The uses of excavation supports or earth retaining structures

Excavation support or earth retaining structures are vital where deep excavation is created and arrangement of necessary slope is not possible. Given below, the details of different types of excavation supports.

What Are Excavation Supports?
Usually, to develop a structure either over the ground or underneath the ground, excavation of soil should be arranged in the ground.

The excavation may come in the form of shallow or deep on the basis of our need. But when the soil is dug deeply, there is a chance for collapsing of the soil from the sides of excavated area because of low strength.

To get rid of this issue and to create the cut vertically perfect, some temporary earth retaining structures known as excavation supports are essential.

The soil cut failure occurs if the limit of excavation surpasses its safe height limit and it is subjected to unconfined compressive strength of soil and cohesion.

From the table, given below, the safe height limit for various soil types are given on the basis of their unconfined compressive strength and cohesion limits.

Types of Excavation Supports: Usually, the following methods are mostly used for providing excavation supports-

• Soldier pile and lagging
• Soil nailing

Soldier Pile and Lagging: Soldier piles refer to I-sections which comprise of web among two flanges. These I-sections are drilled into the ground encompassing the boundary of an excavation. The piles are delivered to the point slightly under the necessary excavation depth.

The concrete with poor strength is utilized for the purpose of grouting of piles. The gap among each two nearby piles is restricted to 10 feet. Once that exaction is completed, the flanges of piles provide good support to the surrounded soil.

Wood lagging is applied among the piles. The lagging comprises of long timber sheets or planks which are arranged behind the front flanges of piles to provide well support to the soil among the piles.

The timber contains 2 to 4 inches depth, there, some excavation should be arranged by hand behind the front flange. To create stable bond among horizontal wood sheets and front flange, welded studs, clips etc. are utilized.

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Published By
Rajib Dey
www.constructioncost.co
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The contractor proposal bid form

The contractor proposal bid form is used by a contractor to provide a construction proposal. It refers as the initial point-of-contact connecting the owner and contractor. In this form a neat, prearranged bid is written on a proficiently designed bid form. The contractor proposal bid form contains the breakdown of all the material, labor and equipment costs to make out the proper quantity of materials, labor and equipment necessary for accomplishing the work project. The form also includes the costs, overhead as well as profit of a contractor. All the taxes, bond premiums and insurance under "Work Scope and Details are also included in the form.

While seeking for work proposal from contractors, it is useful to attach this contractor bid sheet with the request made by the owner. In this way a owner can obtain the accurate information as required from a contractor.

A contractor proposal bid form facilitates a contractor to ensure the customer/owner that he is the best contractor - subcontractor - construction company to execute their project.

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Published By

Rajib Dey

www.quantity-takeoff.com

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