Fly ash (FA) is burning coal product which is used as supplementary cementitious materials (SCM) as the conjunction with cement. The use of FA is considered by its pozzolanic properties i.e. SiO2, Al2O3 and CaO to hardened concrete. The potential of FA as SCM has been well-known over the globe but that significant utilization has to be studied based on its compound’s characteristics and pozzolanic activity. For this case, the amount of FA is added 30% by mass of total cementitious material, concrete with fly ash (NFA) and another blended without FA as normal concrete (NC) made of ordinary Portland cement. This amount is indicated as dosage in moderate to high volume of FA classification. This replacement pairs with water to cement ratio (W/C) with the value of 0.47 and 0.30 e.g., NC1, NC2 and NFA1, NFA2, respectively. These W/C uses considering effect FA on water demand of concrete proportioned for equal slump. The results showed that NC2 and NFA2 in the age of 28-day inform higher compressive strength, 30% and 28%, respectively. Another indication from the comparison of NC2 and NFA2 were also in good agreement that the use of FA decrease the compressive strength around 3% to 6%.

ABSTRAK Penggunaan kolom komposit telah banyak digunakan di berbagai bangunan bangunan tinggi. Dan pada umumnya, Kolom komposit dibagi menjadi 2 macam, yaitu kolom komposit inside steel dan outside steel dengan struktur baja terbungkus oleh beton disebut dengan kolom inside steel atau bisa saja disebut Concrete Encased Column. Sedangkan untuk baja yang berisi beton disebut dengan kolom outside steel atau juga disebut Concrete Filled Column. Penggunaan struktur kolom komposit outside steel sebagai kolom utama dalam mendukung beban lateral pada struktur rangka bangunan belum lazim digunakan dalam perkembangan konstruksi saat ini. Oleh karena itu, perlu dilakukan analisa kekuatan dari 2 macam kolom komposit agar diketahui jenis kolom komposit yang paling efektif dan memiliki kekuatan paling tinggi. Perhitungan yang dilakukan dengan menggunakan perhitungan manual pada kolom komposit inside steel dan outside steel yang berbentuk kotak, sedangkan untuk perhitungan dengan menggunakan program CSICOL dilakukan pada seluruh kolom komposit. Hasil nilai ØPn dan ØMn kemudian dibandingkan antara perhitungan manual dengan program CSICOL. Hasil perhitungan menunjukan bahwa kemampuan kolom komposit outside steel lebih baik dibandingkan kolom komposit inside steel dengan menggunakan standar volume dari ukuran kolom komposit inside steel kotak 400x400 mm. Kolom komposit outside steel berbentuk bundar dengan diameter 431 mm lebih unggul sebesar 17 % dalam menahan gaya aksial nominal (ØPn) dibandingkan semua tipe kolom komposit yang lain. Sedangkan kolom komposit outside steel berbentuk kotak dengan ukuran 405.70x405.70 mm lebih unggul menahan momen nominal (ØMn) sebesar 10,5 % dibandingkan semua tipe kolom komposit yang lain.Kata kunci : kolom komposit; inside steel (concrete- encased column); outside steel (concrete-filled column)ABSTRACT The use of composite columns has been widely used in various high-rise buildings. Composite columns are generally divided into two types: composite columns inside steel and outside steel columns with a steel structure wrapped in concrete called an inside steel column (concrete encased column), while steel containing concrete is called an outside steel column (concrete-filled column). The use of a composite column structure outside steel as the main column in supporting lateral loads in the building frame structure is not yet commonly used in current construction developments. Therefore, it is necessary to consider the strengths of 2 types of composite columns to know which type of composite column is the most effective and has the highest strength. Calculations are performed using manual calculations on composite columns inside steel and outside steel in the form of a box, while calculations using the CSiCOL program are carried out on all composite columns. The results of the ØPn and ØMn values are then compared between manual calculations and the CSiCOL program. The calculation results show that the composite outside steel column's ability is better than the inside steel composite column by using a standard volume from the size of the composite column inside steel box 400x400 mm. The round composite outside steel column with a 431 mm diameter is 17% superior in withstanding nominal axial force (ØPn) than all other composite column types. While the outside steel composite column in the form of a box with a size of 405.70x405.70 mm is superior to withstand the little moment (ØMn) by 10.5% compared to all other types of composite columns.

Increasing of motorcycle numbers in big cities in Indonesia, especially in Surabaya. The traffic becomes crowded and road capacity is exceeded. Because of the increasing of motorcycle volume, especially in western part of Surabaya, the government built a flyover in west outer ring road to provide solution to congestion in Surabaya. This study aimed to determine the comparation between PC-I girder and PC-U girder used. In west outer ring road, the method was used to calculate prestressed beam was fully prestressed. The researcher reviewed the prestressed beam from behavior, reaction, and impact to the all of bridge structures from structure. The Software SAP 2000 V.14.2.5 is used to structure calculation analysis. According to analysis result, the calculation has been carried out, the difference ratio of the bridge floor slabs was studied. Flyover model with PC-U prestressed beam had smaller ratio than PC-I. The comparison of strand used in PC-U beams was more than PC-I with 42.22%. The maximum moment value was occurred in PC-I girder beam was 1541.979 Tons.meter and PC-U girder was 2252.599 Tons.meter. The strand requirements and cross area section was comparised too.

Evaluasi seismik terhadap perilaku struktur tidak beraturan merupakan parameter penting khususnya untuk mengetahui kegagalan yang terjadi pada struktur. Parameter ketidakberaturan tersebut dapat berupa elevasi struktur yang tidak seragam, denah yang memiliki bentuk tidak umum yang mana memiliki pusat massa dan kekakuan yang berbeda serta jenis dan dimensi dari elemen struktur terpasang. Ketidakberaturan tersebut sering tidak dapat dihindari karena faktor arsitektur. Pada studi ini, akan dievaluasi berbagai bentuk ketidakberaturan struktur bangunan yang dievaluasi secara analitis dan numerik. Evaluasi struktur menggunakan metode direct displacement-based design dengan pendekatan ATC-40 disimulasikan untuk mengetahui parameter kinerja struktur. Satu bangunan regular dan tiga bangunan ireguler akan dievaluasi dan dibandingkan satu sama lain. Berdasarkan evaluasi yang dilakukan, nilai kinerja bangunan secara relatif memenuhi standar acuan DDBD dengan tingkat level kinerja berada pada life safety dan intermediate occupancy untuk pendekatan dengan ATC-40.