Foundation Design Problems of Some Bridges near Welland, Ontario

1975 ◽  
Vol 2 (2) ◽  
pp. 193-208
Author(s):  
R. M. Isaacs ◽  
S. T. Maitland ◽  
A. M. Mirza
Keyword(s):  
Skin Friction ◽  
Coal Tar ◽  
Large Diameter ◽  
Highway Bridges ◽  
Lateral Loads ◽  
Foundation Design ◽  
Design Factor ◽  
Intimate Contact ◽  
Negative Skin Friction ◽  
Low Shear

Large-diameter piles socketed into bedrock support the abutments and piers of several large railway and highway bridges across the approach cuts of a tunnel near Welland, Ontario. The design of these piles was governed by the following considerations: (a) the large vertical and lateral loads involved, (b) the low shear strengths of the overburden and the low design factor of safety of the slopes of the approach cuts, (c) the effect of the construction of piers and abutments on the stability of the slopes, (d) the development of negative skin friction on the piles at the abutments and some piers, (e) chemical and micro-biological attack on steel, and sulfate attack on concrete by the constituents of the groundwater, (f) the low shear strength of the gypsum in the bedrock and its tendency to creep, and (g) the possibility that gypsum might be leached out of the bedrock as the groundwater regime changes.The piles used varied from 24 in. (61 cm) and 30 in. (76 cm) in diameter for the highway bridges to 48 in. (122 cm) in diameter for the railway bridges. Where settlement of the overburden was expected to occur, only groups of vertical piles were used and these were coated with coal tar to limit the maximum value of negative skin friction. As these piles also were required to resist large lateral loads, the steel casings used in construction were designed to contribute to the structural strength of the piles and were protected from chemical and microbiological attack by a coat of an epoxy resin beneath the coal tar. The design took into account the lateral resistance of the overburden and, where it was insufficient, that of the bedrock. This type of pile was installed in an overexcavated hole and the casing was concreted several feet into bedrock; where bedrock conditions warranted it, the vertical load on the pile was transferred to the rock by the wedge action of a tapered socket.Where negative skin friction was not a problem, combinations of raked and vertical piles were used. The contribution of the casing to the strength of the piles was ignored and the casings were not protected. Tapered sockets were used on some of these piles where rock conditions were unsatisfactory.All concrete was sulfate-resistant, and for casings socketed into bedrock a method of installation was used that ensured intimate contact of concrete with the casings and the surrounding bedrock.

scholarly journals ANALISIS MODEL KEGAGALAN RUMAH 2 LANTAI AKIBAT NEGATIVE SKIN FRICTION DAN CURAH HUJAN YANG TINGGI

2021 ◽  
Vol 4 (3) ◽  
pp. 623
Author(s):  
Jeanfrie Chandra ◽  
Chaidir Anwar Makarim
Keyword(s):  
Skin Friction ◽  
Soft Soil ◽  
Residential Building ◽  
Frictional Resistance ◽  
Slope Instability ◽  
Foundation Design ◽  
Negative Skin Friction ◽  
Soil Subsidence ◽  
Modeling Analysis

ABSTRACTOne of the problems that appear in a project is the presence of soft soil. In projects with soft soil types, it is necessary to manage the soil to increase the bearing capacity of soil. Soil subsidence on soft soil causes friction between the soil and the pile blanket, called the negative skin friction. Negative skin friction should not be neglected because it exerts a large enough force on the load that the pile must support. In addition, in designing an engineer must also pay attention to the optimal rainfall that will occur during the construction of a project and after that has an impact on the quality of the soil and foundation used. The topography of a project also needs to be considered, building a house on the edge of a slope can cause problems with slope instability. Increasing the load on the edge of the slope can reduce the safety factor of a slope. In this study, a modeling analysis will be carried out on a 2-story residential building that causes the house to collapse due to failure of the foundation design, the existence of negative frictional resistance on soft soil, and slope stability. ABSTRAKSalah satu permasalahan yang muncul pada suatu proyek adalah adanya tanah lunak. Pada proyek dengan jenis tanah lunak, perlu dilakukan perbaikan tanah untuk meningkatkan daya dukung tanah. Penurunan tanah pada tanah lunak menyebabkan gesekan antara tanah denan selimut tiang yang disebut fenomena tahanan friksi negatif. Tahanan friksi negatif tidak boleh diabaikan karena memberikan gaya yang cukup besar terhadap beban yang harus ditopang oleh tiang. Oleh karena itu, seorang insinyur harus memperhatikan dan mengetahui mengenai perilaku tanah lunak. Selain itu dalam mendesain, seorang insinyur juga harus memperhatikan mengenai curah hujan optimal yang akan terjadi selama pengerjaan suatu proyek dan setelahnya yang berdampak pada kualitas tanah dan fondasi yang digunakan. Topografi suatu proyek juga perlu diperhatikan, membangun rumah di tepi lereng dapat menyebabkan permasalahan pada ketidakstabilan lereng.  

