Extract from paper for International Conference on Slope ,2010, held in Chiangmai, Thailand.
"Introduction:
Moonlight Bay is a luxury end, gated property development on Penang Island in Malaysia. The development consists of condominiums and exclusive villas blended into the hill slope with breathtaking sea views of the renowned Batu Ferringhi beaches and the Andaman Sea."
The toughest project.
I remember my father's words looking at the hill in Batu Ferringhi, "It is very difficult to build houses on this piece of land for the terrain is quite steep. " Why is there such a conversation? Well, my friends from a very established company came over to Penang and asked me to help them to survey this land for they were studying whether it was feasible to build houses on it.
They too found that it was very hard to build buildings on it. If my father was around today he would be surprised to learn that Mediterranean- designed bungalows stand beautifully on it.
A Short HistorySeeing my grey hair , many people have asked me how many years I have been in the construction industry?
Counting back the years, I would say around 34 years. I was lucky to have taken many projects
which helped me to understand the technicalities by experience rather by theory. the following is a summary of the various projects that I have gone through: Highway (Malaysia), Chemical Plant ( Singapore), Electrical Substation (Iran), Oil refineries ( Indonesia),Asia Bintulu Fertilser Plant (Malaysia), Hotel Equatorial , Gurney, Northern Suites (Penang, Malaysia), Telecom Tower (Thailand) etc. So What? Well, if you have not done any projects on a hill slope then it will definitely be very tough
The model
which helped me to understand the technicalities by experience rather by theory. the following is a summary of the various projects that I have gone through: Highway (Malaysia), Chemical Plant ( Singapore), Electrical Substation (Iran), Oil refineries ( Indonesia),Asia Bintulu Fertilser Plant (Malaysia), Hotel Equatorial , Gurney, Northern Suites (Penang, Malaysia), Telecom Tower (Thailand) etc. So What? Well, if you have not done any projects on a hill slope then it will definitely be very tough
The model
The Side elevation
The front elevation
Photo taken on 31st December 2010
Completed Moonlight Bay
Construction.
The Preparation work
KAA's Consultant giving us advice
Staff gathering. Need all the ideas to start this job on site
The Guard post
The drainage system and the site requirement.
The erection of a shrine for " Datuk Kong"
Finally, the completed site gate with the guard post shifted into the site.
The determination of the permanent access
Blasting of boulders
Authorities checking before the blasting
Construction of a temporary sedimentation dam.
The construction of the show unit
Initial construction of the show unit
The show unit in progress
Bricking up
Plastering
A short length of counterfort wall being constructed
The Final show unit
The completed show unit
The foundation work: Caissons
A system from Hong Kong, world renowned in hill slope development.
"One type of deep foundations that extend down through unsuitable soil to transfer building loads to a more appropriate bearing stratum and socket into the rock."
Part of an technical paper by Y W Mark (CEng, MIStructE,MICE House Department, Hongkong
Because of the scarcity of land and abundance of hilly terrain in the territory, it is often inevitable that high rise building have to encroach or found in hill slopes. As the foundations have to be on hill slopes, it is difficult, if not impossible, to provide access to piling rigs, Consequently, footing foundations and driven piles are not suitable ,the best foundation option is
hand dug caissons.
Methodology (a brief)
The excavation proceeds vertically downward in lifts of 750mm to form a circular shaft. A concrete lining is then cast in situ to support the soil pressure before going down the next lift. After the excavated shaft has reached the founding rock stratum, it will be back filled with reinforced concrete.
Before concreting the dug shaft, a proof rock drill to a depth of 5m (depending on the Eng'r design) to determine the rate of penetration will be carried out to testify the rock quality. With proper calibration , the integrity of the rock stratum can be revealed.
Hand dug caisson.
Cast caissons
The base of the caisson were blast until integrity of the rock stratum were achieved.
Hand dug caisson in progress
Ventilating system to provide fresh air when necessary
Typical Caisson construction
The Permanent road
Allan Block System
Reinforced soil segmental retaining wall system
Extract from International Conference on Slope 2010 held in Chiangmai , Thailand.
