InTrans / Aug 14, 2018

Timber bridge hardwood glulam deck connector evaluations under static and repetitive loads

Timber bridge deck connectors are crucial to predicted
bridge behavior and long-term serviceability yet only
limited information documents the performance
characteristics for these important bridge connections.
New data are presented on the load resistance
performance of two different fastener installations often
utilized for glulam timber deck-to-girder connection in
bridge superstructure construction. Fastener
installations investigated are the lag bolt connector
and deck clip system. Results on lag bolt and deck
clip performance are based on tests with hardwood
glulam deck-to-girder specimen assemblies. Hardwood
glulam timber are a recent innovation to highway
bridge construction with no detailed information to
describe their connection behavior. Specimen
assemblies were tested to evaluate lateral resistance
(shear) both in primary and secondary load
orientations and withdrawal resistance (axial)
properties. Test efforts for lateral resistance with the
lag bolt connections included assembly evaluations of
load resistance under monotonic conditions and after
repetitive shear displacement up to one million (106)
cycles. Test measurements were made to determine
load-deformation response for characterization of initial
slope or elastic stiffness (Kl), post-yield slope (K2)
and determination of five percent offset load (yield
strength) for both connector systems.