Judul: Analisis Perilaku Dinamika Struktur Jembatan Box Girder Menerus dengan Variasi Bentang.
Abstrak: Box girder bridges are often found on long span bridges. Long span bridge needs to be divided into several groups of span to reduce deflection. Earthquake effect needs to be observed because Indonesia is located in a highly active tectonic zone. The purposes of this study are analyzing period and stiffness value, analyzing length variation effects on structure dynamics, as well as comparing the use effect of response spectrum on the base shear. Preliminary design had done based on AASHTO 2012 and SNI T-12-2004. The used load is dead load. Response spectrum based on earthquake accelerogram created using SeismoMatch v 1.3 program. Analysis of the structure dynamics were calculated with the help of MIDAS Civil program. The 4 span, 5 span, and 6 span bridges have a same natural period. Mass and stiffness of 6 span bridge has the greatest value compared to the others. Mode shapes of 4 span, 5 span, and 6 span bridges are similar. In the x direction, 4 span and 5 span bridges obtaining >90% mass participation in the 6th mode while 6 span bridge on the 7th mode. In the y direction, all bridges obtaining >90% mass participation in the 1st mode. Those bridges can be analyzed using equivalent static method. The use of response spectrum graphs based on earthquake accelerogram is more suitable for base shear calculation compared with response spectrum graphs based on RSNI 2833:2013.
Keyword: accelerogram, box girder, length variation, response spectrum, structure dynamics

Judul: Analisis dan desain struktur continuous box girder dengan variasi bentang
Abstrak: Jenis jembatan yang dipilih pada penelitian ini adalah jembatan box girder. Struktur jembatan perlu didesain dan dianalisis kekuatannya terhadap beban yang direncanakan. Jembatan yang didesain tidak berada di lokasi yang spesifik, akan tetapi perencaan terhadap beban gempa dilakukan pada beban gempa tertinggi di Indonesia. Umumnya, masalah utama dalam pembangunan jembatan terdapat pada sambungan jembatan yang kompleks dan mahal, sehingga sebisa mungkin dihindari dengan membangun jembatan menerus dengan bentang panjang (long span). Akan tetapi, hal tersebut akan menyebabkan defleksi pada struktur yang menyebabkan kerusakan jembatan. Oleh karena itu, diperlukan analisis stuktur jembatan dengan variasi panjang jembatan untuk mengetahui perilaku strukturnya. Berdasarkan analisis yang dilakukan, semakin panjang jembatan maka momen yang terjadi pada approach span akan semakin kecil dan momen pada midspan akan semakin besar. Selain itu, lendutan yang terjadi pada setiap jembatan sama. Tulangan yang digunakan pada kolom adalah D32-140 dan tulangan pada box girder bervariasi. Berdasarkan jumlah tendon yang digunakan, jembatan 5 span lebih ekonomis dibandingkan jembatan lainnya.
Keyword: Bridge, Length variation, Structure Analysis, Structure design, Bridge type, Earthquake loiads, Bridge connection, Long span bridge, Structure behavior

Judul: Detoxification of Cassava’s Acid Hydrolyzate by Activated Carbon Method for Bioethanol Production
Abstrak: Cassava is one of natural resources for carbohydrate that also available for bioethanol production. Starch and fibers hydrolysis maybe conducted on acid condition. The restriction in acid hydrolysis is 5-hydroxymethyl furfural (HMF) and furfural formation, which inhibit yeast fermentation. This study applied two stages of detoxification, which are overliming and activated carbon adsorption methods for lowering HMF and furfural concentrations. In order to obtain tolerable amount in sugar solution, detoxification by activated carbon adsorption was done by concentration of 1%, 2.5%, 5% and 10% and duration of contact are 30 45 and 60 minutes. The results showed that overliming method decreased HMF and furfural concentrations 34.38% and 60.81%, respectively. Overliming followed by 5% activated carbon adsorption for 30 minutes produced the best sugar solution which has a lower HMF and furfural concentrations by 72.03% and 89.11%, respectively. Adsorption constants of HMF and furfural by 5% activated carbon were 0.044 g/min and 3,7 x 10-5 g/min, respectively. The concentration of ethanol produced was 5.00% (b/v) or 63.22% higher than obtained from detoxification by neutralization (NH4OH) which produced ethanol only 3.06%.
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