Disaster Recovery Indicators of Housing Reconstruction: The Story of Post Tsunami Aceh, Indonesia

The earthquake and tsunami that hit Aceh in December 2004 have come to represent the worst natural disaster in living memory. Post-disaster housing reconstruction was one of the concerns in re-building a better and safer Aceh. The rehabilitation and housing reconstruction works pose an immense challenge because of lack of expertise, resources, and coordination. This research was aimed to evaluate the housing rehabilitation and reconstruction process after one decade. Focus Group Discussion (FGD) was selected as the main data collection technique to achieve comprehensive discussion among all actors involved in the reconstruction process. It was concluded that there are four indicators that poses as strains and support of post-disaster housing rehabilitation and reconstruction process in Aceh. They are (1) housing delivery process, (2) community participation in housing design and supervision, (3) procurement for building materials and skilled labors, and (4) government involvement and policy. Coordination is also a significant factor that was neglected. Suggestions for better future practices are presented, such as ensuring the accuracy of beneficiaries’ data to avoid overlapping; intensifying the role of government at every stage of the reconstruction processes; engaging the community to be actively involved in rehabilitation and reconstruction process

Spatially Distribution of Soil Ultimate Bearing Capacity at Singkil-Aceh Based on a Static Cone Penetration Test

The Singkil Sub-district of Aceh Singkil District comprises alluvium deposits with a relatively low ultimate bearing capacity. The ultimate bearing capacity of the soil is closely related to the safety of a building. The important thing related to estimating the ultimate bearing capacity of the soil is in-situ soil investigation. This study aims to estimate the spatial distribution of soil ultimate bearing capacity using field test data in the Singkil Sub-district. Estimating ultimate bearing capacity is useful to provide an initial picture for various planning and infrastructure development activities in the study area. Twenty CPT in-situ tests have been obtained from various field works in Aceh Singkil Regency. Field data analysis, based on empirical methods, was carried out to obtain the value of the ultimate bearing capacity of the soil at the test location. Then, the estimated distribution of the maximum bearing capacity obtained was carried out. The zoning map of the distribution of soil ultimate bearing capacity in the study was developed from this research. This map can be used as a form or effort of disaster mitigation by various stakeholders involved in planning and building various infrastructure facilities in the Singkil Sub-distric

ANALISIS KESTABILAN LERENG BATU DI JALAN RAYA LHOKNGA KM 17,8 KABUPATEN ACEH BESAR

Penelitian kestabilan lereng batuan menggunakan metode analisis kinematik lereng dan klasifikasi massa batuan dilakukan di lereng pinggir jalan Banda Aceh – Calang di Km 17,8 di Kecamatan Lhoknga Kabupaten Aceh Besar. Penelitian ini bertujuan untuk mengetahui jenis longsoran yang akan terjadi di masa yang akan datang, menilai kualitas massa batuan pembentuk lereng, dan tingkat kestabilannya berdasarkan klasifikasi SMR. Akuisisi data struktur massa batuan dilakukan di sepanjang lereng menggunakan metode scanline. Data yang diambil berupa arah kemiringan bidang diskontinuitas, arah bidang, dan kondisi bidang diskontinuitas bidang berupa kemenerusan, kekasaran, bukaan, isian, luahan air dan tingkat perlapukan. Analisis kinematik lereng didapatkan berdasarkan hasil proyeksi stereografi dan analisis kualitas serta kestabilan lereng batuan berdasarkan parameter RMR dan SMR. Hasil analisis kinematik lereng menunjukkan jenis longsoran yang akan terjadi di lereng 1 berupa longsoran  baji dan planar. Di lereng 2 dimungkinkan terjadinya longsoran gulingan/toppling karena bidang joint set yang berlawanan dengan arah lereng. Nilai RMR di lereng 1 sebesar 63 dengan kategori batuan Bagus dan RMR lereng 2 sebesar 57 kategori batuan sedang. Nilai SMR terendah di lereng 1 sebesar 29 (kategori Buruk) untuk longsoran planar dan 53 (kategori Sedang) di lereng 2 longsoran gulingan. Lereng 1 memiliki probabilitas kejadian longsor planar sebesar 60%.Rock slope stability was assessed using the slope kinematic analysis method and rock mass classification on the roadside slope of Banda Aceh - Calang at 17.8 Km in Lhoknga Sub-district, Aceh Besar District. This study aims to determine the types of landslides that will occur in the future by determining the Rock Mass Rating (RMR) and analyzing stability based on the Slope Mass Rating (SMR). The data acquisition of rock mass structures performed the scan line method along the slope. The data taken are the dip and the strike of the discontinuity plane, and the conditions of discontinuity in the form of persistence, aperture, roughness, infilling, weathering and Groundwater conditions. Slope kinematic analysis was conducted based on stereographic projection and analyses of both rock slope quality and stability were based on RMR and SMR parameters. The result of the slope kinematic analysis shows that landslides that occur in slope 1 will be in wedge and planar forms. On slope 2, possible failure is in the form of toppling due to the joint set positioned opposite to the slope direction. The RMR value in slope 1 is 63, categorized as Good rock and the RMR in slope 2 is 57, which is in the medium rock category. The lowest SMR value in slope 1 was 29 as a Bad class for planar failure, and 53 as a Normal category in slope 2 is toppling failure. Slope 1 has a 60 % probability of a planar failure event

