KPOLE TSB Product Information Manual

Transcription

1 KPOLE TSB Product Information Manual

2 Sustainability through Innovation Koppers new utility pole, the KPOLE TSB (Timber, Steel Butt) combines renewable hardwood resource with engineering innovation to create a competitive and sustainable pole supply solution for the utility industry. With the proven benefits of timber, the KPOLE TSB is engineer designed to ensure long lasting performance, compatibility and compliance to the safety requirements of network owners and customers. Sustainability through innovation is delivered with Koppers KPOLE TSB. KPOLE TSB poles combine a steel sleeve with precision machined and treated select grade hardwood to ensure a durable and tight long lasting fit. Engineer designed and manufactured to AS4676, AS4100 and AS the KPOLE TSB has been prototype tested to destruction for end user reassurance and design confirmation. Representing an environmentally sensible option when compared to alternatives, the KPOLE TSB provides network asset owners with a sustainable long term timber utility pole solution. Intended to compliment the ongoing sustainable supply of key size treated hardwood timber poles the KPOLE TSB also ensures continuity of existing work practices for installation and overhead line assemblies, compatibility with the existing pole asset profile, and all the product benefits associated with timber poles. Initially available in the key size lengths of 12.5m and 14.0m, the KPOLE TSB poles combine a 4.0m length steel sleeve (butt) with readily available 9.5m and 11.0m length hardwood poles respectively. Design Loads Reliability-Based Design (RBD) methods (Limit States Design) in accordance with the principles set out in AS and AS 4676 for the timber section and AS 4100 for the steel section have been used to determine the KPOLE TSB capacities. KPOLE TSB design capacity tables are available from Koppers on request. The capacities are by association also in accordance with ENA C(b)-1 guidelines for design. It is noted that the use of limit states design capacities should only be used with loads that have been calculated in accordance with AS 4676 or other relevant limit states loading code for appropriate load combinations that incorporate appropriate load factors. KPOLE TSB load capacities include an allowance for self weight plus an additional compressive load factored up by 1.2 (conservatively between 1.1 for the self weight and attachments such as transformers, and 1.25 for the cables) to suit the strength limit state combinations. This compressive load is checked in conjunction with the horizontal tip load for combined actions capacity. The coach screws have been designed to support this load, but the chamfer on the timber will also add to this. This has not been quantified in the design and is pointed out merely as additional safety benefit. Should higher compressive load capacity be required please contact Koppers for a revised design tip load capacity. Steel Component The steel section is grade C350L0 steel circular hollow section of minimum 4m length, which has a characteristic design yield strength of 350MPa and has guaranteed impact properties at low temperatures (i.e. ductility at low temperatures). It has been designed in accordance with AS4100 and the design includes strength reductions for holes. The steel sleeve contains no concrete infill, is watertight in the region below the ground, and includes one covered inspection/ventilation hole centred 150mm below the butt of the timber when fully assembled. It also includes 12 x 22mm inspection holes in the region of the timber embedment to allow for cores to be taken from the timber during regular maintenance / inspections over the poles service life. In addition to the above there is a minimum of 9 x 20mm coach screws to transfer vertical loads and maintain structural stability of the timber within the steel sleeve if the timber shrinks away from the inside of the steel sleeve. The inspection holes are sealed from external water ingress with an industrial silicon sealant/ adhesive, as are the holes in which the coach screws are inserted upon assembly. Joint is sealed from external water ingress using high grade sealant Grade C350 LO steel pipe Vent hole cover Nominal ground line Pole cap Timber section Inspection holes Coach screws Extent of timber Koppers KN Steelcoat system to protect the steel in ground contact Backfill as per design requirements Timber Component The timber strength used is based on strength group S2 in accordance with AS4676 and AS1720 for both bending and compression. The timber form and grade is select pole grade in accordance with AS2209. The timber is precision machined before treatment in accordance with AS1604 so no additional treatment of the timber butt section is required. Strength group S2 hardwood is perfect round machined prior to CCA treatment to ensure a tight compression fit into the steel sleeve section. Embedment The embedment used in the standard designs is based on 10% x Total pole length + 800mm. This in no way implies that the embedment used in determining the nominal capacities is adequate for each situation, and it is the responsibility of the line designer to specify the required embedment based on the particular loads and soil conditions present. The embedment depth