Experimental study and theoretical analysis on mechanical behavior of screwed connections between steel and laminated bamboo lumber under load perpendicular to the grain

Due to its sustainability and exceptional mechanical properties, laminated bamboo lumber (LBL) was increasingly recognized in structural engineering. This research investigates the mechanical behavior for steel-LBL with screwed connection under loading perpendicular to the grain, employing diverse parameters such as screw diameter, anchorage depth, end distance, center-to-center distance, and row distance. A total of forty-five specimens with single-screwed connections were evaluated, revealing two types of failure modes related to the screws, which align with two yield modes observed in screws. Additionally, eighteen specimens featuring double-screwed connections were examined to formulate design recommendations aimed at preventing brittle failures in LBL. Subsequently, the outcomes of the tests were compared against the predicted values derived from three widely utilized codes. Nevertheless, each of them has significant deviations compared with the test results. Therefore, a more accurate theoretical formula is derived and verified based on the ideal elastoplastic model.