SIST EN 1992-3:2006

SIST EN 1992-3:2006 is the Slovenian adoption of EN 1992-3, Eurocode 2, Part 3. It gives additional design rules for concrete structures that retain liquids or contain granular solids, especially tanks, reservoirs and silos. The document focuses on liquid tightness, cracking, durability, temperature effects and detailing for plain, reinforced and prestressed concrete.

What does SIST EN 1992-3:2006 specify?

SIST EN 1992-3:2006 covers the extra rules needed on top of EN 1992-1-1 for containment structures. It is organised into Sections 1 to 9 and four informative annexes.

The scope is limited to structures in plain or lightly reinforced concrete, reinforced concrete and prestressed concrete that directly support stored liquids or materials. Supporting parts such as a tower for a water tank are designed to Part 1-1.

What are the key requirements of SIST EN 1992-3:2006?

Loads, temperature and analysis

• Clause 2.1.1 links design situations to EN 1990, EN 1991-4 and EN 1991-1-5, and adds cases such as filling and discharge patterns, dust explosions, thermal effects and watertightness testing. In practice, the designer must check operating and accidental conditions, not only normal structural loading.
• Clause 2.3.1.1 takes action factors for these structures from EN 1991-4, and ground-related actions from EN 1997. This matters when tank walls or silos interact with soil or stored material pressures.
• Clause 3 requires temperature effects on concrete to be considered, with Annex K providing guidance. If thermal exposure is important, the designer needs to account for changing strength, stiffness, creep and strain.
• Clause 5.13 distinguishes liquid pressure and solid pressure. Without a more rigorous analysis, liquid pressure may be taken at the centre of the retaining members, while solid material pressure acts on the inner surface.

Crack control and tightness

• Clause 7.3.1 introduces Tightness Class 0 to 3. Class 0 allows some leakage, Class 1 limits leakage, Class 2 seeks minimal leakage, and Class 3 requires no leakage. This classification drives crack limits and whether special measures are needed.
• Clause 7.3.1 also links crack control to compression-zone depth and, for classes 2 and 3, often to liners or prestress. In practice, this means the section must be detailed so cracks do not pass through the full thickness.
• Clause 7.3.5 gives ways to reduce cracking from restraint and shrinkage, including limiting hydration temperature rise, reducing restraints, lowering shrinkage and using prestressing. Annex L and Annex M support the calculation of restrained deformations and crack widths.
• Clause 9.6.6 states that movement joints should be used if cracking cannot otherwise be controlled. Joints must be inspectable and repairable or renewable, because sealants may not last as long as the structure.

Detailing and special cases

• Clause 8.10.1.3 sets rules for post-tension ducts in circular tanks, including duct placement and uniform prestressing. This reduces local failure risk and uneven force effects.
• Clause 9.11.1 gives minimum wall thickness guidance for reservoir and tank walls and requires passive reinforcement where there is no vertical prestressing. This affects buildability and the practical watertightness of the wall.
• Clause 6.9 requires silo structures exposed to dust explosion risk to resist the expected pressure or be vented safely. Actions from dust explosions are treated as accidental actions, so this becomes a separate safety check.

What terms does SIST EN 1992-3:2006 define?

• Tightness Class - The leakage classification for containment structures, ranging from Class 0 with some leakage acceptable to Class 3 with no leakage permitted.
• Rax - A factor that describes the degree of external axial restraint provided by attached elements.
• Rm - A factor that describes the degree of moment restraint provided by attached elements.
• fckT - The characteristic compressive strength of concrete modified to take account of temperature.
• eTr - Transitional thermal strain, the irrecoverable strain that can occur when concrete is heated while stressed.
• wk1 - The crack-width limit used for Tightness Class 1, with the value taken from the National Annex.
• xmin - The minimum compression-zone depth used to show that cracks do not pass through the full thickness in tighter classes.

Who uses SIST EN 1992-3:2006?

Structural engineers use SIST EN 1992-3:2006 to design tanks, reservoirs, silos and similar containment structures. Prestressed concrete designers use it for tendon layout, anchorage details and crack control.

Quality managers and buyers use it when specifying watertightness, durability and acceptance criteria for liquid-retaining concrete works. Geotechnical engineers use it where ground water or soil actions affect the structure.

Inspectors and testing teams use it for reservoir watertightness checks and for judging whether cracking, leakage or joints meet the intended tightness class.

What changed in SIST EN 1992-3:2006 from the previous edition?

SIST EN 1992-3:2006 supersedes ENV 1992-4:1998.

Which standards are used with SIST EN 1992-3:2006?

• EN 1990 - basis of structural design, used for the general design framework.
• EN 1991-1-5 - thermal actions on structures.
• EN 1991-4 - actions on silos and tanks, including partial safety factors for these structures.
• EN 1992-1-1 - the general concrete design rules that this part complements and in some places modifies.
• EN 1992-1-2 - structural fire design and elevated-temperature material data.
• EN 1997 - geotechnical design, used for soil and groundwater actions.
• EN 1991-1-7 - explosion-related considerations, referred to for dust explosion design context.
• EN 1992-2 - referenced for strut-and-tie design and for some crack-control procedures.

What does the SIST EN 1992-3:2006 document contain?

The document contains the Eurocode clause structure for containment design, plus tables, figures and annex methods for crack control, restraint and joint design. Clause 7 includes a tightness classification table and crack-width control figures for reinforcement sizing. Annex K gives temperature-related material behaviour, Annex L gives restraint factors and stress/strain expressions, Annex M gives crack-width expressions for restrained deformations, and Annex N compares full-restraint and movement-joint strategies. These parts are used for design checks, detailing, serviceability assessment and, where needed, testing and inspection planning.