quoted above is the minimum for the KPOLE TSB. The embedment depth can be increased to increase the tip load capacity of the pole, or to cater for weaker soil conditions, but should not be less than this value. The embedment depth required should be specified to Koppers on order of the poles if it differs greatly from the assumed minimum embedment, so that the additional ground line protection can be applied to the correct level. The normal techniques for foundation strength increase (stabilised backfill, concrete backfill) can be used for the KPOLE TSB if required. Installation Installation of the KPOLE TSB should be as per normal timber pole installation procedures. The poles will be approximately the same weight if not lighter than equivalent timber poles. Since the timber section is at the top of the pole, normal timber pole procedures may be used for the attachment of services at the top of the pole. 9 x 20mm coach screws transfer vertical loads and maintain structural stability of the timber and steel connection. The end plate on the base of the steel section has been designed to support a vertical compressive load of at least 3500kg. With a minimum skin friction between the sleeve and the soil of 10kPa, this is extended to at least 5000kg total compressive load. These figures assume the soil can support these bearing pressures and skin frictions and it is the responsibility of the line designer to confirm this aspect. 8mm base plate fully sealed

3 Inspection The KPOLE TSB s unique features include apertures designed and located for inspection of both the interior section of the sleeve and of the interface section between the timber and the steel sleeve. The KPOLE TSB design has evolved with extensive customer consultation and these features have been included to meet pole asset inspection and life time maintenance requirements. Structural Type Tests Koppers have carried out structural type testing of KPOLE TSB. Testing was carried out in accordance with AS4676: Appendix K, in a horizontal test rig at Koppers Grafton plant. Representatives from external companies were present to confirm the methodology and results, and the various endorsements are included in the KPOLE TSB Technical Specification. Testing confirmed the capacities given by the specialist design program that was developed for the poles. KPOLE TSB poles were tested during vertical pull down tests at Koppers Grafton plant facilities to confirm design Mode of failure Progressive Collapse If the design loads are exceeded and the pole fails, the failure mode through testing has been shown to occur with progressive collapse through buckling of the steel section, rather than the sometimes brittle failure normally associated with timber. This means less risk of collateral damage to persons and structures nearby. The KPOLE TSB also proved under testing to be capable of sustaining a significant portion of design ultimate loads after the initial yield of the steel. This means the pole does not completely fail (fall to the ground) after initial yield. Test results were consistent across the sample range, and the mode of failure attributed to the KPOLE TSB provides: Greater certainty of capacity Added safety against sudden and complete collapse This progressive collapse has been shown in our full-scale testing as described in the Technical Specification and a full report may be provided on request. The design capacities and progressive collapse were proven at Koppers Grafton plant in front of industry representatives by means of vertical pull down testing. Termite Susceptibility Sealed bottom section The pole is completely sealed below ground, thus preventing termite ingress. The steel section is immune from termite attack and the timber component is deemed to be a termite resistant material, as defined in AS Termite Management Part 1: New Building Work, by virtue of its preservative treatment according to AS The timber component is located in an above ground situation making concealed termite entry to the KPOLE TSB unlikely. KPOLE TSB may therefore be installed with confidence in areas where subterranean termites pose an economic risk to buildings and structures. This includes locations known to be inhabited by Mastotermes darwiniensis and Coptotermes acinaciformis, which are the most significant of a number of recognised, economically important woodfeeding species of subterranean termites in Australia. Corrosion Protection All mild steel items are hot-dip galvanized in accordance with AS Hot dip galvanizing of ferrous parts including bolts, nuts, and washers is carried out after all machining, bending, cutting, drilling, punching, marking and welding operations have been carried out. All welding is in accordance with AS/NZS The steel sleeve s durability is increased in three ways: 1. Firstly, the interior of the sleeve is made watertight with respect to groundwater to prevent pooling of water inside the tube 2. The 67mm inspection hole below the timber butt also acts as a ventilation hole to prevent condensation of water inside the sleeve and also allow the evaporation of any water that may gather in the sleeve 3. For a distance of up to 500mm above nominal ground line the whole in-ground section is coated with a high performance coating that provides long lasting protection in even the harshest soil