نصر نوري ابراهيم سلمان

Integral abutment bridges (IABs) have been gaining wide popularity in the United States and neighboring countries due to the rapid increase in maintenance costs associated with conventional bridges. The elimination of expansion joints in IABs allows the thermally induced lateral demand in the superstructure to be transferred to the supporting piles. This paper aims to study the behavior of steel H-piles supporting IABs through a detailed nonlinear finite element analysis that was calibrated and validated against available experimental data. A total of 30 models were established to examine the effect of various parameters (pile size, pile orientation, pile material yield strength, pile equivalent cantilever length, and axial compressive load) on piles supporting jointless bridges subjected to a combined axial load and lateral cyclic displacement amplitude.

This paper presents an experimental work of using crushed glass mixed with the poorly graded sandy soil to investigate the possibility of shear strength parameters improvement using the direct shear test. The crushed glass is sieved and prepared for seven sets of percentages, the collected percentages of crushed glass represented a mix of glass retained on sieves No. 4, No. 8, No. 30, No. 100, and No. 200 and were added as a weight ratio of the sample for many cases. The main results of this work show that the mixing 10% of crushed glass for sieves No. 8, No. 200, and No. 50 increase the angle of internal friction of poorly graded sand (Ø˚) about 15%, 3%, and 29% respectively, and mixing 10% of crushed glass retained on sieve No. 4 decrease Ø˚ about 40%.

The displacement of a loaded pile could be vertical (axial) or horizontal (lateral); these displacements are sensitive to groundwater presence within the soil mass. This paper presents a theoretical study to investigate vertical and horizontal displacement of piles embedded in a clayey soil for different levels of groundwater under the ground surface. The study was performed using the commercial finite element package PLAXIS-3D. Three diameters of the concrete piles were considered: 0.5, 0.75 and 1 m, and were subjected to 1,000 kN axial load. The effect of 0, 5, 10, 15 and 20 m groundwater along the 20 m pile in length from the ground surface on the vertical and horizontal displacements was investigated. The results indicated that the vertical and horizontal displacements increase when the ground water level increases towards the base of pile.

In this paper, a finite element (FE) analysis is carried out on a beam to column welded connections with multiple hexagonal web openings. The openings are distributed along the length of the beam which is subjected to cyclic loading protocol proposed by the SAC and FEMA 350 (2000). This study focuses on the interaction of the connections from columns to the perforated beam and mobilization of stresses. Two parameters were addressed: the distance from the face of the column (S), and the web opening spacing (So) including closely spaced opening. The study revealed that the design of mostly controlled reduced web section (RWS) connections should be fundamentally based on the distance of the first opening from the face of the column. Three values of the distance (S) are presented (200 mm, 350mm, and 520 mm).

Integral abutment bridges (IABs) are a special type of bridges that are built free of joints on the superstructure to overcome the undesirable consequences associated with conventional jointed bridges. Despite of the proven advantages of IABs, no consensus exists among bridge engineers about design guidelines. This paper presents a parametric study validated to a field monitored concrete IAB using a three-dimensional finite-element model to study the parameters that affects the bridge response. Bridge length, pile size and orientation, and soil type were included in the study. Bridge components were simulated using 3D solid elements for best reflection of the real behavior of the IAB. Nonlinear p-y method was employed to model soil-pile and soil-abutment interactions. Several shrinkage models, earth pressure theories and temperature distribution across the bridge superstructure were considered in simulating the field response of the IAB. The outcomes of the calibration process were utilized in building sound models for the parametric study. The soil stiffness around the pile was found to has more impact than the pile orientation on the pile displacement. Pile stresses were found to be proportional to the soil stiffness and inversely proportional to the pile stiffness. Moreover, the maximum stresses occurred within the middle segment of the pile rather than the pile-abutment interface due to apparent abutment rotation. The study promotes understanding of important facts which could assist in a better IAB design.

Integral abutment bridge (IAB) length is limited by the lateral displacement capacity of the piles supporting the bridge. This paper presents a numerical study calibrated to experimental tests to investigate the lateral displacement capacity of H-piles (HPs) in integral abutment bridges subjected to combined axial load and cyclic displacement amplitude. Eleven steel HP sections with two axis orientations (weak and strong) commonly used in IAB construction practice were investigated. Several soil types surrounding the piles were examined to investigate the effect of soil stiffness on displacement capacity. Buckling displacement capacity was found to be an average of 3 and 1.5 times the plastic moment capacity for weak and strong axis bending, respectively. It was revealed that soil stiffness has a significant impact on the onset of local buckling of the piles. Based on computed pile displacement capacities, the maximum length of integral abutment bridges was estimated and compared with the current practice of US departments of transportation.