PERILAKU GESER BALOK BAJA CASTELLATED MODIFIKASI PROFIL DOUBLE SIKU DENGAN DIAGONAL SILANG BAJA TULANGAN AKIBAT BEBAN SIKLIK

ARGA FRANSDIKA, Prof. Iman Satyarno M.E., Ph.D; Dr.-Ing. Ir. Djoko Sulistyo

2015 | Tesis | S2 Teknik Sipil

Berbagai macam tipe balok kastela (castellated beam) telah banyak dikembangkan mulai dari bukaan heksagonal, lingkaran, dan persegi. Mengingat tinggi efektif yang dihasilkan terbatas, maka kapasitas beban yang dihasikan tidak dapat ditingkatkan lagi. Penelitian ini merupakan pengembangan dari penelitian sebelumnya tentang perilaku geser balok castellated modifikasi menggunakan batang diagonal baja tulangan. Balok castellated modifikasi dengan penghubung diagonal baja tulangan yang diuji terbuat dari profil siku L30x30x3x3 yang disatukan sehingga membentuk penampang T( 2L30x30x3x3) dan dihubungkan menggunakan baja tulangan D13 secara diagonal dengan sudut 45º sehingga membentuk benda uji dengan tinggi efektif 220 mm dan panjang bentang 820 mm. Metode pembebanan siklik menggunakan displacement sesuai dengan syarat ACI T1.1-01. Perbandingan beban dari hasil penelitian ini setelah dinormalisasi dengan penelitian sebelumnya tentang perilaku geser balok castellated dengan beban statik menunjukkan bahwa beban ultimit yang dicapai menggunakan beban siklik lebih rendah 9,56%. Dari pengamatan visual, batang diagonal mengalami buckling, sedangkan dari data strain gauge batang diagonal sudah leleh dan batang horisontal belum leleh sehingga dapat disimpulkan bahwa kapasitas geser balok castellated ditentukan oleh inelastic buckling pada batang diagonal sehingga mekanisme keruntuhannya bersifat daktail.

Many kind of castellated beams were developed include using hexagonal, circle and square opened. The limited of effective height made the capacity of load cannot be increased anymore. This research was developing from previous research about the shear behavior of castellated beam modified by diagonal bar. Sample of Castellated beam modified by diagonal line bars were made by angle section L30 x 30 x 3 x 3 which were combined and formed a T shape (2 L 20 x 30 x 3 x 3) and were connected by D13 bar diagonally with 45 angle resulting a sample with 220 mm of effective height and 820 mm of length. Cyclical load method used displacement control oads based on the requirements of ACI T1.1-01. Load ratio from this test after normalization compared with the previous test about shear behavior of castellated beam with static load stated that ultimate load that were used by cyclical load was lower 9.56%. Observed visually, diagonal beam were buckling, meanwhile from the strain gauge data, diagonal beam were yield and horisontal beam have not yield yet. Therefore, it can be concluded that castellated beam shear capacity were decided by inelastic buckling on the diagonal beam so that the failure mechanism were ductile.

Kata Kunci : balok castellated, siklik, perilaku geser/castellated beam, cyclic, shear behavior