BESPOKE STEEL STRUCTURE

A Better Solution in Steel Structure

Victor Li
Project Director

“As a team, what matters is how the team members function as a unit, not about an individual’s capability.” Bill Belichick“

“We strongly believe when there’s a will, there’s a way––for there are always more solutions than difficulties.”

“As a team, what matters is how the team members function as a unit, not about an individual’s capability.” Bill Belichick“

“We strongly believe when there’s a will, there’s a way––for there are always more solutions than difficulties.”

H-Zentre, Middle Road

Located in a prime location in Tsim Sha Tsui, H-Zentre is a single commercial complex developed by Henderson Land Development. Formerly a multi-storey car park, it was transformed into a 20-storey Ginza-style complex where dining, clinic, beauty & wellness and retail trade mixes were bundled.

Entrusted by the client, Goldwave delivered a faster, safer and highly efficient structural steel solution that spanned from structural design, fabrication, to onsite erection, as opposed to conventional concrete construction.

The superstructure was designed as an 85.5m-tall building measured from ground floor to main roof with 3 basement floors, in which the lowest level was 14.6m below ground.

Project Summary

Building Height

100 m

Steel Structure Tonnage

7,050 t

GFA

42,000 sqm

Stakeholders

Project Owner

Henderson Land Development Company Limited

Architect

Wong & Ouyang (HK) Ltd.

Civil & Structure Engineer

Ove Arup & Partners HK Ltd.

Main Contractor

Hong Kong Construction (General Builders) Ltd.

Awards

HKGBC BEAM Plus for New Building V1.2 – Provisional Platinum Rating

International Property Awards 2018 - 2019 – Best Mixed-Use Development HK 5 Star Winner

Project Type

CHALLENGES

Complicated Structural Design

H-Zentre was divided into three multi-functional zones: 11 levels of retail and dining; medical centres and 7 floors of car parks. From the 8/F to the main roof and transfer room floor, a complicated multi-storey composite structure and a large span prefabricated modularised transfer truss structure were purposefully designed to support load transfer. A large span cantilever structure was incorporated with curtain wall installation. Hence, the overall building structure was much more complicated than traditional commercial buildings.

To maximise the floor area of car parks below the 8/F, where car parks and retail area were attached, there was a large difference in levels between the two areas. Hence, the E&M design and the access across the difference in levels between the car parks and retail shops posed a huge challenge throughout planning and construction stages.

Main beams were redesigned to optimise large column spacing (some column spacings were larger than 16m). However, since the limited headroom remained unchanged, the general beam depth in the car park area was restricted to 475mm.

Curve-shaped car ramps were composed by beams, in which high quality workmanship was required to shape the curvature during fabrication and site work installation.

Several floors above 8/F were reserved for restaurants and medical centres that demanded more complex E&M and drainage design. Subsequently, a significant number of penetrations were required in various locations to allow necessary routing of services to pass through reinforced concrete and steel members. During the design stage, a significant number of beams were carefully planned and analysed for placing openings to cater for service pipelines. Underneath was also carefully planned and analysed so that the E&M zone was merged with the structural zone to save space to cater for the installation of medical equipment. Our dedicated onsite construction sequence facilitated the overall program of all trade mixes.

The bolt and nut connection scheme was designed to increase installation efficiency for the secondary beams to connect to the main beams.

Sophisticated Fabrication and Precise Quality Control

Besides the skilful welding technique, experience offsite/onsite and rigid quality control, the structural steel components such as the irregular shape of crank beams, 3D curved beams for car ramp, self-fabricated cellular beams (hyper beams), built-up CFT (Concrete Filled Tube) columns and semi-modularised load transfer truss were made by 80mm thick, high strength steel plates to maximise the length of span while minimising the weight of the building structure.

Congested Traffic in the Site Location and Limited Site Space

Being surrounded by tourist spots, commercial buildings & cultural landmarks, a single-way road access and congested traffic to the construction site imposed significant challenges to material transportation, erection sequence and storage of steel structure components. Due to geographical constraints, loading and unloading of materials were restricted to two trucks per day.

Tight Completion Timeline

From submission to Building Authority, completion of foundation work, to the completion of structural steelworks, the construction program was scheduled to be completed less than three years after the contract was awarded.

SOLUTIONS

Technically-Driven and Innovative Structural Steel Design

With the aid of 3D BIM modelling, our innovative design was visualised and shared with all stakeholders throughout the different stages of the project––conception, design, construction sequence planning, downstream for use in material take-off, fabrication, quality assurance/control and construction and facilities management.

80 mm high-strength steel plates were selected carefully and fabricated to cater for higher efficiency of the complex structure. For example, a prefabricated semi-modularised transfer truss structure was designed for load transfer from 8/F to main roof; a complex multi-storey composite structure was used to support the floor where the transformer room was located.

Self-fabricated cellular beams, beams with special opening, and hanging structure components were purposefully designed to simplify the arrangement of Building/MEP services and mitigate clash detection within the structural zone. CFT was designed as structural columns to optimise usable carpet area and to meet the multi-functional purposes of the building.

Our bolt and nut connection design for secondary to main beam connections greatly contributed to the efficiency of onsite erection while minimising the time needed for working at height. With ‘safety first’ being our top priority since day one of design, we have emphasised the importance of maintaining safety for all stakeholders within the site throughout the logistical arrangements and construction sequences.

Just-in-Time Logistics Plan

In view of congested traffic in the construction site, the application of the latest Tekla modelling was adopted throughout the entire fabrication process. The methodology, while facilitating efficient material planning/procurement and optimising the utilisation of material during fabrication, also diminished waste and expedited just-in-time delivery of components.

Total Solution

The actual construction program was completed three months earlier than expected. This brilliant achievement relied heavily on the cohesive collaboration among all teams from innovative design, efficient fabrication/logistic management, experienced project management and skilful onsite erection.

KEY DELIVERABLES

Increase Building Efficiency (Greater Headroom and Usable Area)

More Efficient Construction Program

Mitigate Air Pollution from Concrete Wet Trade

Environmental Friendliness - Reduced Massive Construction Material Debris (Wood Plank)

TIMELINE

JUN 2016

Contract Awarded

AUG 2016

Submission to Building Authority

SEP 2017

Completion of Foundation Work

OCT 2017

Start of Erection of Steel Structure

AUG 2018

Completion of Steel Sub-structure