Search the ASTT technical archive.

99 Avenue Sanitary Trunk Rehabilitation - Stage 2

The 99 Avenue Sanitary Trunk Rehabilitation project is a two-stage project to rehabilitate approximately 1.1 km of monolithic concrete arch-shaped sanitary trunk sewer located about 30 m below ground in Edmonton, Alberta. Stage 1 involved the construction of a ~1.6 km bypass sewer to divert flow, facilitating the…

A Case Study in Direct Pipe Thrust Load Prediction

The Direct Steerable Pipe Thrusting (DSPT) technique, which includes Direct Pipe®, is considered a hybrid of horizontal directional drilling (HDD) and slurry microtunnelling methods. It is a surface-to-surface trenchless method that involves thrusted installation of steel pipe along a typically curved vertical…

A Successful CIPP Lining Project Extends Watermain Lifespan and Minimizes Disruption in Cambridge

In 2024, the City of Cambridge completed a Cured-in-Place Pipe (CIPP) lining project for the watermain on Holiday Inn Drive which was nearing the end of its service life. This project involved rehabilitating 1,359 meters of mainline watermain, replacing 29 valves, 10 hydrants, and 28 large diameter service…

Advancing Exit-Side HDD Operations: Improving Safety & Precision through Mechanised Jointing Management

Australia’s latest workplace safety figures from 2023 report 2 600 serious injury claims in the construction industry (194 claims in the electricity, gas, water, and waste services sector) due to being hit by moving objects—a mechanism that also caused 24 worker fatalities across all industries in 2023, accounting for…

Amendment No. 1 to Specification: Design for Structural Renovation of Pipelines by Internal Lining – Part 1: Circular Non-pressure Pipelines (DS-D001 Amd 1)

Application and Characteristics of Large-Diameter Pipe Jacking Method in the Tsengwen-Nanhua Interconnecting Pipeline Project

Taiwan’s drive toward resilient infrastructure in response to climate variability and energy security has accelerated the adoption of no-dig technologies. The Tsengwen–Nanhua Interconnecting Pipeline Project serves as a critical case, showcasing how trenchless construction can address engineering and environmental…

Application of the Concept of Probabilistic Risk Assessment for the Borehole Stability Evaluation in Horizontal Directional Drilling

The current practice of assessing the risk of hydraulic fracture in horizontal directional drilling (HDD) is conducted by making comparisons between the minimum required annular pressure to maintain drilling fluid circulation (Pmin) and the formation limit pressure (Pmax) along the HDD bore path. Despite the potential…

Application of Tunnelling Technology to the HDD Sector for Full Loss of Drilling Returns Crossings

This submission will detail the customisation and innovation associated with utilising a modified tunnelling mixing system for HDD applications where full drilling losses were predicted. It outlines the process from concept design through to testing and implementation throughout the Jansz IO HDD Project. Three 36-inch…

ASTM F3706 – Reviewing the Key Points of the Newly Published ASTM Standard for Spray Applied Mortar Linings

In December of 2024, ASTM published a new Standard Practice for In Field Spray Applied Mortar Linings for Large Diameter Stormwater and Sewer Conduits under the number ASTM F3706-24. This is the first official ASTM Standard covering Spray applied mortar linings (SAPL) materials. This paper will review the key…

Avoca Lagoon Water Trunk Main Crossing

The Avoca Lagoon Trunk Main Renewal Project was a $3.9 million sustainable infrastructure initiative delivered by Eire Constructions for Central Coast Council. It addressed urgent operational issues arising from ageing water mains, replacing deteriorating DN450 cast iron cement-lined and mild steel cement-lined trunk…

Behaviour of Internal Replacement Pipe Systems Under Vehicular Traffic Loads

Internal replacement pipe (IRP) systems are a new and emerging trenchless technology utilised for rehabilitating legacy gas and oil pipes with circumferential cracks or discontinuities. Effective design and analysis are required to ensure IRP systems will have reliable performance and durability against various types…

Belmore Bridge Sewer Rehabilitation: Applying Trenchless Technology Above the Ground

Belmore Bridge crosses the Hunter River and connects the suburbs of Lorn and Maitland. In October 2000, a DN450 DICL sewer rising main was installed across the bridge. A 2023 condition assessment found the pipe was extensively corroded, much more than expected for its short life. When renewing aboveground sewer…