DESIGN AND CONSTRUCTION OF A 12M HIGH REINFORCED SOIL SEGMENTAL RETAINING WALL FOR HILLSIDE DEVELOPMENT: A MALAYSIAN PERSPECTIVE by
K.T.Khoo
Perunding KAA Sdn Bhd
kaa@perundingkaa.com
K.H.Lee
Landscape Retaining Wall Sdn Bhd
lrwallblock@gmail.com
B.H.Ng & L.K.Lim
TenCate Geosynthetics Asia Sdn Bhd
bh.ng@tencate.com & lk.lim@tencate.com
Important factors to consider using this system
1. Speed in construction of the segmented wall
2. Important advantage of the reinforced soil segmental wall system is that the temporary steep cuts exposure can be kept to a minimum as components like concrete fascia units and soil reinforcements are manufactured offsite and backfilling as the wall is built.
3.2 Segmental blocks facing unit
The facing system is a mortarless, stackable, concrete block retaining wall system. The dimensions of the segmental blocks unit are approximately 203mm height, 457mm length and 304mm width with a unit weight of 34kg/block. The compressive strength required
for the segmental blocks unit at 28 days is 20MPa. The hollow cores in the block are infilled
with 20mm single size aggregate for free draining properties and higher interlocking properties between the block and reinforcing composite geotextile.
The patented interlocking lip automatically locks each row of blocks in place as they are
stacked. With mortarless construction technique, the segmental block requires no grouting, no mortar and no concrete footing. The inherent benefits include site adaptability, easy installation and lower cost.
The hollow core design combines with mortatless construction to allow water to drain freely from behind the wall. A vertical “drained field” is formed by layer of crusher rock placed behind the rock and in the blocks cores. Water moves easily down through the drained field. The dry-stacked construction technique allows the water to escape by flowing around the blocks and out of the wall surface. This built-in drainage system prevents any major build-up of hydrostatic pressure.
The hollow cores in the block are infilled
with 20mm single size aggregate for free draining
The composite reinforcing geotextile was installed at
the required elevation as per in the construction
drawing
Regular checking by Senior and respective department heads regularly
Accurate alignment of the wall forming up the road. This could not have been achieved without Allan Block.
Finally, the walls are up
Earth reinforcement system
The insertion of various tensile -resisting materials into the soil to improve stability.
Completed soil nailing at the hill top
Soil nailing.
It is a reinforcement technique in which closely -spaced parallel steel bars are installed into the face of a slope or vertical cut surface to improve stability. Normally spaced at 6 foot centers vertically and 5 to 8 foot centers horizontally subject to the Geotechnical designer. Soil nail installed for permanent slopes require corrosion-resistant treatment similar to soil anchors.
The most common installation method is to insert the galvanised steel bars into a drill hole and grout from the bottom up by gravity or low pressure. The reinforcing elements pass through unstable (or potentially unstable) soils and provide a tensile pullout resistance.
Soil nailing in progress
The Proof test
This is a simple post tensioning test recommended and used to determine that each soil nailing will carry the designed load,
Set up of a pullout test
Followed by closed turfing and setting out of drainage system
The construction of drains at each cut berm
Authority Requirements
Regular covering up of slope
Workers covering back the cut slope at the end of each day
a
The whole slope being covered up with temporary plastic sheet
Full construction of Units
Half way through the Project
Roofing being installed
The permanent access road with Allan Block system
The Team behind this project
The surveyor teams
We finally finished the project
to cont later.........................with topic
Yet to come
Completed Moonlight Bay
Construction.
The Preparation work
This Mediterranean Project would inevitably crop up in any presentation of Ivory annual dinner or meeting. This shows its utmost importance to the company. At the start, it was very difficult to determine the starting point of this job or in other words, the proposed entrance. Field works or site visits had to be carried out and consultations had to be made with the town planner. My first glimpse of this project was in our main office in Fettes Park. There was a model of the hill and a young architect, Jarvin was repeatedly proposing the idea of building bungalows and then selling them at a later stage with our former GM. Certainly there could be a lot more discussions regarding this project that I did not know.
