Our Team

GZ is assembled of a team including 30+ international experts across various disciplines including tunnel engineers, geotechnical engineers, geologists, tunnel inspectors, CAD technicians, and administrative staff.  Ranging from junior level to well-experienced, our team members represent GZ worldwide.


John Rudolf, P.E.

Chief Structural Engineer

Experience Summary
John Rudolf’s experience with the design and construction management of underground and above ground structures spans a career lasting over 5o years. Mr. Rudolf has been directly involved with the design and construction of the 106 miles of the Washington Metrorail system on multiple major infrastructure projects for over 30 years, including his contribution of approximately 15 miles of aerial structures and over 40 miles of subsurface structures for the system. Mr. Rudolf’s experience involves design and construction of various types of bridges and viaducts, including post-tensioned CIP and post-tensioned pre-cast Concrete Segmental Guideways. John’s tunneling experience includes the design and construction of various tunnels using conventional tunneling methods, including NATM, cut-and-cover, and TBMs, both in soft ground and rock with CIP as well as pre-cast concrete linings.


Günter Pohn

Senior Tunnel Engineer

Experience Summary
Günter Pohn has more than 20 years of experience in the planning, design, and supervision of underground public transit and highway projects. He specializes in NATM / SCL and cut-and-cover design in both soft ground and hard rock, as well as construction supervision, foundations, and rock mechanics. He is well-versed in cost and program estimates for various design stages of major tunnel projects. Mr. Pohn has managed the design efforts of multi-disciplinary teams on numerous large infrastructure projects integrating mechanical, electrical and ventilation systems with the overall design. He has a proven track record of delivering designs that adhere strictly to all budget and time constraints.


Ermin Stehlik

Senior Tunnel Engineer

Experience Summary
Ermin Stehlik has over 39 years of extensive experience in the design and construction supervision of major international tunneling schemes. During his career, Mr. Stehlik has gained specific knowledge and expertise in the design of underground structures, construction methods, and management of tunnel construction.


Walter Klary

Senior Tunnel – Geotechnical Engineer

Experience Summary
Walter Klary has more than fifteen years of extensive experience in geotechnical engineering and tunnel construction using various construction methods, including NATM / SEM and Tunnel boring Machine (TBM). He has worked on high profile international projects in Europe, Asia and USA in all ground conditions ranging from soft to hard rock. He is well experienced in difficult ground conditions and all aspects of tunneling, such as caverns, shafts and pressure tunnels.


Robert Wallner

Senior Tunnel – Geotechnical Engineer

Robert Wallner - Senior Tunnel Geotechnical EngineerExperience Summary
Robert Wallner has more than seventeen years of practical geotechnical experience in tunneling and civil engineering consulting for underground construction, foundations, and rock mechanics. He has been in charge of quality assurance and quality control, control of compliance with various standards and specifications, materials testing, and verification and validation of systems for a wide variety of complex international tunnel projects. As Senior Tunnel Engineer and Project Manager, he has fulfilled organizing, planning, and scheduling functions, and has gained a detailed understanding of both contract administration and project control.


Andrés Giraldo

Senior Project Engineer

Experience Summary
Mr. Andrés Giraldo has over seven years of experience in civil engineering, ranging from basic technical duties to the responsibilities of Senior Bids and Commercial Coordinator. Andrés possesses valuable project management skills, experience in the preparation of construction projects (including planning and budgeting), and commercial experience in processes for new projects in both the public and private domains, as well as knowledge in public-private partnership (PPP) planning and structuring with Capex analysis for concession projects. Additionally, Mr. Giraldo’s status as a native Spanish speaker with fluency in English and proficiency in Portuguese have enabled him to work in various international markets around the globe.


Raimund Noisternig

Tunnel Engineer

Experience Summary
Raimund Noisternig has more than 13 years of extensive, international experience in all aspects of tunneling, including construction management, quality control, and tunnel rehabilitation, as well as modernization, waterproofing and the inspection of tunnels and other underground structures. During his career, Mr. Noisternig has gained hands-on knowledge and experience in the implementation of design and application of NATM/SEM. His experience further encompasses shaft construction, TBM tunneling, drill-and-blast methods and application of ground improvement and pre-support techniques.


Nikolaos Syrtariotis

Tunnel Engineer

Experience Summary
Nikoloas Syrtariotis is a highly-experienced tunnel engineer with expertise in NATM tunneling methods, including SEM and SCL, with a strong background in face mapping and rock mass classification (RMR, Q, GSI), geotechnical monitoring, ground investigations, implementation of tunnel support measures and tunnel construction in conditions ranging from drill-and-blast to squeezing ground.


Dominic Reda

Tunnel Engineer

Dominic Reda - Tunnel EngineerExperience Summary
Dominic Reda graduated from the Polytechnic Institute of New York University with a B.S. and M.S. in Civil Engineering with a focus in Geotechnical Engineering. He has experience in a number of tunneling projects ranging from design, drawing development, independent design checks, tunnel excavation and support inspection, as well as waterproofing inspection. Mr. Reda has also been involved in the development of standards and specifications for small and large scale projects. Mr. Reda is familiar with analysis of underground structures in both two- and three-dimensional numerical modeling programs.


Andreas Gerstgrasser

Tunnel Engineer

Experience Summary Andreas Gerstgrasser - Tunnel Engineer
Andreas Gerstgrasser has gained hands-on experience in generating structural design and as-built drawings utilizing a number of common tunnel design software applications. Mr. Gerstgrasser has gained six years of profound engineering and site supervision experience in underground schemes. His primary duties usually involve developing overall tunnel layouts, cross sections, and excavation and support sequences, as well as the design application of various construction methods.

 

 


Thomas Martin

Tunnel Engineer

Experience Summary
Thomas Martin has been involved in a number of tunneling projects, performing design services and several independent checks. In addition, Mr. Martin has experience in AutoCad drafting shop drawings and design drawings for various national and international projects. He has also been involved in the development of standards and specifications for small and large scale projects.


John Douglas

Advisor – Business Development – United Kingdom

Experience SummaryJohn Douglas, Advisor, Business Development
John Douglas has over fourty years experience in the civil engineering industry. His experience ranges from giving lectures in the collegiate setting to senior management in business development at a major civil engineering company which specializes in public transportation (including the rail sector). He has been a consultant for GZ for the past 3 years as an advisor on business development matters within the United Kingdom.