Abstract.A newly developed vertical steel pipe damper is introduced to improve the seismic performance of steel moment frames. The damper exhibits large lateral stiffness and excellent capability to dissipate energy due to earthquakes. It provides a reliable, compact, inexpensive, and replaceable damper. Improved performance of the structure is verified analitically using a four-story steel moment frame equipped with steel pipe dampers. Vertical steel pipe dampers are placed between any two points where large relative motion exists during earthquake excitation. A nonlinear dynamic analysis of the structure using PERFORM-3D software demonstrated the significant benefit of equipping the structure with steel pipe dampers. All structural components, except the steel pipe dampers, remain elastic during earthquake excitation. Structures properly designed with vertical steel pipe dampers will only require minimum postearthquake inspection and limited damage. Some practical issues associated with the application of vertical steel pipe dampers to building structure for seismic response reduction are presented in this paper.

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Structural systems that do not use a beam as the main component were first developed by Turner in 1906. This structural system is better known as a flat slab. The flat slab structure is supported by column heads and drop panels, or without drop panels, or without column heads. Several building codes such as IS 456: 2000, ACI 318-08, ACI 318-19, EC 2:2004, and NZS 3101 (Part 1):2006 provide guidance for designing flat slab systems under gravity loads only. However, many flat slab buildings are also built in areas with high earthquakes which can cause the collapse of buildings due to earthquake loads. In this paper the 10-level flat slab building structure design results are analyzed using nonlinear time history response analysis with the help of OpenSees Navigator software using several earthquake records, namely Kobe (Japan, 1995), Imperial Valley (California, 1979) and Tabas (Iran, 1978) which has been adjusted to the design spectra of the city of Yogyakarta. From the results of the analysis using OpenSees Navigator, it was found that the story drift that occurred was still within the limits required in the regulations, so that the building being reviewed was still within the limits of life safety design.

Balok dalam dengan kekakuan lentur tinggi dapat digunakan untuk mengurangi simpangan antar tingkat sehingga memenuhi batas yang disyaratkan peraturan. Namun kapasitas lentur yang tinggi pada balok dalam akan meningkatkan kebutuhan kekuatan sambungan. Agar sendi plastis tidak terjadi pada sambungan, sambungan balok-kolom harus dirancang berdasar kuat lentur maksimal balok sekitar (1.1 – 1.2)RyMp. Bila sayap atas dan bawah balok dilas langsung ke sayap kolom dengan las tumpul penetrasi penuh, dengan kapasitas tarik sebesar 0.9FyA, maka dapat terjadi gaya tarik pada sayap balok lebih besar dari kapasitas tarik las sehingga perlu perkuatan dengan cover plates atau side plates. Bila dipakai sambungan Reduced Beam Section (RBS) maka akibat coakan pada ujung balok Mp berkurang sehingga gaya tarik sayap balok berkurang maka cover plates dapat dihilangkan. Bentang balok dalam biasanya pendek maka interaksi gaya geser dan momen lentur diperiksa saat perancangan sambungan. Tulisan ini memakai pendekatan yang berbeda dengan yang ada pada AISC 341-05 saat perancangan sambungan RBS pada balok dalam. Studi eksperimental dan analitikal menunjukkan bahwa hipotesis Euler-Bernoulli tidak dapat diaplikasikan pada daerah sambungan. Maka model truss-analogy dipakai untuk menyatakan aliran gaya-gaya pada sambungan, mulai dari muka kolom sampai ke sendi plastis. Model truss-analogy dari Arlekar dan Murty dipakai untuk merancang sambungan balok-kolom, cover plates pada model ini dihilangkan namun rusuk vertikal dipertahankan sebagai pengaku. Dengan penggunaan balok dalam memungkinkan mengontrol simpangan antar tingkat lebih baik, dengan sambungan RBS akan dihasilkan sambungan ekonomis.