Model Uncertainties in Foundation Design

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Naresh Samtani ◽  
Keyword(s):  
Drilled Shafts ◽  
Driven Piles ◽  
Mechanically Stabilized Earth ◽  
Model Uncertainties ◽  
Foundation Design ◽  
Soil Nail ◽  
Mse Walls ◽  
Braced Excavations ◽  
Helical Piles ◽  
Mechanically Stabilized

The book focuses on providing a foundation designer information on the model factor and its statistics for conventional foundation types such as shallow foundations, driven piles, and drilled shafts as well as special foundations such as spudcans and helical piles. Besides foundations, the book also provides information for other geostructures such as mechanically stabilized earth (MSE) walls, soil nail walls, pipes and anchors, slopes, and braced excavations.

Sonic echo and impulse response tests for length evaluation of soil nails in various bonding mediums

2008 ◽  
Vol 45 (7) ◽  
pp. 1025-1035 ◽  
Author(s):  
Shu-Tao Liao ◽  
Chin-Kuo Huang ◽  
Chung-Yue Wang
Keyword(s):  
Nondestructive Testing ◽  
Impulse Response ◽  
Field Tests ◽  
Drilled Shafts ◽  
Driven Piles ◽  
Soil Nails ◽  
Soil Nail ◽  
Testing Techniques ◽  
Nondestructive Testing Methods

The objective of this paper is to present the results of research for evaluating the installed lengths of soil nails with nondestructive testing methods. Two closely related methods, the sonic echo test and the impulse response test, both of which had been widely applied to assess the integrity of drilled shafts and driven piles, were evaluated to test their capabilities on soil nails. To carry out this study, soil nails of various lengths were embedded in different surrounding materials in the laboratory and then tested with both methods to predict their lengths. The surrounding materials studied in this research included soil and cement grout. Finally, field tests for in situ soil nails were carried out. The results indicated that the relative stiffness of the soil nail to the bond material plays a very important role in the success of testing. It is hoped that through this kind of study, the capability and limitation of using these nondestructive testing techniques to determine the installed lengths or to evaluate the bonding conditions of soil nails can be better understood.

Experimental analysis of large-scale pullout tests conducted on polyester anchored geogrid reinforcement systems

2017 ◽  
Vol 54 (5) ◽  
pp. 621-630 ◽  
Author(s):  
S.H. Sadat Taghavi ◽  
M. Mosallanezhad
Keyword(s):  
Large Scale ◽  
Mechanically Stabilized Earth ◽  
Height Ratio ◽  
Passive Resistance ◽  
Pullout Resistance ◽  
Pullout Tests ◽  
Mse Walls ◽  
Effective Performance ◽  
Mechanically Stabilized ◽  
New System

The pullout resistance of reinforcement, such as geogrids in mechanically stabilized earth (MSE) walls, includes the skin friction between the soil and solid geogrid surfaces. It also includes the bearing resistance against the transverse ribs, which has a greater influence on the production of pullout resistance. Taking the current limitations involved in producing woven polyester geogrids into consideration (i.e., the limited thickness of the transverse ribs), the amount of bearing resistance developed in front of transverse ribs is limited in the pullout mechanism. Thus, along with introducing an innovative and applied system, this research has endeavoured to demonstrate the effective performance of this new system in increasing the passive resistance — and thereby the pullout resistance — of standard geogrids. This new system, which is formed by adding steel transverse elements (a set of steel equal angles) to the ordinary polyester geogrids by means of nuts and bolts, is called an anchored geogrid (AG). The experimental results show that a spacing-to-height ratio of transversal elements equal to 5 gives the maximum pullout resistance for a polyester AG system in sandy soil used in the study. With an optimum arrangement, this system is capable of increasing the pullout resistance of the ordinary geogrid system by 65%. In addition, based on the plasticity solution, the pullout bearing failure mechanisms of a single isolated transverse element in the polyester AG system depend on overburden pressures.

scholarly journals Mechanically Stabilized Earth with Steel Reinforcement

2021 ◽  
Vol 9 (3) ◽  
pp. 135-141
Author(s):  
Magdi M. E. Zumrawi ◽  
Abubaker B. B. Barakat ◽  
Idris M. I. Abdalla ◽  
Rabab A. A. Altayeb
Keyword(s):  
Retaining Wall ◽  
Soil Reinforcement ◽  
Current Status ◽  
Mechanically Stabilized Earth ◽  
Steel Strips ◽  
Wall Structures ◽  
Backfill Soil ◽  
Mse Walls ◽  
Mechanically Stabilized

