No abstract

Abstract. Expansive soil can be easily found at Purwoharjo, a sub-district of Banyuwangi. Swelling and shrinkage behavior of the soil is usually referred to by the local community as a "moving soil" phenomenon. It causes cracks on a number of buildings which is a major issue in that area. Various methods of expansive soil stabilization are available. This work intends to lay comparisons on stabilizations using wood charcoal powder and salt. The stabilizing materials are mixed with the soils under different proportion. Volume weight, index properties, and dry density are parameters to be investigated during the stabilization process. The results show that salt stabilized expansive soil is better than wood charcoal powder. 15% proportion of salt to soils weight increases the density by about 20%. Meanwhile, the stabilized soil is as a result of change to low plasticity silt (ML) from previously high plasticity soil (CH) of the original one.

Low impact development (LID) is a sustainable land use and planning strategy that aims to minimize the environmental impacts of development. Community can enhance their water resources and create sustainable and resilient neighborhood. This approach has demonstrated success in managing stormwater and promoting water reuse globally, however, its suitability in developing countries like Indonesia remains uncertain and requires further investigation. The implementation of LID in developing countries may face several challenges including high-density and complex drainage networks, combined sewer usage, clay soil type, irregular housing layouts, community socio-economic characteristics, affordability, cost, and the availability of regulations and policies. With proper planning and site-specific strategies, LID can be implemented effectively in Indonesia. Clear regulations secured funding source and community-based LID are all essential for successful LID deployment. This paper can be used as a starting point for considering LID implementation in Indonesia and other countries with similar characteristics.

Abstract. Bamboo becomes a promising engineering material widely utilized for constructions. It is likely a composite material with fibred reinforcement in one direction to make its good flexural strength. Bamboo has been traditionally made use for structural components. Recently, the applications of bamboo for earthwork constructions are reported both experimental and real project. Pile foundations for houses, bamboo pile and nail for slope stability, foundation grid for embankment, and bamboo pile-mattress for railway and reclamation project are among others of the application. This paper discusses the use of bamboo for earthwork construction. Particular discussion is addressed to bamboo pile-mattress that successfully installed for various project in Indonesia. The appropriate field characteristic for bamboo application is specified. The design step and theoretical based are discussed as well.

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Flood mapping is an essential component of planning flood mitigation. The availability of remote sensing data makes rapid flood mapping possible. This article develops an accurate method for rapid flood mapping using satellite imagery. Sentinel-2 imagery was tested by acquiring data before and after a flood event in a lowland area. Flooding extraction was performed using the newly developed Flood Inundation Extraction Index (FIEI) and compared to the Modified Normalized Difference Water Index (MNDWI), the most commonly used index. Based on the choice of threshold, the results are divided into flooded and non-flooded areas. Evaluation of the performance accuracy based on the total and kappa coefficients showed that the FIEI approach is more accurate than the MNDWI approach.

The northern coastal areas of Java such as Gresik and surrounding areas have a soil structure of alluvium consisting of gravel / coral, sand, clay soil and shells. Soil basic conditions are soft enough to cause land subsidence (settlement). The need for rapid construction causes the urban areas to become less and more for development land. This requires the improvement of soft soil to be used as a building site. As for the method to be done in this planning using a combination of preloading and PVD methods to accelerate the process of land degradation. Based on the planning result, the total height of embankment (preloading) is 3.5 m and the planning time lasted 4 months. Soft soil improvement is done up to 25 m depth with PVD design using triangle pattern and space 1.3 m. The 95% consolidation decrease due to the load of embankment caused the soil to fall as deep as 1,928 m. In this planning use modeling Plaxis 8.6 2D and the resulting yield of soil is 1,990 m. Wilayah pesisir pantai utara Jawa seperti daerah Gresik dan sekitarnya mempunyai struktur tanah berupa alluvium yang terdiri dari batu kerikil/koral, pasir, tanah lempung dan pecahan kulit kerang. Kondisi tanah dasar yang cukup lunak menyebabkan terjadinya penurunan tanah (settlement). Adanya kebutuhan konstruksi yang semakin pesat menyebabkan wilayah perkotaan menjadi semakin sedikit untuk dijadikan lahan pembangunan. Hal ini mengharuskan dilakukannya upaya perbaikan tanah lunak agar bisa dijadikan lahan bangunan nantinya. Adapun pada metode yang akan dilakukan pada perencanaan ini menggunakan kombinasi metode preloading dan PVD untuk mempercepat proses penurunan tanah. Berdasarkan hasil perencanaan didapatkan total tinggi timbunan (preloading) adalah 3,5 m dan waktu perencanaan berlangsung 4 bulan. Perbaikan tanah lunak dilakukan sampai dengan kedalaman 25 m dengan desain PVD menggunakan pola segitiga dan spasi 1,3 m. Penurunan konsolidasi 95% akibat beban timbunan menyebabkan tanah turun sedalam 1,928 m. Pada perencanaan ini menggunakan pemodelan Plaxis 8.6 2D dan hasil penurunan tanah yang dihasilkan adalah sedalam 1,990 m.

The majority of the government's authorities that are granted to the local government through region autonomy motivates creativity and innovation of the local government in developing good local governance. This research described and analysed the roles and attemps of local government in handling damage of highway and realizing the local government's responsiveness in Gresik regency. Data were collected using interview, observation, and documentation method. The result of this research claimed that the road maintenance efforts by government concept on URC-BIMA was categorized "good enough" and was able to realize responsiveness of the local government. It can be analysed by 24 hours-response of the road damage through hotline, twitter, and whatsApp. Although URC BIMA just temporarily existed in handling damage, this unit fairly succeeded in preventing the further road damage. This research also reported that there were still weaknesses in road construction.