Beneath the Yarra - Duplicating the Hobsons Bay Main Sewer

The construction and commissioning of Melbourne Water’s Hobsons Bay Main Sewer Duplication Project was completed in October 2024. The new 678-metre siphon sewer, constructed underneath the Yarra River between Westgate Park, Port Melbourne and Scienceworks in Spotswood, now transfers 30% of Melbourne’s wastewater to…

Breaking New Ground Beneath Lake Ontario: How Collaboration and Innovation Delivered a Successful Microtunnel Drive

This paper explores the design evolution and successful construction of a 1200mm diameter (1500mm OD), 190m microtunnel drive with a wet retrieval beneath Lake Ontario — a key component of the R.C. Harris Water Treatment Plant Zebra Mussel Control System for the City of Toronto. Designed by Associated Engineering and…

Case Study: Ductile Iron Forcemain Failures - Inspection & Rehabilitation

Ductile iron is a common material for sewage forcemains. However, several forcemain failures on ductile iron pipes occurred in a short period of time in Vancouver. Coincidence or not? Investigations of the breaks showed a similar failure mechanism - internal corrosion on the pipe invert. It is hypothesized that…

Challenges Overcome for the successful Hertel-New York HDD Installation

The Hertel–New York Interconnection Project is a transformative clean energy initiative enabling the delivery of over 1.25 GW of renewable hydroelectricity from Québec to New York City via the Champlain Hudson Power Express (CHPE). The Québec portion, managed by Hydro-Québec and engineered by GHD Ltd., includes a…

CHALLENGING SEWER REHABILITATION OF THE 96-INCH DIAMETER EASTSIDE INTERCEPTOR

King County needed to rehabilitate approximately 3,900 lineal feet (LF) of severely corroded 96-inch diameter reinforced concrete pipe located in Renton, WA. The existing pipe, constructed in 1964, is installed in an urban area between Boeing’s 737 commercial airline facility and a mixed use development. King County…

Challenging the Limits: Class D Pipe Bursting – Connecting Research and Practice

In 2024, the City of Chilliwack, British Columbia, undertook a significant sanitary sewer upgrade, utilizing pipe bursting to increase capacity in the growing Sardis neighbourhood. The project involved upsizing 350m (1,150') of 300mm (12”) ID PVC pipe to 500mm (20”) OD HDPE, a quadruple upsize and increase of…

City of Montreal’s CFRP Pipe Repair Project for 2100mm (84 inch) Mains

In August 2024, the City of Montreal faced a significant water main break when a 2100 mm (84-inch) diameter water main failed along René-Lévesque Boulevard, near the Jacques-Cartier Bridge in south-central Montreal. This incident resulted in the loss of approximately 40 million litres of drinking water, severe…

Comparison of AI with Optimized QC vs Human Condition Assessment of Sanitary Sewers in Boston, MA

The Boston Water and Sewer Commission (BWSC) collects 10-miles (16 kilometers) of closed-circuit television (CCTV) inspection videos per year. These inspections are performed by a combination of in-house staff and contracted resources. Manual coding of CCTV inspections by different resources can be subjective. To…

Comparison Testing of Reinforced Non-Circular CIPP Liners

The use of cured-in-place pipe (CIPP) reinforced liners in non-circular applications has become more common as the technology has developed, especially with the implementation of design standard ASCE MOP 145 and its ability to specifically address non-circular scenarios. The QA/QC testing of non-circular reinforced…

Condition Assessment and Rehabilitation of a 150 year old Brick Sewer Inventory in Victoria

This paper outlines an overview of a condition assessment and rehabilitation program for the City of Victoria’s 150-year-old brick sewer infrastructure. AECOM has provided engineering services for inspection and renewal of storm drain assets since initiation of this program in 2009. The inventory is comprised of…

Condition Assessment and Rehabilitation of Cast Iron Watermains in the City, Singapore

To ensure efficient use of resources, a targeted approach is adopted for water mains replacement by prioritizing highrisk water mains and those with multiple leak history for replacement. In addition, as Singapore’s underground space gets increasingly congested due to the continuous infrastructure developments, it is…

Developing a Risk Matrix for Assessing Seismic Vulnerability of CIPP Rehabilitation of Water Pipelines

This study developed a comprehensive seismic risk matrix framework to evaluate the vulnerability of aging large-diameter water pipelines along Heping West Road, Taipei, before and after rehabilitation with Cured-in-Place Pipe (CIPP) trenchless technology. The framework integrates detailed pipeline segment attributes,…