ANALISIS MODULUS DEFORMASI MASSA BATUAN PADA SEGMEN JALAN USAID KM 27 HINGGA KM 30 BERDASARKAN KLASIFIKASI MASSA BATUAN

Penelitian modulus deformasi dan klasifikasi massa batuan mengunakan sistem RMR (rock mass rating) dan GSI (geological strength index) telah dilakukan di Jalan Raya USAID km 27 hingga km 30. Lintasan jalan di daerah ini berada pada batuan yang mengalami deformasi akibat aktivitas tektonik sehingga pada bagian lereng badan jalan ditemukan rekahan-rekahan yang berpotensi longsor, maka diperlukan rekayasa lereng dengan menganalisis dan menilai klasifikasi massa batuan. Penelitian ini bertujuan untuk mengidentifikasi klasifikasi massa batuan dengan RMR (rock mass rating), GSI (geological strength index), dan besaran nilai modulus deformasi massa batuan yang terdapat pada batugamping lempungan. Metode penelitian yaitu dengan melakukan scanline untuk mengambil data orientasi struktur geologi untuk analisis kinematik lereng dan kondisi bidang diskontinuitas (kemenerusan, bukaan, kekasaran, isian, tingkat pelapukan dan kondisi keairan), termasuk kekuatan batuan utuh yang diambil dari lereng batuan untuk menghitung nilai RMR dan GSI. Pendekatan empiris dilakukan untuk mengestimasi nilai modulus deformasi berdasarkan nilai GSI. Hasil penelitian menunjukkan bahwa longsor batuan yang akan terjadi berdasarkan analisis kinematik adalah longsoran jenis planar, gulingan, dan baji. Nilai RMR masing-masing lereng 1, 2, 3 dan 4 adalah sebesar 60, 64, 60, dan 61, sementara nilai GSI sebesar 50, 51, 52 dan 54 secara berurutan. Nilai modulus deformasi massa batuan untuk batugamping lempungan sebesar 50 GPa untuk semua lereng. ABSTRACTS - Rock mass modulus deformation analysis in USAID highways segment km 27th to km 30th based on rock mass classifications. Rock mass modulus deformation and rock mass classifications utilizing RMR (rock mass rating) and GSI (geological strength index) have been conducted in USAID Highways segment from km 27th to km 30th where is built on the rocks which are highly influenced by tectonic force and deformed by tectonic activity; hence, the rock on the slopes are fractured, folded and potentially to failure. These circumstances need a rock engineering approach by applying rock mass classification methods. This research aims to identify the rock mass classifications based on RMR, GSI, and to estimate the rock mass modulus deformation working on rock slope of argillaceous limestone. Scanline approach was utilized in structural geology data acquisition for rock slope kinematic analysis and joints condition (persistence, aperture, roughness, infilling, weathering, and watering) included the strength of intact rock is obtained from rock slope in calculating the RMR and GSI ratings. The empirical approach was deployed in estimating the rock mass modulus deformation based on GSI value. Rock slope kinematic analysis reveals the possibility of rock failure that will be occurred on the slopes are plane, toppling, and wedge failures. The total RMR ratings are 60, 64, 60, and 61 for slope 1, 2, 3, and 4, while the total GSI values are 50, 51, 52, and 54 respectively. Rock mass modulus deformation for argillaceous limestone in this study area is 50 GPa for every slope.

Shear strength performance of dredged sediment soil stabilized with lime

Dredged sediment soil (DSS) is a type of soil that cannot be directly used for construction due to its hard and strong characteristics in dry conditions and its lose and weak characteristics in wet conditions. Several feasible engineering treatments to improve its properties include stabilization. The dredged sediment soil sample was collected from Lam Glumpang, Banda Aceh. This research aims to determine the shear strength and compressibility of lime-stabilized dredged sediment soil. Various physical and mechanical laboratory experiments were performed on both treated and untreated dredged sediment soil. In addition, scanning electron microscopy was used to examine the morphological change of stabilized dredged sediment soil with lime treatment (SEM). This experiment was carried out by mixing the soil and lime in different ratios of 2%, 4%, 6%, and 8% of the dry weight of the soil. According to AASHTO, the soil is classified as an A-4(8) soil type and according to the USCS, it is classified as an inorganic silt soil type (ML). Findings demonstrate that after lime stabilization, the shear strength and compressibility of dredged sediment soil gradually increased. The combination internal friction angle and cohesion value indicated that the shear strength of the soil was enhanced with the addition of lime up to 6% but then declined with the addition of lime to 8%. In addition, the study of micrographs indicates that the formation of aggregate particles has a substantial effect on the increase in shear strength and compressibility of treated dredged sediment soil

