Application of 3D Printed Segments Designed by Topology-Optimization-Analysis to a Practical-Scale Pre-Stressed Pedestrian Bridge (2020-07)¶

3D printing technologies with cementitious materials have advanced dramatically in recent years. Likewise, we have also developed suitable materials with high thixotropy for layered extrusion and the gantry 3D-printing system, dealing with discontinuous geometry and multi-productions simultaneously. In this way, there have been a lot of studies particularly on material properties and printing processes so far. However, few studies have conducted structural performance testing on a large scale in a systematic manner. Hence, this structural concern is focused on and tackled in this study. The developed materials and printing system are used for the following experiments. As a preliminary test, specific characteristics such as anisotropy and creep of a layerby-layer component are investigated for a structural design in addition to basic fresh and hardened properties. After the rational geometry is determined by topology optimization analysis, in which a practical scale pedestrian bridge under sidewalk loading is designed, its structural performance is evaluated for safety based on FEM (Finite Element Method) analysis, while considering the preliminary tests. The designed bridge structure consists of 44 segments with different complex shapes, which are printed separately, and all the segments are unified as a compression loaded structure through prestressed external reinforcement. Finally, it is confirmed whether the inherent behavior due to the laminar structure is observable in the full-scale bending test.