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PERBAIKAN BALOK BETON BERTULANG YANG TELAH MENGALAMI BEBAN PUNCAK DENGAN BAJA SIKU Masdar Helmi
Rekayasa : Jurnal Ilmiah Fakultas Teknik Universitas Lampung Vol 13, No 1 (2009): Edisi April Tahun 2009
Publisher : UNIVERSITAS LAMPUNG

Show Abstract | Download Original | Original Source | Check in Google Scholar

Reinforced concrete beam can crack caused of load which is bigger than it’s capacity. It need aneffort to repair the beam, so the crack appearance and beam failure can be prevented. One of theways to repair is by installation of angel steel beam on out side of beam.The aim of research is to analyze flexural behavior of repaired reinforced concrete beam. Thebehavior contents : flexural strength, crack pattern, and displacement. The dimension of beam is120 mm x 185 mm x 1550 mm which was charged until crack and failed. There are 3 types ofangel steel beam : (50 x 50 x 5) mm, (40 x 40 x 4) mm, (30 x 30 x 3), that are installed in 3positions based on the eccentricity angel steel beam : behind of beam, inside of beam on bottomside, and beside of beam. Dynabolt, 6.5 cm of length and 8 mm of diameter, is installed 3 pieces in500 mm of distance. The sample is charged on 2 points at 1/3 of span.The results show up that the installation of angel steel beam can increase the flexural strengthcompared to flexural strength rest in reinforced concrete beam which had failed, even the originalone. The new crack are appear at around of dynabolt placed that descript there is force transferfrom concrete beam to angel steel beam. The displacement is less than original beam that showup the toughness also increase.

Efisiensi Pemilihan Jenis Retrofiting dan Perkuatan Struktur (Strengthening) antara Sistem Portal dengan Sistem Prategang Eksternal pada Jembatan Pelat Berongga (Voided Slab) (Studi Kasus Jembatan Way Bako I) Aditia Reshi Dista; Mohd. Isneini; Masdar Helmi; Todo Herdyson Sitohang; Yoga Marta Agustiawan
Jurnal Aplikasi Teknik Sipil Vol 18, No 2 (2020)
Publisher : Departemen Teknik Infrastruktur Sipil Institut Teknologi Sepuluh Nopember Surabaya

Sebuah jembatan dapat mengalami penurunan kekuatan akibat kerusakan struktur atau peningkatan beban sehingga tidak bisa berfungsi sebagaimana mestinya. Retrofiting dan strengthening merupakan alternatif solusi agar jembatan mampu melayani beban yang melintas sampai umur rencana. Penelitian ini bertujuan untuk mengevaluasi kondisi eksisting jembatan dan menganalisis metode retrofiting dan strengthening yang efisien dari segi kekuatan struktur dan biaya konstruksi. Analisis struktur prategang eksternal berdasarkan Pd-T-02-2004-B sedangkan sistem portal sesuai SNI-1729-2015. Hasil pengamatan kondisi jembatan menunjukkan bahwa Jembatan Way Bako I telah mengalami kerusakan struktur maupun non struktur. Nilai momen nominal dan lendutan sebelum perkuatan adalah 5569,57 kN.m dan 18 mm, setelah diperkuat dengan sistem prategang eksternal menjadi 7097,88 kN.m (Mu/Mn = 0,8191) dan 17 mm sedangkan sistem portal 13764,62 kN.m (Mu/Mn = 0,4131) dan 18 mm. Biaya sistem prategang eksternal Rp 1.170.790.000,- sedangkan sistem portal Rp 1.658.740.000,-. Dengan demikian metode prategang eksternal lebih tepat diterapkan pada Jembatan ini.

Fractal Dimension Analysis and Earthquake Repeated Period Estimation in the Southern Part of Sumatra Subduction Zone (Bengkulu-Lampung-Sunda Segment) Syamsurijal Rasimeng; Masdar Helmi; Tugiyono Tugiyono; Suharno Suharno
Indonesian Journal on Geoscience Vol 9, No 3 (2022)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.9.3.383-394