scholarly journals Downdrag Measurements on a 160-Ft Floating Pipe Test Pile in Marine Clay

1972 ◽  
Vol 9 (2) ◽  
pp. 127-136 ◽  
Author(s):  
M. Bozozuk
Keyword(s):  
Skin Friction ◽  
Compressive Load ◽  
Marine Clay ◽  
Positive Skin ◽  
Negative Skin Friction ◽  
Pore Pressures ◽  
Excess Pore Pressures ◽  
Test Pile ◽  
Excess Pore

Large negative skin friction loads were observed on a 160 ft (49 m) steel pipe test pile floating in marine clay. The test pile was driven, open-ended, on the centerline of a 30 ft (9 m) high granular approach fill on the Quebec Autoroute near Berthierville. Since the installation was made in 1966 the fill has settled 21 in. (53 cm), dragging the pile down with it. Negative skin friction acting along the upper surface of the pile was resisted by positive skin friction acting along the lower end as it penetrated the underlying clay. Under these conditions the pile compressed about [Formula: see text] (2 cm). Analysis of the axial strains indicated that a peak compressive load of 140 t developed at the inflection point between negative and positive skin friction 73 ft (22 m) below the top of the pile. Negative and positive skin friction acting on the upper surface of the pile exceeded the in situ shear strength and approached the drained strength of the soil where excess pore water pressures had dissipated. At the lower end where the positive excess pore pressures were high and relative movement between the pile and the soil was large, the positive skin friction approached the remoulded strength as measured with the field vane. Skin friction was increasing, however, as positive escess pore pressures dissipated.This paper shows that skin friction loads are related to the combination of (a) in situ horizontal effective stresses, (b) horizontal stresses due to embankment loads, and (c) horizontal stresses due to differential settlement of the fill.

Evaluation of Negative Skin Friction on Bridge Abutment Piles

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Osama Drbe
Keyword(s):  
Skin Friction ◽  
Pore Water Pressure ◽  
Design Method ◽  
Water Pressure ◽  
Strain Gauges ◽  
Total Stress ◽  
Vibrating Wire ◽  
Negative Skin Friction ◽  
Drag Forces ◽  
Wire Strain

Piles are used to transfer loads of structures to deeper and stronger soil layers through skin friction and/or end bearing. Surcharge loads, site grading, or dewatering may induce downward movement of soil adjacent to piles installed in a compressible medium. This movement creates negative skin friction stresses acting downward at the pile-soil interface, which applies additional loads “drag forces” to the pile causing a maximum axial load in the pile shaft at the “neutral plane”. To evaluate the development of drag forces, a comprehensive field monitoring program was conducted over four years for three instrumented abutment H-piles as part of a three-span bridge project. The soil settlement and changes in pore water pressure in the soil adjacent to the piles due to the construction of an approach embankment were monitored using multiple-point extensometers and vibrating wire piezometers. The piles’ elastic settlement and strains were measured using single-point extensometers and vibrating wire strain gauges. The field measurements are presented and discussed in terms of responses time histories and load distribution along one pile shaft. In addition, the calculated forces from vibrating wire strain gauges are compared with the unified design method prediction considering the total stress method (α-method) for cohesive soils. The results show that the maximum drag force was developed after the complete dissipation of excess pore water pressure and that the location of neutral plane varied during the embankment construction stages. Employing the total stress method in the unified design method provided a reasonable prediction of the drag force and the neutral plane’s location.

Research on Negative Skin Friction on Pile by a Simple Model Experiment

2014 ◽  
Vol 580-583 ◽  
pp. 693-696
Author(s):  
Ting Huang ◽  
Jin Hai Zheng ◽  
Wei Ming Gong
Keyword(s):  
Skin Friction ◽  
Model Test ◽  
Soil Surface ◽  
Test Methods ◽  
Negative Skin Friction ◽  
Experimental Scheme ◽  
Test Conditions ◽  
Surcharge Load ◽  
Conventional Test ◽  
Pile Model

Accompanied by the substantive construction of domestic ports, the negative skin friction on pile becomes a common problem. In order to provide references for the related experiment research in the future, the designs of model experiments reported in the literatures were emphatically analyzed and compared. Compared to conventional pile model test, the model test on negative skin friction on pile needs to apply load on soil surface and it is difficult to simulate large surcharge by conventional test methods. An experimental scheme which could produce large surcharge load by conventional test conditions is given in this paper. Pile stress, displacement of pile top and layered settlement of soil was tested under different surcharge level. The depth of neutral point and the group effect of NSF are discussed.

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