Upload
pavnivsp
View
230
Download
0
Embed Size (px)
Citation preview
8/6/2019 Settlement in Foundations
1/31
23 July 2011 1
G.MADHURI M.E Structural Engineering
Civil Engineering
8/6/2019 Settlement in Foundations
2/31
23 July 2011 2
8/6/2019 Settlement in Foundations
3/31
23 July 2011 3SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
4/31
23 July 2011 SETTLEMENTS IN FOUNDATION 4
8/6/2019 Settlement in Foundations
5/31
CAUSES OF FOUNDATIONCAUSES OF FOUNDATION
PROBLEMSPROBLEMS
Construction Flaws
The Ground Around Your Structure
Uneven Support
The Structure
23 July 2011 SETTLEMENTS IN FOUNDATION 5
8/6/2019 Settlement in Foundations
6/31
IDENTIFYING AIDENTIFYING A
FOUNDATIONFOUNDATIONPROBLEMPROBLEM
23 July 2011 6SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
7/31
EXTERIOR INDICATIONS OF FOUNDATION PROBLEMSEXTERIOR INDICATIONS OF FOUNDATION PROBLEMS
Doors that will not open or close properly
Gaps at the corner of fascia trim
Diagonal cracks in the wall at corners of doors
and windows
Gaps between the garage door and the pavement
at either side of the garage door
Windows that are hard to open and close
Cracks in the exposed grade beam of the house
Cracks in bricks and mortar
23 July 2011 7SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
8/31
INTERIOR INDICATIONS OF FOUNDATION PROBLEMSINTERIOR INDICATIONS OF FOUNDATION PROBLEMS
Unlevel Floors
Large cracks in the concrete slab
Gaps above kitchen cabinets Cabinet doors that will not stay shut
Diagonal cracks in the wall at corners of doors
and windows Leaks and cracks in and around the fireplace
23 July 2011 8SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
9/31
Exterior or interior indications offoundation problems could be caused
by
Upheaval
Settlement
23 July 2011 9SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
10/31
UPHEAVAL :
Foundation upheaval can lift an entire structure but
more often it forces parts of a foundation or slab
upwards while the other section remain stationary.
23 July 2011 10SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
11/3123 July 2011 11SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
12/31
SETTLEMENTSETTLEMENT
Settlement means a portion ofthe house foundation hasdropped below the original
foundation elevation.
23 July 2011 SETTLEMENTS IN FOUNDATION 12
8/6/2019 Settlement in Foundations
13/31
23 July 2011 SETTLEMENTS IN FOUNDATION 13
8/6/2019 Settlement in Foundations
14/31
Weak bearing soils
Poor compaction Changes in moisture
content
Maturing trees and
vegetation Soil consolidation
23 July 2011 SETTLEMENTS IN FOUNDATION 14
8/6/2019 Settlement in Foundations
15/31
REPAIR METHODS FORREPAIR METHODS FOR
FOUNDATIONFOUNDATIONSETTLEMENTSETTLEMENT
23 July 2011 SETTLEMENTS IN FOUNDATION 15
8/6/2019 Settlement in Foundations
16/31
GROUT PUMPING OR MUDGROUT PUMPING OR MUD
JACKINGJACKINGMudjacking is a process by which a mud is pumped, with
pressure behind it under a concrete slab, with enough pressureto raise, to jack up, the concrete slab.
Usually, a low strength concrete is used.
It is used to stabilize soils below settling footings or slabs.
Mud jacking is suitable if bearing rock or stable soils are not toodeep.
23 July 2011 16SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
17/31
ADVANTAGES : Mudjacking is relatively inexpensive and it is fast.
DISADVANTAGES:
That it comes with no warranty,
It can lead to your sewer lines being filled with concrete, Sometimes the concrete emerges in unexpected places,
such as the inside of a wall, where there are unidentifiedholes in a slab.
