9th Australian Small Bridges Conference
 
Our accepted abstracts are shown below, except that we also have others where the asset owner still has to supply comment and/or approval. After this has been done these additional accepted abstracts will also be added.
Our 2019 Abstracts and Speakers already include:
Sunthara Trang
Senior Structural Engineer
KBR
LAIDLEY TIMBER BRIDGES REPLACEMENT

Queensland Rail undertook a project to replace three existing ageing timber rail bridges West of Laidley, Queensland. The purpose of the project was to improve reliability, operational safety and efficiency of services on the rail corridor. In late 2014, Queensland Rail awarded a contract to JF Hull Holdings Pty Ltd (JFH) for the design and construction of new structures to replace the existing timber bridges. Kellogg Brown & Root (KBR) was engaged by JFH for the design component.

A key challenge in the project was to demolish the three existing timber bridges, install the new structures and restore the services in 48-hour full track closures at two separate locations. The short timeframe track closures were planned by Queensland Rail to minimise disruption to freight and passenger train services. KBR and JFH examined risks associated with the project requirements and proposed an effective solution to replace the existing timber bridges with precast box culverts supported on precast base slabs which were joined together by cast in-situ stitches. The proposed precast structures enabled the construction team to install them in place within the short allocated timeframe. KBR design team carried out detailed design of precast base slabs with cast in-situ stitches, precast wing walls, cast in-situ apron slabs and cast in-situ kerbs. Construction staging was also undertaken in the design to allow installation of precast boxes, backfilling and track works prior to casting in-situ stitches to form complete base slabs. The precast box culverts were designed by the third party. Two large box culverts were designed to replace the three existing timber bridges.



The new structures were required to be designed to support dual ballasted tracks with Queensland Rail QR-300A railway loading at each bridge location. Existing rail levels were to be maintained while flood efficiency of the new structures was improved after the construction. The main works to be carried out in the construction were demolition of the existing timber bridges, removal of unsuitable materials, subgrade improvement, installation of new structures, earth works and embankment formation at approaches, track works and restoration of the existing services.

With thorough planning and design, the construction team managed to successfully complete the bridge replacement works in September 2015.

BIOGRAPHY

Sunthara obtained his bachelor’s degree in civil engineering in 1993 at the Kharkov Institute of Municipal Engineers in Ukraine. In 2000, he pursued a postgraduate study at the University of New South Wales in Sydney and obtained his master’s degree in structural engineering. Sunthara has been working as a structural engineer in Cambodia and Australia. His main duties involve structural design of bridges and civil structures.
 
Royce Toohey
Support Services Engineer
Eurobodalla Shire Council
A TALE OF TWO BRIDGES: A COMPARISON OF THE REPLACEMENT OF TWO TIMBER BRIDGES WITHIN EUROBODALLA BY DIFFERENT SOLUTIONS

Eurobodalla has been undertaking a program of bridge renewal and replacements to reduce deficiencies and to better manage its transport network.

Due to significant government funding, a low-level rural timber bridge that was of poor condition and utilised by a high percentage of commercial vehicles, was replaced by a 85m concrete structure at a higher level. This work was done under a Design & Construct Contract.

Simultaneously, a 130m long timber bridge in another rural location was replaced like-for-like by Council’s internal staff, using a combination of Council and grant funding.

Both bridges are single-lane bridges located in remote areas of significant environmental benefit with imposed restrictions on the impacts allowed on their respective marine environment.

This paper will discuss the desired outcomes from each project and compare the techniques used, a cost comparison of the two projects, and issues encountered.

BIOGRAPHY

With over 40 years’ in local government, Royce has had significant experience across the range of local government responsibilities. Currently responsible for the Bridges and Marine Structures of Eurobodalla Council as well as other facets of Service Delivery, he was previously their Asset Engineer providing him with experience from project development through construction to long-term management. He holds a degree in Civil Engineering from USQ as well as a Masters from UTS in Engineering Management.
 
Geoff Thompson
Senior Bridge Engineer
Aurecon NEW ZEALAND
TIROHANGA WHANUI - PEDESTRIAN AND CYCLING BRIDGE

The New Zealand Transport Agency and Watercare Services Limited have jointly funded the design and construction of the Tirohanga Whanui Bridge.

This pedestrian and cycling bridge is being constructed on the North Shore of Auckland across SH1 as a gateway structure within the Northern Corridor Improvements Project. The multi-functional bridge also conveys a 508mm diameter water main across the motorway, building resilience to the water supply network. It is a great example of form meets function whilst expanding the architectural design through structural features. The 106m long truss bridge consists of three spans, with organic voids that vary in aperture by responding to the stresses in the structure.



