"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:4bf469bf-4284-4610-8c81-a2641a7a8df4","http://resolver.tudelft.nl/uuid:4bf469bf-4284-4610-8c81-a2641a7a8df4","The influence of the wave height distribution on the stability of single layer concrete armour units","Zwanenburg, S.A.A.","Uijttewaal, W.S.J. (mentor); Van Vledder, G.P. (mentor); Verhagen, H.J. (mentor); Ten Oever, E. (mentor)","2012","The dimensions of single layer concrete armour units (interlocking armour units) are calculated with a similar stability relation as the stability relation for quarry stone. In these design formulas an 'average/significant' wave load is used (Hs). Since quarry stone gains its stability only from gravity, this type of armour unit is constructed in a double layer and therefore some damage development is allowed. Interlocking armour units are constructed in a single layer and the design should be based on zero damage. This research investigates whether this different approach to damage leads to a different characteristic design wave load which will increase the accuracy of the design method for interlocking armour units. It is focussed on the influence of the wave height distribution on the stability of single layer concrete armour units in general and Xbloc in particular. For Xbloc, zero damage is defined as a criterion for rocking of the armour units: during design conditions ""not more than 2% of the units are allowed to move during more than 2% of the waves"". To find a stability relation based on this criterion, the stability of Xbloc is investigated according to rocking of armour units contrary to the conventionally approach to stability based on the number of displaced units from the armour layer. To find the relation between waves and rocking, physical model tests are performed. In these tests a model breakwater is loaded by wave series with different wave height distributions, wave steepness and groupiness. It resulted that every wave has a certain probability of causing rocking of an armour unit. This probability of rocking is mainly dependent on the height of individual waves and to a lesser extent on the groupiness of the wave series. The steepness of the waves appeared to have a negligible small influence. When the found rocking probability relation is combined with the criterion for rocking, it appears that H2% is mathematically a better fitting parameter for a stability relation according to rocking. A new stability relation for Xbloc is derived based on H2%. Additionally, it is found that very extreme wave heights can dislodge an armour unit in such a way that this armour unit does not interlock anymore. Because it is undesirable that armour units do not interlock anymore, dislodgement of armour units should be accounted for in the stability calculations. Therefore, also a stability relation based on dislodgement of units is provided.","breakwater; Xbloc; armour unit; rocking; wave height distribution; wave load","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:1f995447-3078-4d99-801f-60b19d1116f2","http://resolver.tudelft.nl/uuid:1f995447-3078-4d99-801f-60b19d1116f2","Stability of single layer armour units on low-crested structures","Van der Linde, J.P.","Uijttewaal, W.S.J. (mentor); Vrijling, J.K. (mentor); Verhagen, H.J. (mentor); Ten Oever, E. (mentor)","2009","Two dimensional physical model tests are executed with Xbloc armour units on low crested structures to answer the objective. On the basis of findings in the literature study it can be expected that the stability of the Xbloc elements on low-crested breakwaters is a function of crest freeboard and crest width. The crest freeboard (Rc/Dn) varied from -0.8 to 0.8 in steps of 0.4 and the tested crest widths (Wc) are 3 and 9 armour units wide. Additionally all tests series are executed with a wave steepness of 2 and 4%. All test series are executed once except the reference test series (Rc/Dn = 0, Wc = 3) which are repeated four times to acquire insight into the reliability of the test results. The number of rocking and displaced armour units is registered for the total breakwater, seaside slope and crest (also termed breakwaters sections). Settlements at both the sea- and leeward slope leads to openings in the armour layer at the transition from the seaside slope to the crest. As a consequence the interlocking properties of the upper part of the seaside slope and crest decreases and the area of the Xbloc crest elements normal to the wave induced flow increases. Moreover due to settlement the distance between two succeeding rows at the upper part of the slope increases whereas for the lower part of the slope it decreases. This together with the already decreased interlocking properties of the upper rows at the slopes and crest rocking results at both the upper part of the seaside slope and the outer seaward rows of the crest.","Xbloc; armour unit; breakwater","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""