Sydney Metro Job Structural Failure Leads to Delays

Australia is currently working on a large-scale infrastructure project known as the Sydney Metre Job. Unfortunately, a key component of Australia’s biggest public transport infrastructure project has recently been the subject to a critical technical report that describes an elevated viaduct span fail located at a stitch joint between two precast segments. The fail took place in September of last year and has led to serious setbacks for the job.

Get Your First SmartRock Concrete Sensor for FREE

Giatec SR demo kit_
Giatec SR demo kit_

The affected section, also known as the Skytrain section, is one of the 115 spans under construction using this precast segmental span-by-span method. The method calls for erecting a series of precast box girder segments that are supported by an overhead gantry, which are then stressed longitudinally.

It was last November when engineering consultant Aurecon Australasia released the results of their independent investigation for Transport for NSW. In the report, combinations of errors were highlighted that were believed to have contributed to the failure of Span 60. These results have led to new controls being introduced as a means to improve the construction process, according to TfNSW.

The noted failure occurred in a stitch joint that was used to join two segments at the midpoint of Span 60. Departing from normal practice, a closure concrete pour was used at this location. Usual practice, on the other hand, would be match-cast segmental construction, where each segment is cast against its neighbouring segment as a means of achieving a matching interface. The latter practice was deemed not possible on Span 60 between segments 5 and 6, due to the fact that the original number 5 segment was been used for another part of the project.

The report indicates that a compression failure of the bottom flange of the box girder occurred in the closure pour approximately 33 hours after the final stressing of the tendons. This failure then caused a hinge point to form in the middle of the span. This caused the girder to be lifted about 700 millimetres from its original position. The northern end of the girder then slid forward and the top flange of the southern end clashed with the Span 59 box girder.

Aurecon claims that the damage was due to insufficient temporary clamping pressure during the stitch-joint construction process. As the structures cooled at night, the segments essentially pulled apart which led to cracking of the stitch-joint. Using concrete with insufficient strength and using exposed resin to attempt to fix the cracking only made the problem worse.

Following the reports’ recommendations, TfNSW plan on making a number of changes in their construction processes. These newly implemented procedures will include increased clamping and longer concrete curing times to ensure that the strength of the concrete is more than sufficient.

Get the full report here

Source: Structural Failure of Precast-Concrete Span Sets Back Sydney Metro Job

Leave a Reply

Your email address will not be published.

Related Articles

Level Up Your Project Reports With Giatec 360™ – Part 2

Let’s dive deeper into report generation to learn more about how Giatec 360’s reports help you make better decisions faster on the jobsite. For an introduction to Giatec 360, click to read Part 1 of this blog. Get Your First SmartRock Concrete Sensor for FREE Free Demo Kit Giatec 360 – An OverviewSome of the key features are as listed as follows:   Temperature Differential Analysis  Generating Full PDF/CSV Reports  Customizing the reports as per user’s preferences which includes   Generating reports for a specific data range  Selected…

Level Up Your Project Reports With Giatec 360™ – Part 1

Let’s learn about Giatec 360 and how to make the most of this advanced web-based dashboard for monitoring and managing concrete pours. Get Your First SmartRock Concrete Sensor for FREE Free Demo Kit The construction industry is one of the busiest, most challenging, and constantly evolving industries, globally. A series of activities beginning from the designing, planning, testing, maintenance, etc., are coupled with rising demand for industrial infrastructure. The requirement and expectations of the field are set high, and the demands are more augmented than usual.  Besides the…

Giatec Paper Award

Giatec Award for Best Paper 2022 

We are very excited to announce the launch of our annual sustainability in construction research paper award contest! This is a great opportunity for civil engineers to expose their research and development to a global audience of industry experts. Plus, the winner will receive a monetary award of $1,000 US. The “Giatec Award for Best Paper” is open to civil-engineering professors, students (undergraduate and graduate), and researchers across Canada and the U.S. As a leading innovator in sustainable concrete, Giatec looks to connect academic research and development in…

Claim Your Free Demo Kit

Get Your First SmartRock Concrete Sensor for FREE

Get Real-Time Data with SmartRock®

See how it works today

We use cookies to provide you with a better experience, analyze site traffic and assist in our marketing efforts. By continuing to use this website, you consent to the use of cookies in accordance with our Privacy Policy Page.