Precast Concrete

Precast Deliveries

Precast units require specialised  trailers to tranpsort units to site which come in a variety of types and sizes, each with with varying Height and Length restrictions depending on the tranport route required

• Motorway
• Highroute - Non permit
• Highroute + Permits required   

Please note: Transportation of precast units outside of standard guidelines may require Permits, Pilot Vehicles and Time constraints with associated additional costs.

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Porcupine Trailers:

Height - Motorway : 3.5m
Height - Over Height Route - No Permit / Pilot  : 4.05m 
Length of Panel Std Max : 11.5m +/-

 

Hydraulic Panel Trailers:

Height - Motorway : 3.9m
Height - Over Height Route - No Permit / Pilot  : 4.5 m 
Length of Panel Std Max : 10.5m

 

Step Deck with A-frame Trailers :

Height - Motorway : 3.1m
Height - Over Height Route - No Permit / Pilot  : 3.6 m 
Length of Panel Std Max : 10m 

 

High Deck / Skully with A-frames Trailers :

Height - Motorway : 2.6m
Height - Over Height Route - No Permit / Pilot  : 3.2 m 
Length of Panel Std Max : 14m +/- 

 

Maximum 21 tonne of balanced load weight

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Nauhria allow for delivery to site based on typical standard conditions accommodating the greater Auckland area.

Depending on the delivery location greater distances or access difficulties, additional costs which may be incurred including accomodation, crossings or sea freight, High-routes, permits etc.

Nauhria are experienced in international precast supply.
International deliveries are subject to port and freight weight and dimension limitations, customs and costs - P.O.A.

Safe Lifting Guide for Precast Concrete

IMPORTANT INFORMATION!

Click Here for a copy of the PCNZ Precast Rigging codes

Reid lifting Anchors and Equipment:

Nauhria use only genuine Reid Lifting anchors and equipment unless specifically advised otherwise from the Project Engineer. These are supplied by ITW/Reids and comply with ASTM:E23-1996.

Only approved lifting clutches and equipment should be used and should be regularly inspected and certified by the supplier of the anchors as being suitable for their use.

Reid Lifting equipment and anchors are engineered tested and approved to integrate seamlessly together.  Any substitute or alternative equipment must not be used!

Failure to use correct equipment should be considered extremely dangerous and will instantly void all Product Warranties and Guarantees.

• Nauhria Precast prepare the shop drawings of each precast unit
• Nauhria coordinate with Ramset Reids who determine and advised the correct lifting design to be used.
• Nauhria include the advised lifting code onto the shop drawings and depict the location for each component to be cast in.
• All Lifting Certificates are provided by Ramset Reids.
• The Contractor is responsible for obtaining all necessary approvals from crane operators/riggers, placing contractors, etc.. and to confirm their satisfaction with the lifting anchors and design shown to be cast into the precast units for the safe lifting, handling and placing of the precast units - without overloading any part of the element or lifting component.
• No precast manufacturing shall commence until contractor approval is signed, accepted and returned.

Lifting codes and the cast in lifting connectors are determined by multiple factors including, Unit weight, Shape and Orientation. Lifting should follow the exact instructions provided to ensure the effective and safe handling and installation of the precast units without endangering or causing harm to anybody. Safety of people being of paramount importance at all times. 

Precast Unit Weight Calculation / Crane Lift Weight:

As precast elements vary in reinforcing steel Weights can vary accordingly with steel mass weighing greater than concrete.

Typical Concrete should be calculated at 2.4 tonne (2400kg) per m3 of Concrete
Heavily reinforced concrete we recommend allowing 2.7 tonne (2700kg) per m3 of Concrete.

Remember to check Distance from crane as Lifting weight capacity of cranes reduces as distance from the crane increases. This also vary's for each crane. Check with your crane contractor.

Concrete Strength at Time of Lifting:

Typically Nauhria precast elements have had accelerated curing from heated casting beds and achieve acceptable lifting strengths  within 24 hours following casting. The contractor must confirm with the manufacturer prior to delivery where critical elements or lifting requires concrete strengths exceeding 20 MPa at the time of handling on site.

Safe Lifting Guide and Certification

• All Lifting certification is provided by Ramset Reids

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Click Here for the PCNZ Precast Rigging Code

It is critical that rigging codes are followed precisely when lifting precast.

• For the protection of people and property, Please ensure all people are clear of fall zones either side , beneath and around the vacinity of the product being lifted.
• Ensure stay ropes are attached to prevent unit swing and crashing into buildings, Racks and other structures.
• Prevent and protect from craneage counter weights from swinging and crashing into the precast unit.

NZ Standards

Precast concrete should be designed by professional engineers and architects in accordance with NZ Standards.

Conforming with the standards will ensure that NZ buildings will perform to keep people safe when faced with New Zealand's unique Climate and Seismic environment.

NZ Standard requirements to refer when designing precast should include:

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• NZS 3101:2006 - Concrete Structures Standard-The design of concrete structures
• NZS 3109:1997 - Concrete construction
• NZS 3114:1987 - Specification for concrete surface finishes

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The following information is provided on the Concrete NZ website: Further information can be viewed at concretenz.org.nz/page/noise

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Noise transmission through wall and floor systems is important because the better the system is at reducing noise transmission the more comfortable the living environment.

The New Zealand Building Code Clause G6 Airborne and Impact Sound specifies minimum requirements for noise transmission reduction for walls and floors that are common between two occupancies (intertenancy). The code specifies a Sound Transmission Class (STC) of not less than 55 for walls & floors. It also specifies an Impact Insulation Class (IIC) for floors of not less than 55. STC rating relates to airborne noise transmission whereas IIC rating relates to impact noise transmission.

