COMPARISON OF POWER HOUSE STRESS RATIOS IN MOROWALI USING ELM AND DAM METHODS

Sari

ABSTRAK

Bangunan industri dengan overhead crane menuntut evaluasi stabilitas yang teliti karena menerima kombinasi beban gravitasi, crane, angin, dan gempa. Penelitian ini membandingkan stress ratio struktur baja Powerhouse Crane IMIP Morowali menggunakan Effective Length Method (ELM) dan Direct Analysis Method (DAM) pada model tiga dimensi SAP2000 dengan pendekatan LRFD, geometri, profil, dan kombinasi beban yang identik. Evaluasi difokuskan pada enam kolom dan enam balok kritis. Momen maksimum kolom ELM sebesar 318,4368 kN·m, 1,91% lebih tinggi daripada DAM (312,4806 kN·m); pada balok selisihnya 0,51%. Stress ratio maksimum kolom terjadi pada Frame 6 (ELM 0,9396; DAM 0,9268), sedangkan pada balok Frame 61 DAM sedikit lebih kritis (0,9218 vs 0,9172). Seluruh rasio < 1,0. Temuan menunjukkan metode ELM sedikit lebih konservatif dibandingkan DAM, namun kedua metode masih relevan digunakan karena hasil dari perbandingan sekitar 1-2%.

Kata kunci: struktur baja industri, overhead crane, Direct Analysis Method, Effective Length Method, stress ratio

ABSRACT

Industrial buildings with overhead cranes require careful stability evaluation under combined gravity, crane, wind, and seismic loads. This study compares stress ratios of the IMIP Morowali Powerhouse Crane steel structure using the Effective Length Method (ELM) and the Direct Analysis Method (DAM) in a three-dimensional SAP2000 model under LRFD with identical geometry, sections, and load combinations. Six critical columns and six critical beams were evaluated. The maximum column moment from ELM was 318.4368 kN·m, 1.91% higher than DAM (312.4806 kN·m); the beam difference was 0.51%. The maximum column stress ratio occurred at Frame 6 (ELM 0.9396; DAM 0.9268), while Frame 61 showed DAM slightly more critical for beams (0.9218 vs 0.9172). All ratios were below 1.0. ELM have a little bit more conservative than DAM but all the method still relevant because the gap is about 1-2%.

Keywords: industrial steel structure, overhead crane, Direct Analysis Method, Effective Length Method, stress ratio