Ashar Saputra
Department of Civil and Environmental Engineering, Universitas Gadjah Mada

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Retrofitting on Flexural Strength of RC Columns Using Polyester Resin Concrete Dahlia Patah; Ashar Saputra; Andreas Triwiyono
Journal of the Civil Engineering Forum Vol. 2 No. 1 (January 2016)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, UGM

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (558.436 KB) | DOI: 10.22146/jcef.24305

Abstract

Concrete column structures damages due to flexural moment need to be repaired and strengthened to avoid of sudden failure by applying appropriate methods. The method applied in this study was retrofitting by applying polyester resin concrete. In order to know the effect of polyester resin concrete against axial load capacity, stiffness, ductility and the damage pattern of columns by eccentrically loaded, an experimental laboratory was carried out. In this study, three column specimens are tested. The dimension of the specimen is 150 mm x 150 mm and the high of the column are 1200 mm with the effective high is 600 mm and 600 mm for corbel. The column specimens have a fixed eccentricity of 50 mm. First, initial column tested before yield point of reinforcing bar reached and concrete crack limited to 0,4mm. Further, retrofitting applied to each initial column specimen using normal concrete and polyester resin concrete with the level of resin 15% and 20%, respectively. Retrofitting column tested again with the same loading of initial column until it reaches the collapse load. The result of experiment compares to analysis method by Nawy and Whitney which represent the analysis of normal concrete column capacity. The result showed that levels of resin to be used is 20% because of better workability compared to 15% resin. Further, compressive test on resin concrete cylinder showed that the resin level at 15% and 20% are 82.82 MPa and 76.65 MPa, respectively. The strength of KR-ii decreased about 33.523%. The strength of KR-15ii and KR-20ii increased 5.08% and 24.827% respectively compared to initial column. Specimen column stiffness KR-ii. KR-15ii and KR-20ii decreased about 76.22%, 24.50% and 37.65%, respectively from the initial column. Furthermore, ductility of KR-ii, KR-15ii and KR-20ii decreased about 1.512, 1.250 and 2.50, respectively. The changes of the ultimate capacity load of KR-ii, KR-15ii and KR-20ii by Nawy Method respectively -26.54%, 12.66%, and 13.83%, whereas the method of Whitney respectively -17.68%, 26.25%, and 27.56%. The use of polyester resin concrete can change the pattern of collapse from brittle to ductile columns.Keywords: retrofit, ductility, stiffness, flexural column, eccentricity
Effect of the Skilled Worker Certification on the Sustainable Infrastructure Development Nurin Pramadini; Inggar Septhia Irawaty; Ashar Saputra
Journal of the Civil Engineering Forum Vol. 3 No. 1 (January 2017)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, UGM

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (451.81 KB) | DOI: 10.22146/jcef.26592

Abstract

Infrastructure plays an important role in the occurring development process, in which the human resource is an important factor in it. This research was conducted in the work area of the Construction Training Agency Region II Surabaya Unit (Balai Pelatihan Konstruksi Wilayah II Surabaya). The data were collected by using questionnaire or questions list, which was given to the provider and the user of the skilled labor—consisted of 60 people of 30 certified skilled workers and 30 non-certified skilled workers. The data was processed by using SPSS. The result showed that the number of certified skilled workers that know the characteristic of sustainable infrastructure is higher when compared with the non-certified skilled workers. The average 95.4% of certified skilled workers know about the characteristic, while it’s 91.1% in the non-certified skilled workers. Certified workers that implement the characteristic of sustainable infrastructure is of 75.9% and 62.8% of noncertified workers do the aforementioned. According to the calculation, there is some influence between the knowledge of sustainable infrastructure characteristic and the project implementation, based on 57 from total 65 research variables.
Suitability Analysis of Office Building Design against Maintenance Cost (Case Study of Serayu Opak River Basin Organization, Yogyakarta Province) Mario Puji Hersanto; Ashar Saputra; Suprapto Siswosukarto
Journal of the Civil Engineering Forum Vol. 3 No. 3 (September 2017)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, UGM

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1297.115 KB) | DOI: 10.22146/jcef.26709

Abstract

This study aims to determine the effect of building design's inaccuracy against the cost of maintenance, by taking the research in Serayu Opak River Basin Organization, Water Resources Field and Water Resources Management Center in Yogyakarta Special Region. The first step is to analyze the inaccuracy of building design based on the result of interview and observation during field survey. The second step is to analyze the cost of building maintenance. The third step is to analyze the maintenance costs used to minimize the effects of the inaccurate design of the building. The result shows the inaccuracy of building design in the form of the use of clear glass without coated glass film and the absence of heat insulator on the roof of the building cause the room to become hot. The installation of rain gutters without vertical pipes, toilet facilities in the entire building is not yet complete, inadequate accessibility for persons with disabilities, and inadequate corridor design. There is a small portion of the maintenance budget used for reducing the impact of building design's inaccuracy, so it can be concluded that the design of the building is less meet the requirements of the Government regulations.
Repairing and Retrofitting of Earthquake-Affected Exterior Beam-Column Connection by Using Resin Concrete Rifqi Anra Wijaya; Ashar Saputra
Journal of the Civil Engineering Forum Vol. 2 No. 2 (May 2016)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, UGM

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1893.899 KB) | DOI: 10.22146/jcef.27150

Abstract

Reinforced concrete structures may suffer a failure that caused by natural events such as earthquake. If the damaged building still can be used, then a repair (retrofitting) on the damaged section is highly necessary. Retrofitting materials that can be used is the polymer concrete. The purpose of this study was to determine the behavior of beam-column connections after repair (retrofitting) using polymer concrete. Test sample in the form of exterior beam-column connection with cross-sectional size of the column 30 x 30 cm, length of 3.5 m and the size of the beam cross-section of 17 x 30 cm, length 1.8 m, consists of 3 pieces. Experiment test method was based on ACI T1.1-01. All samples were tested in two stages, the first stage of the test until targeted damaged level which controlled by crack width of 0.4 mm. Furthermore, the test object repaired using normal concrete (BKN- 1N) and polymer concrete (BKN-2R and BKN-3R). The second phase of test is done to collapse. Lateral force, deflection, and strain and crack pattern are observed. The data were processed to obtain the load-deflection relationship curve, stiffness, ductility ratio, energy dissipation and model of collapse. Beam-column joint behavior is compared with the acceptance criteria (ACI T1.1-01) to determine whether in accordance with the criteria required. Test results showed the value of the maximum lateral load test object BKN-1N, BKN-2R and BKN-3R,consecutively were 39.2 kN; 43.77 kN and 46.24 kN in the direction of curvature response (+) and the direction of curvature response (-), respectively for 59.1 kN; 62.73 kN and 69.91 kN. BKN-2R test objects have a greater ductility factor of 24.1% in the direction of curvature response (+) when compared with the test object BKN-1N. At the direction of curvature response (-), BKN-2R sample has a greater ductility 39.3% of the sample BKN-1N. Based on ACI T1.1-01, all samples have the response modification factor of 8. From SAP2000 modeling, BKN-1N, BKN-2R, and BKN-3R consecutively showed ability to withstand earthquake forces 3.36 times greater; 3.77 times; and 3.97 times greater than the earthquake forces are designed based on SNI 1726:2012. An advantage of using a resin concrete repair materials is very fast drying time.