conditions. Koppers KN Steelcoat system is applied to the KPOLE TSB s below ground zone as additional corrosion management to the base hot dip galvanizing protection. Koppers KN Steelcoat System The KN Steelcoat system is a high grade spray on Polyurea product developed by Koppers in association with one of the worlds leading and most progressive industrial coatings manufacturers. It is specially selected to provide the best combination of the following properties that are essential for the utility pole industry: Low cost Robustness Ductility Adhesion Abrasion resistance Non-toxic Repairable Inspectable Fast drying UV resistant Chemical resistant Graffiti resistant Aesthetically pleasing Adaptable The steel coat system has been selected to give a 50 year corrosion protection barrier for the exterior of the steel sleeve in most conditions. If particularly aggressive soil conditions such as highly acidic or highly alkaline exist, or there are exotic contaminants known to be present then the likelihood of termite attack is reduced and a timber pole is recommended, however there is scope to increase the chemical resistance of the KN Steelcoat barrier above the standard for particularly aggressive conditions. The coating can withstand significant handling stress without damage, but if damaged can be repaired using gun grade polyurethane or polyurea sealants. Maintenance At a maximum Koppers recommends ground line and timber butt inspections after the first 7 years, then every 5-7 years after that. At a minimum Koppers recommends visual timber and steel inspections at 25 years, then every 5-10 years after that depending on he results of the initial inspection.these should be a visual inspection firstly, then they should include the normal timber coring and digging to at least 300mm at 2 points around the ground line to expose and inspect the KN Steelcoat System. If severe loss of the coating (considered as 80% of the minimum thickness) is found it should be uncovered to the full extent of the loss, then repaired in accordance with the specification. The interior of the steel and the butt of the timber can also be inspected by removing the vent hole cover and looking inside. We also recommend supplying the inspector with a flexible Borescope to use to look at the bottom of the sleeve interior. This will allow them to see if there is any water in the base of the sleeve, and to monitor the condition of the galvanizing on the interior of the sleeve. Certification KPOLE TSB manufacture and design is in accordance with all relevant Australian standards and in accordance with Koppers quality assurance procedures that are ISO 9001 compliant. The design is certified by a chartered professional engineer.

4 Reliability and Performance Given that the correct limit states loadings have been used and compared with the correct capacities given, the pole will be reliable in its structural performance for as long as the return period used in the determination of the design loads (i.e. up to the line designer to use the loads associated with a 50 year return period), provided a higher return period event doesn t occur within the service life of the pole. If regular inspection and maintenance is carried out on the poles, the poles will be governed by the life of the regular galvanised sections, which is summarised by John Robinson, galvanising and corrosion expert, in his supplementary report provided in the Technical Specification; The galvanized coating life of the hot dip galvanized coating applied to the Koppers Steel Pole Sleeves, in other than marine exposure conditions should exceed 50 years and will more likely be in the order of 75 years, which is consistent with the large number of galvanized monopole structures installed throughout Australia As a guide, the Meuller rating chart as shown in Table 1 is a common way of quantifying when a steel structure should be removed from service. Zero corrosion has a rating of 100%, and the rating used to determine the end life of the steel sleeve is recommended as being 60% as a minimum, but educated judgement should be used as to whether a higher rating is required depending on the loading conditions of the pole. Table 1: Meuller rating chart Rating Percentage Description of steel surface condition 95.0% Galvanizing like new 92.5% Galvanizing dull 90.0% Galvanizing very dull 87.5% Pin-point rust spots 85.0% Galvanizing entirely gone 80.0% Light rust film The steel sleeve section is sealed with an 8mm base plate designed to support vertical compressive load, and to prevent the ingress of ground water and termites. Electrical performance The electrical performance of the KPOLE TSB will be equivalent to a timber pole for pole top leakages such as flashover. However, if the power line is to be earthed, we recommend the inclusion of a timber pole at this location, or the same method used to earth concrete or steel poles (i.e. Insulate the earth wire until it is a sufficient distance from the steel sleeve to prevent a step/touch hazard). Step/ touch hazard is also an issue from current in the ground passing the pole from further down the line. This should be addressed in the line design and is a site specific issue. This is only applicable if the electrical resistance of the KN Steelcoat is insufficient to give required resistance between