Drilled Shaft Wall

Capital Metro Crestview Station Underpass

Project Background

Crestview is a busy commuter station run by Capital Metro in Austin, Texas. The intersection experiences heavy traffic, causing countless hours of delays and frequent auto accidents. Congestion occurs when passing trains restrict vehicle movement at the intersection. It impacts Metro buses and is especially problematic during peak traffic hours and public events frequently held in the area. 

Capital Metro identified a need to resolve these pain points and increase the existing system’s efficiency. Their conceptual plan was to separate the metro and freight traffic by constructing an underpass for the railway system. HVJ was selected to provide drilling, laboratory testing, geotechnical engineering analysis, and recommendations for below-grade retaining structures for the proposed underpass. 

Practice: Geotechnical Engineering 

Sector:  Rail & Transit Public Transportation

Location: Austin, Texas

Services: Geotechnical Engineering Analysis and Recommendations, Field Exploration Services, Laboratory Testing Services

Crestview Station

The Problem

The working area for the project was very narrow, and excavating beyond thirty feet is a considerable proposition with many associated intricacies.  Furthermore, it was costly and time-consuming to begin drilling as we needed to coordinate with many stakeholders, including CapMetro, the City of Austin, and the Texas Department of Transportation, to secure access to the drill boring locations. The intersection had numerous utilities on both sides of the railroad, and we had limited windows in which field operations were possible due to the active railroad.   

The Goal

Our team needed to draw on their industry expertise and experience with complex, non-conventional projects to complete the investigation and provide a reliable recommendation to make the project possible. We worked closely with multiple stakeholders to obtain numerous permits, complete safety training certifications for all field personnel, and meet additional insurance requirements.

Our goal was to retrieve soil and rock testing samples, conduct a thorough analysis, and discuss options with the client so that the structural engineer could select a retaining wall system that could be constructed within the narrow confines of the railroad. We had to provide solutions for a deep-cut retention system without using conventional shoring or benching methods because of the limited width of the railroad and the inability to make deep cuts to construct the underpass. This also required a comprehensive understanding of the Austin Chalk, a clay and marl geologic formation. 

Our Solution

We maintained constant communication with the structural team and worked hand-in-hand with other engineers to complete the analysis. Our proactive communication and extensive knowledge of the Austin Chalk ensured a smooth process. When making deep excavations beyond 30 feet with a tightly limited railroad encasement, we knew that every inch would count in developing a robust, sustainable design for the underpass retention wall. 

To determine the best options, we modeled geometric sections and conducted analysis interactions. We presented viable options to the client and recommended the most feasible option with significant strength while avoiding overburdening materials. Our recommended drilled shaft wall proposed retention system design allowed for the safe construction of the underpass for two rail lines.

The Results

Our comprehensive recommendation considered all aspects necessary for a successful outcome. By thoroughly analyzing the site conditions and providing recommendations for the drilled shaft wall proposed retention system, the client was confident to proceed with the project's next phase. Our plan accounted for construction phasing, considering the limited space restrictions and the need to minimize disruptions to area landowners.

We value working on projects that positively impact communities and are glad to have played a critical role in bringing this project from concept to reality. Upon completion, community residents will benefit from the countless hours saved due to reduced delays and accident rates.


Crestview 1

Crestview 2


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