This paper will cover the design development and construction of the bridge including concept design, layout, stakeholder engagement, structural detailing and analysis, erection methodology, and construction challenges.

BIOGRAPHY

Geoff Thompson has 10 years’ experience in bridge design, management and construction. He has worked across multiple geographies including South Africa, Dubai, Fiji and New Zealand. He is passionate about all things 'bridge' and within Aurecon's Auckland office, leads teams in the delivery of civil structural and bridge projects.
 
Armin Shoghi
Senior Structures Development Engineer
VicRoads, Metropolitan North West
USING INTELLIGENT TRANSPORT SYSTEM STRATEGY TO PREVENT/REDUCE OVER HEIGHT VEHICLES FROM STRIKING THE NOTORIOUS NAPIER STREET RAILWAY BRIDGE

This paper outlines a recent adopted strategy to protect the Napier Street Railway Bridge, in which VicRoads has implemented a new Intelligent Transport System (ITS) strategy to prevent future bridge strikes.

The Railway Bridge over Napier Street in Footscray has a clearance of 4.1 metres and has had a number of strikes by over-height vehicles, resulting in frequent temporary closures of Napier Street to traffic and posing safety risks to road users.

The Napier Street railway bridge has had more than 70 strikes in the last 7 years. The Napier Street Railway bridge is one of the highest impacted structures in Victoria, and hence VicRoads was funded to provide a strategy in preventing/reducing the number of strikes by over-height vehicles at this notorious low clearance bridge.

The paper discusses the design and construction of number of new devices implemented on site as part of the new ITS. The new system can detect any overheight vehicles approaching the bridge that have failed to follow the static signs, electronic message signs and warning line marking. At the last point, new traffic signals have been installed that stop the over height vehicles preventing them from impacting the bridge.

BIOGRAPHY

Armin Shoghi gained bachelors of Civil Engineering with (Hons) from Swinburne University of Technology. He is currently working at VicRoads as a Senior Structures Development Engineer. He has been involved both in delivery and development of bridge projects at the Structures team. His latest project was the delivery of the notorious Napier Street project.
 
Jeevan Senthilvasan
Chief Discipline Engineer Structures
KBR
DESIGN CONSIDERATIONS TO CATER FOR DIFFERENTIAL SETTLEMENT FOR CULVERT EXTENSION

The Gateway Upgrade North (GUN) Project is a major upgrade of an 11.3 kilometre section of the Gateway Motorway between Nudgee and Bracken Ridge, in Brisbane. The scope of the project early works included structural assessment of the existing culverts and extension of the culverts in the widening section of the motorway. Many of the culverts were located in soft compressible soils which were subject to significant settlement. The upgrade works caused increased loading on the existing culverts from additional fill and an increase in design loading from NAASRA-1976 to AS5100-2004 which resulted in predicted differential settlement between the existing culverts and the culvert extensions.

For the existing culverts, while the increased fill above the culverts results in additional loading, it allows the wheel loads to distribute to a larger footprint resulting in reduction of load intensity. A methodology was developed to assess the interaction between the fill depth and the total load applied to the culvert, based on the load effects from the soil and wheel live loads.

Differential settlement between existing culverts and the culvert extension causes a vertical step at the interface unless a shear connection is made at the interface between the culverts. Any vertical misalignment between the culverts can cause hydraulic turbulence which restricts the flow, cause erosion in the long run and generate reflective cracking in the road pavement. However, rigidly connecting the existing culverts to new culverts will cause very high stresses in the reinforced concrete section at the interface when soil under the culvert extension settles.

This paper discusses design considerations for culvert extension in soft soil, high settlement locations and in particular, special connections that are considered to avoid large stresses at the culvert extension interface while maintaining an uninterrupted hydraulic flow in the culvert.

BIOGRAPHY

Dr Jeevan Senthilvasan is a Chief Discipline Engineer and Industry Lead for Bridges and Structures in KBR Brisbane office. He is also the Technical Leader for the Civil Structures group, mentors structural engineers and monitors the standard of the design and documentation. He has more than 25 years experience in design of civil structures and is responsible for providing skills development, providing technical support to design team and promoting innovation and value engineering in major projects.
 
Marcia Prelog
Associate
Aurecon
BEARING REPLACEMENT AT BLAXLANDS CROSSING

The bearing replacement design for the bridge crossing Nepean River at Blaxland’s Crossing, Wallacia, was initially presented at the 2017 Small Bridges Conference by Arcadis.

