GEOMETRY CONTROL OF PRECAST SEGMENTAL BALANCED CANTILEVER BRIDGES ON THE HUNTER EXPRESSWAY

Introduction Authors Jarrod Hitchcox Associate Technical Director Arcadis Australia Pacific jarrod.hitchcox@arcadis.com Alliance Structural Design Representative Daniel Mueller Survey Manager CPB Contractors DMueller@thiess.com.au Senior Surveyor

Project Overview 40km of expressway M1 Motorway to Branxton Two contracts one D&C and one alliance Hunter Expressway Alliance (HEA) 13km from the M1 Motorway to Kurri Kurri through the Sugarloaf Mountains HEA partners Thiess Roads & Maritime Services Parsons Brinkerhoff Hyder Consulting (now Arcadis Australia Pacific)

Viaduct Bridge Design Three twin viaduct bridges (three, four and five span configurations) Maximum span of 75m End spans varying from 52m to 60m Haunched superstructure varying from 3.0m to 4.2m deep Free and guided bearings Fixed and guided shear keys Precast pier segments Pile caps and bored piles

Proposed Construction Sequence Self launching overhead erection gantry

Proposed Construction Sequence Self launching overhead erection gantry 12 segments per span Six to eight backspan segments supported by gantry

Geometry Control Report Key design assumptions Relative humidity: 61% Average temperature: 18 C Characteristic compressive strength of concrete: 65MPa Elastic modulus of concrete: 35,600MPa Age of deck segments at erection: 28 days End span construction period: Four days

Design Changes Mine subsidence Geotechnical investigations during pile boring Adjusted shear planes

Construction Sequence Changes Segment release timing

Construction Sequence Changes Segment release timing Key segment support From support from the gantry

Construction Sequence Changes Segment release timing Key segment support From support from the gantry To support from the cantilever tip

Construction Sequence Changes Segment release timing Key segment support From support from the gantry To support from the cantilever tip Construction loadings

Construction Sequence Changes Segment release timing Key segment support From support from the gantry To support from the cantilever tip Construction loadings Program accelerations

Site Changes Superstructure stressing

Site Changes Superstructure stressing Temperature

Site Adjustment Mechanisms Vertical geometry Segment shims

Site Adjustment Mechanisms Vertical geometry Segment shims Counterweights

Site Adjustment Mechanisms Vertical geometry Segment shims Counterweights Nailing tendon

Site Adjustment Mechanisms Vertical geometry Segment shims Counterweights Nailing tendon Abutment segment jacking

Site Adjustment Mechanisms Vertical geometry Segment shims Counterweights Nailing tendon Abutment segment jacking Pier segment rotation

Site Adjustment Mechanisms Longitudinal geometry Abutment segment size and position

Site Adjustment Mechanisms Longitudinal geometry Abutment segment size and position Span closure pours

Finishing Works Surfacing and approach slabs Concrete barriers

Finishing Works Surfacing and approach slabs Concrete barriers Barrier railings

Finishing Works Surfacing and approach slabs Concrete barriers Barrier railings Drainage

Finishing Works Surfacing and approach slabs Concrete barriers Barrier railings Drainage Expansion joints

Design Recommendations Site investigations Geometry control in design team s scope of works Material variability Construction options Additional capacity Stressing cantilever, continuity and external Bearing and joint movement Bearing rotation Strength Allowable tolerances Structural Other disciplines Design adjustment options

Delivery Recommendations Setting of design parameters Alliance or ECI Survey and timely reporting Site design presence Site adjustment options

GEOMETRY CONTROL OF PRECAST SEGMENTAL BALANCED CANTILEVER BRIDGES ON THE HUNTER EXPRESSWAY Questions