Entrant details
Role or Job Title on the Project
Developer for the Long Span Footbridge Construction at Northwest Reclamation (NWKR) Site 6
Employer
Employer Role
Public Sector Owner/Client
Are you or your employer a member of buildingSMART?
No
Submission details
Submitting Party Company Name
Housing Department
Submitting Party Company Location
Hong Kong, China
Submitting Party Role on Project
Developer
Submitting Party Company Website
Full Project Name
Long Span Footbridge connecting Hoi Ying Estate and Hoi Tat Estate
Project Location (Country)
Hong Kong
Project Objectives
The construction of a long span footbridge with overall length of about 145m is to connect two public housing estates (i.e. Hoi Ying Estate and Hoi Tat Estate), which are physically separated by major highways in 16 lanes and railways. It also enhances the connectivity between the Cheung Sha Wan waterfront developments and the inland developed areas.
openBIM Achievements
• Reduce collaborative errors, improve the interoperability between software, and ensuring accuracy of multi-party collaboration, thus improving the efficiency of the whole project.
• Capture and specify the whole process and information flow during the footbridge life cycle, and able to ensure relevant data is exchanged in a way that can be interpreted by the recipient software.
• Smoothen installation progress. High quality steel truss fabrication, zero latency of footbridge lowering process and most of all accuracy of connection which allow overall , a safe and successful project.
openBIM used
IFC 2x3
Software used
Revit, ArchiCAD, Tekla BIMsight, Tekla Structures, Trimble Realworks, Naviswork, Vico Office, BIMx viewer.
Highlights
To minimize the closure of highways for installation, a pioneer "lowering" method was adopted. The major span was divided into two halves and constructed in vertical positions within two sites, these two halves were lowered by hinge joints and connected in one overnight with full road closure. The whole process have been well planned and controlled to meet the tight installation period. By using the BIM and laser scanning technology, high quality steel structural fabrication, zero latency of footbridge lowering process and most of all accuracy of lowering connection were secured, which resulted an overall safe and successful project.
Project and Stakeholder Logos (compiled into one .ppt/pptx file for upload)
Project Address
This is a comprehensive development project at north-west Kowloon, Hong Kong. The project address is 38 Sham Mong Road, Kowloon.
Project Type
Mixed-Use
Size of Project
The whole project consists of four public housing blocks, a social welfare block, a government building with library/ sports centre and five footbridges for linkage to the surrounding areas.
The overall site area is approx. 46,500sq.m. The long span footbridge covers a deck area of approx. 900 sq.m.
Detailed description of the project
The long span footbridge forms part of the construction at North West Kowloon Reclamation (NWKR) Site 6 (i.e. Hoi Tat Estate), which is a comprehensive developments including public rental housing developed by the Housing Department of Hong Kong. The site is located at the western side of Nam Cheong MTR Station at western Kowloon. The footbridge connects two public housing estates, namely Hoi Ying Estate and Hoi Tat Estate, with one end connecting a lift tower at Hoi Ying Estate and the other end connecting to the roof top garden of government building within the housing estate. It spans across total 16 lanes of West Kowloon Highway and Lin Cheung Road, with railways including Tung Chung Line, West Rail Line and Airport Express underneath the highway. The construction aims to improve the pedestrian connection between two housing estates, it also helps to increase the physical tie between the new isolated waterfront developments and the inland developed district.
The total length of footbridge is about 145m. It is designed in 2 spans with intermediate pier provided at Hoi Ying Estate. The main span in 111m across West Kowloon Highway is designed in a tied-arch structure, with suspension rods hanging from the arches to support the footbridge deck. While the shorter span in 35m is supported on main arch by steel columns. The main structure is designed in a converging steel arch form with two arches meet at a point near the ground. This arch form helps to integrate the two spans as a unified structure with optimum structural performance, the dynamic architectural expression also visually enhances the connection of footbridge at high level and ground.
The footbridge is a steel structure, the construction involves off-site fabrication at mainland China, delivery and installation. Considering the long span across major highway and the need of road closure, instead of using traditional method of construction by connecting the footbridge piece by piece with temporary support, a pioneer “lowering” method was adopted for the installation. The major span was divided into two halves and the structural components were installed in vertical positions within two sites. Once the installation was completed, these two halves were lowered by hinge joints and connected in one overnight with full road closure. This installation method greatly enhanced the safety of workers and public as the works were limited within construction sites with proper protection, it also reduced the numbers of road closure and eliminated the need to construct temporary intermediate support on highway. However, accuracy in built form of structure during installation in vertical position and lowering process, as well as the connection points should be precisely controlled. Besides, the whole process should also be well planned to meet the tight lowering and connection programme in about six hours.
