2016-03-17 velocity 2_construction of steel dome
TRANSCRIPT
Knowledge Topic Construction of Steel Dome
Project Velocity 2
Project PIC Mr. Hew Kok Meng, [email protected]
Contributor
Knowledge Leader Mr. Cheor Wai Kit, [email protected]
Team Members Mr. Tee Wai Seng, [email protected]
For Administrative Use
Filename Revision Date
Construction of Steel Dome 00 17-Mar-16
Table of Contents
1. Introduction2. Process Flow
– Design Stage– Pre-installation Stage– Installation Stage
3. Challenges- During installation
4. Lessons Learnt Appendix
1. Introduction
Dome is located on top of the mall, level 6, where it is near to the intersection between Jalan Cheras and Jalan Peel.
• Original steel design is by consultant.• At later stage, the dome structure is redesigned, which results in less and
simpler member, lower cost and more constructible.
2. PROCESS FLOW
A. Design Stage - Comparison between ORGINAL and FINAL design
ORGINAL DESIGN DESIGN AFTER VALUE ENGINEERED
Steel Weight 90T, bulkier 70T, lighter
Cost RM 800K RM 497K
Installation Upper middle ring = 20T• Requires propping as high as 43m from
ground floor• Exceeds tower crane hoisting limit
(max TC hoisting capacity at dome area is 6 tonnes)
• Does not require propping or working platform at below, as installation can be fixed from top.
• Speed - able to complete installation within a month
Adopted
Final Design
12 nos. Main UC (Universal Columns)
Triangle Bracing
Dome Upper Ring
Width vary from 27794mm to 28779mm due to oval shape
Height is 10094mm
2. PROCESS FLOW
B. Pre-installation
• After shop drawing being approved, YSS proceeds to material procurement and steel member fabrication at the factory.
• In the mean time, reinforced concrete gutter to support the dome steel strucutre is being constructed.
RC gutter in progress
• Before casting of RC gutter, bolts for dome steel structure base plate are being secured with a steel template and then the bolts are casted together with concrete.
• 6M24 GR8.8 bolts with 400mm embedded length into concrete.
Step 1 - Installation of first UCDate: 14-Jul-15
Step 2 - Installation of Triangle Bracing after UC installationDate: 15-Jul-15
2. PROCESS FLOW
C. Installation Stage
Step 3 - Continuous installation of triangle bracingDate: 20-Jul-15
Step 4 – Assembling of Upper Level Dome (5T) at lower floor before hoisting upDate: 27-Jul-15
2. PROCESS FLOW
C. Installation Stage
Step 5 - Hoisting and installation of Upper Level Dome (5T)Date: 29-Jul-15
Step 6 - Completion of upper part dome installation through bolt connectionDate: 11-Aug-15
2. PROCESS FLOW
C. Installation Stage
Step 7 – Completion of Dome Date: 14-Aug-15
2. PROCESS FLOW
C. Installation Stage
Item 1Installation without scaffold and working platform at belowThe dome is from level 6 and above. Workers exposed to void that is as high as 43m during installation. The top of dome steel until slab on ground floor is 43m high. Workers are required high level of focus during installation or else fear of falling will cause accident.
3. CHALLENGES
Ground Floor
Level 1
Level 2
Level 3
Level 4
Level 6
Level 5
Top of dome
Item 2Difficulty in accessWorkers climbs up and down to dome through a ladder that is welded onto the UC as shown in photo. Movement between UC’s and triangle bracing of UC is on the hollow section that is welded onto the bracing. Workers face strong vertigo but have to work in great focus. No incident happens during installation.
Hollow section
Ladder is welded to main UC before installation
3. CHALLENGES
Item 3Installation of 5 Tonnes Upper Level DomeThis process requires precise measurement before installation, skilled workers and supervisor during installation. Slight mistake during installation will result in failure of connecting the bolt that joints the upper and lower dome structure.
3. CHALLENGES
5. LESSONS LEARNT
Design can be improved to execute value engineering thus results in faster,better and cheaper construction. We can only determine which is the best by having an open mind, daring to challenge and willing to consider idea from different parties.
AppendixA1 - PhotoA2 - Original Design DrawingA3 - Shop Drawings
PhotoCompleted dome steel structure
PhotoCompleted dome with metal roof
PhotoCompleted dome with aluminium panel and glazing
THANK YOU