the steel and earth. Fire Resistance Resistance to fires is offered by the hot dip galvanized steel section at the base of the pole. Once installed, with nominally 2.0m below ground and 2.0m above ground the steel section provides the KPOLE TSB with higher resistance to fires at the base, such as grass fires (the main type of fire affecting lines with well maintained vegetation clearances). The hot dip galvanizing protection provides a physical barrier and is highly resistant to the temperatures typical of a moving fire front. If the KN Steelcoat protection is damaged by fire it can be easily re-instated by cleaning and re-painting the affected area, rather than being destroyed and requiring complete removal and reinstatement as would be the case with physical barriers. More information on hot dip galvanizing performance in fire is available from Koppers on request. Disposal Koppers request that they are invited to view any KPOLE TSB poles that are to be disposed of in case we can re-use any part of the pole (timber or steel), by either re-using a suitable timber section, or by re-galvanizing and protecting the ground line of the steel sleeve. Koppers are participating in industry groups assessing the disposal of treated timber products, however there are specialty timber recycling companies that can, and in some cases, prefer to recycle used timber poles. Regardless, the timber can be disposed of in approved landfill, and the steel sleeve and components can be recycled at a steel recycling plant. Environmental considerations The KPOLE TSB pole is an environmentally sensible option when compared to other alternatives to timber, such as concrete and full length steel. While accounting for the steel component, the KPOLE TSB still provides a negative carbon emission status in production as the timber component makes up approximately 75% of its length. No other material can claim the environmental credentials of timber with around 1800kg/m 3 of CO2 absorbed from the atmosphere and stored in the wood structure during the tree s growth cycle, while the production of steel and concrete expel 25,120kg/m 3 and around 500kg/m 3 respectively. Sustainable management of the resource base from which KPOLE TSB poles are drawn also greatly contributes to the positive environmental impact of this new product, and this is highlighted by our major supplier, Forests NSW achieving certification to the Australian Forestry Standard for sustainable forest management. Environmentally sustainable timber pole processing is also demonstrated by comparing the year service life of the finished product with the tree s 30 year growth cycle. Koppers takes carefully selected timber and preservative treat it so it lasts up to 30 years longer as a utility pole than it takes to grow the tree replacing it twice the time. This highlights the positive net contribution the pole supply chain provides to the ongoing sustainability of managed native forest reserves. Sustainability The KPOLE TSB provides network asset owners with a sustainable long term timber pole solution. While the search and evaluation of other unproven and expensive alternatives continues into the future, this new timber based hybrid product provides network asset owners with an immediate insurance policy intended to supplement and support the ongoing supply of timber poles. Benefits to network asset owners are: Continuity of work practices for installation Continuity of work practices overhead line assemblies Compatibility with the existing asset profile Higher equivalent strengths than other timber alternatives High value competitive and durable All the product benefits associated with timber poles low conductivity, versatile, robust, and easily handled KPOLE TSB is a cost effective, competitive solution providing a guaranteed ongoing supply of key size timber hybrid based poles, as opposed to alternatives which are less compatible, have less environmental credentials, less sustainability, less proven, less safe and more expensive on both an upfront and on a whole of life basis. 70.0% Shallow pitting 60.0% Scaly rust or pits less than 50% penetration of metal 45.0% Heavy rust or pits half way through metal Industrial grade sealant is used in the joint between steel sleeve and chamfered timber section at the top only, to seal from external water ingress. 30.0% Heavy rust or pits approx. three quarters of the way through the metal 15.0% Localised complete perforation 0.0% General complete perforation KPOLE TSB poles awaiting vertical pull-down tests at Koppers Grafton plant, intended for customer reassurance and to further confirm the poles design

5 Koppers KPOLE range For further information on Koppers KPOLE range of utility distribution and transmission poles, telecommunication poles, foundation and marine piles please contact: Koppers Wood Products Pty Ltd North Sydney, NSW P.O. Box 2122 North Sydney NSW 2059 Level 5, 53 Walker Street North Sydney NSW 2060 Telephone: Fax: Grafton Plant, NSW PO Box 335, Grafton NSW 2460 Telephone: Takura Plant, Queensland PO Box 162, Hervey Bay QLD 4655 Telephone: Longford Plant, Tasmania PO Box 29 Longford Tas 7301 Telephone: Bunbury Plant, WA PO Box 100 Picton WA 6229 Telephone: Newsletter: If you would like to receive regular news updates please your details to us. enquiries: poles@koppers.com.au