Statybos techninis reglamentas STR 2.02.06:2004 – Lithuanian Hydraulic Structures Code
The Statybos techninis reglamentas STR 2.02.06:2004, titled Hidrotechnikos statiniai. Pagrindinės nuostatos (Hydraulic Structures. Basic Provisions), is a mandatory technical regulation issued by the Ministry of Environment of the Republic of Lithuania (Lietuvos Respublikos aplinkos ministerija). Approved by Order No. D1-538 on October 18, 2004, this document establishes the fundamental requirements for the design and construction of new, reconstructed, and fundamentally repaired hydraulic structures (HTS). It functions within the broader legal framework of the Lithuanian Law on Construction (Statybos įstatymas) and is harmonized with European standards, specifically the Eurocodes and Directive 89/106/EEC regarding essential requirements for construction works.
The scope of the regulation encompasses all hydraulic facilities, including dams, dykes, canals, reservoirs, and sea port structures classified as transport infrastructure. It details regulatory domains such as structural reliability, environmental protection, and safety during operation. The document is structured into twenty-one chapters and five technical annexes, defining critical domain-specific terms such as akvatorija (water area), bjefas (reach/pool), debitas (discharge/flow), and polderis (polder). It explicitly governs the classification of structures based on the potential consequences of failure, designated as consequence classes CC1 through CC4, and sets specific thresholds for Ypatingi statiniai (extraordinary structures) involving power capacity, height, and reservoir area.
The following sections provide a structured overview of the technical requirements for different hydraulic categories and the mandatory calculation principles for engineering professionals and developers.
Classification of Hydraulic Structures (HTS)
Structures are classified based on their location, functional purpose, service life, and the potential consequences of failure (pasekmių klasės). The regulation distinguishes between inland and marine HTS, further categorizing them by their technical role in water retention, discharge, intake, or transport.
- Consequence Classes (CC1–CC4): Range from CC1 (simplest/lowest risk) to CC4 (highest importance/catastrophic risk).
- Ypatingi statiniai: Structures are categorized as extraordinary if they exceed thresholds such as a power plant capacity of 1 MW, a retention height of 3 m, or a reservoir area of 5 ha.
- Functional Groups: Includes structures for water head maintenance (vandens patvenkimo), discharge (praleidimo), and special-purpose facilities like fish passes (žuvų pralaidos).
Mandatory Calculation Provisions
Design calculations must account for the specific interactions between water and the structure. Professionals must evaluate mechanical, physical, chemical, and biological impacts as defined in VII SKYRIUS. PAGRINDINĖS SKAIČIAVIMŲ NUOSTATOS.
- Mechanical Impacts: Static water pressure, ice pressure, wave loads, and dynamic flow effects.
- Physical Impacts: Damage from periodic freezing and thawing within material pores.
- Chemical Impacts: Corrosion from aggressive water and sediment-induced clogging of drainage systems.
- Biological Impacts: Decay of wooden elements and activity of iron bacteria in pipelines.
Specific Requirements for Dams and Dykes
Chapter VIII specifies that the selection of dam type and construction materials must be technically and economically justified, considering geological and seismic conditions. The regulation permits the use of local soils, concrete, reinforced concrete, or composite materials.
- Earth-fill Dams: Prioritized for plains rivers; must utilize local materials to simplify construction and ensure reliability.
- Concrete Dams: Typically constructed on rocky foundations; requires evaluation of joint sealing and thermal-settlement stresses.
- Protective Dykes: Classified based on the density and importance of the protected residential or industrial territory.
Hydroelectric (HE) and Pumping Stations
The regulation provides specific provisions for hydroelectric plants (HE) and pumping stations, including small-scale facilities known as mHE (Mažosios hidroelektrinės) with a capacity up to 10 MW.
- Small Hydro (mHE): Encourages the use of unified designs and factory-made equipment for facilities between 100–200 kW.
- Pumping Stations: Requires a balanced operation mode synchronized with water intake regulations.
- Emergency Systems: Provisions for automated remote control and ice/debris protection at intakes.
Frequently Asked Questions
What is the threshold for a hydraulic structure to be classified as 'extraordinary'?
A hydraulic structure is classified as extraordinary (ypatingas) if it has a power capacity greater than 1 MW, a retention height exceeding 3 m, or a reservoir area larger than 5 ha.
How are consequence classes CC1 to CC4 defined for HTS?
Classes are defined based on the potential damage from failure; CC1 represents the lowest consequence level (simplest structures), while CC4 represents the highest risk level, involving significant potential loss of life or catastrophic economic and environmental damage.
Are sea port structures covered by STR 2.02.06:2004?
Yes, the regulation applies to reconstructed and fundamentally repaired sea port structures classified as transport infrastructure.
What is the maximum capacity for a 'small hydroelectric plant' (mHE)?
A small hydroelectric plant (mažoji hidroelektrinė) is defined as having an installed capacity not exceeding 10 MW (10,000 kW).
Does the regulation require fish protection measures?
Yes, Section XI specifies that fish passes or protection measures must be provided at water intakes and hydraulic hubs to ensure the migration of valuable fish species.
What are the requirements for ice protection at hydroelectric plants?
Structures must be designed to pass ice and debris from the upper to the lower reach (bjefas) or utilize heated grids and floating barriers to prevent blockage of intakes.
