Volume Displacement Effects on Pile Capacity in Loose Sand

1973 ◽  
Vol 10 (4) ◽  
pp. 645-647
Author(s):  
Eli I. Robinsky ◽  
Christopher B. H. Cragg

Preliminary tests in the new large-scale testing facility at the University of Toronto reveal that bearing capacity on a pile volume basis is more efficiently developed by a long slender pile or a group of short slender piles than by a pile of larger diameter. The authors attribute this to increased arching in the soil around the pile of greater volume displacement, believing arching buffers the pile from the effects of lateral soil pressure.

2016 ◽  
Vol 32 (2) ◽  
pp. 1261-1279
Author(s):  
Tarek Abdoun ◽  
Waleed El-Sekelly ◽  
Ricardo Dobry ◽  
Sabanayagam Thevanayagam ◽  
Marcelo Gonzalez

Centrifuge and large-scale testing in geotechnical engineering are very useful tools for modeling soil behavior under different loading conditions, particularly under earthquake loading. The paper presents an extensive database of nine centrifuge and large-scale liquefaction experiments performed both at the geotechnical centrifuge testing facility at Rensselaer Polytechnic Institute (RPI) and the large-scale testing facility at the University at Buffalo (UB). The database described herein was generated using the NEEShub online DataStore tool under the name “CENSEIS: Centrifuge and Large (Full)-Scale Modeling of Seismic Pore Pressures in Sands” (DOI: http://dx.doi.org/10.4231/D3GF0MX4F ). The paper discusses the tools and materials used in the experiments along with an explanation of each item in the database. Sample analyses are also presented in the paper to give an insight on the capabilities of the database for numerical and analytical applications. The paper is concluded with some possible applications along with tips and limitations of the database.


Author(s):  
Lori Stahlbrand

This paper traces the partnership between the University of Toronto and the non-profit Local Food Plus (LFP) to bring local sustainable food to its St. George campus. At its launch, the partnership represented the largest purchase of local sustainable food at a Canadian university, as well as LFP’s first foray into supporting institutional procurement of local sustainable food. LFP was founded in 2005 with a vision to foster sustainable local food economies. To this end, LFP developed a certification system and a marketing program that matched certified farmers and processors to buyers. LFP emphasized large-scale purchases by public institutions. Using information from in-depth semi-structured key informant interviews, this paper argues that the LFP project was a disruptive innovation that posed a challenge to many dimensions of the established food system. The LFP case study reveals structural obstacles to operationalizing a local and sustainable food system. These include a lack of mid-sized infrastructure serving local farmers, the domination of a rebate system of purchasing controlled by an oligopolistic foodservice sector, and embedded government support of export agriculture. This case study is an example of praxis, as the author was the founder of LFP, as well as an academic researcher and analyst.


2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Kaiyang Wang ◽  
Yanjun Shang

This paper examines the performance of a novel technology, vertical steel floral tube micropiles with double grouting. It is the combination of micropile technology and double grouting technology. A large-scale model tank was applied to impart horizontal bearing capacity, and the slope soil pressure and flexural performance of the micropile were investigated under four experimental conditions. The peak grouting pressure during the double grouting process was defined as the fracturing pressure of the double grouting, and it was positively correlated to the interval time between first grouting and secondary grouting. Compared with traditional grouting, double grouting increased the horizontal bearing capacity of the single micropile with the vertical steel floral tube by 24.42%. The horizontal bearing capacity was also 20.25% higher for the structure with three micropiles, compared with a 3-fold value of horizontal sliding resistance. In the test, the maximum bending moment acting on the pile above the sliding surface was located 2.0–2.5 m away from the pile top, and the largest negative bending moment acting on the pile below the slip surface was located 4.0 m away from the pile top. The ultimate bending moment of the single pile increased by 12.8 kN·m with double grouting, and the bending resistance increased by 96.2%. The experimental results showed that the double grouting technology significantly improved the horizontal bearing capacity of the micropile with the steel floral tube, and the soil reinforcement performance between piles was more pronounced. Also, the shear capacity and the flexural capacity were significantly improved compared with the original technology.


2014 ◽  
Vol 996 ◽  
pp. 417-423 ◽  
Author(s):  
Arne Kromm ◽  
Thomas Kannengiesser

Results obtained from laboratory tests mostly need to be verified under fabrication conditions in order to incorporate design specifics (joint configuration and restraint), which effect the residual stress state considerably. For this purpose, multi-pass sub merged arc welding was performed in a special large-scale testing facility. The impact of varying interpass temperatures could be proven in-situ by means of a pronounced stress accumulation during welding and subsequent heat treatment accompanied by stress determination using X-ray diffraction.


