Bridge Beams

Product brochure

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DurabilityStahlton Super Tee and Single or Double Hollowcore bridge deck units meet exposure classifications A2, B1, & B2 as per table 3.7 of NZS3101:Part 1:2006 for a 100 year life. By specific design we can cater for harsh marine environments.

LoadingsStahlton Super Tee and Single or Double Hollowcore bridge deck units are designed to meet the traffic loading criteria described in the New Zealand Transport Agency Bridge Manual (SP/M/022) third edition 2013.

Our design applies HN-HO-72 & HN loadings in accordance with section 3 or we will apply appendix D for “lightly trafficked rural bridges” if your bridge is a one lane bridge that has:

▪ A traffic count less than 100 vehicles per day

▪ A road that cannot become a through route

▪ An alignment is such that speeds are generally below 70Km per hour

▪ The route is unlikely to be used by logging trucks and

▪ No significant overloads are expected to occur or the bridge can be bypassed.

We do not expect there to be an asphalt layer applied in the 85% of HN rural bridge cases and we make allowance for the weight of a light handrail or barrier. For the HN-HO loaded bridges we allow a minimum of 1.75kPa for asphalt surfacing and services plus additional superimposed dead load if there is a levelling layer. Barrier loads are either TL-3, TL-4 or TL-5 traffic impact loadings.

End seating, topping & connectionsNZTA Standard Pre-stressed Concrete Bridge Beam Drawings provide typical support and connection details for Stahlton Super Tee and Single or Double Hollowcore bridge deck units. Refer to NZS3109 Table 5.1 for manufacturing tolerances.

Stahlton’s Single or Double Hollowcore units do not normally need in-situ topping concrete when they have cast in ducts for post-tensioning the deck units together transversely that are later grouted on-site. Our design can incorporate an in-situ topping slab that eliminates post-tensioning. We can also cast in inserts for bolting a handrail or guard rail of your design.

Stahlton’s Super Tees require in-fills between the webs and cast in-situ reinforced concrete deck slab.

Exposed steel hardware for these connections is generally hot dipped galvanised. In a marine environment the hardware is usually required to be stainless steel.

Design scopeAn excellent resource is the NZTA Standard Precast Concrete Bridge Beams Drawings. The specifications are included in this document.

Bridge BeamsStahlton offers economic bridge systems to suit a variety of spans, loadings and site conditions. Our Super Tee and Single or Double Hollowcore elements are manufactured to length in moulds, which give a smooth and light broom top finish, providing grip for vehicles, topping concrete or an asphalt layer if required.

Pre-stressed concrete bridges are well proven to survive the test of time in the harshest of environments. The bridge deck units do not require temporary propping or works and once in place provide an immediate working platform. Our products are made of high strength concrete and has an accelerated curing time, meaning that the bridge can be used just a few days after it is manufactured.

At Stahlton, we pride ourselves on providing our customers quality, safety driven, products and services. All Fulton Hogan businesses are ISO9001 certified and our Stahlton Auckland and Christchurch plants have been certified by Precast New Zealand Incorporated.

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Typical span arrangementsStahlton Super Tees with 180mm thick in-situ deck topping slab

5kPa Footbridge

85% of HN HN-HO

Unit Depth mm

2.4m unit width

2.4m unit width

2.4m unit width

775 23.5 22.0 18.5 Max span (m)

1025 29.0 27.0 23.0 Max span (m)

1225 34.0 33.0 28.0 Max span (m)

1525 41.0 40.0 34.0 Max span (m)

Longer spans can be achieved by reducing the width of the Super tee flanges. For example 2m wide spacing extends maximum span to 30m for a 1225mm deep Super tee with 180mm deck topping slab.

Stahlton Single and Double Hollowcore with no topping slab

5kPa Footbridge

85% of HN HN-HO

Unit Depth mm

1.145m unit width

1.145m unit width

1.145m unit width

460 18.0 15.5 13.0 Max span (m)

585 23.5 19.5 16.5 Max span (m)

650 26.5 22.0 18.5 Max span (m)

900 34.0 30.0 25.5 Max span (m)

Stahlton can make variations to the depth of the bridge beams shown above. Please contact Stahlton’s Technical Department to discuss the most economical solution for your project.