23 July 2011 SETTLEMENTS IN FOUNDATION 17
8/6/2019 Settlement in Foundations
18/31
23 July 2011 18SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
19/31
A pattern of 1-5/8 inch holes are drilledthrough the sunken slab.
A grout mixture is pumped under the slab
with our specializedequipment. Once any void is filled, the
grout becomes
pressurized, hydraulically raising the slab
to the desired height.
The holes are patched using a concrete
mixture.
SLABSLAB
JACKINGJACKING
23 July 2011 19SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
20/31
It can be done in virtually any weather.
The grout used to raise the slab provides a stable base, thus strengthening
the slab.
Nothing needs to be moved off the slab, as the pump can lift the weight of
the slab.
Low cost: The cost to raise the concrete slab to its original position is
approximately one third compared to replacement.
No loss of use: This technique allows the client to use the slab
immediately.
If the slab is replaced the concrete has to cure for a minimum of 28 days.
BENEFITS TO SLAB JACKINGBENEFITS TO SLAB JACKING
23 July 2011 20SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
21/31
DRIVEN STEELDRIVEN STEEL
PINSPINS
These are used to stabilize settling foundation wallsor footings. A pin is driven next to the foundationand is inserted into the soil until it contactsbedrock.
The driven pin foundation repair method is oftenused when a portion of a foundation wall is movingor settling, perhaps because of improper site workor footing undermining.
The steel pin foundation repair method permitsmore precise leveling control across the buildingthan grout pumping.
23 July 2011 21SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
22/31
23 July 2011 22SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
23/31
HELICAL PIER ORHELICAL PIER OR
SCREW-PIERSCREW-PIERHelical / Screw piers are an approach
similar to the driven steel pins, but may beshorter in length and useful where soilconditions do not provide shallow bedrock.
Helical piers to repair sinking foundationsare often used in building repair orreconstruction, and include models whichcan be used to level floor slabs as well.
23 July 2011 23SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
24/31
23 July 2011 24SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
25/31
No heavy equipment required
Quick installationLower costs
Time-proven engineered system
Installs in limited access areasLimited excavation required
23 July 2011 25SETTLEMENTS IN FOUNDATION
HELICAL PILE FOUNDATION REPAIRHELICAL PILE FOUNDATION REPAIR
ADVANTAGESADVANTAGES
8/6/2019 Settlement in Foundations
26/31
ROD & STEEL U-CHANNEL ORROD & STEEL U-CHANNEL OR
I-BEAMI-BEAMRod & Channel Repair to Stabilize
Structures over Poor Soils.
Rod and u-channel structural repairs are more
likely to be used where soil conditions prohibitthe other pier or jacking methods
Threaded steel rods are run through the widthor length of the damaged structure and boltedto vertical steel U-channels on the buildingexterior.
23 July 2011 26SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
27/31
23 July 2011 27SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
28/31
RECONSTRUCTION OFRECONSTRUCTION OF
FOUNDATIONSFOUNDATIONS Some engineers who examine a failing
foundation may prescribe excavation andreconstruction, possibly with reinforcement
over the original design and with additionalfoundation and site drainage. And indeed insome cases these extensive foundation repairsteps are completely appropriate andnecessary both to repair the building and toprevent a recurrence of the trouble.
23 July 2011 28SETTLEMENTS IN FOUNDATION
8/6/2019 Settlement in Foundations
29/31
For smaller slabs of sunken concrete, suchas residential slabs, driveways, sidewalks,swimming pool decks, etc. is slabjacking.
For larger problems,especially those foundin house and commercial building
foundation shifting, piering is typicallyused to lift and stabilize the foundation.
23 July 2011 SETTLEMENTS IN FOUNDATION 29
8/6/2019 Settlement in Foundations
30/31
23 July 2011 SETTLEMENTS IN FOUNDATION 30
8/6/2019 Settlement in Foundations
31/31
23 J l 2011 SETTLEMENTS IN FOUNDATION 31