The five span prestressed concrete bridge comprises slender concrete blade piers within the Nepean river. A distinctive twist to the pier layout provides perpendicular support to the superstructure, whilst lessening the impedance of flood water by skewing the base of the pier parallel to water flow.

Aurecon prepared an alternative bearing support design which resulted in Wollondilly Council awarding the construction contract to Complex Civil contractors.

The new bearing supports feature innovative steel brackets braced to the sides of the pier with high strength stress bars. This design has been successfully adopted on other Aurecon bridge projects in the past.

Whilst this project is ultimately about the replacement of elastomeric bearings, this paper discusses the progression of this innovative design from concept stage at tender, the use of LIDAR technology through to detailed design, fabrication and construction.

BIOGRAPHY

Marcia Prelog is an Associate within Aurecon who has extensive experience a variety of bridge structures in Australia and overseas. Her 18 years in the Bridges discipline encompasses design in steel, concrete, composites and timber.
 
Hari Pokharel
Associate Technical Director
Arcadis Asia Pacific
TRACING LOAD PATH AT A NODE OF CONCRETE TRUSS BRIDGES FOR THE DETAILING OF REINFORCEMENT - A REFERENCE TO THE PEDESTRIAN BRIDGE IN FLORIDA THAT COLLAPSED IN MARCH 2018

The focus of this paper is to explore the requirements for detailing proper reinforcement arrangements at the node of a concrete truss so that controlled performance can be achieved to create elegant concrete truss bridges.

The industry should not discourage adopting suitable concrete truss bridges in new projects after the collapse of a pedestrian bridge at the Florida International University in March 2018

BIOGRAPHY

Hari has worked more than 30 years in the civil engineering industry, dedicated his services to major infrastructure projects in Australia and Asia. His core interest remained in the research, design, construction and management of rail and road bridges and associated projects. Core skills include the development of computational analysis, better understanding of concrete material and behaviour of structures made of concrete and active user of special purpose-built software for the analysis of concrete bridges including time dependent construction stage analysis.
 
Ken O'Neill
Bridges Leader NSW
Aurecon
Co-authors
Brian Killeen

Senior Bridge Engineer,
Aurecon

Jaime Granell
Technical Director Australia & New Zealand
Ferrovial

"PERGOLA” RAIL BRIDGE OVER UPGRADED PACIFIC HIGHWAY

The new railway crossing of the Pacific Highway at Warrell Creek on the NSW North Coast comprises an innovative “pergola” structural form to carry the railway loading over two spans. The single track North Coast Line was deviated during a track possession to allow for a bulk excavation and bottom-up construction of the structure. The substructure comprises reinforced concrete gravity retaining walls up to eight metres in height and supports a superstructure comprising prestressed concrete girders that vary in spacing for the high skew of 50 degrees.



The presentation will cover the design process including the alternative design options considered, the constructability considerations and the benefits of deviating the rail alignment temporarily to facilitate construction.

BIOGRAPHY

Ken leads Aurecon's bridges team in NSW comprising approximately thirty people and is a Technical Director within the Infrastructure Group in Sydney. He has nineteen years’ experience in the detailed design, documentation and construction of major highway and motorway upgrades in NSW and Victoria. Ken was the structural design leader on the Warrell Creek to Nambucca Heads project which comprised fifteen major bridges.
 
Dara McDonnell
Associate
Arup
THE APPLICATION OF STRUCTURAL HEALTH MONITORING TO THE LOAD RATING OF A HISTORIC JACK ARCH BRIDGE OVER RAIL IN NSW

Arup undertook a condition assessment of a historic jack arch bridge at Maitland NSW. Working closely with the client, John Holland Country Rail Network and Arup’s specialist subcontractor, Strainstall, Arup undertook a detailed condition assessment of the asset that included load testing, a period of structural health monitoring (SHM) and a programme of structural investigation and non-destructive testing (NDT).

Arup used the monitoring programme to develop a numerical model of the bridge structural behaviour, to load rate the bridge and develop a maintenance programme to extend the life of the asset and manage the future structural integrity.

The paper will provide details of the investigation programme including NDT, the monitoring programme, the asset management plan and lessons learned for future assessment of historic bridge assets like jack arch bridges.

BIOGRAPHIES

Dara is a senior bridge and civil structures engineer in Arup’s Sydney office. He has over 15 years of experience in the assessment of existing infrastructure structure assets on a wide range of transport and energy infrastructure.

