Details:

Alternative Title:
A numerical investigation into the performance of the soil nail wall and pile foundation at the Swift Delta I-5 Interchange : final report.
Creators:
Smith, Trevor D.
Corporate Creators:
Portland State University. Dept. of Civil Engineering
Corporate Contributors:
United States. Federal Highway Administration ; Oregon. Dept. of Transportation. Research Unit
United States. Federal Highway Administration ; Oregon. Dept. of Transportation. Research Unit Less -
Subject/TRT Terms:
[+]
Bridges Computer Programs Earth Walls Finite Differences Finite Element Method Performance Evaluations Pile Foundations Soil Nailing Soil Nail Walls
Publication/ Report Number:
FHWA-OR-RD-95-15
Resource Type:
Tech Report
Geographical Coverage:
Portland (Oregon)
Corporate Publisher:
Portland State University
Abstract:
Finite Difference Methods (FDM) and Finite Element Methods (FEM) studies are reported studying the soil nail wall construction at the Swift Delta I-5 Interchange bridge reconstruction in North Portland, Oregon. Five layers of soil nails were installed between existing bridge supporting pipe piles, and a shotcrete finished face applied to stabilize the fill sand. Instrumentation on the project at two sections, S1 and S2, included strain gages on the nails, and on a single pile at S1, load cells on the nail heads, inclinometers in the wall and in the fill at S2 outside of the bridge, and tiltmeters with an extensometer on the pile cap at S1.

Some interpretive comments are made on the measured wall and nail readings, which are used to back calculate possible earth pressures for FDM techniques. The lateral load program COM624P is used to explore the limitations for FDM techniques for direct pile analysis in Swift Delta's soil/nail/pile system. Two dimensional FEM analysis is conducted by a new code, Finite Element analysis of NAILS (FENAIL), written specifically for this study. Modeling in both linear elasticity, and nonlinear plasticity, is reported at the bridge instrumented section S1 and the wall section S2 outside the bridge footprint. The model features included: full geostatic conditions, excavation modeling sequences and nail activation with beam elements. An innovative interference element is introduced to link the "out of mesh" pile to the soil and nail model, and generate pseudo 3 dimensional (3D) effects.

A full 3D FEM analysis is reported of the top soil nail, adjacent pile and soil, by the code ABAQUS running on a CRAY MPX supercomputer. Linear elastic, anisotropic elastic and a single elastic plastic model were completed to study interaction and global stiffness contributions from the pile and nail.

Based on FENAIL work overall replication of the Swift Delta soil nail wall is good. In general, only limited pile influence can be seen and deflections and stresses do not appear highly sensitive to the piles presence. The reinforced soil mass behaves similar to a reinforced wall structure without piles. The lack of any significant pile influence is also found in the 3D ABAQUS study under nail tension conditions. However, the pile's lateral load stiffness response is improved by nailing of the soil mass.


Format:
PDF
Funding:
SPR #5292
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:0307a3bc2f75ab0fc587a7bcd366094a03da56585d8e9afb1ff7ffb39432f4bb
Download URL:
https://rosap.ntl.bts.gov/view/dot/22874/dot_22874_DS1.pdf
File Type:

Supporting Files

• No Additional Files

More +