Not too long after joining the company, my boss took us on a study trip to Hong Kong. During the trip , he intentionally asked the tour bus to take the small hilly road up to the top of the hill. Upon reaching there, he told us that if Hong Kong could have houses built on a slope , why couldn't we.? During that trip , he took part of the team comprising of architects and engineers to the renowned Geotechnical Department of Hong Kong. Once we returned to Malaysia, I was informed by my GM that he had brought back many books and articles from Hong Kong's Geotechnical Department for me to read. Other than this , he also recommended many websites. I started to research on hillslope development in the USM ( Universiti Sains Malaysia) library. Assistance also came from my brother -in -law, Ir. Choo who lent me a book from one of the IEM seminar he had attended and Ir.Chow , Mr. Phoon who constantly giving additional advice during our weekly consultant meetings.
Together with Mr. Ng ,formerly from LTS, who was also very good in earthwork (highly recommended by my boss)and our Senior Head, Mr. Tan, we made our first attempt in determining the entrance and set up our site office there. Later on staff like Robinson, Yeoh, Jasper, Chow, Junior Ng and many more also chipped in and contributed to the success of this project.
Before we started our project, my boss gave us very solid advice-make sure that public safety is your top priority when you start this project. In my head, till today, these words still echoed in my brain. Ah ya!, more white hair.....!!!!! I will try ...
I will need all types of religions to help me complete this job,starting with prayers to Datuk Kong, Jesus, Buddha and finally the most important of all ,God of the Underworld during the 7 lunar month prayer.
Other than that, all the respective consultants who constantly gave me advice were equally important in minimizing errors.
The site office and the temporary access road
As required by the Engineer, we had to proceed our earthwork by cutting first from the top of the hill and then down to its bottom. Initially, we still had to cut an access route and put a guard post beside the entrance. The urgency of the guard post was due to the arrival of the excavators at site . It was the same with hoarding and the gate which we eventually installed .
The site office and the temporary access road
As required by the Engineer, we had to proceed our earthwork by cutting first from the top of the hill and then down to its bottom. Initially, we still had to cut an access route and put a guard post beside the entrance. The urgency of the guard post was due to the arrival of the excavators at site . It was the same with hoarding and the gate which we eventually installed .
The erection of a shrine for " Datuk Kong"
Finally, the completed site gate with the guard post shifted into the site.
The determination of the permanent access
Blasting of boulders
Authorities checking before the blasting
Construction of a temporary sedimentation dam.
The construction of the show unit
Initial construction of the show unit
The show unit in progress
Bricking up
Plastering
A short length of counterfort wall being constructed
The Final show unit
The completed show unit
The foundation work: Caissons
A system from Hong Kong, world renowned in hill slope development.
"One type of deep foundations that extend down through unsuitable soil to transfer building loads to a more appropriate bearing stratum and socket into the rock."
Part of an technical paper by Y W Mark (CEng, MIStructE,MICE House Department, Hongkong
Because of the scarcity of land and abundance of hilly terrain in the territory, it is often inevitable that high rise building have to encroach or found in hill slopes. As the foundations have to be on hill slopes, it is difficult, if not impossible, to provide access to piling rigs, Consequently, footing foundations and driven piles are not suitable ,the best foundation option is
hand dug caissons.
Methodology (a brief)
The excavation proceeds vertically downward in lifts of 750mm to form a circular shaft. A concrete lining is then cast in situ to support the soil pressure before going down the next lift. After the excavated shaft has reached the founding rock stratum, it will be back filled with reinforced concrete.
Before concreting the dug shaft, a proof rock drill to a depth of 5m (depending on the Eng'r design) to determine the rate of penetration will be carried out to testify the rock quality. With proper calibration , the integrity of the rock stratum can be revealed.
Hand dug caisson.
Cast caissons
The base of the caisson were blast until integrity of the rock stratum were achieved.
Hand dug caisson in progress
Ventilating system to provide fresh air when necessary
Typical Caisson construction
The Permanent road
Allan Block System
Reinforced soil segmental retaining wall system
Extract from International Conference on Slope 2010 held in Chiangmai , Thailand.
