An Experimental Investigation Into the Pull-Out Capacity of Suction Caissons in Sand

2011 ◽  
Author(s):  
Siamak Kakasoltani ◽  
Mostafa Zeinoddini ◽  
Mahmoud R. Abdi ◽  
Hamid Arabzadeh
Keyword(s):  
Experimental Investigation ◽  
The Other ◽  
Silty Sand ◽  
Small Scale ◽  
Soil Density ◽  
Pull Out ◽  
Aspect Ratios ◽  
Rate Effects ◽  
Wall Slope ◽  
Suction Caissons

The pull-out performance of conventional suction caissons (with upright walls) has been previously investigated by a number of researchers. However, less attention has been formerly paid to tapered suction caissons. This paper reports some results from an experimental investigation into the pull-out performance of tapered suction caissons. The 1g experiments have been carried out on eight small scale suction caissons. Four specimens have had upright walls while the other four had a positive wall slope of 10%. The caissons have been installed in a soil tank containing very fine saturated silty sand. The caissons have then been subjected to vertical pull-out loads with different speeds. The effects of variations in soil density and pull-out rate on the pull-out capacities have also been investigated. In general, tapered caissons have been noticed to present enhanced pull-out capacities as compared to those from their equivalent upright caissons. The enhancement rate has been found to be more significant in suction caissons with higher aspect ratios. With both upright and tapered caissons the pull-out capacity increases by an increase in the pull-out rate. The pull-out rate effects are more significant with upright caissons in comparison to the corresponding tapered caissons. The density effects, however, are more significant with tapered caissons as compared to their equivalent upright caissons.

On Penetration of Upright and Tapered Suction Caissons in Sand: An Experimental Study

2010 ◽  
Author(s):  
Siamak Kakasoltani ◽  
Mostafa Zeinoddini ◽  
Mahmoud R. Abdi ◽  
Seyyed Abbas Mousavi Behnam
Keyword(s):  
Silty Sand ◽  
Offshore Wind ◽  
Small Scale ◽  
Geometrical Parameters ◽  
Soil Density ◽  
Aspect Ratios ◽  
Full Penetration ◽  
Sea Bed ◽  
Penetration Force ◽  
Suction Caissons

Over the past two decades, suction caissons have been increasingly utilized as deep water anchors for floating structures, foundations of offshore wind turbines and even for jacket platforms. They penetrate into the sea bed by a combination of their buoyant weight and under base suction. Suction caissons have appeared as an efficient and economic alternative for foundations in the offshore industry. This concept, however, is relatively new, so the knowledge about their behavior has not yet gone far deep as that for other offshore foundation solutions such as driven pile systems. This paper reports some results from an experimental investigation into the installation of upright and tapered suction caissons. The 1g experiments have been carried out on eight small scale suction caissons. The aspect ratios, (the caisson length/its diameter) have been 1, 2, 3 and 4. The diameter has been constant and equal to 80 mm. Four specimens have had upright walls while the other four had a positive wall slope of 10%. The caissons have been installed in a soil tank containing very fine saturated silty sand. The penetration has been achieved under forced driving using a constant penetration rate. The effects of geometrical parameters and the soil density on the overall penetration force have been studied. it has been observed that, with both the upright and tapered caissons, the required force for full penetration increases by an increase in the aspect ratio. The penetration force required for full penetration of tapered models, has been two to three times higher than an equivalent upright caisson. With tapered caissons, the penetration forces have been found to be more sensitive to the soil density as compared to that with upright caissons. The experimental results for upright suction caissons have also been compared with a closed form analytical solution proposed by other researchers.

Tapering Effects on the Installation of Suction Caissons in Clay

2008 ◽  
Author(s):  
Mostafa Zeinoddini ◽  
Woorya H. Shariati ◽  
Mahmood Nabipour
Keyword(s):  
Finite Element ◽  
Finite Element Models ◽  
Finite Element Approach ◽  
Pull Out ◽  
Full Penetration ◽  
Element Approach ◽  
Numerical Finite Element ◽  
Wall Slope ◽  
Suction Caissons ◽  
Considerable Enhancement