Although noise transmission requirements of the building code do not apply to stand alone homes, the living environment within these homes can be significantly improved by using concrete wall and floor systems which inherently have good noise transmission reduction properties.

Typical STC Values for Concrete Walls
The following are typical STC values that have been obtained from testing conducted by the Prestressed Concrete Association in the USA for normal weight concrete.

Wall System STC Rating
100 mm concrete wall    STC - 44
150 mm concrete wall    STC - 55
200 mm concrete wall    STC - 58

Floor System STC Rating
150 mm precast or insitu concrete with carpet on underlay   STC - 52
200 mm precast or insitu concrete with carpet on underlay   STC - 56

Openings
Even small openings can significantly reduce effectiveness. It is important to ensure there are no gaps that sound can pass through. Small gaps around services and unfilled joints must be adequately filled

Indirect Noise Transmission
Connection details and sound transmission properties of floors and ceilings are also important. The effectiveness of a wall in reducing sound transmission may be reduced if the sound can travel through the ceiling into the next room.

Colours

When it comes to Architectural Concrete, No one knows it better than Nauhria...

Natural Concrete

Natural Concrete is typically coloured Portland Grey , the resulting formulation of Grey cement, sands and aggregates being mixed together.

White Concrete can also be made substituting the Grey cement for White cement where Carbon has been reduced from the cement.

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Oxide Colours

Enhancing concrete colours to achieve pre-coloured concrete requires the addition of coloured Oxide powder to the concrete formulation.

Oxides come in a range of standard base tones  including: Black, Brown, Terracotta - Red, White - titanium dioxide, Green, Yellow and Blue.

Most oxide distributors like Peter Fell Ltd offer formulated preblend colours to provide a unique colour offering more in keeping with modern decor trends and the subtle accentations of space.

To see a full range of oxide standard colours we recommend viewing the Peter Fell website.

 

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Oxide Dosing

Achieving a consistency of colour managed by dosing common percentages of oxide by the cement content of the concrete.

Typically most oxides are dosed at 5%  EG. if there is 400 kg of cement per /m3 5% would require 20kg of oxide powder to be added per m3.

Offset Shades of colours can be achieved by lessening or increasing the oxide dosage to a maximum saturation level of what is typically considered to be achieved at 10%

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Colour variations

Whilst Nauhria take all practical precautions to manage colour consistency as close as is practically possible It is important to be aware that environmental factors outside of their control can also effect the colour of concrete whether colour enhanced or natural. This includes Humidity, Sun, Wind, Raw ingredient moisture content and naturally occurring contaminants like dust and other source debris.

Coatings can also cause a significant variation in colour tone ranging from Acrylic Silane siloxane based coatings that will render a natural dry colour to Solvent based penetrating coatings that will provide a deep dark and lustrous wet look appearance. combinations of contrasting coatings are commonly used for Dynamic decorative effects providing perfect colour harmony and an offset of colour tone.

The Base ingredients of the concrete formula can also effect the concrete colour with cleaner sands aggregates and white cement resulting in more dynamic vibrant colour enhancements.

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Costs

As base oxides are made from naturally occuring - colour fast materials, So do the costs associated with their abundance impact the cost accordingly. In New zealand our most cost effective colour is Black, made from carbon and Iron ferrox.  While colours like White -Titanium Dioxide and Greens and Blue - Cobalt typically at the higher price range of colours.

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Colour Permanence

Dosed and blended in with the cement, Oxides are entrained throughout the concrete matrix for the life of the concrete.

Oxides - being made of powdered colour fast solid matter rather than pigmented dyes cannot fade over time however salts within the concrete can be brought up to the concrete surface wet dry action on the panel of which water evaporates leaving the white salt on the surface atop the oxide giving the appearance of a gracefully aged faded colour. This is known as efflorescence and is a common phenomenon found in concrete and concrete blocks. It can also be easily removed and washed away by professional cleaners with chemical treatment.

Prevention of efflorescence is best achieved by preventing the transfer of moisture into and out from the concrete through water proofing or repelling coatings and admixtures

As Colours are locked in for the life of the concrete it is important to consider also changes to the use of the building over long periods of time, Changes in Decor, Changes in tenancies, or just evolution of personal preferences. Keeping with neutral tones will help to compliment and change of decor, colour or aesthetics, brands or furnishings which more easily changed.  Colours like black, White, Greys and earthen tones tend to be best for complimentary longevity of colour.

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Concrete Stains

Modern concrete treatments also include colour fast concrete stains that are specialist applied to the surface of the concrete. Concrete stains offer an excellent life of aprox 20 years before requiring any degree of recoating.  Colours can also be matched to blend concrete imperfections or to make good concrete repairs and remedials.

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Exposed Concrete colours

During some Concrete exposure techniques like Monarc's Diamond Honing, Bush Hammering or Diamond brushing, Natural aggregate colours become visible revealling the beauty of the polished surface itself. this revealling can make visible variable aggregate properties include veins of quartz and other minerals, fossils, and simple variatons of natural colour occuring with chemical compositions of the aggregate.

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Play of Light 

Natural Light is made up of all colours bouncing off surface to reflect certain frequencies of light and to absorb others, To our eye the reflecting light frequencies are interpreted to what we refer as colour. Keep in mind the light frequencies bouncing first off other items like green from trees, The blue of the sky or the high vis vest your wearing when you view a sample, commonly impacting on the true colour we see.

As light changes colours so does the appearance of Darkness and Shadow - Through the movement of the Earth around the sun and the changing angles of light through the day, variabilities of colour and tone is commonly experienced.