Chris Rivielle

was named president and CEO of Plant Construction Co. in San Francisco, succeeding John Wilson. Rivielle previously served as first vice president with Tishman Construction Corp. in New York City; as senior managing director at Newmark Knight Frank; and as vice president and project executive at Structure Tone.

Turner Construction Co. added David Burrus as its aviation project executive for the Southern California office, where he will primarily focus on the construction of the Midfield Satellite Concourse Project at Los Angeles International Airport. Burrus previously worked at Clark Construction, where he was recently named one of ENR's top 25 newsmakers for his work on the Anaheim Regional Transportation Intermodal Center.

Aaron Wiehe

has transferred to PCL Construction's San Diego office as vice president and area manager. Previously, he served as vice president and district manager for Nordic PCL Construction in Hawaii. Wiehe joined PCL in 1998 after graduating from Purdue University. He is a past ENR California Top 20 Under 40 honoree.

The Associated General Contractors of California added Albert Aragon as the manager of industrial relations for Northern California. He will work out of AGC's Concord office. Aragon's 20-year background in labor relations and human resources includes previous roles as Kaiser Permanente's employee and labor relations consultant and Contra Costa County's principal labor relations negotiator.

Jonas Radstrom joined Atkins as national rail systems director, based in the engineering firm's San Francisco office. He will focus on major systems programs nationally and rail and transit project development in the Western U.S. He has more than 20 years of rail systems experience for clients such as Caltrain, Sonoma-Marin Area Rail Transit, SoundTransit and Houston Metro.

Richard Holzer

was named managing principal engineer at Southland Industries' Southern California division, where he will lead the design engineering, building information modeling and constructibility departments. He will also offer strategic guidance for the building systems contractor's engineering services. With more than 25 years of experience, Holzer previously managed several large-scale, complex mechanical engineering design projects for health care, educational and commercial clients.

Mat Guerrero was hired as health, safety and environmental director for SC Builders in Sunnyvale, where he will leverage more than 17 years of safety experience to provide all prevention, training, compliance and documentation activities for the general contractor.

SCS Engineers hired Tracie Onstad Bills to lead the firm's sustainable materials management practice in Northern California. She formerly served as president of the California Resource Recovery Association.

Sharon Bison, SCS Engineers' business development manager, was appointed president of the Orange County Post of the Society of American Military Engineers.

Christine Grossenbacher

was named principal and business center managing leader for Stantec's transportation group, based in Walnut Creek. She has been a member of the firm's transportation practice since 2000. Grossenbacher also begins a two-year term as vice president of the Women's Transportation Seminar's San Francisco Bay Area chapter, where she has served as a board member for the last seven years.

Doug Ahlstrom was hired as director of KTGY Group Inc.'s Los Angeles-based 55+ design studio. He brings more than 35 years of experience in the senior-targeted design field, including roles as director of senior housing at KEPHART and as a principal with Professional Design Consultants.

Soo Im

was also added to KTGY's 55+ studio as senior project manager. With more than 18 years of industry experience, she previously worked as a senior project architect for DiMella Shaffer. She also spent 10 years as an adjunct teacher and adviser at Boston Architectural College.