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Which Construction Technology?

From an ILO newsletter of 1991 (artist?)

Mechanisation of construction became necessary at the turn of the century to replace labour which was becoming ever more expensive and scarce. However, in many third world countries labour is now  prepared to work for tragically low wages. Moreover, construction equipment and the inputs needed to keep it running must be imported, diverting scarce foreign exchange from more vital purposes. In such circumstances it is not surprising that efforts began some twenty-five years ago to develop construction techniques more appropriate to the economic and social conditions in developing countries.

The International Labor Organisation and more recently the World Bank have been the driving force behind this. The former have developed techniques and procedures for planning, managing, and executing public works which promote the use of unskilled labour using simple hand tools and light machinery without significantly sacrificing construction quality. The latter concentrated on the integration of these techniques within an institutional framework to ensure their sustainability. It has been now realised that the sustainability of labour-based methods depends totally on a institutional framework at the national level and the ILO strategy has been adapted to this.

Such projects can generate around 2 500 person days of employment per kilometer.With recent work on intermediate construction techniques intended to increase productivity, this can be a bit less. As a result around 40% to 50% of total expenditure can be distributed as wages as opposed to 5%-10% on machine-based projects. They also offer the only feasible approach to providing low-cost preventive maintenance in rural areas.

Labour-based techniques do not imply the complete elimination of machinery but rather selective replacement, usually with machinery lighter and cheaper machines, which can work locally on other tasks when available. Certain tasks, for example, compaction of the road surface material are better done by mechanical compactors while transport over long distances is better handled by farm tractors with trailers or by trucks, depending on distance. Both of the latter have the advantage of being multi-use which is essential in third world countries where specialised equipment tends to be under-used. For other tasks, simple tractor-towed machines have been developed which can be used to save labour if wages or scarcity justify it. These can sometimes be manufactured locally, or at least in another developing country.

Up to recently it was generally held that labor-based works help mainly to ensure a better use of local resources rather than to reduce costs. It is now becoming clear that, at prevailing wage rates, labour-based methods have become significantly cheaper in  rural areas. The real cost of using heavy equipment was greatly underestimated in the past, failing notably to take account of low utilisation rates of about 20% , lower still for small and remote rural network improvements where breakdowns can last for weeks. Comparisons were clouded by the fact that many countries have acquired large equipment fleets through grants, which although regarded, reasonably enough, as free in the short term, are ageing rapidly and must eventually be replaced. In the meantime, they become horribly expensive to run. Finally, the environmental destruction caused by heavy machinery must not be forgotten.

Unfortunately, labor-based works have not had the success they merit. Changing a well-established technology requires an integrated strategy  at national and local levels of government as well as the private sector. It cannot be done piecemeal and hurriedly. Putting aside the profound shifts in attitude which must be induced, they require extensive retraining of public works managers and engineers and, given the trend towards private sector involvement, technical and financial assistance to construction firms. These in turn can only survive if they can be guaranteed a steady flow of similar work, which can only be assured by a multi-level commitment.

Their relative simplicity facilitates decentralisation to local level management. However,  we need to train and supervise their implantation to ensure that the acquired knowledge will continue to be used after the project is over. Too often works have been carried out without adequate training and supervision and have been of poor quality. In other cases, managers and enterprises have been trained and equipped but could not continue subsequently to apply their skills and have found themselves unemployed or bankrupt.

In conclusion, labour-based works must be introduced within a high level commitment to privatisation to local firms, decentralisation, employment creation and poverty alleviation. Labour-based works can be powerful policy instruments to support these objectives. However, without a real rather than rhetorical commitment of government and donors they will not realise their potential.

On a less serious note, have a look at some interesting videos (for the history buff in all of us) showing road construction methods before and immediately after the First World War.