16/11/2016 1 INTRODUCTION . GABION WALL . RUBBLE PITCHING . RUBBLE WALL MOHD TAUFIK HARON KUMPULAN IKRAM SDN BHD DATE: 22 nd NOVEMBER 2016 TIME: 3.00 P.M – 5.00 P.M PENENTUAN KAEDAH PEMBAIKAN CERUN BENGKEL PENENTUAN KAEDAH PEMBAIKAN CERUN UNTUK PIHAK BERKUASA TEMPATAN (PBT) I-KPKT 2016 Introduction to Retaining Wall 1. Retaining wall is a structure that retains (holds back) any material (usually earth) and prevents it from sliding or eroding away. It is designed so that to resist the material pressure of the material that it is holding back. (Civil Engineering Dictionary) 2. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to (typically a steep, near-vertical or vertical slope). They are used to bound soils between two different elevations often in areas of terrain possessing undesirable slopes or in areas where the landscape needs to be shaped severely and engineered for more specific purposes like hillside farming or roadway overpasses. (Wikipedia) 3. Retaining walls are structure used to retain soil, rock or other materials in a vertical condition. Hence they provide a lateral support to vertical slopes of soil that would otherwise collapse into a more natural shape. (L. Prieto-Portar 2008) TERMINOLOGY OF RETAINING WALL Embedment Footing Width Toe Footing Key Stem Retained Height Footing Weepholes Backfill (granular material) Sliding plane 45 Heel
Transcript
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INTRODUCTION . GABION WALL .
RUBBLE PITCHING . RUBBLE WALL
MOHD TAUFIK HARONKUMPULAN IKRAM SDN BHD
DATE: 22nd NOVEMBER 2016 TIME: 3.00 P.M – 5.00 P.M
PENENTUAN KAEDAH PEMBAIKAN CERUN
BENGKEL PENENTUAN KAEDAH PEMBAIKAN CERUN UNTUK PIHAK BERKUASA TEMPATAN (PBT) I-KPKT 2016
Introduction to Retaining Wall
1. Retaining wall is a structure that retains (holds back) any material (usually earth) and prevents it from sliding or eroding away. It is designed so that to resist the material pressure of the material that it is holding back. (Civil Engineering Dictionary)
2. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to (typically a steep, near-vertical or vertical slope). They are used to bound soils between two different elevations often in areas of terrain possessing undesirable slopes or in areas where the landscape needs to be shaped severely and engineered for more specific purposes like hillside farming or roadway overpasses. (Wikipedia)
3. Retaining walls are structure used to retain soil, rock or other materials in a vertical condition. Hence they provide a lateral support to vertical slopes of soil that would otherwise collapse into a more natural shape. (L. Prieto-Portar 2008)
• Gravity walls depend on the weight of the material
(stone, concrete or other heavy material) to stop
pressures from behind and improve stability by leaning back into the retained soil.
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GRAVITY WALL
These walls depend
upon their own
weight to provide
resisting forces
against forces trying to topple the wall.
RESISTING
FORCES
GABION WALL
• A gabion wall is a retaining
wall made of stacked stone-
filled gabions tied together with wire.
• Gabion walls are usually
battered (angled back
towards the slope), or stepped back with the slope, rather than stacked vertically.
GABION WALL
• Gabion walls are suitable for retained heights typically up to about 10 m.
• Gabions are large rectangular cages or baskets, made of hexagonal woven steel wire or square welded mesh, filled with stone.
• Gabions are used to build retaining walls, revetments, and anti-erosion works.
• Box gabions are normally available in 0.5 m modules of length 2 m to 6 m, width 1 m to 2 m, and in depths of 0.3 m, 0.5 m,and 1 m.
• *BS 8002 – Code Of Practice for Earth Retaining Structure
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GABION WALL
Cube or rectangular cage like structures fabricated of heavy wire mesh and filled with rocks
GABION WALL AT TAMAN TAN YEW LAI
WIRE MESH (BS 443)Minimum diameter of 2.7mm Overall diameter after PVC coating 3.8mmMaximum mesh size 80x100mm
ROCK FILLS (BS 433)Clean, Natural, Hard and DurableMinimum density of 2650 kg/m³
Typical Section Of Gabion Wall
Typical Proposed Height and Base of
Gabion Wall
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Typical Section Of Gabion Wall
Example Of Gabion Wall
Gabion Wall
Gabion Wall
Example Of Gabion Wall
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Installation of Gabion wall (video)
CRIB WALL
• Crib walls are gravity retaining
walls, constructed from interlocking, precast, concrete
components.
