Pengaruh penggunaan wiremesh terhadap perbaikan kolom pendek penampang bulat akibat beban eksentris 1,0h

SUSANTI, Irma, Ir. Suprapto Siswosukarto, Ph.D

2008 | Tesis | S2 Teknik Sipil

Kolom merupakan elemen struktur yang menahan tekan dan momen. Secara struktural, kolom merupakan komponen yang terpenting, sebab kolom merupakan tempat pelimpahan beban-beban yang berasal dari balok dan dari elemen-eleman di atasnya. Rusaknya kolom dapat menyebabkan keruntuhan secara struktural. Perlunya dilakukan studi mengenai metode perbaikan kolom yang tepat. Metode yang umum digunakan adalah concrete jacketing. Penelitian ini bertujuan untuk mengetahui seberapa besar pengaruh penggunaan wiremesh terhadap perbaikan kolom beton bertulang menggunakan metode concrete jacketing yang rusak akibat pembebanan eksentris. Pada penelitian ini dibuat tiga buah kolom beton bertulang dengan tampang persegi berukuran 150 mm x 150 mm, tinggi total benda uji 1200 mm dengan tinggi test region 600 mm dengan 600 mm untuk korbel sebagai aplikasi tumpuan rol-rol pada kedua ujung kolom. Pengujian dilakukan dalam dua tahap, tahap pertama yaitu preloading kurang lebih 75%-85% Pmax atau hingga timbul kerusakan-kerusakan pada kolom awal. Kolom dilapisi beton bertulang menjadi tampang bulat dengan variasi tulangan yang digunakan adalah diameter 3, 4, dan 5 mm. Tahap akhir yaitu pengujian kolom hingga kolom beton benar-benar runtuh atau mencapai kekuatan ultimatenya. Hasil penelitian menunjukkan terjadi penambahan luas tampang beton ratarata 118,17% pada tiap kolom yang diperbaiki. Tampak kapasitas beban aksial kolom yang diretrofit menggunakan wiremesh Æ 4 menurun sebesar 26,35 % dari kolom yang diperbaiki menggunakan wiremesh Æ 3, sedangkan kekuatan kolom yang diretrofit menggunakan wiremesh Æ 5 memiliki kapasitas yang sama dengan kolom yang diretrofit menggunakan wiremesh Æ 3. Hal ini terjadi kemungkinan karena kolom retrofit porous akibat perbaikan yang tidak sempurna, namun terjadi peningkatan nilai kekakuan dan faktor kekakuan tampang sebagai pengaruh penggunaan wiremesh Æ 4 dan Æ 5 mm berturut-turut sebesar 155, 91 %, 2162,91 %, diiringi peningkatan daktilitas sebesar 72,67 % and 145,32 % dari kolom yang diretrofit menggunakan wiremesh Æ 3 mm.

Roof is one of the primary structures of a building. The utilization of concrete roof-tile by public is quite reasonable because the maintenance is easy, it is easy to adjust to the need of construction, it may hold heavy load, it is resistant to high temperature, and it is fire proof and corrosion proof. One of the characteristics of concrete roof-tile is fragile. It is not really fine in holding the bending load. Therefore, concrete roof tile can be mixed with natural material such as coconut fiber. Besides, other alternative material is needed to replace half of sand to reduce the ram material cost without decreasing the product quality. One of the alternatives to replace half of the sand is glass powder. The quantity of both materials is abundant so that some will be waste. Thus, “clean technology” can be developed to utilize the waste optimally by using coconut fiber and glass powder waste in the production of fiber concrete roof-tile. The objectives of this research are to identify and to compare the physical and mechanical characteristics of some mixture variations of coconut fiber, glass powder, and fiber concrete roof-tile mortar according to the standard of SII.0447-81 and to calculate the material need to produce 1 m3 of fiber concrete roof-tile. The production process of fiber concrete roof-tile was started by calculating the composition of every roof-tile with the variation of glass powder addition of 0, 5, 10, 15, 20, 25, 30, and 35% in the fiber concentration of 0,2%. All materials were mixed and put into the molder. Afterward, they were vibrated and then pressed for 60 seconds. The mortar was let down for 24 hours and then it was taken out and soaked 7 days. After being soaked for 7 days, it was lifted out from the soaking basin and put in open air. The fiber concrete roof-tile can be tested after 3 - 4 weeks. The testing result shows that the average bending load of fiber concrete rooftile with the 30 % glass powder has the highest bending strength with the average bending load of 121 kg (quality level II), while the fiber concrete roof-tile without glass powder addition has the lowest average bending load of 57 kg so it does not meet the quality standard of SII 0447-81 yet. The testing to water absorption and seepage shows that all variation of fiber concrete roof-tile meet the standard of SII 0447-81 with maximum water absorption (< 10%) and the under part of the roof tile look dry (normal). According to the economic analysis and investment, the fiber concrete roof-tile has the PBP of 1.28 years, the BEP is 41,613 unit/year, the B/C ratio is 1.15, the ROI is 67.98% and the production primary cost is 3,900 rupiahs which is lower than the market price which 4,500 rupiahs.

Kata Kunci : Kolom,Eksentristas,Kekuatan,Daktilitas, fiber concrete roof-tile, coconut fiber, glass powder, bending strength