scholarly journals LOADING OF VERTICAL WALLS BY OVERTOPPING BORES USING PRESSURE AND FORCE SENSORS - A LARGE SCALE MODEL STUDY

2012 ◽  
Vol 1 (33) ◽  
pp. 44 ◽  
Author(s):  
Karunya Ramachandran ◽  
Rebeca Roldan Genzalez ◽  
Hocine Oumeraci ◽  
Stefan Schimmels ◽  
Matthias Kudella ◽  
...  

This study is based on the data obtained from tests carried out in the Large Wave Flume (Grosser Wellenkanal (GWK)) in Hannover in the frame of a joint research project of Ghent University (Belgium) and Forschungszentrum Küste (FZK, Germany). The goal of the research project is to determine the wave induced loads on vertical storm walls located at the end of overtopped dike, which are designed to protect coastal cities from overtopping and floods. The loads resulting from waves overtopping the dike and impacting the vertical wall as a bore are measured by means of both force and pressure sensors. This paper describes the results of pressure and force records at the vertical wall, including a comparative analysis of the overall forces obtained by pressure integration and force sensors for two different wall setups: Fully blocked wall and partially blocked wall.

Author(s):  
Lisham Bonakdar ◽  
Hocine Oumeraci

Wave loads on a slender pile within a group of piles are studied by means of (i) large-scale laboratory tests carried out in the Large Wave Flume (GWK) of the Coastal Research Centre (FZK) in Hannover, and (ii) small scale experiments performed in 2 m-wide wave flume of Leichtweiss-Institute for Hydraulic Engineering and Water Resources (LWI), in Braunschweig, Germany. The small scale model tests (LWI) were scaled down (1:6.5) by Froude law from the large scale model tests (GWK). Scale and model effects are examined by comparing the results of small and large scale laboratory tests.


2012 ◽  
Vol 1 (33) ◽  
pp. 45 ◽  
Author(s):  
Sven Liebisch ◽  
Juan Carlos Alcérreca Huerta ◽  
Andreas Kortenhaus ◽  
Hocine Oumeraci

The porosity and roughness of bonded revetments are both crucial for the hydraulic performance and the wave loading of the revetment and its foundation, and thus for the stability and durability of the entire structure. This is briefly shown by the selected results of a tentative comparative analysis of two large-scale test series performed in the Large Wave Flume (GWK) Hanover with two significantly different revetments: a highly porous and rough polyurethane bonded aggregate (PBA) revetment and an almost impermeable and relatively smooth interlocked pattern placed block (IPPB) revetment. These results motivated the initiation of the three years research project BoPoRe (Bonded Porous Revetments) which has the primary objective to investigate more systematically and separately the relative importance of both porosity and roughness for different slope steepnesses. This project is briefly introduced and the first results of preliminary scale model tests using 9 configurations for the porosity and roughness of the revetment subject to a wide range of wave conditions (surf similarity parameters 0.93-7.21) are briefly discussed.


Author(s):  
Chiwan Hsieh ◽  
Jeng Wu

A research project that involves the construction of a full-size geogrid-reinforced test embankment was conducted. Waste tire chips were used as the lightweight backfill for the embankment. The joint research project involved participants from government agencies, academic research institutes, consulting firms, and material suppliers. To meet the function requirements, the north side of the embankment had to be built essentially as a vertical wall. To maintain stability, the vertical side of the embankment was reinforced with geogrids and covered with segmental retaining-wall facing. The objectives of the research study were to evaluate the feasibility of using waste tire chips as embankment backfill material when coupled with geogrid reinforcement and to evaluate the performance of various types of goesynthetic drainage products in the test embankment. To minimize settlement due to compression of the tire chips, various combinations of tire chips and soil mixtures or interlayers were used in the embankment construction. The details of the design and construction of the test embankment are described. Performance of the test embankment is evaluated based on available observation data.


2011 ◽  
Vol 1 (32) ◽  
pp. 17
Author(s):  
Gisa Ludwigs ◽  
Hocine Oumeraci ◽  
Tijl Staal

Permeable revetments made of bonded mineral aggregates may increasingly be favoured compared to standard revetments. However, the physical processes associated with the water–structure–soil-interaction for a wide range of wave conditions are still not well understood. Therefore, systematic large-scale model tests have been performed in the Large Wave Flume (GWK) of the Coastal Research Centre (FZK) in Hannover, with the intention of improving the understanding of these processes.


Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 163
Author(s):  
Masaru Ogura ◽  
Yumiko Shimada ◽  
Takeshi Ohnishi ◽  
Naoto Nakazawa ◽  
Yoshihiro Kubota ◽  
...  

This paper introduces a joint industries–academia–academia research project started by researchers in several automobile companies and universities working on a single theme. Our first target was to find a zeolite for NH3-SCR, that is, zeolite mining. Zeolite AFX, having the same topology of SSZ-16, was found to be the one of the zeolites. SSZ-16 can be synthesized by using an organic structure-directing agent such as 1,1′-tetramethylenebis(1-azonia-4-azabicyclo[2.2.2]octane; Dab-4, resulting in the formation of Al-rich SSZ-16 with Si/Al below five. We found that AFX crystallized by use of N,N,N′,N′-tetraethylbicyclo[2.2.2]oct-7-ene-2,3:5,6-dipyrrolidinium ion, called TEBOP in this study, had the same analog as SSZ-16 having Si/Al around six and a smaller particle size than SSZ-16. The AFX demonstrated a high performance for NH3-SCR as the zeolitic support to load a large number of divalent Cu ionic species with high hydrothermal stability.


Author(s):  
Hans Friderichs ◽  
Dieter Gerdesmeier ◽  
Elisabeth M. Kremp ◽  
Bernard Paranque ◽  
Annie Sauve ◽  
...  

2020 ◽  
Vol 9 (1) ◽  
pp. 29
Author(s):  
Rebekka Gieschen ◽  
Christian Schwartpaul ◽  
Jannis Landmann ◽  
Lukas Fröhling ◽  
Arndt Hildebrandt ◽  
...  

The rapid growth of marine aquaculture around the world accentuates issues of sustainability and environmental impacts of large-scale farming systems. One potential mitigation strategy is to relocate to more energetic offshore locations. However, research regarding the forces which waves and currents impose on aquaculture structures in such conditions is still scarce. The present study aimed at extending the knowledge related to live blue mussels (Mytilus edulis), cultivated on dropper lines, by unique, large-scale laboratory experiments in the Large Wave Flume of the Coastal Research Center in Hannover, Germany. Nine-months-old live dropper lines and a surrogate of 2.0 m length each are exposed to regular waves with wave heights between 0.2 and 1.0 m and periods between 1.5 and 8.0 s. Force time histories are recorded to investigate the inertia and drag characteristics of live mussel and surrogate dropper lines. The surrogate dropper line was developed from 3D scans of blue mussel dropper lines, using the surface descriptor Abbott–Firestone Curve as quality parameter. Pull-off tests of individual mussels are conducted that reveal maximum attachment strength ranges of 0.48 to 10.55 N for mussels that had medium 3.04 cm length, 1.60 cm height and 1.25 cm width. Mean drag coefficients of CD = 3.9 were found for live blue mussel lines and CD = 3.4 for the surrogate model, for conditions of Keulegan–Carpenter number (KC) 10 to 380, using regular wave tests.


Sign in / Sign up

Export Citation Format

Share Document