Large-scale OT-slab tests: Laboratory measurements and evaluation

Full-scale testing of existing bridges is one of the main tasks in an ongoing Danish research project. One of the initial tasks of this project involved full-scale load tests of multiple OT-slab bridges, which showed a large unexpected capacity reserve compared to the theoretical predictions. A part of this reserve may be dedicated to a higher shear load transfer between OT-beam elements than anticipated. Laboratory testing of scaled OT-slab bridge elements was initiated to examine the load transfer in OT-slabs and investigate the precision and robustness of the applied monitoring approaches used for in-situ load testing. Each OT-slab element consisted of seven adjacent OT-beams with a width of 246 mm, height of 300 mm, and length of 8400 mm. Including an additional concrete top layer, the slab elements had a dimension of 1722 mm in width, 8400 mm in length, and 370 mm in height. The slab elements were supported along three edges and loaded by a point load in the middle of the unsupported edge. The monitoring setup included internal measurements (strain gauges), external contact measurements (distance lasers, LVDT’s), and non-contact measurements (Digital Image Correlation). Qualitative findings regarding transverse load transfer are presented for the first OT-slab test, along with a performance evaluation of the laboratory and monitoring setup for the given application.