Civil Engineering

Demokrasi di Mesir ibarat kolam tanpa ikan dan air. Ikan-ikan di kolam tersebut mati, karena tidak ada air yang memungkinkannya hidup dan beranak-pinak". 3 Itulah perumpamaan yang dipopulerkan Muhammad Husein Haikal perihal rapuhnya wacana dan tatanan demokrasi di negeri Piramid tersebut.

Nakayasu Unit Hydrograph is a simple  method by using spreadsheet to calculate run off or reservoir Inflow for example in Malahayu reservoir located in Kabuyutan river of Pemali Comal - Central Java jurisdiction basin under Cimanuk Cisanggarung RBO Management

Last Planner System (LPS) is one of Lean Construction's tools for scheduling to enhance project's reliability, productivity, and performance. It has already been widely adopted in many developed countries and shown benefits, such as shorter duration, less rework, and better communication. Despite its benefits, the use of LPS is almost unheard of in Indonesian. The aim of this exploratory research is to investigate the readiness of LPS implementation for Indonesia's projects. The assessment is based on five principles of LPS, i.e. Master Schedule, Pull Planning, Making Work Ready, Weekly Work Plan, and Learning, using four categories of assessment, i.e. not aware, aware, willing, and implemented. The levels of readiness are categorised into none, poor, moderate, high and excellent. Data was collected by interviews and questionnaire surveys with project managers and observations of four construction projects. The results show that on average the readiness level is moderate, particularly for Pull Planning and Look-ahead Plan. The main challenges identified include lack of confidence and resistance to change. These research findings provide an initial understanding of LPS as perceived by contractors, and later can be used as inputs to build a strategic framework to enable wider LPS adoption to improve Indonesia's project performance.

Last Planner System (LPS) is one of Lean Construction's tools for scheduling to enhance project's reliability, productivity, and performance. It has already been widely adopted in many developed countries and shown benefits, such as shorter duration, less rework, and better communication. Despite its benefits, the use of LPS is almost unheard of in Indonesian. The aim of this exploratory research is to investigate the readiness of LPS implementation for Indonesia's projects. The assessment is based on five principles of LPS, i.e. Master Schedule, Pull Planning, Making Work Ready, Weekly Work Plan, and Learning, using four categories of assessment, i.e. not aware, aware, willing, and implemented. The levels of readiness are categorised into none, poor, moderate, high and excellent. Data was collected by interviews and questionnaire surveys with project managers and observations of four construction projects. The results show that on average the readiness level is moderate, particularly for Pull Planning and Look-ahead Plan. The main challenges identified include lack of confidence and resistance to change. These research findings provide an initial understanding of LPS as perceived by contractors, and later can be used as inputs to build a strategic framework to enable wider LPS adoption to improve Indonesia's project performance.

To date, non-destruction testing (NDT) method is the most popular method to assess the condition of road pavement. Among all evaluation procedures of the NDT method, load-deflection backcalculation analysis is one that is developed widely to understand the structural behavior of road pavement. On one side, the use of this analysis is greatly beneficial for presenting the layer characteristic accurately. However, the analysis requires specialist expertise. To overcome this, deflection bowl parameter application could become one alternative. The parameters are very easy to use; however, the intention of the parameters so far is only as an indication of the condition of the structural layer of the road pavement. Therefore, the parameters have to be used with careful consideration. In this study, the parameters were evaluated to determine the optimal usage of the parameters against different structures of road pavements. The results showed that a simplification of the number of paramete...

In 1943, Burmister introduced an analytical solution to overcome a practical problem in designing an economical pavement with sufficient thickness over a subgrade to provide adequate support for traffic load. Using this solution, a backcalculation algorithm can be developed to obtain the layer elastic moduli. Making use of hypothetical data, this paper evaluates the choice of the optimum configuration of deflection measurements for backcalculating the layer elastic moduli of a flexible pavement system consisted of three layers, i.e. surface layer, subbase layer and subgrade. Two computer programs (FPAVE3 based on closed-form backcalculation algorithm; and EVERCALC based on iterative trial and error backcalculation algorithm) were evaluated based on two types of deflections, exact and random deflections. The assessment of the optimum deflection selection was conducted by comparing the discrepancies between the computed elastic moduli against their true moduli and analyzing the dispersion of the computed moduli calculated based on random deflection. The results showed that the deflection sensors near the load could better estimate the layer moduli, especially for elastic moduli of surface and subbase layer. On the other hand, the estimation of elastic modulus of subgrade is not much dependent on the choice of deflection sensor configuration.