This paper reports results from an investigation on the tapering effects on the installation and pull-out performance of suction caissons. A numerical finite element approach has been used for the study. The finite element models have first been calibrated/verified against several available experimental data for the installation of the upright suction caissons in clay. The verified models have then been used to examine the behaviour of the tapered suction caissons during the pull-out and installation phases. Numerical results indicate that tapered caissons present considerable enhancement in their pull-out capacity comparing to those from corresponding upright caissons. Also it has been noticed that in general tapered caissons of positive wall slopes need extra forces, in comparison to their equivalent upright caissons, to achieve a full penetration. However, at least with those models studied, these extra forces have found to be less than twenty five percent when the wall slope varies from zero (upright) to 15%. This is while the additional pull-out capacities that might be achieved from these tapered suction caissons could reach to several hundred percents. An almost linear relationship has been observed between the total installation force and the caisson’s wall slope.

scholarly journals Confinement of Masonry Columns with the FRCM-System: Theoretical and Experimental Investigation

2020 ◽  
Vol 5 (11) ◽  
pp. 101
Author(s):  
Maria Antonietta Aiello ◽  
Alessio Cascardi ◽  
Luciano Ombres ◽  
Salvatore Verre
Keyword(s):  
Experimental Investigation ◽  
Stress Transfer ◽  
Experimental Results ◽  
The Other ◽  
Analytical Models ◽  
Small Scale ◽  
Structural Element ◽  
Technical Literature ◽  
Number Of Layers ◽  
Other Hand

Fabric Reinforced Cementitious Matrix (FRCM) systems are promising solutions for the confinement of masonry columns because they demonstrate strengthening effectiveness and, at the same time, compatibility with historical substrates. Nevertheless, the matrix is responsible for the stress-transfer from the structural element to the fabric-reinforcement. Therefore, in the case of poor-quality mortar, the effectiveness of the strengthening can be limited or even compromised. On the other hand, the low content of fibers utilized for FRCM systems generally involves the need to apply more layers in order to accomplish design requirements and a continuous configuration of the reinforcement is more often addressed. Few experimental and theoretical investigations have been targeted to the before mentioned aspects in the recent past, namely the influence of the kind of mortar, the number of layers, and the strengthening configuration (continuous, discontinuous) on the effectiveness of confinement. The present paper refers to the results of an experimental investigation on FRCM confined clay brick masonry. A series of small-scale masonry columns were tested under monotonic centered load until collapse. The varied parameters were the number of confining layers (i.e., 1, 2, and 3) and the confinement configuration (i.e., continuous and discontinuous). The performed research aims to contribute in strengthening to the knowledge in the field of FRCM-confinement, mainly focusing on some of the mentioned unexplored aspects (number of layers, strengthening configuration) that could be considered for validation/improvement of analytical design-oriented formulas. In particular, some analytical models, available in the technical literature, were adopted for predicting the herein reported experimental results. Even if based on few experimental results, the outcomes showed that the number of FRCM-layers and the confinement configuration were crucial parameters affecting the confining effectiveness. The compressive strength was satisfactorily predicted in all cases by the two available utilized models. On the other hand, an improvement in the utilized AOM model is suggested in order to include the stress–strain curves of the hardening type.

scholarly journals The Pull-out Capacity of Suction Caissons in Model Investigations

2016 ◽  
Vol 63 (2-3) ◽  
pp. 157-171
Author(s):  
Andrzej Sawicki ◽  
Łukasz Wachowski ◽  
Marek Kulczykowski
Keyword(s):  
Model Experiment ◽  
Extraction Process ◽  
Experimental Results ◽  
Scale Model ◽  
Small Scale ◽  
Extensive Discussion ◽  
Pull Out ◽  
Small Scale Model ◽  
Suction Caissons ◽  
Good Agreement

AbstractA small-scale model experiment on the pull-out resistance of suction caissons is described. The pull-out force and suction developed within the caisson in the extraction process were recorded during the experiment. A simple breakout model, together with an elementary static formulae, is applied to predict the results obtained experimentally. There is a reasonably good agreement between the experimental results and predictions. An extensive discussion of the approach applied is included. The analysis presented in this paper is original, as it differs from other approaches mentioned in this paper, and leads to acceptable predictions. At the end, the results are also compared with another approach for predicting the capacity of suction caissons.

scholarly journals Wall slope effects on the vertical pull-out capacity of tapered suction caissons

2011 ◽  
Vol 18 (3) ◽  
pp. 313-325 ◽  
Author(s):  
M. Zeinoddini ◽  
J. Keyvani ◽  
M. Nabipour
Keyword(s):  
Pull Out ◽  
Wall Slope ◽  
Suction Caissons

scholarly journals A Small-Scale Experimental Investigation on the Benefits of a Hybrid Pile/Footing System on Sand