Both the 3-dimensional arch form and the new "lowering" installation method required high accuracy, every stage of construction should be well planned and designed. The use of BIM enhanced the fabrication and installation accuracy. OpenBIM also facilitated project management, structural design, quality control and site planning.
Detailed description of openBIM on the project
OpenBIM was the key to success for the construction of this long span footbridge in 3-D form.
To start with, the footbridge BIM model was constructed on the basis of first set of construction drawings from the construction team by using Graphisoft ArchiCAD software. The software created a hyper-model within their unique model viewer called BIMx, a technology for integrated 2D and 3D building project navigation. It was useful for the construction team to check on the footbridge drawings in pdf and overlay with 3D model at the same time. The BIM model could be viewed by portable devices, such as tablet or mobile phones to facilitate field discussion or easy mark-up on pdf drawings for amendments.
At early stage of construction, the main contractor was managed to produce the construction programme in 4 days by using Trimble Vico office to carry out a quick programming and 4D construction sequences for presentation. The footbridge ArchiCAD model and the Revit model of surrounding were imported into Vico office. 5D BIM Model based quantity take off were carried out and construction programme was developed within Vico Office. Linkages were matched between models and activities to produce the 4D construction sequence simulation. The whole installation process was clearly presented and considered feasible for execution.
Once the footbridge design was finalized and authored in ArchiCAD, the BIM model was subsequently exported to, .ifc format and passed to the steel fabricator for their fabrication modeling. By using Trimble Tekla software, all fixing details including welding joints, bolts and nuts and temporary fixing could be designed. The model could also be applied directly for the precise cutting of each component even in 3-D form.
An off-site mock up was constructed at fabrication stage. Laser scanning survey of mock-up was conducted to capture data of the main structure, the unwanted point cloud model was filtered out to remain the main frame for QAQC checking with the footbridge BIM model.
The point cloud data were exported into .e57 format and imported to Autodesk Revit, which further converted into .rcp format. At the same time, the fabrication Tekla model was converted into IFC format and imported to Revit for an overlay comparison between point cloud vs. BIM model with the share coordinate. Even the mock-up was expected to be different due to different dead and live loads and deflections, but the comparison provided useful information for project and construction teams to review and fine tuning the design. The result of the horizontal displacement at the major joints were approx. 180mm off set from each other, which was used as a reference for further planning.
After fabrication, components of the footbridge structure were delivered to site and erected vertically on both sides. On-site laser scanning and drone were deployed to assist the construction team for evaluating the construction progress and collecting as-built records. Both technologies enhanced the overall construction accuracy and precision.
To cater for the strict planning of lowering operation in one overnight, the final Tekla model and Revit model were imported to Naviswork to carry out a construction simulation of the whole lowering process. It helped all stakeholders to fully understand the sequence for better control and logistic planning, as well as to allow workers to familiar with the sequence of works for minimizing any risk of delay.
The lowering operation was carried out on 29 December 2019 at mid-night, with a large section of Lin Cheung Road and West Kowloon Highway completely closed for traffic. The connection works including the release of tension cables, lowering of footbridge in position and final connection by bolting were carried out smoothly according to the previous planning. The operation was completed smoothly overnight and the traffic of Lin Cheung Road and West Kowloon Highway were re-opened thereafter. With the joint effort between all parties plus all innovative technologies and openBIM approach, the whole installation process was carried out sucessfully within an extremely tight schedule.
Software ecosystem map
openBIM Supporting Evidence
Benefits from using openBIM
The OpenBIM work flow encouraged all project members to participate regardless of the software tools they used. It facilitated fruitful discussions, enhanced collaboration and data sharing among project members. It also provided enduring project data for use throughout the asset life-cycle, avoiding multiple inputs of the same data and any consequential errors. In this project, participants like the fabricator could select the modeling software based upon their professional expertise, rather than limiting any particular software being used.
The Open BIM movement also offered this project an additional merit of "sustainability". Future operators of this footbridge could have better chances to further utilize the BIM model as it was using the Open BIM approach.
OpenBIM is the way for architects, builders, engineers, and other stakeholders to collaborate efficiently and ensure a commercially viable project. By structuring data correctly, we can make information-sharing easier and enable everyone to work efficiently without costly mistakes and exceeded time schedules and budgets.
I agree to be contacted about the project BIM uses outside of this awards program.
Stakeholders
Yau Lee Construction Co.Ltd., Hong Kong, China,
https://www.yaulee.com, Main Contractor, Richard Fung
Global Virtual Design and Construction Limited, Hong Kong, China,
http://www.globalvdcl.com, BIM Consultant, Benny Liu