The temperature within the asphalt pavement layers varies due to the influence ofenvironmental factors including air temperature, humidity, solar radiation, wind speed, and the reflectance of pavement surface. The temperature distribution on the cross section of asphalt pavement layer is considerably important in connection with the strength characteristics of various asphalt pavement designs. This study develops model of asphalt pavement temperature for tropical climate conditions in Indonesia which has a specific climate characteristics. Indonesia is located on a narrow range of latitudes (6 0 North-11 0 South) and is crossed by the equator. Indonesia has a tropical climate and experiences lots of sunlight, rainfalls and high humidity throughout the year. The national road of Denpasar-Gilimanuk (Km 102) segment, Negara regency in the western of Bali is selected as a case study area. Thermocouples sensors equipped with data loggers were installed in various depths. Based on the SAGA Technology program, the temperatures were recorded every 30 minutes. About 336 observational data were recorded which include hourly variations of temperature and humidity as well as pavement temperature in various depth. It was found that there was a strong positive linear correlation (r > 0.8) between the air temperature and the temperature of the asphalt pavement. On the other hand, a strong negative linear correlation (r >-0.8) between the humidity and temperature of the pavement was found. Linear regression models were developed to predict the temperature of the asphalt pavement by using temperature and humidity as independent variables. The results indicated that the model has a good estimation accuracy.

Construction of the first toll road in Indonesia, namely Jagorawi connecting Jakarta and Bogor, started in 1973 and operated in 1978. In further developments, since 1987, the government provides an opportunity for the private companies to manage tollroad through a public private partnership (PPP) with Build Operate Transfer (BOT) scheme. Using this scheme, the private sectors build, operate at their own expense and after the period of the concession, they should hand it back to the government. In the construction phase, all the risks that must be handled by the private sectors (either in the form of financial or technical one) generally have be planned and managed, but not the ones occurred during post-construction (operational) phase, where a lot of them are often unexpected or unpredictable. The purpose of this study was to analyze how the post-construction risk management applied to the toll road with Build Operate Transfer (BOT) scheme from the operator's point of view. In this study, the risk of post-construction of toll roads were mapped and evaluated. For this purpose, risk identification, risk levels and strategies in response to the risks that occur in the post-construction were performed. Two relatively new toll roads opened to the public, i.e. Semarang-Solo toll road section 1 and 2; and Kanci-Pejagan toll road, were selected as case studies. The process of data collection was done by means of questionnaires and interviews to the parties concerned. The method used for the analysis of risk management was Risk Breakdown Structure (RBS). Data were analyzed by ranking the risks and risk responses, and then the proposed risk management strategies were selected. The results of this study indicated that the highest risk that may occur in Semarang-Solo toll road section 1 was associated with less effective maintenance of damaged surface of the road so that it contributed on the increase of the overhead cost. On the other hand, the highest risk for Kanci-Pejagan toll road was the unexpected projected revenue in the business plan.

