GEOTECHNICAL & STRUCTURAL ENGINEERING

ASC has over 40 years of proven experience in transportation project development and delivery globally. With expertise in planning, design, construction, and long-term support, our client-first solutions are tailored to the unique needs of each project and budget.  Pressure on transportation systems worldwide is mounting due to aging infrastructure, population growth, increased freight volumes, and funding limitations. Today’s challenge is to maintain the integrity and increase the capacity of existing facilities to meet this demand – economically, safely, and within the tight schedules required.

ASC’s broad-based Geotechnical & Structural Engineering project services include:

• Transportation
• Rail and transit
• Commercial and industrial projects
• Public buildings and infrastructure
• Water resources and flood control projects
• Airports and associated improvements
• Utilities and retention facilities

Some recent noteworthy projects include:

The $3.8 billion Silicon Valley Rapid Transit (SVRT) Project will extend the San Francisco Bay Area Rapid Transit (BART) System south from Fremont to the cities of Milpitas, San Jose, and Santa Clara, California.  The 16.3-mile extension will connect the Silicon Valley communities to the San Francisco Bay Area cities served by BART. The SVRT extension will include six passenger stations, three above and three below ground, a maintenance and vehicle storage facility, and the upgrading of the existing BART "core system" to permit integration of the SVRT extension into the existing rapid transit system.  The alignment is comprised of 11 miles of at-grade, elevated, and cut-and-cover track, and a 5-mile tunnel segment consisting of twin bores and a cut-and-cover crossover structure.

ASC provided Tunnel & System Value Engineering Services on this project for five years!

Dots Oyenuga, Ph.D., P.E. conducted a review of a Composite DSM / Concrete Wall VE Alternative proposed for use as a permanent wall on the project for the trench structures at Zones 5 and 6 (Contracts C203 and C202, respectively).  This review provides answers to specific questions posed by VTA on the Composite DSM / Concrete Wall as a viable permanent wall.  The concept is a refinement of the original concept and considers the potential cost benefit of using the current steel soldier pile reinforced DSM walls, in combination with a shotcrete wall section, as both permanent and temporary structural walls.

ASC was the Construction Geotechnical Engineer on the vibro-replacement along the Trans-Bay Tube at the Port of Oakland, which was conceived to prevent damage to the tube from the next big earthquake, as part of BART’s System-wide Seismic Retrofit Program.  ASC was in charge of verification of the ground improvement program, consisting of Grouting and stone column installations along the Trans-bay Tube.  ASC supervised all verification testing on the project, including CPTs; HCTs, LPTs and SPTs, etc.  ASC also provided verification of the efficacy of the grouting program.

Dr. Oyenuga was Project Manager; he also managed the soil-structure interaction task and the modeling effort (implemented with the Finite Element Program ADINA).  The Wharf and Embankment Strengthening Program (WESP) is a structural improvement plan for specified harbor terminals of the Port of Oakland driven by two initiatives – the “50 Federal Dredging Project”, and the “Seismic Risk-Reduction Plan”.

The former will result in a berth depth of –55 ft, prompting the Port to implement structural modifications and improvements to abutting wharves as well as perform embankment stabilization.  The Seismic Risk-Reduction Plan necessitated additional engineering analysis to determine current seismic risks for the Port’s waterfront components at the specified berths, including the acceptable level of seismic risk reduction improvements. The performance-based structural analysis approach incorporated 3D non-linear time histories.

Dr. Oyenuga managed a Methodology Comparison Study, implemented for the Port of Oakland, to provide approximate correspondence between two seismic analysis methods, enabling comparative evaluation of the seismic risk evaluation of, and facilitating seismic risk reduction planning for, the Port’s berths.  One methodology incorporated non-linear 3D time history analysis, while the other utilized simplified, 2D Pushover / Response Spectrum Analysis methodology.  The study examined the validity of assumptions used and the effects of these assumptions on the vulnerability evaluation of one of the existing APL berths.  The differences in methodology were examined by evaluating the seismic response of the structure.

Study on Piles with Missing Data; Port of Oakland:

Dr. Oyenuga managed studies on piles with missing pile-driving records for the Port of Oakland.  The study was conducted as a part of the Seismic Risk Evaluation Phase of Wharf and Embankment Strengthening Program, to estimate response of piles to lateral load.  The study employed Pile Integrity (PIT) Testing.

Dr. Oyenuga managed a parametric study conducted for the Port of Oakland.  A slice of Berth 63 wharf was modeled in detail to study the relative sensitivities of the system response to variations in input parameters, such as: pile length, soil properties, and a combination of these parameters.  Results of the study will provide guidance for developing retrofit strategies in the Seismic Risk Reduction phase of the Port’s Wharf and Embankment Strengthening Program.