Tinjauan Perencanaan Struktur Atas Gedung Laboratorium Kesehatan Masyarakat Kota Manado dengan Analisis Respons Spektrum Berbasis ETABS

Abstract

The Public Health Laboratory building in Manado stands in an area with a mapped short-period spectral acceleration of 1.1415 g, so its superstructure has to be checked against the seismic provisions currently in force. This study re-examines the columns, beams, and floor slabs of the two-storey reinforced concrete frame through a three-dimensional model built in ETABS Ultimate v19.1.0. Seismic demand was taken from modal response spectrum analysis following SNI 1726:2019 for site class SD, with SDS of 0.794 g and SD1 of 0.6612 g. The frame uses 25 MPa concrete and 420 MPa reinforcement, with 450 mm square columns, 300 mm by 600 mm main beams, and a 120 mm slab. The fundamental period of 0.367 second stays under the 0.414 second upper bound, and cumulative modal mass passes 90 percent as early as the fourth mode. Flexural steel demand is governed almost everywhere by the minimum area of 542 square millimetres, peaking at 969 square millimetres in the 7.0 metre span. Three items remain unresolved: the slab is thinner than the code minimum for the largest panel, the drift output reads exactly zero and was replaced by an analytical estimate of 11.2 millimetres against a 40 millimetre limit, and second-floor joints on grids F to I return a capacity ratio of 1.48. A hand check shows that 500 millimetre columns with eight 25 millimetre bars bring that ratio down to 0.85.