RAR – 402
SHORING AND UNDERPINNING
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
SHORING
Provides support to unsafe structures which under the repair.
It is used to make openings, enlargement of wall, dismantling parallel
structures.
Types of Shores
1. Raking Shore
2. Flying Shore
3. Dead Shore
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Raking Shore
In this arrangement, inclined supports are given
to external walls from ground.
It consists of :
• Wall Plate
• 200 to 250 mm wide & 50 to 75 cm thick
• Needles – 100 x 75 section
• Cleats
• Rakers
• Bracing and
• Sole Plates
Following should be noted:
1. Centre line of raker & of wall should meet at
floor level
2. Rakers should be preferably inclined at 45º
with ground. Angle of inclination may vary from
45º to 75º.
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Flying/Horizontal Shore
1. Centre line of flying shore & struts & those of
walls should meet at floor levels.
2. If floor levels of two buildings are different levels,
framework may be suitably designed & made
unsymmetrical.
SINGLE FLYING SHORE
3. Struts are generally inclined at 45º & in no case,
Upto 9.0 m between wall
angle of inclination should increase 60º .
4. Flying shores are inserted when old building is
removed & kept in position till new building is
constructed to sufficient height of to provide
necessary stability
5. Flying shores should be spaced at 3 to 4.5 m
centres along the two walls and horizontal braces
should be introduced between adjacent shores.
DOUBLE FLYING SHORE
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Flying Shore
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Flying Shore
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Dead/Vertical Shore
In this arrangement, horizontal members, known as needles are supported by vertical
members known as dead shores.
Needles are driven at right angles to wall through holes made in wall. Dead shore is used
under following circumstances:
• Lower part of wall has
become defective
• Foundations are to be
deepened
• Lower part of wall is to
be rebuilt or
reconstructed
• Large openings are to
be made in existing wall
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Dead/Vertical Shore
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Dead/Vertical Shore
Points to be noted:
1. Needles are placed at distance of about 1 to 2 m & are suitably braced.
2. Floors are suitably supported inside .
3. Openings above & near dead shore are suitably strutted.
4. Raking shore may be provided as additional safety in case of weak walls.
5. Shores should be removed at least 7 days of construction of new work.
This period is necessary for new works to obtain strength.
6. Sequence of removal should be:
a. Needles
b. Strutting from opening
c. Floor strutting inside and
d. Raking shores, if any
It is desirable to allow an interval of two days between each of these
operations
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
UNDERPINNING
Placing of new foundation below existing foundation or process of strengthening
existing foundation is known as underpinning of foundations.
Following situations demands underpinning:
• To strengthen the shallow foundation of existing building when a building with
deep foundations is to be constructed adjoining to it.
• To strengthen existing foundation
• To deepen the existing foundation
• To construct a basement in existing building
Underpinning can be carried out by the following methods:
1. Pit method 2. Pile method
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Pit Method
• Existing wall is divided into suitable section of width about 1.2 to 1.5m
• Holes are then made in existing wall
• Needles with bearing plates are then inserted through these holes & supported on jacks.
• Pit is excavated & existing foundation is taken up to required level
Following precautions are necessary:
1. One section should be excavated at a time
2. Alternate sections should be taken in
succession
3. If length of wall is more underpinning is
started from middle & then extended in both
directions
4. Proper timbering should be provided for
trench
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Pit Method With Cantilever Needle
If space to support needles on outside is not available, cantilever needles,
projecting inside & provided with fulcrums & loading, may be adopted.
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Pile Method
In this method piles are driven along both sides of existing wall & then needles in form of
pile caps are provided through existing wall . Thus existing wall is relieved of loads coming
on it.
Useful in
• Clayey soils
• Water logged areas &
• Walls carrying heavy loads
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
Thanks...
AR. AMITABH TYAGI APEEJAY SCHOOL OF ARCHITECTURE AND PLANNING GREATER NOIDA
