Masyhur Irsyam

Development of spectral hazard maps for a proposed revision of the Indonesian Seismic Building Code

The need to revise the current Indonesian Seismic Hazard Map contained in Indonesian Earthquake Resistant Building Code SNI 03-1726-2002 which partially adopts the concept of UBC 1997, was driven among others by the desire to better reflect the potential larger earthquake disasters faced by the nation in the future. The much larger than maximum predicted Aceh Earthquake (M w 9.0–9.3) of 2004, followed by the destruction observed during the 2005 Nias Earthquake (M w 8.7) urgently underline to need to consider the new conceptual approach and technological shift shown in the transition of UBC 1997 to IBC 2006. This paper presents research works for developing spectral hazard maps for Indonesia. Some improvements in seismic hazard analysis were implemented using recent seismic records. Seismic sources were modeled by background, fault, and subduction zones by considering a truncated exponential model, pure characteristic model or both models. A logic tree method was performed to account for the epistemic uncertainty and several attenuation functions were selected. Maps of PGA and spectral accelerations for a short period (0.2 s) and for a 1-s period were then developed using a probabilistic approach. The maps will be proposed as a revision for the current seismic hazard map in the Indonesian Seismic Building Code.

Analysis of Coseismic Fault Slip Models of the 2012 Indian Ocean Earthquake: Importance of GPS Data for Crustal Deformation Studies

Based on continuous GPS data, we analyze coseismic deformation due to the 2012 Indian Ocean earthquake. We use the available coseismic slip models of the 2012 earthquake, derived from geodetic and/or seismic waveform inversion, to calculate the coseismic displacements in the Andaman-Nicobar, Sumatra and Java. In our analysis, we employ a spherical, layered model of the Earth and we find that Java Island experienced coseismic displacements up to 8 mm, as also observed by our GPS network. Compared to coseismic offsets measured from GPS data, a coseismic slip model derived from multiple observations produced better results than a model based on a single type of observation.

Development of an engineering bedrock map beneath Jakarta based on microtremor array measurements

Abstract Jakarta has been selected as a study area for seismic microzonation by considering its population and its infrastructure growth, seismicity and geological setting. One of the important factors in seismic hazard analysis is the characteristics of the ground overlying bedrock, and, as yet, this has not been studied for Jakarta. This study was intended to estimate the depth to bedrock by applying microtremor array exploration. The phase velocity of microtremors was estimated by the spatial autocorrelation (SPAC) method, whereas the S-wave velocity profile was estimated by inversion using a genetic algorithm. Microtremor array analysis has been conducted at 55 sites that covered the whole of Jakarta. The result of one-dimensional (1D) S-wave velocity profile estimation indicates that the engineering bedrock depth has pronounced differences between northern (>700 m) and southern Jakarta (about 300 m). A 3D S-wave velocity model was constructed from 1D profiles resulting from a second inversion in which the depth of constant-velocity layers, with velocities of 500, 700 and 900 m s−1, was determined. The constructed 3D velocity structures show a bedrock morphology that has a depth range of 350–725 m, with depths increasing towards northern Jakarta. The implication of differences in bedrock depth is that estimated seismic amplification for the thicker sediment will be higher.

Design and implementation of wireless sensor network on Ground movement Detection System

The raise of land usage and human population increase the number of areas which are prone to landslide disaster. Real time monitoring system on these risk areas can minimize the losses caused by it. One physical phenomenon that can be observed from this disaster is ground movements. This paper discusses about the implementation of wireless sensor network for real time ground movement monitoring. The system consists of Inclinometer, GPS, Xbee Pro, SIM900 and a 9 V power supply. To detect the ground movement, the system used inclinometer sensor. The calibration was done using a homemade tilt calibrator. Xbee pro was used as node transmission system with star topology and then SIM900 was used as a transmitter between the coordinator with the server. The system additionally used GPS to show the position of node and to detect the occurrence of landslide at certain area. Code igniter was used to build web server so that the data can be accessed in real time. From the test, it was shown that the system could detect the ground movement and the observation data was sent to the server precisely.

