PENGARUH PERSENTASE COAKAN PADA DENAH BANGUNAN STRUKTUR FLATSLAB TERHADAP GAYA GESER DAN SIMPANGAN

Abstract

Coakan adalah lubang pada sudut bangunan, SNI 1726:2012 menjelaskan bentuk bangunan dibagi menjadi dua jenis dilihat dari persentase coakan, yaitu beraturan dan tidak beraturan. Dikatakan bangunan tidak beraturan jika memenuhi salah satu klasifikasi ketidakberaturan bangunan. Besarnya persentase coakan berpengaruh pada gaya geser dan simpangan.

Penelitian bertujuan mengetahui perbedaan gaya geser dan simpangan akibat adanya penambahan coakan. Direncanakan memiliki 11 lantai, menggunakan struktur flatslab, berdiri di Surabaya dengan kondisi tanah lunak. Analisa dilakukan dengan software ETABS 2016.

Hasil penelitian menunjukkan rasio perbandingan gaya geser antara bangunan A, dengan bangunan B (1:0.97), dengan bangunan C (1:0.76), dengan bangunan D (1:0.92). Simpangan arah melintang, perbandingan displacement antara bangunan A dengan bangunan B (1:1.31), dengan bangunan C (1:1.35), dengan bangunan D (1:1.32). Sedangkan arah memanjang, perbandingan displacement antara bangunan A, dengan bangunan B (1:1.36), dengan bangunan C (1:1.66), dengan bangunan D (1:1.40). Bangunan dengan coakan >15% (bangunan B, C, D) merupakan bangunan tidak beraturan dan masuk kondisi tidak aman karena simpangan antar lantai melebihi simpangan ijin.

Kata Kunci: Coakan, Gaya Geser, Simpangan, Bangunan Beraturan dan Tidak Beraturan

ABSTRACT

Re-entrannt corners is a hole in the corner of the building, SNI 1726: 2012 describes the criteria of building form is divided into two types seen from the percentage of re-entrant corners, namely irregular and irregular. It is said the building is irregular if it meets one of the classification of building irregularities. The amount of re-entrant corners percentage also affects the shear force and drift.

This research is to know the difference of shear force and drift due to the addition of re-entrant corners. The building is planned to have 11 floors,using flatslab methodsin Surabaya with soft soil conditions. The analysis was done with ETABS 2016.

The results showed the ratio of shear force between building A, with building B being 1: 0.97, with building C being 1: 0.76, with building D being 1: 0.92. Cross direction drift, the roof displacement ratio between building A and building B is 1: 1.31, with building C being 1: 1.35, with building D being 1: 1.32. While the direction is elongated, the displacement ratio between building A, and building B is 1: 1.36, with building C being 1: 1.66, with building D being 1: 1.40. Buildings with re-entrant corners > 15% (model B, C, D) are irregular building and have unsafe condition because drift does not exceed the limit of drift.

Keywords: Re-entrant Corners, Shear Forces, Drift, Regular and Irregular Building