Effect of Casing and High-Strength Reinforcement on the Lateral Load Transfer Characteristics of Drilled Shaft Foundations

2019 ◽  
Vol 145 (9) ◽  
pp. 04019056 ◽  
Author(s):  
Qiang Li ◽  
Armin W. Stuedlein ◽  
Antonio Marinucci
Keyword(s):  
Load Transfer ◽  
High Strength ◽  
Lateral Load ◽  
Drilled Shaft ◽  
Transfer Characteristics ◽  
Drilled Shaft Foundations

Torsional Load Transfer of Drilled Shaft Foundations

2017 ◽  
Vol 143 (8) ◽  
pp. 04017036 ◽  
Author(s):  
Qiang Li ◽  
Armin W. Stuedlein ◽  
Andre R. Barbosa
Keyword(s):  
Load Transfer ◽  
Drilled Shaft ◽  
Torsional Load ◽  
Drilled Shaft Foundations

Full-scale coupled torsion and lateral response of mast arm drilled shaft foundations

2016 ◽  
Vol 53 (12) ◽  
pp. 1928-1938 ◽  
Author(s):  
Sudheesh Thiyyakkandi ◽  
Michael McVay ◽  
Peter Lai ◽  
Rodrigo Herrera
Keyword(s):  
Lateral Load ◽  
Full Scale ◽  
Load Test ◽  
Wind Loading ◽  
Drilled Shaft ◽  
Penetration Test ◽  
Lateral Resistance ◽  
Torsional Resistance ◽  
Drilled Shaft Foundations ◽  
The Impact

Drilled shaft foundations supporting mast arm assemblies are subjected to significant torsion and lateral load during severe wind loading (e.g., hurricane). Past centrifuge studies in granular soils suggest that the design of such foundations should be performed for a coupled load case, since the lateral resistance is considerably reduced by the concurrent application of torsion. However, current design practice still considers lateral load and torsion independently due to the lack of field verification of centrifuge results. This paper reports on a full-scale test program to investigate the coupled load behavior of drilled shafts. A novel load test setup (with a heavy-duty mast arm assembly) and instrumentation were used for the combined torsion and lateral loading (e.g., wind loading). The study revealed a significant reduction in lateral resistance due to the influence of torque as observed from previous centrifuge studies. Torsional resistance was reduced (approximately 20%) by the impact of lateral load when compared with the anticipated torsional resistance based on unit skin friction values, derived from the axial load test results (i.e., no influence of lateral load). A comparison of measured torsional resistance during the combined loading with the predicted values using different approaches was also made. O’Neill and Hassan’s beta (β) method (sand) and alpha method (clay) are found to predict the torsional resistance reasonably well (±10%), while all other methods based on the standard penetration test and cone penetration test considered in the study overpredicted or underpredicted the resistance.

Mandibular Implant-Supported Overdenture: An In Vitro Comparison of Ball, Bar, and Magnetic Attachments

2013 ◽  
Vol 39 (3) ◽  
pp. 302-307 ◽  
Author(s):  
V. Manju ◽  
T. Sreelal
Keyword(s):  
Stress Distribution ◽  
Strain Gauge ◽  
Load Transfer ◽  
Implant Surface ◽  
Transfer Characteristics ◽  
Ball Bar ◽  
Different Types ◽  
Dial Gauge ◽  
In Vitro Comparison

In an implant-supported overdenture, the optimal stress distribution on the implants and least denture displacement is desirable. This study compares the load transfer characteristics to the implant and the movement of overdenture among 3 different types of attachments (ball-ring, bar-clip, and magnetic). Stress on the implant surface was measured using the strain-gauge technique and denture displacement by dial gauge. The ball/O-ring produces the optimal stress on the implant body and promotes denture stability.

Exploration of novel faying surface treatment for high-strength frictional bolted joints to enhance its after-slip performance

2021 ◽  
Author(s):  
Hitoshi Moriyama ◽  
Ryo Sakura ◽  
Takashi Yamaguchi ◽  
Takai Toshikazu ◽  
Yuta Yamamoto
Keyword(s):  
Surface Treatment ◽  
Load Transfer ◽  
High Strength ◽  
Bolted Joints ◽  
Deformation Capacity ◽  
Slip Coefficient ◽  
Faying Surface ◽  
Treatment Concepts ◽  
Local Slip

<p>Welded joints is adopted rather than bolted joints for megastructure’s connections because the former can carry large force. However, the former has several problems, such as quality control of welding in situ, which the latter can solve. By contrast, as the load transfer ratio of each bolt becomes uneven proportionally to the number of bolts, local slip around extreme bolts occurs before the whole slip. Extreme bolts to which a large shear force is applied will break before other bolts. For utilizing the strength of all bolts, the problem is solved by improving shear deformation capacity in faying surface with novel surface treatment. Here, the treatment concepts were explored, and the coating’s effectiveness was evaluated through friction tests. The deformation capacity can be twice or more than that of conventional treatment, and the slip coefficient doesn’t depend on contact pressure. These features have the advantage to give stable slip behaviour.</p>

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