An Assessment of Mangrove Rehabilitation Programs in Bolaang Mongondow Selatan Regency, North Sulawesi

While the results of many mangrove rehabilitation efforts have not been optimal due to various factors, the rate of mangrove forest deforestation remains high in Indonesia. This research was designed to test the principle “planting certain mangrove seedlings on suitable habitat would be survived”. The test was based on an assessment of six locations in Bolaang Mongondow Selatan Regency where mangrove rehabilitation programs were implemented. This assessment was conducted by using a spot check method to analyze any variables associated with plantation area feasibility, and the use of a participative approach to collect additional information. Results from this study confirmed that mangrove seedlings have to be planted on the right habitat and that the implemented rehabilitation programs have followed a try and error or speculative approach, and have not been supported by sufficient technical and theoretical competencies. Keywords: artificial plantation, natural regeneration, mangrove, rehabilitation Deforestasi hutan mangrove di Indonesia berlangsung cepat, sementara itu banyak upaya rehabilitasi belum memberikan hasil yang optimal karena berbagai faktor. Penelitian ini menguji secara khusus prinsip “benih yang ditanam di tempat yang cocok akan tumbuh”, melalui penilaian enam lokasi program rehabilitasi mangrove di Kabupaten Bolaang Mongondow Selatan. Penilaian dilakukan menggunakan metode pengecekan lapangan (on spot check) untuk menganalisis variabel-variabel yang berkaitan dengan kelayakan lahan tanam, dan pengumpulan informasi melalui pendekatan partisipatif. Hasil penelitian menegaskan bahwa “jenis bibit yang ditanam harus sesuai dengan lahan tanam”. Upaya penanaman yang dilakukan masih menggunakan pendekatan coba-coba atau spekulatif, dan tidak didukung pemahaman teknis maupun teoritis yang memadai

New Landfill System in North Kolaka Regency, Southeast Sulawesi, Indonesia

Most waste disposal sites in developing country are still using open dumping and open burning However, in developing countries, there are a lot of economically and technical problems with high level landfill technologies of first world countries making implementation of improvement not feasible. Therefore, there is significant need for transfer of landfill technology that is simpler, low cost, and that can be maintained locally. A method that provides this that has recently gathered attention is the Fukuoka Method (semi-aerobic landfill). By life cycle cost analysis method, with the lifespan of the landfill is 20 years and an estimated volume of 586,789 m3 (469,431tonnes), the capital investment required was about US$296,739 (natural clay liner) and US$463,406 (synthetic-liner) or about US$0.63 and US$0.99/tone of waste, the total cost of operation was about US$3,187,728 or US$6.79/ton of waste. The closure cost of the landfill was estimated to beUS$278,116 or US$0.59/ton of waste

Modified Yield-Line Theory for Prestressed Concrete Deck Slabs with Interface between Old and New Deck Slabs

In a technique for widening prestressed concrete (PC) deck slabs proposed by some researchers in Japan, the shear transfer between the old and new deck slabs is achieved through the external prestressing force, and the rebars extending from the old to the new deck slab. To simulate this condition in the experimental test, three PC deck slabs under a concentrated load were tested by taking the initial prestressing level as the parameter. Observations suggest that the capacity of the widening PC deck slabs was difficult to predict due to the current analysis technique does not consider the presence of the interface between the old and new deck slab. Therefore, the conventional yield-line theory, as one of methods for calculating the flexural capacity, was modified in this study. The results indicated that the modified yield-line theory showed better accuracy compared to the conventional yield theory for lower initial prestressing level. However, for higher initial prestressing level, both conventional and modified yield line theory highly overestimated the experiment

Pengaruh Ikatan Diagonal GFRP Pada Hubungan Balok Kolom Pracetak Terhadap Kekuatan Sambungan

Precast system is one of the reinforced concrete construction methods that can be used for development. GFRP-S (Glass Fiber Reinforced Polymer Sheet) is one of material that can be used as materials in precast concrete connections. The research aimed at analysing the strenght and behaviour of the concrete beams on beam-column joint precast with GFRP-S.The research was conducted at the Laboratory of Civil Engineering Structures  and Materials Hasanuddin University. Beams dimensions was 15cm x 20cm x 120cm and the column was 45cm x 20cm x 100cm. The testing materials were the precast beams with GFRP-S. The imposition given is monotonic static load in one direction.The results showed that an increase in stiffness of the precast beams with GFRP-S. LSI amounted to 16.64% of the LS. LIS amounted to 31.70% of the LS. The average deflection of LS are 55.05 mm. The average deflection of LSI are 45.89 mm. The average deflection of LIS are 37.60 mm. The models of failure in the precast beams with GFRP-S are rupture failure of GFRP-S

Flexural Behavior of Styrofoam-Filled Concrete

Various kinds of innovations have been made to obtain lightweight concrete, for example using Styrofoam as partial replacement of aggregates. The objective of this study was to analyze the flexural behavior of Styrofoam-filled Concrete (SFC) by adding Styrofoam 30 % to replace the concrete volume. The testing was carried out on three variations specimens with a total of 6 specimens, which each variation consist of 2 specimens. The characteristic of Normal Concrete (NC) and SFC was first evaluated. Then, the behavior of SFC beam was compared with the behavior of NC beam and SFC with CFRP strengthening (SFC-CFRP). The specimens were statically loaded using two-point load system with constant speed ramp actuator at 0.1 mm/second until the beam failure. The results indicate that the strength of normal concrete (NC) and SFC has decreased with addition of 30% Styrofoam. However, when the SFC beam was combined with deformed bar, the ultimate bending strength of SFC specimens increase 12.6% compared to the NC specimens. Similarly, the ultimate strength of SFC-CFRP specimens improved by 39.74% compared to the SFC specimens

