Reliability-based design optimization of strengthened and reinforced glulam beams in bending

Over the past 60 years, research has been carried out to provide glulam members with enhanced mechanical performance. Strengthening and reinforcing methods tested to improve the behavior of glulam beams have been predominantly focused on the use of Fiber-Reinforced Polymer (FRP) and steel products. Glulam beams with such modified cross-sections have been shown to be rational alternatives to steel and concrete counterparts in designing stiff and strong structural systems, attracting research interests for reliable long-span and heavy-loading applications. There is, however, no comprehensive study indicating which strengthening configuration is optimum. In this paper, glulam beams in bending are investigated through Reliability-Based Optimization (RBO) to propose a quantitative strengthening scheme. Seven strengthening and reinforcing configurations made in steel and FRP materials are accounted for glulam beams of lengths up to 30 m. RBO results indicate that glulam beams can be configured optimally with more sustainability. Additionally, it allows for the definition of specific safety levels for optimally reinforced and strengthened glulam beams at the lowest cost compared to non-strengthened glulam beams. Furthermore, prestressed material offers the most cost-effective way to create glulam beams that are more sustainable, strong, and safe.