kurilpa bridge investigation structural engineering
Slide 1 Structural Case Study The Goodwill Bridge and Your Kuripla Bridge Investigation Assoc Prof Jon Bunker EGB123 Civil Engineering Systems Semester 2, 2018 Contents Contents About the Goodwill Bridge Structural Design Imperatives and Drivers The “Three Structures” Piling, Reinforcement and Deck Construction Techniques Queues to Your Kurilpa Bridge Investigation Contents Contents About the Goodwill Bridge Structural Design Imperatives and Drivers The “Three Structures” Piling, Reinforcement and Deck Construction Techniques Cues to Your Kurilpa Bridge Investigation Goodwill Bridge vs Kurilpa Bridge • Kurilpa Bridge is at northern end • Goodwill Bridge is at southern end South Brisbane Reach of Brisbane River: Pedestrian & bicycle bridges Kurilpa Bridge was built a decade after the successful Goodwill Bridge Use Goodwill Bridge case study to inform what is important to your Kurilpa Bridge investigation History [after 2] Pedestrian and bicycle link across Brisbane River connecting South Bank Parklands to Gardens Point Opened in 2001 2001 cost $23 million (equivalent to $38 million now) Construction contractor was John Holland (now part of China Communications Construction Co.) J Bunker Configuration [after 1] Overall length 470m North approach: Multiple, steel superstructure spans supported by substructures of steel piers, concrete headstocks, concrete pile foundations Middle of River: A main cable stayed pavilion with concrete substructure, supported by concrete pile foundation Configuration [after 1] 102m main span is an asymmetrical steel dual-arch structure, between pavilion structure and south abutment South approach: Multiple, steel superstructure spans supported by substructures of steel piers, concrete headstocks, concrete pile foundations Irregular, three-dimensional shapes of heavily reinforced concrete support the structures Contents Contents About the Goodwill Bridge Structural Design Imperatives and Drivers The “Three Structures” Piling, Reinforcement and Deck Construction Techniques Queues to Your Kurilpa Bridge Investigation Structural Design Imperatives [after 1] Architectural “3 structures” form Pier and rampart approaches A cable stayed pavilion An arched main span J Bunker Structural Design Imperatives [after 1] • 6.5m clear deck provided between handrails, which is shared by: • cyclists • pedestrians • mobility users • steepest grade is 7%, on southern approach • (7m rise per 100m of distance) User comfort and safety J Bunker 6.5m 7% Structural Design Imperatives [after 1] Structural Action Load capacity and clearances • provided to accommodate emergency, service vehicles Dynamic performance • no excessive vibrations due to footfall, wind… J Bunker Structural Design Imperatives [after 1] • Required clearances match those of Captain Cook Bridge (in background) • Vertical clearance 12.7m above Highest Astronomical Tide (HAT) • 102m horizontal clearance provided for wide vessels e.g. barges, vessels passing opposite • Designed to resist vessel impact, river flooding debris River navigation J Bunker 12.7m 102m https://www.ausmarinescience.com/marine-science-basics/tides/highest-astronomical-tide/ Structural Design Drivers [after 1] Design drivers: Economy Constructability Durability Structural design ensured: minimised materials cost maximised use of standard and prefabricated components robust detailing and use of durable materials to avoid corrosion traps Contents Contents About the Goodwill Bridge Structural Design Imperatives and Drivers The “Three Structures” Piling, Reinforcement and Deck Construction Techniques Queues to Your Kurilpa Bridge Investigation Main Span [after 1] 102m main span Incorporates two inclined steel arches tied together by K truss system at each end For unique aesthetics, each arch has different inclination from vertical plane Arches support reinforced concrete deck, and via tie system and struts, shade panels 29° 7° J Bunker tie system Main Span [after 1] Arch members fabricated from trapezium shaped, steel box sections up to 1000mm (south) and 500mm (north) depths J Bunker Main Span [after 1] • allow free expansion/ contraction of main span relative to pavilion and south abutment • provide lateral (sideways) restraint Both tied arches supported at south abutment on stainless-steel pot bearings J Bunker Main Span [after 1] • tie together both ends of each arch Longitudinal, fabricated box beam members: • vertically support each longitudinal box beam member from its arch • arranged to provide shear force resistance to longitudinal loading Circular Hollow Section (CHS) hangers J Bunker C T T T = tension (pull) C = compression (push) S = shear (across) Main Span [after 1] Longitudinal box beam members support regularly spaced Universal Beam (UB) cross beams UB cross beams in turn support, and act “compositely” with, reinforced concrete deck (see later) J Bunker Main Span [after 1] • lifting during construction • fine tuning the shape • (think of a coat hanger pulled together by string at the bottom) Stressed (pulled) tendons within longitudinal box beam members were incorporated for: J Bunker C Main Span [after 1] Structural analysis typically simplified when structure is symmetrical (same either side of its centre) Due to Goodwill Bridge asymmetry, structural analysis and design required sophisticated computer modelling Dynamic performance investigated extensively to ensure acceptable, comfortable responses to pedestrian loads (Millenium Bridge, London illustrated for comparison) Pavilion [after 1] • series of stay cables acting in tension (force pulling away) • supported by two steel mast struts acting in compression (force pushing together) Pavilion deck and northern end of main span arch suspended from: • installation • stressing sequence Complex structural analysis