Knowledge Topic Construction of Steel Dome

Project Velocity 2

Project PIC Mr. Hew Kok Meng, hewkm@sunway.com.my

Contributor

Knowledge Leader Mr. Cheor Wai Kit, cheorwk@sunway.com.my

Team Members Mr. Tee Wai Seng, teews@sunway.com.my

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