Justin St George, Senior Engineer, Strainstall, Singapore Justin is a senior engineer in Strainstall’s Singapore office. He is a lead engineer for strain gauge based monitoring solutions, including the design, installation, data acquisition, data analysis and test reporting of complex systems. Strain gauge results can be used for stress calculations and stress analysis of structural elements, FEA/FEM validation, residual and thermal stress determination, as well as structural health analysis
 
Emson Makita
WA Bridges and Civil Structures Team Lead
Arup
REPLACEMENT OF TIMBER BRIDGES WITH PRESTRESSED CONCRETE BRIDGES IN WESTERN AUSTRALIA

The proportion of timber bridges in Western Australia (WA) is approximately 45 percent of the state stock. The timber bridges are largely located in the South West, Great Southern and Wheatbelt Regions of WA.

This paper discusses a selected number of timber bridge replacement projects that have recently been undertaken in WA, on which the author was involved as a design leader.

Design considerations such as geotechnical, waterways requirements, future maintenance, environmental issues, durability, whole of life cost, construction staging, community requirements and expectations, and heritage are discussed. Whilst the paper provides an in-depth discussion on the design and replacement of Bridges 0024A and 0025A, which both carry the Albany Highway in Williams - Wheatbelt Region, the author also discusses the challenges met and solutions adopted for Bridges 0083A, 0661A, 0541A, 0904A, 3197A, 3210A and 4860A. Except for Bridge 0904A, which carries a road over rail in a significantly constrained built-up residential area in Perth, the rest of the bridges discussed are in Regional WA. The design solution for the superstructures largely entailed the use of precast prestressed concrete planks and Teeroffs. Simply supported and integral superstructure solutions are discussed as part of this paper.

BIOGRAPHY

Emson is Chartered Engineer with both the ICE in the UK and Engineers Australia. He has experience in the inspection and design of bridges of various forms of construction in the UK and Australia. He has led and delivered numerous bridge and civil structures projects for Main Roads WA, VicRoads, Public Transport Authority of Western Australia, Brookfield Rail, Network Rail, and the Highways Agency.
 
Michael Kakulas
Principal Bridge Engineer
AECOM
Nicholas Keage 
Senior Bridge Engineer
AECOM

ACHIEVING SIMPLICITY FOR CONTINUOUS TEEROFF BRIDGES

Bridges comprising precast Teeroff Beams made continuous offer a number of advantages, and have been used increasingly on projects in Western Australia.

Typical methods of achieving continuity rely on specialised construction techniques (i.e. post tensioning) or extensive formwork in constructing in-situ transverse diaphragms. To maximise the combined benefits of a continuous design and precast Teeroff beams, the design of the bridge, and in particular the stitch detail, needs to be as simple as possible.

On Northlink Central Section, a new method of achieving continuity for the highly skewed multi-span bridges was devised. The design innovatively used the standard Teeroff geometry and a voided end block to construct a cast in-situ continuity stitch without any additional onsite formwork. The geometry of the continuity stitch eliminates the need for couplers in the Teeroff beam, or bars protruding through the stitch formwork.

This paper presents the detail used for Northlink Central Section bridges. The resulting savings in materials, formwork and construction costs are compared to the conventional simply supported alternatives.

BIOGRAPHIES

Michael Kakulas has over 24 years’ experience in bridge design, focussing primarily on the technical aspects of the business, undertaking Design, Discipline Lead and Design Manager roles on road and bridge infrastructure projects across various contract delivery types, including D&C and Alliance Contracts.

Nicholas Keage is a Chartered Professional Engineer with over 8 years’ experience in the analysis, design and documentation of bridges across Australia. His design experience ranges from award winning architectural pedestrian bridges, through to major highway and rail bridges, including incrementally launched bridges
 
Graeme Joynson
Technical Director - Bridges
GHD
BRIDGE OVER THE MAIN NORTHERN RAILWAY LINE AT LISAROW, NSW

The Pacific Highway north of Gosford is the urban arterial road providing access to Gosford’s northern suburbs and the Pacific Highway (M1) at Ourimbah.

This project represents Stage 3B of the NSW State Infrastructure Strategy, which consists of upgrading approximately 1.6 km of the Pacific Highway to a four-lane urban arterial road between Ourimbah Street and Parsons Road, Lisarow, and includes the replacement of the existing steel bridge over the Main Northern Railway Line at Railway Crescent on the Pacific Highway.

The new bridge is a complex structure of two simply supported spans of prestress Tee-bulb girders with an in-situ concrete deck.

The skew and bridge width varies considerably between the two spans, due to a tight horizontal curve in the road design line within the second span. The first span is a conventional arrangement with a 45 degree skew, and the second span, which is significantly wider, forms an 80 metre long skewed tunnel over the railway.

