Case Study — International
USW Elevated
Motorway Project
.JPG&w=3840&q=75)
USW Elevated Motorway — segmental erection (2013)
Project Overview
The USW Elevated Motorway is a major urban expressway constructed primarily on elevated viaduct structures through a densely populated metropolitan corridor in Southeast Asia. The project required the production, transport, and erection of thousands of precast concrete box girder segments, assembled span-by-span using overhead launching gantries and stressed together with multi-strand post-tensioning systems to form the continuous elevated deck structure.
Working with Freyssinet, the global specialist in post-tensioning and precast segmental construction, Jerome served as Post-Tensioning and Bridge Engineer responsible for coordinating the interface between segment production, erection sequencing, bearing installation, and post-tensioning operations. The project demanded sustained production rates of up to 15 segments per day from the casting yard, with corresponding erection rates on-site that required precise coordination of launching gantry movements, segment delivery logistics, and stressing operations.
The scale of the bearing installation programme — approximately 400 individual bearing units across the elevated structure — required systematic quality control from manufacture through installation, including dimensional verification, load testing, and alignment checking at each pier location. Jerome managed the bearing installation sequence to ensure each unit was correctly positioned, levelled, and grouted before segment erection proceeded above.
Scope of Work
JCY delivered post-tensioning and bridge engineering services including:
- Post-tensioning system coordination including tendon layout verification, stressing sequence planning, and grouting supervision
- Precast segment production quality coordination at the casting yard (geometry, reinforcement, duct alignment)
- Segment erection sequencing and interface management with launching gantry operations
- Bearing installation coordination across approximately 400 individual bearing units
- Bearing dimensional verification, load testing documentation, and alignment checking at each pier
- Stressing operation supervision including elongation measurement verification and force monitoring
- Grouting operation coordination for post-tensioning ducts with void detection and quality verification
- Segment geometry control and match-casting quality monitoring during production
- Erection tolerance monitoring and adjustment coordination during span assembly
- Technical reporting on production rates, quality metrics, and programme progress
Key Challenges & Solutions
15 Segments/Day Production Rate
Sustaining a peak production rate of 15 precast segments per day required the casting yard to operate as a precision manufacturing facility, with match-cast moulds cycling on a tight timetable, concrete batching plants running continuously, and quality hold points integrated into the production flow without creating bottlenecks. Jerome coordinated the interface between production scheduling and erection demand, maintaining a buffer stock of completed segments to absorb short-term disruptions at either end. Quality surveillance focused on the critical parameters that affected erection fit: segment geometry, duct alignment accuracy, and match-cast face profiles.
Post-Tensioning in Tropical Climate
The Southeast Asian tropical climate presented specific challenges for post-tensioning operations: high ambient temperatures affected stressing calculations due to thermal elongation of tendons, and the monsoon season created humidity conditions that required accelerated grouting timelines to prevent tendon corrosion. Jerome developed temperature-corrected stressing procedures that accounted for steel temperature at the time of stressing, and implemented a “stress-and-grout-same-day” protocol during the monsoon season that eliminated the risk of ungrouted tendons being exposed to moisture overnight.
400-Bearing Installation Programme
With approximately 400 bearing units to install across the elevated structure, any systematic error in bearing positioning would compound across multiple spans. Jerome established a bearing installation procedure that included survey verification of pier head levels before bearing delivery, factory acceptance testing documentation cross-referenced to each installation location, shimming calculations specific to each pier based on as-built survey data, and photographic documentation of every bearing at four stages: delivery, positioning, grouting, and post-erection load verification. This systematic approach achieved zero bearing replacements across the entire programme.
Technical Details
Construction Method
- Precast segmental construction with match-casting
- Span-by-span erection using overhead launching gantries
- Multi-strand post-tensioning with cement grout protection
- Elastomeric and pot-type bearing systems
- Epoxy joint compound between precast segments
Quality Metrics
- Segment geometry tolerance: +/-3mm on critical dimensions
- Duct alignment accuracy: verified by mandrel passage test
- Stressing elongation compliance: within 5% of theoretical
- Grout void ratio: zero voids confirmed by gamma-ray testing
- Bearing installation: 100% photographic documentation
Project Partners
Related Services
Project Gallery
On-the-ground photography from this project.
Need a Similar Capability on Your Next Project?
JCY brings international precast segmental and post-tensioning experience to Australian bridge projects, from casting yard coordination to on-site erection management.