LEWIIN ANAK ROMAN¹

Belian timber (Eusideroxylon zwageri) can withstand local weather conditions but this timber is heavy and getting more scarce and expensive. Fibreglass reinforced products (FRPs) were introduced as an alternative for the construction of 212m of plankwalk and 825m of handrailing along the Telok Melano Trail at Tanjung Datu National Park. The trail connects park headquarters to Telok Melano village, where a homestay programme operates. Construction took place between December 2000 and May 2001.

This paper reports on the construction methods used for FRPs, and the advantages and disadvantages compared with belian timber.

FRPs are composed of a resin matrix reinforced by embedded glass fibre that enhances the strength, flexibility or rigidity of the product. The resins are very toxic and contain chemicals that cause skin irritation, which is a health hazard and a common problem for the workers.

The features claimed for the products are i) corrosion resistance, ii) high impact resistance, iii) light weight, iv) electrical insulation, v) low thermal conductivity, and vi) low maintenance.

A range of mouldings of different shapes and sizes are available, including I-beam, U-channel, square hollow tube and angle. The material can be given an anti-skid surface, somewhat like coarse sandpaper, and this was used for the floorboards. Various colours are available: for the Telok Melano trail, floorboards were green and other components brown.

Concrete is used for the footings, while L-angles, glue and stainless steel bolts and nuts are used for joining the components. Nails cannot be used. Aluminium U-channel is needed underneath the FRP floorboards where they are screwed to the joists. The material can be cut with a steel saw or electric cutter and bolt-holes drilled with a standard electric drill.

Comparison of weight and price per metre for materials typically used for posts, beams and floorboards are shown in table 1. As can be seen, FRPs are significantly lighter, which is important in remote areas where transport costs are high. On the other hand, an FRP plankwalk requires more concrete for footings than a belian plankwalk, which would increase the weight of materials. FRP components are much more expensive then belian, being five or six times the price.

Table 1: Weight and price of plankwalk components

Although it is faster to cut FRP profiles than belian, it is difficult to join the structures as nails or simple joints cannot be used. Skilled labour is needed, and park staff are currently not skilled in this work. Personal protective equipment has to be used, as the sawdust and swarf are toxic and irritant. FRP columns require reinforced concrete footings, whereas belian can be placed directly in the soil.

It is expensive to repair damaged walkways, bridges and hand railings (eg after a tree-fall) because the FRP components have to be ordered from West Malaysia.

Fibreglass Reinforced Products will degrade if exposed to light and become brittle with age. They have a life span of about 15 years (Ian Domigan, pers.comm.). They splitter very easily and when cracked they need to be repaired quickly as water will cause them to swell and delaminate.

FRPs cannot be recycled and are not biodegradable. Belian sawdust, off-cuts and even old structures abandoned in the forest are not an ecological problem (though they may be unsightly). This is not true of FRPs, which are not environmentally friendly.

The use of Fibreglass Reinforced Products for the nature trail at Tanjung Datu National Park provides experience in the construction techniques and an opportunity to assess its advantages and disadvantages compared with belian timber.

FRPs look appropriate in the natural environment except for the cold green colour of the U-channel floorboards. However, they cannot be recycled, are not biodegradable, and are toxic. They are light but much more expensive than belian.

Monitoring of the FRP plankwalk will allow all the factors to be weighed, and decisions about whether the Department will use them in other parks or reserves in future will depend on priorities in each case.