This paper focuses on the design of the new concrete structure to fit within numerous constraints presented by bridge construction on a busy highway over a major railway.

BIOGRAPHY

Graeme Joynson is a Bridge Design Engineer who has a career spanning 4 decades encompassing experience in both structural design, and construction of bridge, marine and road projects. This includes detailed structural design and documentation of all forms of bridges, both as a team leader, and the primary designer.
 
Nasir Hossain
Structural Engineer
Aurecon
LOAD RATING, CONDITION ASSESSMENT & REFURBISHMENT OF THE JAMES STREET UNDERBRIDGE LITHGOW NSW

The James Street underbridge is a masonry arch bridge built in 1869, which is a Sydney Trains asset. The bridge is west of Lithgow Railway station and carries two tracks.

The bridge is of heritage significance as it is the second oldest stone arch railway bridge in NSW still in use and was designed by renowned engineer John Whitton. The bridge is a three-span sandstone arch structure and is a great example of sandstone arch construction of its era.

Aurecon undertook a load rating assessment with the aid of specialist arch analysis software Archie-M and with guidance from Australian and international standards and codes.

The findings of the initial condition assessment and load rating suggested possible settlement and lateral instability of the arches, necessitating arch crack repairs and lateral strengthening. The load assessment provided a decreased capacity to carry freight loads due to the existing defects.

To increase the arch capacity for current loading and further extend the service life of this historic structure, Aurecon undertook the design of replacement tie rods, arch lateral strengthening and crack repairs. The design was heavily coordinated with NSW heritage.

The behaviour of stone masonry arch structures, the effect of the tie rods’ contribution to the spandrel walls and the significance of defects such as arch cracking on the load rating and refurbishment design are some of the important features that are explored in this paper.

BIOGRAPHY

Nasir Hossain is a Structural Engineer in Aurecon who has worked within the infrastructure, petrochemical, mining, ports and telecommunications sectors over the past 12 years. He has a range of experience in the structural assessment of a variety of bridge forms in steel and concrete.
 
David Hildebrand
Senior Officer of Asset Management
VicRoads, Western Victoria
WE NEED TO TALK ABOUT LEVEL 2 BRIDGE INSPECTIONS…

How much confidence do we have in Level 2 Bridge Inspections?

They’re a staple of the management of structures and have been so for decades. They are amongst our first ‘informers’ of a structures condition; providing condition information on the individual structure as well as allowing us to infer the health of the network of structures we manage. But how good are they? There are numerous examples, too many to count really, of inspectors both new and the very experienced making obvious ‘misses’ in what is essentially an inspection which relies on good observation skills more than anything else. Why? And is this a problem? Do we put too much reliance on the Level 2 Inspection; should we be more pragmatic and accept their fundamental flaw; that is people; and just deal with an expected level of inaccuracy? Or do we hand this responsibility over to the machines?

This paper will explore these themes and hope to provoke conversation about an inspection that every manager of bridges relies on.

BIOGRAPHY

David Hildebrand has 16 years’ experience in the completing and auditing of L2 Inspections and the identification, development and sometimes delivery of Bridge Projects big and small in country Victoria.
 
Behzad Golfa
Structural Engineer- Bridges
GHD
DESIGN OF ASHTON AVE INTEGRAL BRIDGE WITH BATTLE DECK PLANK SUPERSTRUCTURE

This paper presents the utilised method to reduce the depth to span ratio of Ashton Avenue Bridge. The bridge is a single span with an overall length of 20m and overpasses the Perth Fremantle Railway in Claremont WA.

Due to the restriction of vertical clearance, a superstructure with a maximum deck thickness of 520mm was allowed to be used. To achieve this and to reduce the superstructure thickness, the battle deck plank with integral abutments was used as the preferred option.

This paper will firstly, recall the bridge specifications and the other constraints that characterised the design of the battle deck planks and the integral abutments. In the second part, the design criteria followed in designing the battle deck, abutment and foundation are presented.

The structural analyses were set out in accordance with the construction sequences using Spacegass and Aces software.

The design results indicate that using the battle deck plank superstructure on a bridge with integral abutments may reduce the depth to span ratio considerably. Details of completions and finishing works are finally given.

BIOGRAPHY

Behzad Golfa has over 14 years of experience in the investigation, design, construction and management of Australian and international infrastructure projects, involving work with major Iran and Australian consultants and contractors. Behzad’s experience covers a wide variety of projects including road and rail bridges, offshore and oil and gas projects and infrastructure development. This has involved planning and delivery of projects at all stages from initial feasibility