DESIGN AND CONSTRUCTION OF A 12M HIGH REINFORCED SOIL SEGMENTAL RETAINING WALL FOR HILLSIDE DEVELOPMENT: A MALAYSIAN PERSPECTIVE by
K.T.Khoo
Perunding KAA Sdn Bhd
kaa@perundingkaa.com
K.H.Lee
Landscape Retaining Wall Sdn Bhd
lrwallblock@gmail.com
B.H.Ng & L.K.Lim
TenCate Geosynthetics Asia Sdn Bhd
bh.ng@tencate.com & lk.lim@tencate.com
Important factors to consider using this system
1. Speed in construction of the segmented wall
2. Important advantage of the reinforced soil segmental wall system is that the temporary steep cuts exposure can be kept to a minimum as components like concrete fascia units and soil reinforcements are manufactured offsite and backfilling as the wall is built.
3.2 Segmental blocks facing unit
The facing system is a mortarless, stackable, concrete block retaining wall system. The dimensions of the segmental blocks unit are approximately 203mm height, 457mm length and 304mm width with a unit weight of 34kg/block. The compressive strength required
for the segmental blocks unit at 28 days is 20MPa. The hollow cores in the block are infilled
with 20mm single size aggregate for free draining properties and higher interlocking properties between the block and reinforcing composite geotextile.
The patented interlocking lip automatically locks each row of blocks in place as they are
stacked. With mortarless construction technique, the segmental block requires no grouting, no mortar and no concrete footing. The inherent benefits include site adaptability, easy installation and lower cost.
The hollow core design combines with mortatless construction to allow water to drain freely from behind the wall. A vertical “drained field” is formed by layer of crusher rock placed behind the rock and in the blocks cores. Water moves easily down through the drained field. The dry-stacked construction technique allows the water to escape by flowing around the blocks and out of the wall surface. This built-in drainage system prevents any major build-up of hydrostatic pressure.
The hollow cores in the block are infilled
with 20mm single size aggregate for free draining
The composite reinforcing geotextile was installed at
the required elevation as per in the construction
drawing
Regular checking by Senior and respective department heads regularly
Accurate alignment of the wall forming up the road. This could not have been achieved without Allan Block.
Finally, the walls are up
Earth reinforcement system
The insertion of various tensile -resisting materials into the soil to improve stability.
Completed soil nailing at the hill top
Soil nailing.
It is a reinforcement technique in which closely -spaced parallel steel bars are installed into the face of a slope or vertical cut surface to improve stability. Normally spaced at 6 foot centers vertically and 5 to 8 foot centers horizontally subject to the Geotechnical designer. Soil nail installed for permanent slopes require corrosion-resistant treatment similar to soil anchors.
The most common installation method is to insert the galvanised steel bars into a drill hole and grout from the bottom up by gravity or low pressure. The reinforcing elements pass through unstable (or potentially unstable) soils and provide a tensile pullout resistance.
Soil nailing in progress
The Proof test
This is a simple post tensioning test recommended and used to determine that each soil nailing will carry the designed load,
Set up of a pullout test
Followed by closed turfing and setting out of drainage system
The construction of drains at each cut berm
Authority Requirements
Regular covering up of slope
Workers covering back the cut slope at the end of each day
aThe whole slope being covered up with temporary plastic sheet
Full construction of Units
Half way through the Project
Roofing being installed
The permanent access road with Allan Block system
The Team behind this project
The surveyor teams
We finally finished the project
to cont later.........................with topic
There were slight incidents along the way with slope stabilizing. The public service, police, road works sand , and fire department asked for our assistance during a very heavy down -pour. A SMS from a neighboring church thanked me and my team for help rendered to the public. However,there were rude remarks from drivers who blamed us for the slow-down in traffic. It was the cooperation of our team of staff and workers who helped to get things done not forgetting the policeman and other authorities on duty that night.
It was indeed the TOUGHEST PROJECT!!!
Excellent explanation! Congratulation on the success!
ReplyDeleteWonderful explanation!your performance are absolutely superb..!
ReplyDelete