similarity with hinged support. It can withstand both vertical and horizontal forces devoid of a moment.
It facilitates the structural member to rotate, but not to translate in any direction. Many connections are taken as pinned connections although they might withstand a small amount of moment in reality. It is known fact that a pinned connection can facilitate rotation in only one direction by providing resistance to rotation in any other direction.
Ideal pinned and fixed supports are not often detected in practice, but beams supported on walls or simply connected to other steel beams are treated as pinned. The distribution of moments and shear forces is dependent on the support condition.
INTERNAL HINGE: Interior hinges are mostly used to join flexural members at points other than supports.
In some cases, it is purposely introduced with the intension that additional load breaks this weak zone in spite of damaging other structural elements.
Source: aboutcivil.org
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Published By
Rajib Dey
www.constructioncost.co
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Monday, February 5, 2018

Why RC Structural Slabs and Beams are provided in plinth level

Given below, the detailed information on the importance of arranging RC structural slabs and beams at plinth level (GF-Finished Floor Level).

Wherever low/poor bearing capacity soils met with, the Architects and also certain Builders think and believe that If the bearing strength of soils become weak or low, RC Structural slabs & Beams may be arranged at plinth level (GF-Finished floor level) with the purpose of preventing settlement of foundation and subsequent development of cracks in walls.

By applying your own experience and expertise in foundation structure, it is possible to have clear idea on the behavior of weak bearing soil if loaded heavily. The foundation cost is raised by 50% with the inclusion of the cost of setting up RC Structural Slabs & Beams.

But the provision of RC structural slabs and Beams at plinth level may not be considered as useful solution to get rid of foundation settlement and subsequent cracks. Rather it will be treated as extra expenses that is incurred on the construction of structure.

It is recommended to apply the following measures to resist the settlement of foundation systems and wall cracks efficiently.

The foundation soil at a depth of 00 m to 2.70m (if it belongs to a weak bearing soil like soft/medium clay) should be artificially reinforced with Geogrids/Geotex layers supported with Quarry dust:Gravel Mix 1:3 or cement.

Quarry dust 1:10 mix in 4 or 5 layers of 200 mm thick will enhance the SBC of soil at 2.00m/1.80m level to 200kN/m2 from 100kN/m2.

Arrange an extra layer of Geogrid/Geotex over and then apply the PCC 1:5:10 for 100 mm. Over which the foundation system should be provided as designed-combined strip Raft/combined/isolated footings as per situation. Inspite, under reamed piles with pile cap may be arranged directly.

To get more details, go through the following link onlinecivilforum.com
Why RC Structural Slabs and Beams are provided in plinth level

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Published By
Rajib Dey
www.constructioncost.co
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