A simple and low cost tilt examiner system development for a precise landslide early warning system

Historical data for every disaster provide the information about every single physical phenomenon that can be observed to estimate and monitor the happening of the next disaster event. Some physical parameter that often be investigated are ground movement and changing inclination of the land. Those phenomena are the key points on predicting the occurrence of disaster especially landslide and volcano eruption. One of the method that can be used to prevent the loss of life caused by the disasters is by observing the movement and the change of the slope of inclination at the prone areas using tilt sensor. The increase of possibility of disaster occurrence is reflected on the increase of tilt sensor usage. Therefore, a simple system for testing the performance of a tilt sensor is required. A simple and low cost tilt calibrator has been made by using a stepper motor that is controlled by AVR ATMega8 in which its data and control parameter would be displayed in a 16×2 LCD. The system calibrator was developed to...

Past Earthquakes in Indonesia and New Seismic Hazard Maps for Earthquake Design of Buildings and Infrastructures

This chapter presents the process in developing new seismic hazard maps and the progress of seismic disaster study in Indonesia. In recent years, the Indonesian government has become more aware of the seismic effects on their structures such as buildings, bridges, dams, and other critical facilities because great earthquakes occurred in Indonesia repeatedly over the last few years. Almost every year huge earthquakes with a magnitude greater than 6.5 occur in Indonesia, which has caused total losses of US

Proposed Site-Specific Response Spectra for Surabaya-Madura Bridge

4,745 million. Therefore, research in earthquake engineering is urgently required in Indonesia so as to predict the possibility of earthquakes in the future and find the solution for mitigating their effects. This is further compounded by the fact that Indonesia is rapidly developing and many high-rise structures and critical facilities are being constructed at a rapid pace. The latest approach in developing new seismic hazard maps has considered the new conceptual approach and technological shift shown in the transition of UBC 1997 to ASCE 2010. Some improvements in seismic hazard analysis were implemented by considering recent seismic records, new attenuation functions, and the latest research regarding fault locations and fault characteristics around Indonesia. Three spectral hazard maps for several return periods of earthquakes including 475 and 2,475 years were developed in the research by using probabilistic approaches. These maps have been officially approved and signed by the Ministry of Public Work of Indonesia.

Study of soil moisture sensor for landslide early warning system: Experiment in laboratory scale

