Karakteristik Dinamik Dan Estimasi Kekuatan Sisa Rangkaian Balok Beton Bertulang Menggunakan Mode Kelengkungan Eksperimental = Dynamic Characteristic and The Residual Strength Estimation

• Main Author: Perpustakaan UGM, i-lib
• Format: Article NonPeerReviewed
• Published: [Yogyakarta] : Lembaga Penelitian dan Pangabdian kepada Masyarakat, Universitas Gadjah Mada 1999
• Subjects: Jurnal i-lib UGM
• Online Access: https://repository.ugm.ac.id/23247/; http://i-lib.ugm.ac.id/jurnal/download.php?dataId=6189
• Institution: Universitas Gadjah Mada

ABSTRACT The damage or crack on reinforced concrete structure causes strength deterioration of the structure. It will result in degrading of stiffness and strength of the overall structure. Therefore, a simply periodical detection of the strength could be developed. This research was carried out to study the dynamic characteristic of grid structures to investigate natural frequency, damping ratio, mode displacement, and dynamic residual strength of the damage structural system. A series of 4 sets of reinforced concrete beams (grid system) was used as the model in this research. Each beam consisted of two 3200 mm longitudinal beams which connected by five 400 mm diagonal beams (diaphragm). The longitudinal beam cross section was 90/200 mm and the diagonal beam cross section was 80/140 mm. These models were tested with gradually static loading. Meanwhile, to measure natural frequency and displacement for each level of crack, a dynamic loading test was applied. The dynamic loading is a sinusoidal loading at frequency of 15 Hz which was lower than the natural frequency system. The lower frequency was governed in order to get any measurrement in the first mode of the structural system. Based on the test result the following conclusions were deduced: (a) natural frequency of the damage system was smaller than original structural system, and related to the level of damage. The decreases of the natural frequency of GRD-1, GRD-2, GRD-3, and GRD-4, were 1556%, 6.25%, 14.1%, and 17.78% respectively, (b) mode displacement of the damage system was found to be greater than the original structur, depending on the level of damage,(c) first crack load of the structure system had been found about 26.1% Pmax to 47.6% Pmax, (d) location of crack and dynamic residual strength of damage system at the first crack had been detected but required verification for further crack, (e) the residual strength which was estimated from the static data (load-displacement), the dynamic test data (natural frequency) as well as the dynamic result (absolute different betwen the curvature mode shape) showed a realistic result at the initial damage condition. However, it could be unrealistic at the consecative level of damage. Key words : grid system, natural frequency, displacement mode, curvature mode, residual strength