By Vishal Patel, P.G., edited by Brian Heinzl, P.E.
More than 75 ASCE members and guests gathered at the Gaetano’s Banquet Restaurant on Thursday, February 23rd, 2017 for an ASCE Pittsburgh Section Geo-Institute Chapter meeting. Dr. Suresh K. Gutta, P.E. of American Geotechnical and Environmental Services, Inc. presented the lecture “New Baltimore Landslide Remediation – Design Perspective.” The presentation focused on monitoring an active landslide, remedial design methods, and construction observations.
In 1940 the Pennsylvania Turnpike was constructed mostly along the path of the original alignment of the old South Penn Railroad, and thus passed through the Borough of New Baltimore, PA, and the Allegheny Mountains. The original construction reactivated an ancient landslide, referred to as the ‘New Baltimore Slide’ that had occurred in the geologic past due to undercutting of the mountain slope by the Raystown Branch of the Juniata River, which lies in the valley just beyond the limits of the present Turnpike alignment. This reactivated slide zone extends to 800 feet along the roadway alignment and 1,500 feet upslope. An average of 60 feet of soil and bedrock overburden has been slowly sliding along a weathered clay-rich siltstone failure plane for over 70 years, resulting in a recorded movement of 13 feet and causing major cracks along the mountainside.
The current widening and the reconstruction of the Turnpike required the removal of the toe support of this active slide. Dr. Suresh Gutta talked about the how the design involved characterizing the failure mechanism, the challenges of installing geotechnical instrumentation in the rugged mountainous terrain, and the technologies used to record and report the data remotely. The talk also addressed the design treatments required to stabilize the slide mass, including the development of a specific sequence of construction, and safety systems necessary for the protection of traffic during construction. Construction of the remediation was completed in September 2016.
Attendees earned 1.0 PDH for the presentation.
The February meeting also brought out a number of the past Pittsburgh Geo-Institute Chairpersons. We seized the opportunity to capture a ‘geotechnical cross-section’ of these stewards of our professional society. Thank you all for your contributions in making our local Geo-Institute Chapter such a longstanding, successful program.
From left to right in the picture:
- William R. Adams Jr., PhD, PE, PG;
- Andrew T. Rose, PhD, PE;
- Don Splitstone, PE;
- Craig W. Steigerwald, PE;
- Suresh Gutta, PhD, PE;
- Brian F. Heinzl, PE;
- Sebastian Lobo-Guerrero PhD, PE;
- James V. Hamel, PhD, PE, PG.