Graduation Semester and Year




Document Type


Degree Name

Doctor of Philosophy in Civil Engineering


Civil Engineering

First Advisor

Sahadat MD Dr. Hossain


RPPs have been in use as a sustainable and effective technique to stabilize and reinforce weak ground for geotechnical purposes. Application of RPP in stabilization of slopes and improvement of load carrying capacity of foundation soil has yielded tremendous results. However, to facilitate the seamless integration of RPPs in design of foundation requires the load carrying capacity of RPP to be known. As RPP has been in use for both its vertical and lateral load carrying capacity, exploration of the load capacity of this material is essential. The objective of the study is to determine the load carrying capacity of RPPs in order to develop design charts that can be used towards designing foundation for improving the vertical and lateral load carrying capacity of soil. This endeavor involved an extensive field-testing program, which encompassed the determination of the vertical and lateral load capacities of RPPs in various sizes and arrangements. A total of 16 full scale vertical load tests were conducted of four different sizes (10 cm x 10 cm, 15 cm x 15 cm, 25 cm x 25 cm and 30 cm x 30 cm) of single RPPs and groups 10 cm x 10 cm and 15 cm x 15 cm RPPs arranged in two different spacings of 0.6 m and 0.9 m. 16 lateral load tests were conducted on RPPs of 10 cm x 10 cm, 15 cm x 15 cm and 25 cm x 25 cm sizes embedded in three depths of 2.7 m, 2.4 m and 2.1 m into the ground. Based on the load test data, an empirical and analytical approach was undertaken for determining the vertical load capacity of the single and group RPPs, whereas p-y analysis was undertaken for determination of ultimate lateral load capacity of RPPs. The average vertical load capacity ranged from 50 kN to 207 kN for the single RPPs whereas for RPPs arranged in a group had load capacity ranging from 193 kN to 477 kN. The lateral load capacity of RPP was found much less than its vertical load capacity and ranged from 16 kN to 125 kN for varying sizes and embedment depths. Furthermore, the load settlement response was assessed through numerical modeling using finite element software PLAXIS 3D for the vertical load tests, and the LPILE software was employed for the lateral load test response. A parametric study was conducted using the calibrated model to evaluate the influence of foundation soil strength, RPP size, spacing and embedment depth on settlement due to application of load. In total, 540 different scenarios involving various sets of data were investigated using numerical models to develop design charts for predicting settlement or deformation responses to applied load. Moreover, a prediction model was established using MATLAB to forecast the settlement or deformation responses of different RPPs under different site-specific soil conditions.


Load capacity, Recycled plastic pin, Vertical load capacity, Lateral load capacity


Civil and Environmental Engineering | Civil Engineering | Engineering


Degree granted by The University of Texas at Arlington