CamberStahlton bridge deck units will arrive at site with some camber (hog). This is unavoidable due to the nature of pre-stressing. The amount of camber will depend on a number of factors, including amount of prestress, how long the units have been manufactured and exposed to the elements and length of the unit to name a few variables. In our design, we do consider long term shrinkage and creep effects.

Handling & storageStahlton bridge deck units are usually designed to be lifted at the ends using Reid Swiftlift type lifting anchors specifically designed and detailed on our shop drawings.

If the units are stored on site, they will need to be dunnaged near the lifting eyes. If stacking the units, dunnage blocks need to be aligned on top of each other so as to not induce large point loads on the units below. Care needs to be taken as to the suitability of the ground and dunnage block to resist the weight of the units stored on top.

TransportStahlton Bridge Beams in excess of 18m will need a permit and at least one pilot to escort the specialised truck and extended trailer or truck and jinker unit to site on public roads.

Contact usIn addition to the standard bridge beam units in this brochure, Stahlton’s experienced and qualified Engineers can also design bridge deck units to meet your specific needs. For example, varying depths of the Standard Stahlton Super Tee, Single or Double Hollowcore bridge beams, using other modified Stahlton standard flooring products, as well as pre-stressed concrete slabs fixed to steel beams. Contact us to discuss your project’s specific needs.

Super Tee beams being placed

Northern Gateway Arterial - Super Tee bridge

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Steel bridges Gallery

Sylvia Park, Auckland

Double Hollowcore bridge beams - Clearwater Resort, ChristchurchWaikato River Bridge - Prestressed Flatslab on steel girders

East Taupo Arterial Bridge - Steel bridge

Contact usIn addition to the standard bridge beam units in this brochure, Stahlton manufactures prestressed concrete flatslabs with cast-in pockets for connections to steel bridge girders to form a composite deck. Contact us to discuss your project’s specific needs.

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Gallery

Ormiston Road BridgeBlenheim Road Overbridge, Christchurch

Dilworth Footbridge over State Highway 1, Auckland - Precast concrete deck cable stay

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(v) Force in strands immediately prior to transfer shall be accounted for in the jacking force required to achieve this value. Typically relaxation prior to transfer is in the order of 1% where curing at elevated temperatures is employed, high relaxation rates may result and due allowance for this shall be made by the precaster in determining the jacking force required to achieve the minimim force specified.

(vi) Ends of strand shall be cut flush and protected with a minimum of 5mm epoxy mortar.

(vii) Upward deflection of girders due to prestress is given a beam hog table. These are estimates only. Estimates are made for hog at transfer and minimum 60 days with due allowance for increase in hog due to creep of concrete under sustained load.

(viii) Components prefixed RB are reidbar items. Reidbar or approved alternativeshall be Grade 500E to AS/NZ 4671. Cast iron components are not allowable.

Concrete cover (Minimum)Cover to all prestressing components 40mm Cover to all reinforcement exposed surface 40mm Cover to all reinforcement internal surface 30mm Cover adjacent to cored holes 30mm Cover to bridge deck and all cast insitu concrete 50mm Cover to barrier fixing steel (within barrier) 50mm

Design loadingHN-HO-72 (Including SLS live load factor of 1.35 x Impact Factor)

TolerancesDimensions at time of erection:

Actual overall length and squareness

(i) The underside of the beam for the end 700mm shall be true plane

(ii) The beam end surfaces shall lie within the “Tolerance boxes”

(iii) Plane surface, deviation from a 1.5m straight edge 5mm

(iv) Beam hoging (see specification)

(v) Cross section dimensions up to 0.5m +-5mm

(vi) Cross section dimensions 0.5m to 2.0m +-10mm

(vii) Horizontal bow of longitudinal axis +-20mm

(viii) Longitudinal steel arrangement +-10mm

(ix) Location of an item in relation to any other item within its group or to the midpoint of the beam ends +-10mm

(x) Pretensioning prestressing strands in any direction +-5mm

HandlingExtremes of vertical lifting points or ground support shown hatched. Central support position as shown is preferred (beam in upright position at all times).