Kinerja campuran beraspal perlu ditingkatkan dengan memodifikasi campuran beraspal untuk menghasilkan campuran yang kuat, tahan lama dan tahan terhadap deformasi plastis. Sementara kehadiran sampah plastik yang melimpah membutuhkan 1.000 tahun untuk diurai sempurna oleh tanah. Bedasarkan fakta ini, penelitian ini diusulkan untuk meningkatkan kinerja campuran beraspal dengan memanfaatkan sampah plastik. Hal ini karena plastik memiliki titik lembek tinggi sehingga diharapkan dapat meningkatkan ketahanan campuran bersapal terhadap pengaruh suhu dan elastisitas. Penelitian ini dilakukan dengan mengganti sebagian filler dengan sampah plastik LDPE dalam campuran beraspal. Perbedaan kadar dari LDPE yakni 0%, 2%, 4% dan 6% dari berat aspal, digunakan dalam penelitian ini untuk mensimulasikan efek dari kadar plastik pada kinerja campuran. Lima belas sampel campuran AC-WC dibuat untuk setiap variasi kadar LDPE kemudian dipadatkan dengan tumbukan 2x75. Kemudian, campuran dievaluasi oleh hal enam karakteristik Marshall, yaitu, stabilitas, flow, MQ, VIM, VMA dan VFA, satu parameter tambahan, yaitu indeks kekuatan sisa (IRS). Berdasarkan penelitian ini dihasilkan campuran dengan plastik cenderung kurang padat (seperti yang ditunjukkan oleh rongga udara yang lebih tinggi) dan menjadi lebih kaku (seperti ditunjukkan oleh stabilitas tinggi tetapi kelelehan rendah). Hal ini menunjukkan bahwa penambahan LDPE bisa membuat campuran menjadi lebih kaku namun berpori menyebabkan campuran memiliki ketahanan yang baik terhadap deformasi plastis tetapi lebih rentan terhadap retak dan kurang tahan lama. Meskipun hasil penelitian menunjukkan bahwa campuran dengan LDPE adalah tidak lebih baik dari campuran konvensional, penggunaan campuran ini untuk lapisan dasar seperti AC-BC masih mungkin. Dan ini didukung oleh semua sifat Marshall pada jenis-jenis terpilih (2% dan 4%) bisa memenuhi spesifikasi yang dikeluarkan oleh Direktorat Jenderal Bina Marga (Bina Marga).

Teknologi campuran aspal hangat (WMA) memungkinkan pencampuran, penghamparan, dan pemadatan pada temperatur lebih rendah dibandingkan pencampuran aspal panas (HMA). Teknologi ini dilakukan dengan menambahkan bahan aditif bernama Sasobit. Oleh karena itu dilakukan percobaan terhadap campuran beraspal dengan metode Asphalt Institute dengan kadar aspal 4,5%, 5%, 5,5%, 6%, dan 6,5% yang ditambahkan Sasobit dengan kadar 0%, 2%, 3%, dan 4% guna menentukan temperatur suhu pencampuran dan pemadatan pada campuran, membandingkan kualitasnya dengan campuran tanpa Sasobit sebagai kontrol. Dari hasil percobaan disebutkan bahwa penurunan suhu akibat penambahan Sasobit dengan kadar 2% turun hingga 6°C, akibat penambahan Sasobit dengan kadar 3% turun hingga 7,5°C, dan akibat penambahan Sasobit dengan kadar 4% turun hingga 7,8°C. Manfaat lain dari penambahan Sasobit kepada campuran beraspal adalah meningkatkan nilai stabilitas, menurunkan kadar persentase penggunaan aspal, dan mengurangi emisi gas buang hasil proses pencampuran aspal. Namun campuran dengan tambahan Sasobit juga memiliki kekurangan dimana campuran menjadi lebih kaku dan keras sehingga dapat lebih rentan rusak akibat retak bila dibandingkan campuran tanpa Sasobit.

Instances of missing data are common in pavement condition–performance databases. A common practice today is to apply statistical imputation methods to replace the missing data with imputed values. Pavement management decision makers must know the uncertainty and errors involved in the use of data sets with imputed values in their analysis. Equally important information of practical significance is the maximum allowable proportion of missing data (i.e., the level of missing data) that can still produce results with an acceptable magnitude of error or risk when the imputed data are used. This paper proposes a procedure for determining such useful information. A numerical example analyzing pavement roughness data is presented to demonstrate the procedure through evaluating the error and reliability characteristics of imputed data. The roughness data of three road sections were obtained from the Long-Term Pavement Performance database. From these data records, data sets with different ...