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Dams safety improvement and cost savings
ICOLD Bulletin 80
Dam construction sites accident prevention
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1. INTRODUCTION
When one talks of" safety " in large engineering construction and particularly in dams, experienced engineers as weIl as laymen think first of the intrinsic safety of the structure, that is, aIl those provisions in the design and performance of the work devised to prevent the total or partial collapse of the structures, and thus to prevent damage to future users and residents in the area adjacent to the work being constructed. Secondly, they usually consider the conditions of temporary instability of component elements, but still with a view to preventing damage that might occur to the work during its construction.
Conversely, the safety of the personnel working on-site is a problem that in symposiums dealing with safety in dams is generally neglected or, at best, considered of minor importance. For instance, we noticed that during a congress on " Dams and Their Safety ", held in Milan in 1986, just a few words were spent on occupational accident prevention. Up to 1988 even the reports published by ICOLD gave little consideration to the safety of construction personnel.
On the contrary, it is a very important problem, because the effects of accidents on job sites are very serious, for the injuries suffered by workers, with consequent disability or even death, for the material damage to machinery, equipment and plant, and, more generally, for the loss of site morale, for slowdowns of work and slackening in productivity.
This problem is mentioned in ICOLD Bulletin No. 73 of 1989" Savings in Dam Construction". In Section (1) " Introduction", it states: " At most sites, the risk of fatal accidents to workmen during construction is greater than the risk from dam failure " and: " Statistically, therefore, failure of recently built dams causes much less than one victim per dam. "
No doubt it is quite hard to compare these types of hazards; the former related to accidents on the job, has a medium frequency rate with consequences of medium importance (if this expression is acceptable for the loss of human lives); the latter related to structural collapse has a very small frequency rate, but its effects are extremely serious.
It is also for this reason that, apart from a certain presumption of fatalities, occupational accidents have not been publicized in the past, while disasters caused by the failure of operating projects have always been widely reported by the media.
ln truth, in recent years also public opinion has been more attentive to the problem of occupational accidents, thanks mainly to the many efforts being contributed aIl over the world to emphasize these major topics of labour safety and health.
ln the following Sections of this report, we will be evaluating - to our best efforts - accident losses in dam construction, suggesting also the methods and procedures to prevent them.
2. CONCLUSIONS - RECOMMENDATIONS
We have noted that occupational accidents and occupational diseases are
continually decreasing aIl over the world and in aIl construction fields, especially
on large dam sites, thanks to the experience of owners and project designers, the
skills of contractors, and the use of advanced technologies.
However, the efforts for an effective prevention must not be discontinued, since new dams will be built in the near future for power production, irrigation, and fiooding control, mainly in developing countries, where prevention activities, which are the result of industrial progress, have a very poor tradition.
ln previous Sections, we have outlined the resources that can be used to fight occupational accidents and occupational diseases; the organizational tools and working and control procedures that can be utilized; the costs to be faced; and the benefits that can be achieved. These advantages can be both direct: reduced number and severity of occupation al accidents and occupational diseases; and indirect:
more effective work organization and better image of owners, project designers,
contractors towards public opinion.
But, since prevention involves substantial organizational costs, especially at the initial phase of works, it is neither right nor fruitful that in those countries where there are no legal regulations (or, even, if there are, they are only partially enforced), its accomplishment should rely only on contractor's voluntary efforts. Therefore, we deem it useful to make the following recommendations.
2.1. SUGGESTIONS FOR FUTURE CONTRACfS
While waiting for legal regulations to enforce health and safety procedures in ail countries (the European Community has the opportunity to set a good lead by the enforcement in aIl the EEC countries of the complete regulations provided for by the EEC Directives), we consider that ICOLD has sufficient worldwide prestige to promote the initiative for the main large dam owners to include in their contract specifications for new works some specifie conditions which require contractors to provide adequate organization and operating methods for labour safety and health.
That would put aIl bidders at the same starting level in this respect. And owners, who do not award a contract solely on the basis of priee (which is common for major projects), but also consider a wider range of elements (construction quality, technology used, performance timing, financial guarantees, etc.), will find in the proposed organization for labour safety and health an important additional point for evaluating tender quality.
It is obvious that, during the performance of the work, the owner must effectively monitor the safety measures actually adopted, through its own personnel and/or through outside consultants, in addition to the checks performed by public supervisors.
On our part, as a conclusion to this report, we wish to suggest the following
provisions for inclusion in contract documents.
2.2. INVITATION TO TENDER
The tender documents supplied by the owner to contractors should include a series of general - rather than exhaustive - data and information that may affect occupational safety and health.
Based on this data, the contractor must develop and submit the following, along
with his tender:
i) A " Summary Study " on the safety and health measures planned to be
adopted when arranging and organizing the different work areas, namely :
- camps;
- offices;
- site plant and workshops;
- transit roads and personnel transportation; - work areas.
ii) A "Specific Study " on the safety, protection, and health measures planned to be adopted on the major works, such as :
- excavation and earthworks;
- production of aggregates;
- tunnels for diversions and spillways;
- formwork;
- reinforcing steel;
- concrete pouring;
- installation of electro-mechanical equipment;
- marine equipment and underwater works.
iii) A detailed description of the organization planned to be set up on the site
as to :
- assignment of tasks, development and supervision of safety and health measures (Labour Safety and Health Office);
- organization of first aid and medical treatment;
- personnel instruction and training in safety rules.
Small & medium dams
Spillways