Ct2 latest1-1 (3)

Tan Kai Xuan (0325066) | Chai Jia Ern (0324653) | Tee Wan Nee (0325074) | Tang Lam Yu (0324966) |
Lai Eugene (0324075) | Goh Pei Jeng (0329735) | Andy Chin (0326973)| Eric Wee Hiong Kiet (0329601)
1. Describe 5 comparison between poured concrete & block wall basement
What is Poured Concrete & Block Wall Basement ?
Poured Concrete Block Wall Basement
• Alternative to precast concrete
• Concrete cured on site
• Similar to bricks in that
they use an overlapping pattern to
interlock them together

Comparing…
Formwork
Strength of Foundation Resistance to water
Transportations
Reinforcement
Bar

Formwork
Poured Concrete BlockWall Basement

Reinforcement Bars
• Installed BEFORE the
concrete made is poured
• Need to be inserted
DURING the construction

Transportations
• Transporting and
carrying the blocks are
much less of a hassle
• Transporting woods can only be
transported by lorries and need
more than 2 people to carry it

Resistance to water
• Joint free structure of wall gives
the building HIGHER resistance
to water
• Joint as mortar to hold and
secure the block wall basement
is very porous and creates weak
point.

Strength of the foundation
• Stronger because it is being
poured into a piece and doesn’t
have any hollow voids
• May be only half as strong as
poured concrete because of it’s
hollow voids within the blocks

2. Explain any 5 DOSH rules & regulations on excavation works.
5 DOSH RULES
of Excavation Rules
1. General Requirement
2. Positioning of Machinery
3. Protection of The Public
4. Stability of Structure
5. Access

1. General Requirement
• Employee permitted to enter excavated area unless sheet piling or other
safeguards protection are provided.
• Check excavation site after every rainstorm or other hazard-increasing
occurence.
• Install sheet piling to permit the construction of retaining wall are not
allowed to be removed until the wall develop its full strength.
• Excavated materials and load placed 610 millimeters away from the edge
of excavation and trenches, to prevent fall into the excavation.

2. Positioning of Machinery
• No people shall permitted to position machinery
in manner to endanger himself.

• Substantial guard-rails or board
fences around excavation site and
footpath.
• Danger or warning signs posted at
entrances and exits
• During darkness, public sidewalks
put warning lights to ensure safety
3. Protection of The Public

4. Stability of Structures
• Use structures to support to
prevent injury to people by
according to design of
Professional Engineer such as :
a. Underpinning
b. Sheet piling
c. Shoring
d. bracing

5. Access
• Provide ladders, stairways or
ramps in every excavation
more than 1.2 meters deep.
• Such ladders, stairways or
ramps shall comply with the
provisions and install in
sufficient numbers.

3. Explain what is ground anchor excavation & its method
•
What is Ground Anchor Excavation?

Common applications are :
1. Stabilizing a retaining structure
2 . Stabilizing general slope
3. Stabilizing for diaphragm walls
4. Tying back the entire building from possible
uplifting
•
Ground Anchor

Ground
Anchor
A.Rock anchor
B.Injection anchor
– for anchorage in rock
– suitable for most cohesive
and non-cohesive soils

Method to form a ground anchor
1. Drilling of holes 2. Insertion of
Rock Anchors
3. Inject Grout
- A hole is predrilled
on rock in position.
- An anchor bar with
expanded sleeves at
the end is inserted
into the hole.
- A dense high strength
grout is injected over
a required length
- To provide sufficient
resistance to hold the
bar when it is
stressed.
A. Rock anchor

4. Install Bearing Plate 5.Tension the Anchor
Appropriately
- There will also be a
retaining nut that will
screw down the rock
anchors together with
the bearing plate.
- When the stress is
developed, head of the bar
is hold by an end plate and
nut.
A. Rock anchor

A. Rock anchor

B. Injection anchor- 3 types
A.
B.
C.

1. Drilling
- A hole has to be
bored usually with
an expanded end
to increase
anchorage ability.
2. Grout Injection & Insert Strands
- Pre-stressing bar is placed into
the bored hole and pressure
grouted over the anchorage
length.
B. Injection anchor
- Protective grout
injected under gravity.

4. Pressurization 5. Post- Tensioning
- Pressure grouted over
the anchorage length.
** The bar may be coated with bitumen, wrapped by greased tape
or filled with non-pressurized grout after stressing is completed.
B. Injection anchor

4. Explain 2 other problems related to basement construction.
- A house built on soils with high clay
content will be susceptible to heaving
forces because clay-rich soil expands
significantly when it gets wet.
i. ) Expansive Soils

4. Explain 2 other problems related to basement construction.
- Over time, this moisture can cause the
soils underneath the foundation to
expand, which will then cause them to
push up on the structure above
ii.) Plumbing Leaks

THANK YOU

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