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. Shoring comes from shore, timber, or metal prop, it may be vertical, angled, or horizontal.
Shoring follows a double-funnel principle signifies that an edge collects a load, channels it and safely redistributes it to a different surface or structure that may assist it.
Here we are going to learn about shoring, types of shoring & much more.
Introduction to shoring:
Shoring is the availability of a support system for sludge, underground utilities, roadways and trench faces used to prevent foundation movement.
Shoring or shielding is used when the cut place or depth makes the back slope the utmost allowable slope impractical.
When shoring is preferred:
- When a structure has become or likely to become unsafe due to differential settlement, bad workmanship, negligence of maintenance.
- When an adjacent structure is to be dismantled.
- Supports may be given externally or internally or both.
Types of shoring:
1.Raking shoring or inclined shoring:
Raking shoring consists of bent wooden members called rakers.
One end of which rests against a faulty wall through the wall plate and the other end against the sole plate which is embedded in the ground in a tilt to distribute the load evenly.
The wall plate, approximately 20 to 25 cm wide and 5 to 7.5 cm thick, stands along the wall face and it is secured through 10 cm x 7.5 cm section needles.
These needles penetrate the wall by about 10 cm, a wallplate is provided to distribute the load.
The rakers are joined together by braces and tied at the bottom by hoop iron.
The following points should be kept in mind while erecting the raking shoring:
- Racers must be tilted to the ground at 45 ° to make them more effective, however in practice the angle can vary from 45 ° to 75 °, the top raker should not be tilted more than 75 °.
- To maintain balance, the three forces must meet at a point and form a triangle of forces.
- Racers should be braced properly at intervals.
- Racers should not be fixed by providing wedges, likely to damage the building.
- The size of the rakers should be decided based on the thrust anticipated from the wall.
- There is more uncertainty about the magnitude of destabilizing forces, so a higher factor of safety must be provided.
- If support, spacing is required based on requirements for long lengths of wall.
2.Flying shoring or horizontal shoring:
Horizontal shoring are termed as flying shoring, which are ideal edges to resist the horizontal component of unsteady force.
Such shores are used to offer horizontal support to two adjoining, parallel party walls which have to become unsafe as a result of removing or collapse of the intermediate building.
The following points should be kept in mind while erecting the flying shoring:
- The centerline of horizontal shore and wall should meet at floor level.
- Wedges are driven in between straining piece and strut.
- The angle of the inclination of the strut should be between 45 to 60°.
- Single shores must be used solely up to 9 m distance between two walls.
- Flying shores are inserted when the outdated building is being removed and needs to be kept in position until the new unit is constructed.
3.Vertical shoring or dead shoring:
This vertical shorings are provided when:
- It is necessary to strengthen or replace the existing unprotected foundation.
- For rebuilding the faulty lower part of the wall.
- To make large doors, windows, or openings in existing walls.
- Dead shores have vertical members known as dead shores and horizontal members are known as needles.
The following points should be kept in mind while erecting the vertical shoring:
- Doors, windows, open floors, and other parts of the structure, which are likely to be affected by the removal of a defective wall or demolition of the wall are properly straightened or supported.
- The section of needles and dead shores should be sufficient to move the load, which can be estimated with reasonable accuracy.
- Needles should be suitably braced.
- The approximate end of the beam is supported by a heavy vertical strut called a dead shores.
- Dead shores are supported on sole plates, the folding wedges are between them.
- The floor must be suitably supported from the inside.
- All the struts provided in all openings have been properly tested, then the faulty part is gradually removed.
Also read: Scaffolding & Formwork