International engineering and underground construction experts have joined forces to publish a new form of contract for tunnelling and underground works.
The Conditions of Contract for Underground Works (The Emerald Book) has been produced by the International Federation of Consulting Engineers (FIDIC) and the International Tunnelling and Underground Space Association (ITA-AITES).
It was launched last week at the World Tunnel Congress 2019 in Naples. FIDIC said take-up of the new contract is expected to be widespread, with tunnelling a growing market in a number of areas including energy, transportation, urban infrastructure and as a result of space shortages in cities due to population increases.
Contracts committee chair Zoltán Záhonyi said: ‘Working together, FIDIC and ITA-AITES have created a contract that we believe, and hope will command the respect and authority of the tunnel engineering and construction sector and that both clients and contractors can use with confidence.
‘The new Emerald Book addresses several critical areas that should lead to the smoother running of contracts in the growing tunnelling and underground works sector.’
Tarcisio Celestino, president of ITA-AITES, said the contract will bridge an important gap.
‘Despite all the technological developments of equipment and techniques in the field, many underground construction projects end up unsuccessful because of contractual disputes,’ he said.
FIDIC stressed that underground construction is highly dependent on the geological, hydrogeological and geotechnical properties of the ground.
In addition, the difficulty in predicting ground behaviour and foreseeable conditions implies an inherent uncertainty in underground construction, which gives rise to unique contractual risks regarding construction practicability, time and cost.
FIDIC said the contract addresses several issues around equitable risk allocation and dealing effectively with conditions typically unforeseeable in such projects.
The new contract specifically addresses the following key areas;
- Allocation of risk.
- Disclosure of all available geological and geotechnical information.
- Inclusion of a contractual geotechnical baseline.
- Inclusion of a tailored “Unforeseeable Physical Conditions” clause.
- Implementation of a ground classification system and of supporting particular conditions that properly reflect the effort of excavation and stabilisation.
- Time for completion is largely influenced by ground conditions.
- Provision of a flexible mechanism for remuneration according to ground conditions, foreseen and unforeseen.