Vietnam: What are the principles for design of marine port facilities specified in National Standard TCVN 11820-1:2017?
- What is the scope of application of National Standard TCVN 11820-1:2017 on marine port facilities in Vietnam?
- What are the principles for design of marine port facilities in Vietnam?
- What are the assessment contents when determining the characteristic wave and water level conditions for the planning and design of marine port facilities in Vietnam?
What is the scope of application of National Standard TCVN 11820-1:2017 on marine port facilities in Vietnam?
National Standard TCVN 11820-1:2017 is formulated by the Institute of Transport Science and Technology based on OCDI: Technical standards for ports and port tanks of Japan and BS 6349: Maritime facilities, proposed by the Ministry of Transport, appraised by the Directorate of Standards, Metrology and Quality is an agency under the Ministry, and announced by Ministry of Science and Technology.
Accordingly, National Standard TCVN 11820-1:2017 prescribes general principles in the design, new construction, renovation, upgrade and maintenance of various types of marine port facilities.
The design method used in National Standard TCVN 11820-1:2017 is to design according to limited states. In some cases of calculation, if there are suitable arguments, it is possible to use the design method according to the allowable stress.
Marine port facilities mentioned in this set of standards include:
- Harbor facilities;
- Breakwaters, sand breakwaters, and shore protection structures;
- Ship channels and port tanks;
- Dry docks, locks, and docks for shipbuilding and repair facilities;
- And some other types of port facilities (when conforming to the requirements of National Standard TCVN 11820-1:2017).
What are the principles for design of marine port facilities in Vietnam?
Under subsection 7.1 Section 7 of National Standard TCVN 11820-1:2017 as follows:
General Provisions
7.1 Design Principles
The durability and stability of port facilities should be checked according to the following limit states:
- EQU: static imbalance of a building or any part of a building that is considered a solid, then:
+ Small fluctuations in the value or spatial distribution of impacts from an independent source will have great consequences and
+ The intensity of building materials or soil in general does not play a leading role in maintaining balance.
- STR: due to the excess strength of building materials, internal damage or excess deformation of structures or structural parts occurs.
GEO: damage caused by soil deformation is exceeded when the strength of the soil or rock acts as a significant resistance.
FAT: damage to fatigue of structures or structural parts.
The extreme limit states UPL (due to lift/buoyancy thrust) and HYD (due to hydraulic gradient/hydraulic outcrop) should also be checked where appropriate and necessary.
In testing according to limit states, it is necessary to ensure that no limit states exceed the corresponding design values of:
- Payload
- Material characteristics or product features and
- Geometrics.
Thus, the design of marine port facilities must meet the basic principles mentioned above.
What are the assessment contents when determining the characteristic wave and water level conditions for the planning and design of marine port facilities in Vietnam?
Under Clause 7.2.3, Subsection 7.2, Section 7 of National Standard TCVN 11820-1:2017, the assessment contents when determining the characteristic wave and water level conditions for the planning and design of marine port facilities in Vietnam are:
- When designing facilities such as breakwaters, sea dikes, wharf walls or aluminum/piers, wave loads (e.g. shocks, tumbling or lifting waves) or hydraulic reactions (e.g. creeping waves, overflows or wave propagation) should be taken with an extreme wave and water level conditions (with low probability) at or near the base of the building.
- When calculating loads on piles (single or rows of piles) or other relatively thin structural parts, it is necessary to consider the wave spectrum or wave statistics (taking into account the wave frequency range and fatigue loads).
- In cases where large ships need to anchor in relatively open locations along the shore or inside harbor tanks, it is necessary to assess the possibility that long waves will occur at that location.
NOTE 1 TO ENTRY:
Because long-cycle wave impacts accompany groups of waves, for example when a series of high waves followed by a series of low waves usually causes the greatest anchor loads.
- When wave conditions and water levels are used for yard design or design correction facilities, long-term wave statistics or time-series data (seasonal, including annual and decade-by-decade) should be obtained as well as information on short-term storm events.
In all cases, the design should take into account the frequency distribution (and direction) of the wave energy spectrum, as longer period waves (illustrious waves) usually have greater energies (and/or come from a different direction) than shorter period higher waves in the wave spectrum.
NOTE 2 TO ENTRY:
Complex sea states (of many types) or in multiple directions can have more severe consequences for some design cases, such as payloads due to ship displacement and anchorage, creep/overflow/wave propagation, or shore response (or kinetic structures).
- In many cases, incident wave conditions are often influenced by wave-building interactions (e.g. reflection or diffraction) and design should take into account the extent to which the method of obtaining wave conditions and/or the design methodology considers or exhibits such effects.
- For certain design applications that are based on empirical relations (usually sea dikes or breakwaters), unharmonized wave conditions should be calculated based on statistical or spectral parameters such as height, periods, and directions, but the assessment of waveforms (e.g. non-breaking waves, kneading waves, surges) are important to better understand the likelihood or structural response that may occur.
NOTE 3 TO ENTRY:
Some types of facilities are suitable for adopting a reaction-based approach when the response of the building (or component) is assessed over the entire range of expected environmental loads (either statistical or sequenced over time).
Accordingly, the probability of a given reaction can be directly assessed (and described according to the concept of probability) by the input parameters that define the load.
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