• They are filled with free draining
material and earth backfill to eliminate the hazards of
hydrostatic pressure building up behind the wall.
Typical Detail Crib Wall
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Example Of Crib Wall
Crib wall (video)
KEYSTONE WALL
• Keystone created the mortar
less segmental retaining wall
market with its patented interlocking modular design.
• This wall are able to resist
lateral pressure with their unit
weight and deep embedment
shape.
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Example Of Keystone Wall
Keystone wall (video)
RUBBLE WALL
• The wall use of undressed, rough stone,generally in the construction of walls.
• Its is suitable for smaller retaining wall especially where the finished appearance is important.
• Rubble walls are suitable for retained heights typically up to 1.5 m (in the case of a simple stem wall) or greater heights (in the case of stepped or buttressed walls). An advantage of masonry retaining walls is they require minimal construction plant.*
*BS 8002 – Code Of Practice for Earth Retaining Structure
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Typical Section Of Rubble Wall
Base Slab
Toe Drain
Rubble Wall
Weep Hole
Cut-off Drain
Backfill Material
Lean Concrete
Rubble Wall
RUBBLE WALL AT TAMAN TAN YEW LAI
Stones being laid or bed in mortar
RUBBLE WALL AT KEM TENTERA SG. BESI
Example Of Rubble Wall
Rubble Wall
Rubble Wall
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RUBBLE PITCHING
1. Pitching shall consist of irregular stones selected to roughly fit together and placed on bedding material having a mean thickness of 100 mm.
2. The stone facing shall have a mean thickness of 300 mm with at least 90 percent of the individual stones having a mass not less than 40 kg.
3. The stones shall be firmly bedded without any tendency to rock and, where necessary, shall be securely wedged in position by stone spalls.
4. The spaces between them shall be completely filled with hand-placed mortar from bottom to top, and the surface shall be cleaned to expose the individual stone faces. All mortared joints shall be raked 5 mm below the adjacent surface of the rock pitching.
Rubble Pitching
Rubble pitching or stone pitching consists
of rocks that are placed on a geotextile
fabric material
Stone pitching are generally used as
erosion protection
Rubble pitching at Taman Tasik Permaisuri
Rubble pitching at Taman Tasik Permaisuri
Example Of Rubble Pitching
Rubble Pitching
Rubble Pitching
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MECHANICAL STABILIZATION EARTH
WALL (MSE WALL)
• Nahemiah Wall
• Anchor Sol Wall
• RE WALL
MECHANICAL STABILIZATION EARTH
WALL (MSE WALL)
• In Mechanical stabilization, layered horizontal mats provide internal shear resistance in addition to that of simple gravity wall structures. Other options include steel straps, which are also layered. This type of soil strengthening usually requires outer facing walls to attach the layers to and vice versa.
• The wall face is often made of precast concrete units that can handle differential movement. The reinforced soil's mass, along with the facing, then acts as an improved gravity wall. The reinforced mass must be built large enough to hold the pressures from the soil behind it.
Typical Detail MSE Wall
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Nehemiah Wall
Anchor Sol Wall
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Design consideration
• Sliding
• Overturning
• Bearing
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Design Consideration
• Typically a retaining wall design has to consider the following:
• a) Sliding stability of retaining walls:
– This calculation considers the retaining wall stability in the horizontal direction.
– Under normal conditions a safety factor of at least 2.0 is required.
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Overturning failure
Overturning Failure is Rotation of wall about its
toe due to exceeding of moment overturning to
moment resisting
Moment Overturning, M0
Moment Resisting, MR
The Factor of Safety against Overturning :
F.O.S OVERTURNING = ∑ MR > 2.0∑ M0
∑ MR = Sum of Resisting moment about Toe
∑ M0= Sum of Overturning moment about Toe
Design Consideration
• c) Bearing Stability in retaining wall design:
– In all cases a retaining wall has to be founded in some kind of base material (be that rock or soil). Compute bearing stresses on the toe and heel of the wall. The reason why bearing stresses have to be computed on both sides is because the overturning causes increased stresses in the toe and reduced stresses on the heel base.
– minimum safety factor of 3.0 is typically specified. *Guideline For Slope Design JKR
Bearing failure
Mass of earth on heel acts downwards
Unsuffcient Bearing capacity of soil
Mass of wall acts
downward
Pressure exerted by resultant vertical force at toe wall must not exceed
