Seismic Stability of a Multi-Storey Glulam Building Designed using Indonesian Timber Standards

Abstract

This study assesses the stability of a three-story glue-laminated timber (glulam) office building in Jakarta (Site Class SE, SDC D). Four alternative beam–column cross-sections (P1: 20×40; 20×20 cm, P2: 25×45; 25×25 cm, P3: 30×50; 30×30 cm, and P4: 40×60; 40×40 cm) were evaluated according to SNI 7973:2013, while the seismic parameters were determined according to SNI 1726:2019. Seismic response was assessed using the equivalent lateral force (ELF) procedure and linear time-history analysis (LTHA) with seven recorded ground motions scaled to the Jakarta MCEr target spectrum, assuming a semi-rigid diaphragm. Both procedures used a linear-elastic structural model, and the calculated displacements were amplified using the code-prescribed deflection amplification factor. The peak interstory drift ratio remained below 2% in both principal directions, with drift profiles consistent with first mode-dominated response. Models P2 and P3 met the strength and stiffness requirements while maintaining moderate drift, therefore providing the best balance under the assumptions adopted in this study. Section sizes within the P2–P3 range are recommended for this prototype, subject to adequate connection design. Further studies should examine taller or irregular buildings using explicit torsional checks and nonlinear connection models where inelastic behavior is of interest.