2013 ◽  
Vol 6 (3) ◽  
pp. 200-206 ◽  
Author(s):  
Matthias Baeßler ◽  
Werner Rücker ◽  
Pablo Cuéllar ◽  
Steven Georgi ◽  
Krassimire Karabeliov

2011 ◽  
Vol 38 (3) ◽  
pp. 319-330 ◽  
Author(s):  
Reem Sabouni ◽  
M.H. El Naggar

Circular precast concrete manholes are widely used in sanitary sewer and storm water systems. The lack of detailed technical information on them and the conservatism of their governing codes and standards call for a detailed investigation on them. The main objectives of this paper are to evaluate the state of strains in the precast concrete manhole and state of stresses in the soil beneath the base to be used in developing enhanced guidelines for the design of their bases. Three full-scale circular precast concrete manholes, two 1200 mm in diameter and one 1500 mm in diameter, were tested in the large-scale geotechnical testing facility (LSGTF) at the University of Western Ontario. Only one 1200 mm manhole base was reinforced. Twenty seven load tests were performed on the manholes, which involved loads representing the Ontario truck loads incorporated in the Canadian Highway Bridge Code. None of the manhole sections tested in the experimental program experienced any cracks. The test results showed that traffic loading had a small effect on the pressure under the manhole base. All three specimens could withstand the critical Ontario truck loads, even the non-reinforced ones.


2021 ◽  
Vol 28 ◽  
pp. 100517
Author(s):  
Buddhima Indraratna ◽  
Trung Ngo ◽  
Fernanda Bessa Ferreira ◽  
Cholachat Rujikiatkamjorn ◽  
Ameyu Tucho

1985 ◽  
Vol 22 (3) ◽  
pp. 267-276 ◽  
Author(s):  
G. G. Meyerhof ◽  
V. V. R. N. Sastry

The ultimate bearing capacity of instrumented vertical single rigid model piles in homogeneous loose sand and soft clay under vertical eccentric and central inclined loads has been investigated. The results of these load tests provide a more realistic lateral soil pressure distribution on the pile shaft and better theoretical estimates of pile capacity under pure moment and under horizontal load. For intermediate eccentricities and inclinations of the load, the bearing capacity can be obtained from simple interaction relationships between the axial load and moment capacities and between the axial and horizontal load capacities, respectively. The influence of lateral soil pressures due to installation of displacement piles in clay is examined in relation to the ultimate load of the pile. The analyses are compared with the results of model tests and some field case records. Key words: bearing capacity, clay, eccentric loading, horizontal load, instrumentation, model test, pile, sand.


1987 ◽  
Vol 32 (9) ◽  
pp. 768-772 ◽  
Author(s):  
H.C. Stancer ◽  
C. Mellor ◽  
L.R. Weitkamp ◽  
T. Jorna ◽  
C. Flood ◽  
...  

This report constitutes the Newfoundland component of a large scale replication study to assess the relationship of HLA to affective disorders; the Ontario component will be published subsequently. In a collaborative study between the University of Toronto, Memorial University and the University of Rochester, first degree family members of Probands with major affective disorder in Newfoundland were assessed for the lifetime presence of psychiatric disorder; their blood was also typed for Human Leucocyte Antigens (HLA). Because of the high rate of refusal to participate, only 10 Newfoundland families could be assessed completely. While this number of families is too small to evaluate the role of HLA as a marker of susceptibility to affective disorder, the results will be added to those of the larger Ontario component. Some problems of conducting research in communities similar to those found in Newfoundland are briefly discussed in the context of characteristics of the Probands in the study group as compared with those of subjects who refused entry into the study.


Author(s):  
Alan Chong ◽  
Lisa Romkey

This work outlines the process of testinginter-rater reliability in rubrics for large scaleundergraduate independent projects; more specifically,the thesis program within the Division of EngineeringScience at the University of Toronto, in which 200students work with over 100 supervisors on anindependent research project. Over the last few years,rubrics have been developed to both guide the students inthe creation of their thesis deliverables, and to improvethe consistency of supervisor assessment. To examineinter-rater reliability, 12 final thesis reports wereassessed using the course rubric by the two generalistexperts, who have worked extensively with the thesiscourse and designed the rubrics, alongside the projectsupervisor. We found substantial agreement between thetwo generalist experts, but only fair agreement betweenthe generalist experts and the supervisors, suggesting thatwhile the rubric does help towards developing a commonset of expectations, there may be other aspects of thesupervisor’s assessment practice that need to beconsidered.


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