This paper presents the Mechanically Stabilized Earth (MSE) technique as a practical option for earth retaining wall structures. The literature pertaining soil reinforcement methods and their application in MSE walls were intensively reviewed. The present work focused on evaluating the performance of MSE walls with backfill soil reinforced by steel strips. Almolid square overpass bridge in Khartoum, which was constructed in 2015 with MSE walls as lateral support of the overpass ramps, was considered as case study. Based on field observations, the current status of the overpass bridge has proven that the use of MSE walls is successful and beneficial for sustainability of the overpass.  

scholarly journals Behaviour of Single and Group Helical Piles in Sands from Model Experiments

2019 ◽  
Vol 278 ◽  
pp. 03007
Author(s):  
Jongho Bak ◽  
Byung-hyun Choi ◽  
Junwon Lee ◽  
Jonghwan Bae ◽  
Kicheol Lee ◽  
...  
Keyword(s):  
Rotation Speed ◽  
Axial Loading ◽  
Complete Removal ◽  
Drilled Shafts ◽  
Load Test ◽  
Oil Sand ◽  
Driven Piles ◽  
Pile Installation ◽  
Helical Piles ◽  
Pile Load Tests

Mainly used foundations of oil sand plants are drilled shafts or driven piles. As environmental regulations become increasingly strict, complete removal of the foundation is becoming more important during the step of plant dismantling. However, it is difficult to remove completely drilled shafts or driven piles which are deeply installed to obtain more bearing capacity. Helical piles can be easily removed and recycled after use. This study analyses the behaviour of single and group helical piles in sands. For single helical piles, pile load tests of helical piles were conducted varying helix spacing, rotation speed and weight of axial loading during pile installation. The single pile tests determined the optimal helix spacing, rotation speed, weight of axial loading during pile installation. And then, pile load test of group helical piles was performed varying pile spacing from the centre place of upper connector based on the optimal installation conditions.

scholarly journals Mobile LiDAR for Scalable Monitoring of Mechanically Stabilized Earth Walls with Smooth Panels

2020 ◽  
Vol 10 (13) ◽  
pp. 4480
Author(s):  
Abdulla Al-Rawabdeh ◽  
Mohammed Aldosari ◽  
Darcy Bullock ◽  
Ayman Habib
Keyword(s):  
Data Acquisition ◽  
Performance Measures ◽  
Visual Inspection ◽  
Precast Concrete ◽  
Point Clouds ◽  
Mechanically Stabilized Earth ◽  
Qualitative Approaches ◽  
Transportation Corridors ◽  
Mse Walls ◽  
Mechanically Stabilized

Mechanically stabilized earth (MSE) walls rely on its weight to resist the destabilizing earth forces acting at the back of the reinforced soil area. MSE walls are a common infrastructure along national and international transportation corridors as they are low-cost and have easy-to-install precast concrete panels. The usability of such transportation corridors depends on the safety and condition of the MSE wall system. Consequently, MSE walls have to be periodically monitored according to prevailing transportation asset management criteria during the construction and serviceability life stages to ensure that their predictable performance measures are met. To date, MSE walls are monitored using qualitative approaches such as visual inspection, which provide limited information. Aside from being time-consuming, visual inspection is susceptible to bias due to human subjectivity. Manual and visual inspection in the field has been traditionally based on the use of a total station, geotechnical field instrumentation, and/or static terrestrial laser scanning (TLS). These instruments can provide highly accurate and reliable performance measures; however, their underlying data acquisition and processing strategies are time-consuming and not scalable. The proposed strategy in this research provides several global and local serviceability measures through efficient processing of point cloud data acquired by a mobile LiDAR system (MLS) for MSE walls with smooth panels without the need for installing any targets. An ultra-high-accuracy vehicle-based LiDAR data acquisition system has been used for the data acquisition. To check the viability of the proposed methodology, a case study has been conducted to evaluate the similarity of the derived serviceability measures from TLS and MLS technologies. The results of that comparison verified that the MLS-based serviceability measures are within 1 cm and 0.3° of those obtained using TLS and thus confirmed the potential for using MLS to efficiently acquire point clouds while facilitating economical, scalable, and reliable monitoring of MSE walls.

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