Kapasitas Mekanik Panel Komposit Beton Ringan terhadap Beban Siklik

The position of our country is included in the area Ring of Fire, where 90% of earthquakes on earth will occur in this region. Earthquakes in West Sumatra (2009), Mentawai (2010), Lombok and Palu (2018) have claimed more than 10,339 lives and more than 100,000 heavy damage to buildings. Building walls are generally made of brick or adobe, but these two materials have several disadvantages including weight and brittle. As a result of its considerable weight, it will increase the dead load of the structure so that the earthquake load will also increase. Thus, lightweight and clay materials (ductile) will be better if used as earthquake-resistant building walls and the level of risk is lower. Prefabricated sandwich panels produced by PT. BUILDING TECHNOLOGIES INDONESIA within BUKAKA TEKNIK UTAMA Tbk Group. to be a series of cyclic load tested full scale wall constructions. The conventional panel circuit model obtained the behavior of each swaying wall segment as an independent individual panel. Cyclic test results up to drift 12 were obtained with a maximum load of 4.245 kN with a maximum displacement of 106.28 mm compressive direction and a maximum load of 1.425 kN with a maximum displacement of 75.68 mm pulling direction. Deviation behavior is obtained that continues to increase as horizontal loads increase, but not until structural damage occurs in the series of 3 sandwich walls. This condition is a positive thing in the development of buildings with light materials to reduce the magnitude of the earthquake force and minimize damage and casualties

Studi Perubahan Lahan Pantai Kolongan Di Kelurahan Malalayang Dua Kota Manado

TeridentifikasiPantai Kolongan telah dimanfaatkan secara intensif, salah satunya yaitu dengandibangunnya bangunan pelindung pantai T-groins.Efektivitas peran bangunan pelindung pantai T-groinsdalam meredamaksi faktor hidro-oseanografi serta menjalankan fungsinya dalam menangkapsedimen, merupakan faktor yang dikaji dalam studi ini. Diketahui bahwa faktorhidro-oseanografi sebagai agen geomorfik, merupakan kontributor terbesar dalamproses perkembangan suatu lahan pantai. Penelitian ini dilakukan dengan caramengamati kondisi lahan pantai dan menganalisis Perubahan lahan pantai melaluipengamatan citra google sertamenganalisis karakteristik arus yang terjadi pada lahan yang diobservasi. Hasil penelitian menunjukkan T-groinsmelindungi lahan pantai dibelakangnya. Hal ini ditunjang dengan hasil pengukurankemiringan lereng yang menunjukkan keberadaan lereng pantai yang cenderungdatar danlandai. Berdasarkan hasil analisis granulometri sedimen, Pantai Kolongansementara atau sedang dalam proses pendeposisian sedimen. Data hasil pengukuran arus di Pantai Kolongan bervariasi di setiap titikpengamatan, dengan kisaran kecepatan arus 0,08 knot – 0,47 knot saat pasang dan0,27 knot – 0,55 knot saat surut

Studi Perubahan Lahan Pantai Kolongan Di Kelurahan Malalayang Dua Kota Manado

TeridentifikasiPantai Kolongan telah dimanfaatkan secara intensif, salah satunya yaitu dengandibangunnya bangunan pelindung pantai T-groins.Efektivitas peran bangunan pelindung pantai T-groinsdalam meredamaksi faktor hidro-oseanografi serta menjalankan fungsinya dalam menangkapsedimen, merupakan faktor yang dikaji dalam studi ini. Diketahui bahwa faktorhidro-oseanografi sebagai agen geomorfik, merupakan kontributor terbesar dalamproses perkembangan suatu lahan pantai. Penelitian ini dilakukan dengan caramengamati kondisi lahan pantai dan menganalisis perubahan lahan pantai melaluipengamatan citra google sertamenganalisis karakteristik arus yang terjadi pada lahan yang diobservasi. Hasil penelitian menunjukkan T-groinsmelindungi lahan pantai dibelakangnya. Hal ini ditunjang dengan hasil pengukurankemiringan lereng yang menunjukkan keberadaan lereng pantai yang cenderungdatar danlandai. Berdasarkan hasil analisis granulometri sedimen, Pantai Kolongansementara atau sedang dalam proses pendeposisian sedimen. Data hasil pengukuran arus di Pantai Kolongan bervariasi di setiap titikpengamatan, dengan kisaran kecepatan arus 0,08 knot – 0,47 knot saat pasang dan0,27 knot – 0,55 knot saat surut

Marshall Characteristics of Hotmix Cold Laid Containing Buton Granular Asphalt (BGA) with Modifier Oil Base and Modifier Water Base

The need of asphalt mixing plant (AMP) in the hot mix asphalt (HMA) production resulting in the construction of hot rolled asphalt (HRS) is restrained mostly at the areas that possess AMP. Many remote areas or remote islands cannot possess AMP hence the construction of HRS cannot be optimized at those areas. Natural rock asphalt that deposited in Buton Island, Southeast Sulawesi in Indonesia is crushed to produce Buton granular asphalt (BGA). BGA and cold modifier were utilized to produce hot mixture that can be laid at cold temperature of 50OC to 27OC. The employment of hotmix cold laid mixture containing BGA and cold modifier as pavement mixture is one solution to substitute hot rolled asphalt application in the remote and distance areas. The experimental results to investigate the Marshal Characteristic showed the hotmix cold laid containing BGA and cold modifier can attain an adequate compaction. At an optimum bitumen content of 8% within BGA, no significant differences on VIM, VMA and VFB were observed when the storing and compaction time were extended from 3 to 7 days. The stability value and tend to decline and the flow value increased with the extension of the storing and compaction time