• Manufacturing of Pre-tensioned Railway Sleepers

    by  • December 29, 2010 • Prestressed Concrete Structures, Subjects • 1 Comment

    Manufacturing of Pre-tensioned Railway Sleepers

    The following photos show the sequence of manufacturing of pre-tensioned railway sleepers (Courtesy: The Concrete Products and Construction Company, COPCO, Chennai). The steel strands are stretched in a stress bench that can be moved on rollers. The stress bench can hold four moulds in a line.

    The anchoring device holds the strands at one end of the stress bench. In the other end, two hydraulic jacks push a plate where the strands are anchored.

    The movement of the rams of the jacks and the oil pressure are monitored by a scale and gauges, respectively. Note that after the extension of the rams, the gap between the end plate and the adjacent mould has increased. This shows the stretching of the strands.

    Meanwhile the coarse and fine aggregates are batched, mixed with cement, water and additives in a concrete mixer. The stress bench is moved beneath the concrete mixer. The concrete is poured through a hopper and the moulds are vibrated.

    After the finishing of the surface, the stress bench is placed in a steam curing chamber for a few hours till the concrete attains a minimum strength. The stress bench is taken out from the chamber and the strands are cut. The sleepers are removed from the moulds and stacked for curing in water. After the complete curing, the sleepers are ready for dispatching.

    Travelling pre-tensioning stress bench

    Anchoring of strands

    Stretching of strands

    Stretching of strands

    Material storage

    Batching of materials

    Pouring of concrete

    Concrete after vibration of mould

    Steam curing chamber

    Cutting of strands

    Demoulding of sleeper

    Stacking of sleeper

    Water curing

    Storage and dispatching of sleepers

    Manufacturing of pre-tensioned railway sleepers