3. 3
A - Strengthening isolating footing
1- jacket to the existing footings.
2- Combined footing
3- transfer isolating footing–to continous
strap
4- transfer isolating footing–to mat – raft
4. 4
5- Strengthening footing by piles- micro piles
B - Strengthening strap footing
1- jacket to the existing footings.
Columns foundations need strengthening in
the case of applying additional loads.
Widening and strengthening of existing
foundations may be carried out by constructing a
concrete jacket to the existing footings.
The new jacket should be properly anchored to the
existing footing and column neck in order to
guarantee proper transfer of loads
6. 6
This can be accomplished by drilling holes into
existing concrete of footing and epoxy
grouting the longitudinal reinforcement of
jacket.
When the bearing area of footing is not sufficient,
the size of the footing should be increased.
If the column is also being jacketed, the transfer
of load from column to footing becomes easy
7. 7
An isolated footing is strengthened by increasing the
size of the footing and the reinforcement steel
bars as follows:
1. Excavating around the footing
2. Cleaning and roughening the concrete surface.
3. Installing dowels at 25-30cm spacing in both
directions using an appropriate epoxy material.
4. Fastening the new steel bars with the dowels
using steel wires. The diameter and number of
steel bars should be according to the design.
8. 8
5. Coating the footing surface with a bonding
agent in order to achieve the required bond
between old and new concrete.
6. Pouring the new concrete before the bonding
agent dries. The new concrete should contain a
non-shrinkage material.
11. 11
•In all ways of strengthening the foundation should be
linked to the old with the new base d owels iron no less
depth within the old base of 30 cm with cement mortar
and 50 once diameter they emerge outside the base
length can be reduced -15-20sm according to strength
of cohesion epoxy used and the instructions of the
manufacturer