DETAIL OF CHANGES
1) Piling at AB11 & AB12
The combination of two pile group of 600 dia. and single pile 800 dia. were the original foundation
system proposed for Academic Building 11 & 12 (Refer Dwg. RB 6199-CD-G-AB 12-PL-1 (Rev.00), RB
6199-CD-G- AB 11-PL-1 (Rev.00), 6199-CD-G-GN-PD-1 (Rev.00), RB 6199-CD-G-GN-PD-5 (Rev.00)).
The quantity of rock socket were the concern during these time as cost of piling work are high due to
the cost of rock coring. Majority of pile are having rock coring length about 12m. The length of rock
socket during these time are based on SI report prepared by United Soil Sdn Bhd which indicated
layer of Sandstone around 12m bgl. However actual rock coring length at site will be confirm based
on the following criteria for the contractor to claim as rock coring which is:1) Change of Coring Tools,
2) Index Strength of rock sample, Is50 are more than 2MPa, for at least three (3) samples picked by
the S.O Representative, and
3) Rock sample recovered are more than 70%.
All criteria stated above must be achieved for the contractor to claim as coring in rock and for the
designer to design as pile in rock.
In order to minimize the rock socket depth for the piling, Value Engineering exercise has been done
and we have work closely with JUBM in order to determine the most cost effective foundation
system. After several option have been developed and proposed, it has been confirmed by JUBM
that 900dia pile are the most economical and effective in term of reducing the pile socket length and
thus reduce the foundation cost for AB 11&12. Majority of rock socket length required for 900dia.
Pile are around 8m. Thus we revised the dwg based on single pile 900dia for all column (refer Dwg.
RB 6199-CD-G-AB 12-PL- 1 (Rev.01), RB 6199-CD-G-AB 11-PL-1 (Rev.01), 6199-CD-G-GN-PD-1
(Rev.01), RB 6199-CD-G-GN-PD-5 (Rev.01)). Two (2) Preliminary Test Pile were conducted on May
2018 for TP-1 at AB11 area by the Sub Con of AZSB, Samalaju Sdn Bhd and Intrumentation contractor
Strainstall Sdn Bhd. During the boring process for TP-1 pile, rock are encountered at 12m bgl. As the
rock sample were extracted from the rock auger, we have found that the rock majority of them are
completely weathered SHALE/SANDSTONE with Rock Quality Designation, RQD equal to 0%. After
inspecting all the sample extracted, the rock are found to be not satisfying the rock coring criteria
stated above thus the contractor can only claim it as boring in soil. The boring are continued until
the desired pile toe level and all the rock found are still not satisfying the rock coring criteria as well,
thus the designer have changed the design on site based on pile in soil for the TP-1 pile. The boring
process shifted to preliminary test pile, TP-2 at AB12 are afterward, and rock encountered at
14mbgl. The rock sample extracted from the rock auger are similar and identical to TP-1 borehole
and still not satisfying the rock criteria mentioned in the drawing, thus based on what we have
discovered during the boring of TP-1 and TP-2 we decided that the pile are to be design as purely in
soil as all of the rock encountered at site during boring process of TP-1 and TP-2 are not satisfying
the rock criteria mentioned above.
Based on the preliminary test pile result conducted, we found that the soil condition are better than
expected. We found that the 900dia can be reduced to 800dia pile in order to reduce the concrete
and steel bar volume up to 20% reduction from previous 900dia foundation system. Furthermore as
no rock were satisfying rock socket criteria during test pile, the rock coring length are omitted. The
column load also being reduced by the Structural Engineer thus reducing the required pile length in
soil for majority of the pile. We revised our drawing and adopted 800dia single pile for all column
except column at B-C/9 where two pile group 600dia pile were introduced in order to cater for the
high loading due to canopy roof tied to the building(refer Dwg. RB 6199-CD-G-AB 12-PL-1 (Rev.02),
RB 6199-CD-G-AB 11-PL-1 (Rev.02), 6199-CD-G-GN-PD-1 (Rev.03), RB 6199-CD-G-GN-PD-5 (Rev.03),
RB 6199-CD-G-GN-PD-7 (Rev.00), RB 6199-CD-G-GN-PD-8 (Rev.00)).
2) Piling at Service Tunnel
Originally the service tunnel were designed as pile raft without consideration of ground support
(Totally relying on the pile friction). 600 dia. Bored Pile were adopted as a support of service tunnel
scatter through the whole length of tunnel and column from toilet area are supported by isolated
Four (4) and Two (2) 600dia. Bored Pile Group. (Total of 153 nos) (Refer Dwg. RB 6199-CD-G-ST-PL-1Rev.00). The quantity of rock socket were the concern during these time as cost of piling work are
high due to the cost of rock coring. Majority of pile are having rock coring length about 7m for
service tunnel area. The length of rock socket during these time are based on SI report prepared by
United Soil Sdn Bhd which indicated layer of Sandstone around 12m bgl. However actual rock coring
length at site will be confirm based on the following criteria for the contractor to claim as rock coring
which is:1) Change of Coring Tools,
2) Index Strength of rock sample, Is50 are more than 2MPa, for at least three (3) samples picked by
the S.O Representative, and
3) Rock sample recovered are more than 70%.
All criteria stated above must be achieved for the contractor to claim as coring in rock and for the
designer to design as pile in rock.
In order to minimize the rock socket depth for the piling, Value Engineering exercise has been done
and we have work closely with JUBM in order to determine the most cost effective foundation
system. After several option have been developed and proposed, it has been confirmed by JUBM
that 800 dia pile are the most economical as this system does not require the pile length to go
deeper into rock layer thus omitting the rock socket cost for service tunnel. Nos of pile for that
option also have reduced to 85 nos. compared to original design of 153nos. Based on these we
revised the dwg based on 800dia bored pile pile raft system for service tunnel and column from
toilet area are supported by isolated one (1) and Two (2) 800dia. Bored Pile Group. (refer Dwg. RB
6199-CD-G-ST-PL-1-Rev.01).
Based on the preliminary test pile result conducted, we found that the soil condition are better than
expected. After carefully studied we found that the ground can be used to support the service
tunnel, only at the area where the column from the building connecting to the service tunnel wall
which is supported by 600 dia bored pile as the column load there are very high and cant be
supported by the ground. Thus Bored Pile nos can be reduced to 50 nos. Furthermore as no rock
were satisfying rock socket criteria during test pile conducted at AB11 & AB12 (TP-1 & TP-2), the rock
coring length are omitted (refer Dwg. RB 6199-CD-G-ST-PL-1-Rev.02).