needed for: J Bunker T TCC TT Pavilion [after 1] • connection results in highly asymmetrical arrangement • supporting cables and inclined struts finely tuned by applying forces to induce movements required for positioning An axle connects main span to pavilion: J Bunker T Pavilion [after 1] • system of cable stays supported by two steel mast struts • one set into counterfort footing (S) • other supported by A-shaped reinforced concrete shaft (NW) • two inclined steel struts set into counterfort footing (NE) • steel member extending outward to A-shaped reinforced concrete shaft • steel member aligned to S arch, set into S counterfort footing Pavilion support system incorporates: J Bunker C C TTTTT CC C NW S NE Pavilion [after 1] Pavilion’s two counterfort footings and A-shaped reinforced concrete shaft in turn supported by reinforced concrete pilecap J Bunker pilecap Pavilion [after 1] • 1,500t steaming at 8 knots • (equivalent to mass of 1,000 cars at 15km/h) Pilecap and supporting piles designed to withstand impact of loaded coal barge • through deep, alluvial soil deposits • into strong bedrock (see later) Piles penetrate: J Bunker South Abutment [after 1] Reinforced concrete headstock supports southern end of main span via bearings (discussed earlier) Twin tapering, raking reinforced concrete columns support headstock J Bunker headstock C C South Abutment [after 1] • Steel members aligned with both arches to appear as an extension • Steel member supporting deck Two concrete anchor headstocks buried into counterfort footings, each supporting: Footings rigidly connected to reinforced concrete pilecap J Bunker C C C C pilecap headstocks c/footings South Abutment [after 1] • e.g. large anchor bolt groups innovative connection details between steel and concrete components J Bunker Approaches [after 1] • Components carefully shaped and connected to achieve “composite action” • working together to carry the loads • Each approach provides desired appearance of a pier • Design satisfied budget constraints Approach structures a combination of standard steel and concrete components J Bunker C C S Approaches [after 1] Reinforced concrete pilecaps spaced at 20m • Raking (angled) provides for lateral (sideways) restraint Pilecaps support twin raked steel Welded Beam (WB) columns T C C Approaches [after 1] Standard steel Welded Beam (WB) sections span 20m between supports WB sections support tapered steel Universal Beam (UB) cross beams spaced at 2.25m centres These in turn support precast concrete deck panels (see later) and kerb units T Contents Contents About the Goodwill Bridge Structural Design Imperatives and Drivers The “Three Structures” Piling, Reinforcement and Deck Construction Techniques Queues to Your Kurilpa Bridge Investigation Piling and Reinforcement (after 1) • Caged, steel reinforced concrete piles provide foundations to supports • Pile diameters range between 360mm and 750mm North and south approach structures: Former QUT L Block Piling and Reinforcement (after 1) • 68t of caged reinforced concrete piles • Each pile: • 1,500mm diameter • 30m length • socketed 2m into bedrock beneath Brisbane River Centre pavilion structure: Piling and Reinforcement (after 1) • Equivalent mass to 350 cars 516t of reinforcing steel used on entire project Deck (after 1) Conventional concrete slabbing construction would have required: Formwork Scaffold support system This would have been too difficult and expensive J Bunker Deck (after 1) • pre-cast, steel reinforced concrete panels • stiffened by steel lattice trusses • covered in-situ (in place) by concrete topping • provides a monolithic suspended concrete slab • plastic services conduits were placed within the topping HumeSlabTM used Deck (after 1) • Panels spanning up to 4.5m allowed deck construction without need for propping between supporting girders 2145m2 of HumeSlabTM used • Increased strength • Reduced thickness and weight • Better structural integrity • Reduced construction cost Composite action between concrete deck and supporting steel girders: J Bunker Contents Contents About the Goodwill Bridge Structural Design Imperatives and Drivers The “Three Structures” Piling, Reinforcement and Deck Construction Techniques Queues to Your Kurilpa Bridge Investigation Construction Techniques (after 1) Reinforced concrete piles fabricated off-site Floating pipeline installed to deliver concrete to structures that were constructed on river www.meales.com.au https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjLo-Xnw63MAhXlL6YKHQrMACsQjB0IBg&url=http://www.meales.com.au/mining_resource.html&bvm=bv.120551593,d.dGY&psig=AFQjCNH43goa_Vivogfgeft3TXH4paMxPQ&ust=1461802229116427 Construction Techniques (after 1) • Simplified complex reinforcement details • Clash-proofed reinforcement • Assisted Contractor with assembly • Helped steel fixers to visualise cages before assembly Computer modelling of reinforcing bar arrangements Construction Techniques (after 1) Main span arch-structure floated upriver from riverside fabrication site Construction Techniques (after 1) • Main span progressively hoisted from central pavilion and then south abutment ends • Crane used for stabilisation (not for lifting!) • Main span fixed into place onto: • axle connection (pavilion) • pot bearings (abutment) Main span lift planned and executed carefully Contents Contents About the Goodwill Bridge Structural Design Imperatives and Drivers The “Three Structures” Piling, Reinforcement and Deck Construction Techniques Cues to Your Kurilpa Bridge Investigation Matters about the Kurilpa Bridge Today I provided some background on Goodwill Bridge for pedestrians and cyclists But your study will focus on Kurilpa Bridge upriver Provide some insight on history of Kurilpa Bridge Why was it considered to be needed? What if any other options were considered e.g