Kabul Basah Suryolelono

Behavior of Expansive Clay of Ngawi Region (East Java) Under Water Content Variation

The key in developing a strategy for management of non-revenue water (NRW) is to gain a better understanding of the reasons for NRW and the factors which influence its components. The components of NRW can be determined by conducting a water balance analysis. The International Water Association (IWA) provides a water balance calculation that gives guidance to estimate how much is lost as leakage from the network (physical losses), and how much is due to non physical losses. Further, IWA has established the Infrastructure Leakage Index (ILI), a performance indicator for comparisons of leakage management in water supply systems. This paper introduces ILI and reasons why it is a more appropriate approach to use than the percentage of system input volume.This paper reviews the applicability of nine selected expressions in determining the equivalent value of the Manning coefficient of roughness. For this purpose, a prismatic 4m-long and 0.05m-wide trapezoidal-shape channel was constructed, namely the homogeneous channel and the composite channel. The homogeneous channel had the same surface lining, whereas the composite channel had two different surface linings. Four different lining materials were considered: plaster, small, medium, and large-sized aggregates. The homogeneous channel showed a reliable Manning coefficient prediction, provided that a uniform flow was achieved. The roughness of the composite channel can be predicted accurately by the nine expressions; the average was 0.96, with standard deviation of 11.13%. Out of the nine expressions, the expression that considers wet-perimeter as its main parameter showed the best estimate. The error was about 2% with standard deviation of 5.15%. This can be actually traced back to the limited width of the test channel, thereby increasing the role of wet perimeter.This paper presents an experimental and analytical research conducted to study the in-plane behavior of reinforced concrete (R/C) frames in-filled with lightweight materials. The tests were performed on two single bay, single story in-filled frame specimens with 1⁄2 scale models. One of the test specimens was in-filled with lightweight materials, i.e. autoclaved aerated concrete (AAC) blocks, and the other, used as the comparison, was in-filled with clay brick materials. The loading used in the tests was in the form of cyclic in-plane lateral loads, simulating earthquake forces. Behavior of the frame structures was evaluated through the observed strength and deformation characteristics, the measured hysteretic energy dissipation capacity and the measured ductility. The experimental results show that the R/C frame in-filled with AAC blocks exhibited better performance under in-plane lateral loads than that in-filled with conventional clay bricks. In the analytical work, the performance of some analytical models available in the literature was evaluated in simulating the experimental results

CHEMICAL CHARACTERISTICS OF VOLCANIC ASH IN INDONESIA FOR SOIL STABILIZATION: MORPHOLOGY AND MINERAL CONTENT

Indonesia region which has approximately 83 active volcanoes are a source of wealth of this region. The last five years, active volcanoes in Indonesia, Mount Merapi, Kelud and Sinabung eruption issuing experiencing the abundant material. A volcanic ash from the eruption of volcanic material can be used as soil stabilization. Volcanic ash is a pozzolanic material which can be used as a soil stabilizing agent. However, it should be done the first step characterization testing of chemical properties, mineralogy and morphology volcanic ash from different sources. Accordingly, this paper presents results of a test chemical characteristics, mineralogy and morphology of volcanic ash in Indonesia derived from the Mount Merapi, mount Sinabung and mount Kelud using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Based on specific gravity test results on some volcanic ash in Indonesia, it can be classified in light material category. Merapi, kelud and Sinabung volcanic ash has a different shape morphology. Merapi is a form of fibrous glass particles Contain elongated vesicles. While, the texture Sinabung is a berry-like glass particles show angular blocky forms and texture kelud are sponge like glass. The SEM-EDS test obtained Si content of the three types of volcanic ash ranges 45-60% and elements of Al ranges 14-20%. This can be a reference for further research on the utilization of materials of volcanic ash as a pozzolanic material in soil stabilization.

MECHANISM AND CHARACTERISTICS OF THE LANDSLIDES IN BONE BOLANGO REGENCY, GORONTALO PROVINCE, INDONESIA

One of the regencies in Gorontalo Province, Indonesia, Bone Bolango is an area in which landslides occur frequently. This study was at identifying the mechanism and characteristics of landslides in Bone Bolango Regency. This study is important to minimize hazards caused by this disaster. Data were obtained from the results of site survey, surface geological survey and geotechnical investigation. Cohesion during the dry season ranged between 0-15kPa, and the angle of internal friction ranged between 30 o -44 o . The topography of this area indicates a steep slope (>40°), with weathered rock and discontinuity. These internal factors made the slopes prone to landslide. Meanwhile, external factors that trigger landslides are high precipitation (>100mm), the absence of vegetation covering the slopes, as well as land use on the slopes. In general, the types of the landslide in the study area were debris flows, rotational slides, and rock falls. At the period of high precipitation, the rate of infiltration of rainwater into the soil was slower than the rate of the increase in the volume of rainwater deposited and flowing into the slope surface, resulting in the debris flow. Slope-forming material became soft due to the rise of groundwater levels. This caused a decrease in shear strength and pore water pressure that turned into positive. In the rock slope, rainwater filled the crack of slope discontinuity area so that rock got loose and fell freely. Therefore, a further research is necessary to conduct in order to determine the most accurate and efficient method for slope stability.