Surface finishesTop surface of flange Type B construction joint In direct contact with insitu diapgragm Type B constuction joint Hidden formed surface F1 All other formed surface F4

Drawing call-upTo specify the Stahlton bridge beam on your drawings, we suggest you use the following designation:

Stahlton depth bridge beam

For example if the project is to be made from 650mm deep Stahlton Double Hollowcore, then the specification would read:

Stahlton 650 Double Hollowcore bridge beam

If Stahlton 1225mm deep Super Tee with 180mm in-situ deck slab is desired, then:

Stahton 1225 Super Tee with 180mm in-situ deck topping

Written specification clausesStahlton Bridge beam products in general comply with the following standards:

(i) NZS 3101:2006 ‘Concrete Structures Standard Part 1 & 2’

(ii) NZS 3109:1997 ‘Concrete Construction’

(iii) AS/NZS 4671:2001 ‘Steel Reinforcing Materials’

(iv) BS 5896:1980 ‘Specification for High Tensile Steel Wire and Standard for the Prestressing of Concrete’

(v) NZTA Bridge Manual 3rd Edition (SP/M/022)

Design(i) The design of Stahlton Bridge beams shall be in accordance with

the requirements and recommendations of NZS 3101:2006 ‘Concrete Structures Standard Part 1 & 2’ and/or any recognised international Standard or part thereof, for example BS 8110:2007 ‘The Structural Use of Concrete’.

(ii) The prestress strand pattern in the Stahlton bridge beams shall be designed to sustain the loadings shown on the Consulting Engineer’s drawings and allowance will be made for self weight of the unit and topping concrete.

(iii) The Stahlton bridge beams shall be designed for exposure classification A1/A2/B2/B2 as per table 3.7 in NZS 3101:2006 for 100 year design life.

(iv) The Stahlton bridge beam unit shall have a FRR (Fire Resisting Rating) of 90/90/90. Penetrations through the flooring system shall be reinstated to the required FRR by an approved fire protection system.

(v) Stahlton bridge beams shall be designed to have a maximum crack

width of 0.3mm under full live load conditions.

(vi) The Stahlton bridge beam units shall have a minimum end seating detailed by the engineer plus tolerance. Refer NZS 3109 Table 5.1 or this document.

Manufacture(i) Materials, execution of stressing prestress strand and workmanship

of the Stahlton bridge beam units shall conform with Stahlton Engineered Concrete ISO 9001 Quality Assurance Operating procedures.

(ii) Stahlton Hollowcore bridge beam units shall be nominally 1145mm wide and made in the nominal depths not limited to 460mm, 585mm, 650mm and 900mm. Stahlton Super Tee units shall be made between 1800 to 3000mm flange width made in nominal depth of 775mm, 1025mm, 1225mm or 1525mm.

Materials(i) Concrete shall be specifically mixed depending on environmental

conditions and should have a 28 day cylinder strength of 50MPa as a minimum.

(ii) Specified Concrete Compressive Strengths

Precast beams at transfer - Pretensioning ................................30MPa Precast beams at 28 days...................................................................50MPa Insitu concrete (Deck slab, diaphragms) at 28 days..............40MPa

(iii) All concrete shall show signs of thorough compaction otherwise rejected if repair cannot be undertaken to bring the unit back to the original specification.

(iv) An air entraining agent complying with BS EN 934-2-2001 may be

included in the concrete mix to improve workability.

(v) Reinforcement and Prestressing

(i) Prestressing strand shall be clean and free from deleterious substances. Superficial rust is acceptable, however strand with corrosion that has caused surface pitting shall be rejected for the main longitudinal reinforcement of the unit.

(ii) All reinforcement shall be Grade 500E to AS/NZS4671

(iii) All prestressing strand shall be 12.7mm, 12.9mm or 15.2mm diameter low relaxation stress relieved super grade 7 wire strand complying with AS/NZS 4672 or BS 5896

(iv) Minimum breaking load of strand 184KN for 12.7mm and 12.9mm, and 250KN for 15.2mm

Specifications

Stahlton Christchurch133 Waterloo Road, Hornby Christchurch 8042Ph: +64 3 344 3014Fax: +64 3 344 3018Email: info@stahlton.co.nz

Stahlton Technical departmentPh: + 64 3 344 4310

www.stahlton.co.nz

Stahlton Auckland47 Airdrie Road, RanuiAuckland 0612Ph: +64 9 831 0107Fax: +64 9 833 4408Email: info@stahlton.co.nz