Shoring is the process of temporarily supporting a building, vessel, structure, or trench with shores (props) when in danger of collapse or during repairs or alterations. It may be vertical, angled, or horizontal. A shoring erection is one of the most common methods for stabilizing a potentially hazardous construction area.
When shoring is used construction?
Shoring is used in the following situations:
- The stability of a structure is endangered due to removal of a defective portion of the structure.
- The stability of a structure is endangered due to unequal settlement during construction itself or in long run. Eg: When a wall cracks due to unequal settlement of foundation and cracked wall needs repairing.
- Certain alterations are to be done in present structure itself. Eg: remodeling of walls, changing position of windows, When a wall shows sign of bulging out due to bad workman ship. etc.
- Alterations are carried out in adjacent building for remodeling, strengthening of foundation, etc.
- It is used when an adjacent structure is to be dismantled.
- When a tunnel is being constructed, we use shoring to make sure that the opening of the tunnel is supported and protected from accidental collapse.
Types of Shoring
- Raking or inclined shores
- Flying or horizontal shores
- Dead or vertical shores
1. Raking or inclined shores
Ranking shores is a system of giving temporary support to an unsafe wall. In this method, inclined members known as rakers are used to give lateral supports to walls. A raking shore consists of the following components:
- Rakers / inclined members
- Wall plate
- Sole plate
The following points are to be kept in view for the use of the raking shores:
- Rakers are to be inclined in the ground at 45°. However the angle may be between 45° and 75°. he most effective support is given if the raker meets the wall at an angle of 60 to 70 degrees.
- The size of the rakers is to be decided on the basis of anticipated thrust from the wall.
- Rakers should be properly braced at intervals.
- For tall buildings, the length of the raker can be reduced by introducing rider raker.
- The center line of a raker and the wall should meet at floor level.
- The sole plate should be properly embedded into the ground on an inclination and should be of proper section and size.
- Wedges should not be used on sole plates since they are likely to give way under vibrations that are likely to occur.
- Shoring may be spaced at 3 to 4.5 m spacing to cover longer length of the bar.
2. FLYING / HORIZONTAL SHORES
Flying or Horizontal Shores, in this type horizontal supports are provided for supporting temporarily the parallel walls of the two adjacent buildings, which may tend to collapse or damage when one of the intermediate buildings has to be pulled down and rebuilt. All types of arrangements of supporting the unsafe structure in which the shores do not reach the ground come under this category.
3. DEAD SHORES
Dead Shores or Vertical Shores, In this system of shoring, the vertical members known as ‘dead shores’ are used to support temporarily the walls, roofs, floors, etc., by providing horizontal members known as needle.
Dead shores provided for the following purpose:
- To rebuild the lower part of a defective load bearing wall.
- To provide large openings in the existing walls such as doors, windows, shop fronts or garages at a lower level.
- To rebuild (or replace) or deepen the existing foundations.