Studi Kedalaman Dan Pola Gerusan Lokal Yang Terjadi Di Hilir Bendung Dengan Kolam Olakan Tipe Bucket Dan USBR III

Most of spillways failure in Indonesia are caused by local scouring that happens continuously at downstream, and at time local scouring get the foot of spillway will dangerous for its operational. This scour occurs because of advanced value of specific energy overflow with high head relatively so that it appear unbalance velocity flow and turbulence flow. An effort to protect foot spillway is build the structure energy dissipator. From this concept at foot spillway is designed with one, two, or more energy dissipator agree with condition and many variables at deform process mechanism appropriately. At laboratory two dimensional physical test had done the consideration of spillway with bucket of type stilling basin to conventional spillway and having USBR III stilling basin at many discharges pattern and its influence for hydraulic jump bucket flow, energy reduction, along with local scour at downstream. This local scouring was caused by major water flowing passing the dam where there is a high difference level between the top and the end of the dam. Furthermore, it generates inbalancing water flow speed and additional water turbulence. There are different approachs to prevent such damage, and for example by providing one or more additional construction at the end part of the dam. This structure is designed and installed at the bottom part of the dam. Various empirical functions have been developed to design this structure, and one of them is developed by Lacey, Laursen, Froehlich, Mellvile and so on. However, that function has some limitation. For examples are the local river and dam construction characteristics. Therefore, it is required to be validated by developing a model of dam contructed in a laboratory. Experiments was undertaken by using the model with different characteristics of water flow in order to investigate the scouring patter

Scour Depth Estimation on Abutment With HEC RAS and Some Empirical Equation

Toe Scour around abutment will be very dangerous and cause loss of stability on the bridge. The case of structure failure on Batang Kalu bridge in Korong Pasa Usang Nagari Kayu Tanam, Padang Pariaman Regency on Monday (10 December 2018) is a clear example of toe scouring. A case study of toe scour was on the Batang Kalu River bridge structure has been carried out. Rainfall data closest to the study location, Kandang Empat Station was used to minimize the errors in the calculation of flood discharge design. Numerical modeling with HEC RAS and scouring estimation with some empiric equation was conducted to predicting scour depth on abutment. Simulation results show scour depth results to an average of 2.731 m and close to the scour depth that occurred in the field (2.83 m). Results showed that the local scouring in the Batang Kalu River bridge structure can be suspected as the influence of the increasing river steepness. Discharge that is triggered by heavy rain with a long duration and increased river flow velocity due to steepness has the potential to create a very intense scouring. Increasing of steepness may have been caused by sand mining activities in the upper reaches. Further studies are needed to see the potential slope changes due to exploitation in the Batang Kalu River upper reache

Gerusan Lokal yang Terjadi di Hilir Bendung dan Upaya Pengendaliannya

Majarity of damages on the dam construction in Indonesia is caused by continuous local scouring at the end side of the dam construction. It grows and reach its lower/bottorm part. It could results in degradation in the dam operation safety. This local scouring was caused by major water flowing passing the dam where there is a high difference level between the top and the end of the dam. Furthermore, it generates inbalancing water flow speed and additional water turbulence. There are different approachs to prevent such damage, and for example by providing one or more additional construction at the end part of the dam. This structure is designed and installed at the bottom part of the dam. Various empirical functions have been developed to design this structure, and one of them is developed by Lacey. The function is reprsented by D = 0.47 * (Q/F)1/2 (D= scouring depth, Q= Discharge, F= the size of the sand particle). However, that function has some limitation. For examples are the local river and dam construction characteristics. Therefore, it is required to be validated by developing a model of dam contructed in a laboratory. Experiments was undertaken by using the model with different characteristics of water flow in order to investigate the scouring pattern, and than method prefentif wor

Studi Kedalaman dan Pola Gerusan Lokal Yang Terjadi di Hilir Bendung dengan Kolam Olakan Tipe Bucket dan USBR III

Most of spillways failure in Indonesia  are caused by local scouring that happens continuously at downstream, and at time local scouring  get the foot of spillway will dangerous for its operational. This scour occurs because of advanced value of specific energy overflow with  high head relatively so that it appear unbalance velocity flow and turbulence flow.  An effort to protect foot spillway is build the structure energy dissipator. From this concept at foot spillway is designed with one, two, or more energy dissipator agree with condition and many variables at deform process mechanism appropriately.  At laboratory two dimensional physical test had done the consideration of spillway with bucket of type  stilling basin to conventional spillway and having USBR III stilling basin at many discharges pattern and its influence for hydraulic jump bucket flow, energy reduction, along with local scour at downstream.  This local scouring was caused by major water flowing passing the dam where there is a high difference level between the top and the end of the dam. Furthermore, it generates inbalancing water flow speed and additional water turbulence. There are different approachs to prevent such damage, and for example by providing one or more additional construction at the end part of the dam. This structure is designed and installed at the bottom part of the dam. Various empirical functions have been developed to design this structure, and one of them is developed by Lacey, Laursen, Froehlich, Mellvile and so on. However, that function has some limitation. For examples are the local river and dam construction characteristics. Therefore, it is required to be validated by developing a model of dam contructed in a laboratory. Experiments was undertaken by using the model with different characteristics of water flow in order to investigate the scouring patter

Site Specific Response Analysis Kota Padangdari Input motion Conditional Mean Spectrum(CMS)Menggunakan Software NERA