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Mohammed Maadheedi ◽  
Keyword(s):  
Experimental Investigation ◽  
Laboratory Tests ◽  
Steel Plate ◽  
Sustainable Design ◽  
Back Analysis ◽  
Ground Surface ◽  
The Other ◽  
Small Scale ◽  
Model Design ◽  
Hypothetical Scenario

This paper explores the capacity effects of a square steel plate welded at the ground surface on a driven open-ended steel pile (i.e. the plate would touch the ground surface after the pile achieves the required penetration). A series of strain-controlled, 1-g small-scale laboratory tests were undertaken on piles with and without a square steel plate attached. The piles were driven in dry, loosely packed, uniform sand. Two plates were used, one with a breadth equal to two times the diameter of the pile (2D) and the other with a breadth equal to three times the diameter of the piles (3D). A 20% increase in capacity was recorded for the 2D plate, and a 110% increase in capacity was recorded for the 3D plate when compared to the pile without an attached steel plate. The back-analysis of the results allowed the derivation of a new expression to calculate the capacity of bearing plates and plot its load-settlement profile, which accounted for the effects of sands compaction and dilation. By extrapolating the findings of these tests to a hypothetical scenario, a model design problem was described where the length of a pile can be reduced by 20% to 60% (depending on the load) by using a plate attached to the pile. The results of this study can help designers to minimise penetration depth; thus, achieving a more economical and sustainable design.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

scholarly journals Analysis of Operational Efficiencies and Costs for Extracting Thinned Woods in Small-Scale Forestry, Nasunogahara Area, Tochigi Prefecture, Japan

2020 ◽  
Vol 3 (1) ◽  
pp. 61
Author(s):  
Kazuhiro Aruga
Keyword(s):  
Transportation Costs ◽  
The Other ◽  
Small Scale ◽  
Light Truck ◽  
Operation Costs ◽  
Other Hand ◽  
Light Trucks ◽  
The Cost ◽  
Manual Extraction ◽  
Truck Transportation

In this study, two operational methodologies to extract thinned woods were investigated in the Nasunogahara area, Tochigi Prefecture, Japan. Methodology one included manual extraction and light truck transportation. Methodology two included mini-forwarder forwarding and four-ton truck transportation. Furthermore, a newly introduced chipper was investigated. As a result, costs of manual extractions within 10 m and 20 m were JPY942/m3 and JPY1040/m3, respectively. On the other hand, the forwarding cost of the mini-forwarder was JPY499/m3, which was significantly lower than the cost of manual extractions. Transportation costs with light trucks and four-ton trucks were JPY7224/m3 and JPY1298/m3, respectively, with 28 km transportation distances. Chipping operation costs were JPY1036/m3 and JPY1160/m3 with three and two persons, respectively. Finally, the total costs of methodologies one and two from extraction within 20 m to chipping were estimated as JPY9300/m3 and JPY2833/m3, respectively, with 28 km transportation distances and three-person chipping operations (EUR1 = JPY126, as of 12 August 2020).

Mining discriminative patches for script identification in natural scene images

2021 ◽  
Vol 40 (1) ◽  
pp. 551-563
Author(s):  
Liqiong Lu ◽  
Dong Wu ◽  
Ziwei Tang ◽  
Yaohua Yi ◽  
Faliang Huang
Keyword(s):  
Neural Networks ◽  
Experimental Results ◽  
The Other ◽  
Natural Scene ◽  
Fixed Size ◽  
Script Identification ◽  
Aspect Ratios ◽  
Novel Approach ◽  
Public Datasets ◽  
Natural Scene Images

This paper focuses on script identification in natural scene images. Traditional CNNs (Convolution Neural Networks) cannot solve this problem perfectly for two reasons: one is the arbitrary aspect ratios of scene images which bring much difficulty to traditional CNNs with a fixed size image as the input. And the other is that some scripts with minor differences are easily confused because they share a subset of characters with the same shapes. We propose a novel approach combing Score CNN, Attention CNN and patches. Attention CNN is utilized to determine whether a patch is a discriminative patch and calculate the contribution weight of the discriminative patch to script identification of the whole image. Score CNN uses a discriminative patch as input and predict the score of each script type. Firstly patches with the same size are extracted from the scene images. Secondly these patches are used as inputs to Score CNN and Attention CNN to train two patch-level classifiers. Finally, the results of multiple discriminative patches extracted from the same image via the above two classifiers are fused to obtain the script type of this image. Using patches with the same size as inputs to CNN can avoid the problems caused by arbitrary aspect ratios of scene images. The trained classifiers can mine discriminative patches to accurately identify some confusing scripts. The experimental results show the good performance of our approach on four public datasets.

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