Perilaku Tanah Dasar Fondasi Embankment dengan Perkuatan Geogrid dan Drainase Vertikal

Abstrak. Tanah lunak sebagai tanah dasar fondasi di bawah konstruksi embankment sering menimbulkan permasalahan dalam hal stabilitas dan penurunan. Oleh karena itu, perlu dilakukan perbaikan kondisi tanah lunak sebagai tanah dasar fondasi. Salah satunya menggunakan perkuatan geogrid di bawah embankment dan drainase vertikal. Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan geogrid dan drainase vertikal terhadap perilaku tanah dasar fondasi berupa tanah lunak. Penelitian berdasarkan analisis metode elemen hingga dengan menggunakan program Plaxis versi 8.2. Konstruksi embankment dimodelkan dua dimensi pada kondisi plane strain, model material Mohr-Coulomb dan tipe material undrained. Geogrid dimodelkan sebagai geogrid elemen, model bidang pertemuan antara tanah dan geogrid adalah rigid embankment dan interface embankment. Drainase vertikal dimodelkan sebagai drain dengan kelebihan tekanan air pori ditetapkan nol. Hasil analisis numeris terhadap normal embankment menggambarkan bahwa perpindahan maksimum arah vertikal saat ketinggian embankment mencapai H=3,1 m adalah sebesar 0,827 m (dalam bentuk penurunan) dan arah horisontal 0,203 m, sedangkan tegangan efektif sebesar 29,38 kN/m2. Penggunaan perkuatan geogrid dan drainase vertikal pada konstruksi normal embankment dengan model interface reinforced embankment dapat mempercepat proseskonsolidasi hingga 99%, mereduksi perpindahan horisontal hingga 40,5% dan meningkatkan tegangan efektif hingga 35,9%.Abstract. Soft soil as the sub base under/beneath construction of embankment often appears the problem of the stability and the settlement. Therefore, it is necessary to improve the soft soil as the sub base. One of that is using geogrid reinforcement beneath of embankment and the vertical drain in soft soil. This research isaimed to investigate the influence of using geogrid and vertical drains to the behaviour of the sub base which is soft soil. This research based on the finite element analysis by using Plaxis v.8.2. The contruction of embankment was modelled in 2D condition of plane strain, with Mohr-Coulomb material model and undrained material type. Geogrid was modelled as element geogrid, and the contact plane between soil and geogrid was modelled as rigid and interface embankment. The vertical drains was modelled as a drain with excess pore water pressure was specified at zero value. The result of numerical analysis at normal embankment demonstrated that the maximum vertical displacement, when the height of embankment 3,1 m was 0,827 m at vertical direction (manifested as settlement) and the horizontal displacement at this height is 0,203 m, while the effective stress was 29,38 kN/m2. The use of the geogrid and vertical drains at the normally embankment, which is modeled as interface reinforced embankment can accelerate the consolidation process by 99%, to reduce the horizontal displecement by 40,5% and to increase of the effective stress by 35,9%

La prospettiva vichiana nella comparazione giuridica: natura comune e identitaria dell’età della globalizzazione

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Rock slope kinematic analysis for planar failure: A probabilistic approach

The probabilistic kinematic analysis for rock slope has been conducted on one slope along USAID road in Aceh Province, Indonesia. This research aims to develop the modelled probability density function (PDF) and determine the probabilistic of planar failure occurrence (Pop). The geometry of discontinuity planes (dip and dip directions) and slope geometry (slope angle and slope face) were collected from our previous study. One slope with planar failure criteria was selected. The Monte Carlo simulations were performed in generating 100 new random values in 100 time iterations to produce modelled PDFs for the geometry of discontinuity plans based on statistical parameters of field observed data. The probabilistic of each experimental PDFs were computed to produce the probabilistic of planar failure occurrence. The result reveals that the distribution of dip and dip directions for experimental PDFs are considered Beta and Normal distributions. The statistical parameters produced in the model are almost likely similar to observed data. It means the model that was developed are reliable and conscientious. The rule of Φ < βj < βs and dip directions (αj) within ±20° to slope face (αs) are utilised as the boundaries to calculate the probabilistic of planar failure occurrence (Pop) which revealing 0.26