A meshless local Petrov-Galerkin (MLPG) method that employs polygonal subdomains constructed from several triangular patches rather than the typically used circular subdomains is presented. Moving least-squares approximation is used to construct the trial displacements and linear, Lagrange interpolation functions are used to construct the test functions. An adaptive technique to improve the accuracy of approximate solutions is developed to minimize the computational cost. Variable domain of influence (VDOI) and effective stress gradient indicator (EK) for local error assessment are the focus of this study. Several numerical examples are presented to verify the efficiency and accuracy of the proposed adaptive MLPG method. The results show that the proposed adaptive technique performs as expected that is refining the problem domain in area with high stress concentration in which higher accuracy is commonly required.The effect of loading on the chloride penetration into plain concrete (PC) and fiber reinforced concrete (FRC) was studied experimentally by using modified NT Build 492 – Nonsteady state chloride migration test that include the application of loading on the specimen during the test. Three types of polypropylene fibers with different lengths and shapes were used. The concretes were tested for chloride penetration at different stress ratios under static and cyclic loading. The results of the static loading showed that there was a slight reduction in the chloride penetration under low level of compressive stress while an increase in the chloride penetration was found at higher stress level. There are significance difference in chloride penetration behavior of the plain concrete, long fiber FRC and short fiber FRC. Chloride penetration increased even more at cyclic loading conditions showing difference behavior of FRC and PC at difference number of cycle and load level.Billet scales are by-products from steel rolling mills in Nigeria that presently constitute environmental pollution. This paper reports studies carried out using these solid wastes as a partial replacement for sand in the production of concrete. Various percentages of billet scales were used in a concrete mixture of 1: 2: 4 by weight to cast concrete specimens. The compressive and tensile strengths developed were tested after 7, 14, 21, and 28 days of curing. The result of the compressive and splitting tensile strengths tests indicated that concrete strength increased with curing age. The compressive strength of 0%, and 15% replacement of sand with billet scales as obtained at 28 days are 26.0N/mm2, 26.2N/mm2. 15% optimal replacement of sand with billet scales had similar results as the control mixture of 0%, which could be used in reinforced concrete structures. Other replacements could be useful as mass concrete for non-structural construction applications.This paper presents a site-specific seismic hazard study to determine the recommended seismic design criteria for Suramadu Bridge. The study is performed using probabilistic seismic hazard approach to determine maximum acceleration and response spectra at bedrock and followed by local site effect analysis to determine maximum acceleration and response spectra at ground surface. The probabilistic seismic hazard analysis (PSHA) is carried out using 3-dimension (3-D) seismic source models (fault source model). Two hazard levels are analysed to represent 150 and 3,300 years return period of ground motion around site location. The local site effect analysis is performed using 1-dimension (1-D) shear wave propagation theory to obtain peak ground acceleration and response spectra at ground surface. Finally, the site-specific surface response spectra with 5 percent damping are developed based on the mean plus one standard deviation concept from the result of local site effect analysis.Appropriate trust and leadership have been frequently cited as key answer to the problems of cooperation and coordination in contractor’s teamwork. The objectives of this paper are to measure trust level of construction projects team, to investigate trustworthy leadership behavior of project managers, and to model the influence of project managers’ trustworthy leadership behavior upon team trust level. Sixty-one respondents from nine on-going construction projects participated in the questionnaire survey. The analyses show that in general the levels of trust and project managers’ trustworthy leadership behavior are medium (scores of 82.71 and 102.09 respectively). Meanwhile the positive influence of project managers’ trustworthy leadership behavior upon team trust level, modeled through multiple regression analysis with one dependent variable (i.e. trust) and three independent variables (i.e. leadershipresults, leadership-integrity, and leadership-concern), is found to be significant. The model is evaluated and validated; the results reveal that the prediction of the model is satisfactory.

Instrumentation system design and laboratory scale simulation of landslide disaster mitigation

The high rate of rainfall is the main trigger factor in many cases of landslides. However, each type of soils has unique characteristics and behavior concerning the rainfall infiltration. Therefore, early warning system of landslide will be more accurate by monitoring the changes of ground water condition. In this study, the monitoring of ground water changes was designed by using soil moisture sensor and simple microcontroller for data processing. The performance of soil moisture sensor was calibrated using the gravimetric method. To determine the soil characteristic and behavior with respect to water content that induce landslides, an experiment involving small-scale landslide model was conducted. From these experiments, the electric resistance of the soil increased as soil water content increases. The increase of soil water content led to the rise of the pore pressure and soil weight which could cause soil vulnerability to the movement. In addition, the various soil types were used to determine the responses of soils that induce the slope failure. Experimental results showed that each type of soils has different volumetric water content, soil matrix suction and shear strength of the slope. This condition influenced the slope stability that trigger of landslide.

Design of Deformation Monitoring System for Volcano Mitigation

Research on landslide has been developed recently because it may endanger human life. Landslide is the movement of rock, detritus, or soils caused by the action of gravity. Landslides are influenced by several factors such as ground slope, degree of rainfall, land cover (ground layers), and the vibration around the slopes. From these factors, tilt detection sensors and soil moisture sensor have been developed to detect landslide failure. These sensors mounted so that it can detect the occurrence of landslides. The study was conducted on a container which contains the sloping ground. Landslide, slope processes, and soil humidity were investigated in this container. MMA8451Q accelerometer was used as a tilt sensor to detect the acceleration assembled in MEMS (Micro Mechanical System) technology since it is easily available, mass- produced, inexpensive, and high-precision output data. Landslide simulator has been developed hence the process leading to landslide event can be directly analyzed without the need of real life occurrence of landslides. The simulator was made from glass with size 80 cm × 20 cm × 40 cm that was filled by soil. Based on the simulation results, there were changes on accelerometer and soil moisture data during the landslide occurrence.