Dalam perencanaan struktur bangunan tahan gempa, tujuan umum dari analisa struktur dinamis adalah memprediksi respons dari struktur terhadap pengaruh ground motion yang memiliki Spectral Acceleration (Sa) pada periode tertentu berdasarkan tingkat kemungkinan terlampui (Probability of Excedence/PE)10% atau 2% masa layan bangunan 50 tahun.  Prediksi respons struktur ditentukan dengan memilih ground motion yang cocok dengan beberapa target spektra dan nantinya ground motion tersebut digunakan sebagai input dalam analisis dinamis struktur. Pada paper ini menyajikan analisis perambatan gelombang gempa dari batuan dasar ke lapisan permukaan (Site Specific Response Analysis/ SSRA). Data-data yang diperlukan adalah data stratifikasi tanah dan parameter kecepatan gelombang geser yang didapatkan dari korelasi empiris terhadap data hasil pemboran dan uji N-SPT. Ground motion synthetic batuan dasar yang digunakan untuk perambatan gelombang gempa diperoleh dari hasil penelitian sebelumnya yang mengadopsi pendekatan statistik Conditional Mean Spectrum (CMS) agar ground motion  yang dihasilkan dipermukaan cocok dengan prediksi masalah respon struktur yang sebenarnya. SSRA dilakukan berdasarkan teori perambatan gelombang geser satu dimensi dalam time domain dengan menggunakan program Non-linear Earthquake Response Analysis (NERA). Hasilnya diperoleh percepatan maksimum gempa dipermukaan (peak surface acceleration/ PBA)berbeda-beda di kedua lokasi tergantung pada faktor amplifikasi, karakteristik dan jenis gempa yang terjadi.Direkomendasikan respons spectra desain untuk periode ulang 475 tahun dan 2475 tahun wilayah 4 kelas tanah sedang (SD) untuk kedua lokasi tersebut.Data-data tersebut digunakan sebagai input dalam penentuan beban gempa pada bangunan dalam analisis struktur dinamis

Site Specific Response Analysis (SSRA) Kampus UNP Air Tawar, Kota Padang

In general, the seismic design provisions around the world present different criteria for local soil conditions depending on soil and rock properties to determine the design spectra representing seismic design. On the other hand, site-specific analysis results not only show the main characteristics of soil-rock profiles but also local soil characteristics where detailed studies are needed to review the earth response to earthquakes. In this study conducted Site Specific Response Analysis (SSRA) is to analyze the earthquake wave propagation from the bedrock to the surface layer. The data needed are ground stratification data and shear wave velocity parameters obtained from empirical correlation to N-SPT test drilling data. In addition, the required data is ground motion synthetic at baserocks used for the earthquake wave propagation obtained by Probabilistic Seismic Hazard Analysis (PSHA) 3-dimensional earthquake source referring from the results of previous research. SSRA is based on the theory of single-dimensional wave propagation in time domain using NERA (Non-linear Earthquake Response Analysis) program. Various inputs of earthquake movement are taken by considering suitable for Padang area. The results of this analysis are shown in the form of historical time acceleration graph and peak acceleration from each bore point location which is then processed to obtain amplification and response spectra design factors for the re-quake period of 475 years and 2475 years

Site Respon Analysis (SRA) Teluk Bayur (Kota Padang) Menggunakan Software NERA

In general, the seismic design provisions around the world present different criteria for local soil conditions depending on soil and rock properties to determine the design spectra representing seismic design. On the other hand, site-specific analysis results not only show the main characteristics of soil-rock profiles but also local soil characteristics where detailed studies are needed to review the earth response to earthquakes. In this study conducted Site Response Analysis (SRA) is to analyze the earthquake wave propagation from the bedrock to the surface layer. The data needed are ground stratification data and shear wave velocity parameters obtained from empirical correlation to N-SPT test drilling data. In addition, the required data is ground motion synthetic at baserocks used for the earthquake wave propagation obtained by Probabilistic Seismic Hazard Analysis (PSHA) 3-dimensional earthquake source referring from the results of previous research. SRA is based on the theory of single-dimensional wave propagation in time domain using NERA (Non-linear Earthquake Response Analysis) program. Various inputs of earthquake movement are taken by considering suitable for Padang area. The results of this analysis are shown in the form of historical time acceleration graph and peak acceleration from each bore point location which is then processed to obtain amplification and response spectra design factors for the re-quake period of 475 years and 2475 years

Analisa Debit Andalan Pada Das Batang Arau Dengan Menggunakan Model Soil And Water Assessment Tool (SWAT)

Batang Arau is one of the rivers that flows in the city of Padang, the upstream part of the Batang Arau watershed starting from the Lubuk Paraku river which is in the northeast of Padang City, with a water catchment area of 2,504 hectares which is Dr. Muhammad Hatta, Nature Reserve Area Barisan I and Arau downstream. The Batang Arau watershed has decreased its primary forest area due to the large number of additional settlements. The increase in residential area resulted in the land that was previously not waterproof. The mainstay discharge always increases in the rainy season and decreases in the dry season. The mainstay discharge in the Batang Arau watershed is calculated using the Fj Mock method. The Batang Arau watershed also knows the mainstay discharge that occurred in 2010, 2012 and 2018 using the Soil and Water Assessment Tool (SWAT) model. The analysis was obtained from four processes, namely delineation of the watershed, the formation of the Hydrologic Response Unit (HRU), the formation of climatological data, and the simulation process. For the HRU analysis of the Batang Arau watershed, it was obtained 7 sub-watersheds, the dominant HRU, namely primary dryland forest, was 74.68%