Western helps re-construct WTC complex

The formation of the Boundary Layer Wind Tunnel Laboratory (BLWTL) in the Faculty of Engineering at The University of Western Ontario was a direct result of its founding director Alan G. Davenport being asked to lead a team of researchers investigating the wind loads for the tallest buildings in the world. One of the earliest projects for the team was the iconic World Trade Center (WTC) in Lower Manhattan.

Western’s involvement with the WTC complex of buildings continues today with its testing of the new Port Authority Trans-Hudson (PATH) Terminal building, designed by renowned architect/engineer, Santiago Calatrava of Valencia, Spain.

“The World Trade Center in New York did much to define the field of wind engineering as we know it today,” says Peter King, BLWTL director. “And it is a great honour to be continuing our efforts with the PATH Terminal.”

PATH will serve as a major regional transportation hub as well as a significant cultural and retail centre. An integral component of the master plan for the World Trade Center site, it will be an entryway for commuters, workers, residents and visitors – in many ways it is the heart of the trade center redevelopment project.

The above-ground curving wing-like canopies will run the length of the oblong glass-and-steel shell that is to serve as a large skylight over the terminal concourse. These wings extend over the plazas created to the northeast and southwest of the terminal building. At the highest point of its arc, one wing will reach about 200 feet into the air. The wings can pivot aside to create an opening to the sky along the main axis of the terminal.

The wind engineering program for the PATH Terminal included the study of the wind-induced pressures on the hall structure, pedestrian level wind speeds around the site, and structural loads on the portal legs and wing-like structures. Through the progression of the wind studies, geometry updates required re-evaluation of pressures and plaza level wind speeds. Several configurations of the trade center redevelopment were considered.

A study of wind-induced cladding pressures was carried out for locations distributed over the PATH Terminal hall. Pressure results were also used to develop loads on the portals using a pressure integration technique. Aeroelastic studies at 1:200 and 1:68 model scales were carried out on specific elements of the wing-like structure. The aeroelastic models provide direct information on the mean and dynamic wind-induced loads, as well as allowing an evaluation of the aerodynamic stability of the elements.