LaGuardia Airport Pedestrian Bridge

Pedestrian Bridge B in LaGuardia Airport connects the Head
House and the new Concourse B. It has a span of about 450ft
and is made of steel trusses and plate girders. Heavy built-up
or rolled W-shape sections were used for the truss chords
and the braced frames at the north end of the bridge.
CHI conducted a peer review of the bridge design. The
purpose of the review is twofold: 1. To verify pedestrian-
induced vibrations are within allowable limits; 2. Checking the
stresses at truss connections.

An evaluation of pedestrian-induced vibrations was conducted
using two types of empirical equations and a 3D finite
element model, which operated under the assumption of
different densities of pedestrians and various levels of
damping.


Two truss connections were modeled using a 3D finite
element program: Midas FEA. One is at the top chord level
and the other is at the bottom chord level, and both have
relative high out-of-plane bending moments. Detailed stress
contours were obtained for assessing the adequacy of the
connection design.


In addition, the connection details of trusses and braced
frames were reviewed. Recommended changes were
proposed to the original design for consideration and
incorporation.