DOI:10.17014/ijog.9.3.383-394An earthquake seismicity parameter study has been conducted in the southern part of the Sumatra Subduction Zone (SSZ) for the period of 1919 to 2019 with a hypocentre depth of 120 km and magnitude of ≥4Mw. The researched area is divided into three segments, Bengkulu, Lampung, and Sunda segments, respectively. This study aims to evaluate the seismicity parameters in the form of a-value, b-value, fractal dimension, and probabilities of earthquake recurrence period. Frequency-magnitude correlation statistical approach introduced by Gutenberg-Richter was used to calculate the seismicity parameters based on catalogue data obtained from USGS. An a-value variation of 5.11±1.84 to 5.85±2.46 obtained indicates the most dominant seismic intensity. b-value of 0.69±0,.17 to 0.83±0.35 correlates with high-stress levels, the level of spatial heterogeneity on the SFZ, and the probabilities of bigger earthquakes in the future. The calculation of fractal dimension of 1.4±0.33 to 1.7±0.71 indicates an earthquake distribution pattern was caused by a single fracture zone along the southern part of SSZ. The fracture zone is located on the left and right sides of the southern part of SSZ, which may not have been connected. In addition, the calculation result of earthquake recurrence period with magnitude ≥6.5Mw indicates that there will be an 5 - 6 earthquake event in the Bengkulu segment, 2 - 3 event in the Lampung segment, and 1 - 2 event in the Sunda segment, while the probabilities of an earthquake with magnitude ≥7.5Mw along the southern part of SSZ is 1 - 2 times.

Fractal Dimension Analysis and Earthquake Repeated Period Estimation in the Southern Part of Sumatra Subduction Zone (Bengkulu-Lampung-Sunda Segment) Syamsurijal Rasimeng; Masdar Helmi; Tugiyono Tugiyono; Suharno Suharno
Indonesian Journal on Geoscience Vol. 9 No. 3 (2022)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.9.3.383-394

DOI:10.17014/ijog.9.3.383-394An earthquake seismicity parameter study has been conducted in the southern part of the Sumatra Subduction Zone (SSZ) for the period of 1919 to 2019 with a hypocentre depth of 120 km and magnitude of ≥4Mw. The researched area is divided into three segments, Bengkulu, Lampung, and Sunda segments, respectively. This study aims to evaluate the seismicity parameters in the form of a-value, b-value, fractal dimension, and probabilities of earthquake recurrence period. Frequency-magnitude correlation statistical approach introduced by Gutenberg-Richter was used to calculate the seismicity parameters based on catalogue data obtained from USGS. An a-value variation of 5.11±1.84 to 5.85±2.46 obtained indicates the most dominant seismic intensity. b-value of 0.69±0,.17 to 0.83±0.35 correlates with high-stress levels, the level of spatial heterogeneity on the SFZ, and the probabilities of bigger earthquakes in the future. The calculation of fractal dimension of 1.4±0.33 to 1.7±0.71 indicates an earthquake distribution pattern was caused by a single fracture zone along the southern part of SSZ. The fracture zone is located on the left and right sides of the southern part of SSZ, which may not have been connected. In addition, the calculation result of earthquake recurrence period with magnitude ≥6.5Mw indicates that there will be an 5 - 6 earthquake event in the Bengkulu segment, 2 - 3 event in the Lampung segment, and 1 - 2 event in the Sunda segment, while the probabilities of an earthquake with magnitude ≥7.5Mw along the southern part of SSZ is 1 - 2 times.

Green Building Assessment and Recommendations for Optimization Case Study of the Rectorate Building the University of Lampung Ika Kustiani; Masdar Helmi; Nur Syahidah Aini
Journal of Engineering and Scientific Research Vol. 5 No. 1 (2023)
Publisher : Faculty of Engineering, Universitas Lampung Jl. Soemantri Brojonegoro No.1 Bandar Lampung, Indonesia 35141

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jesr.v5i1.135

The Green Building Concept is a concept that offers a method of managing buildings with less energy and resources utilization to minimize the environmental impact. Since its implementation to be mandator, it is time for the University of Lampung to start implementing this concept. This research was aimed at assessing the Rectorate Building rating based on the national standard on Green Building Certification (Greenship-GBCI). There were several steps in conducting this research. Firstly, an opinion survey was conducted to measure the level of satisfaction of the building’s users. Secondly, a series of measurements related to lighting, temperature, humidity, noise, and air quality were carried out. Furthermore, an interview survey related to the operation and maintenance of the building were conducted. Finally, all of these data were entered in the Green Building rating tool for existing buildings. The results showed that the Rectorate Building score was 23 out of 117. This score is way below the score for a bronze rating of 35. Therefore, corrective action must be taken in order the building operation management to meet the Greenship-GBCI standard. Assessment also needs to be done on buildings througout the university for a reference in developing the University of Lampung Eco-campus program.

Effects of Carbon Fiber on Mechanical Properties of Reactive Powder Concrete Helmi, Masdar; Alraimi, Ala Ali Qasem
Journal of the Civil Engineering Forum Vol. 10 No. 3 (September 2024)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jcef.12439

The use of fiber generally might change the mechanical properties of concrete in flexural or compressive strength. Reactive powder concrete (RPC) is one of the ultra-high-performance concrete types that has been applied for some constructions. Carbon fiber, having high strength in tensile, also has the potency to improve the physical characteristics of RPC. The purpose of this study is to evaluate the flexural and compressive performance of RPC, focusing on the interfacial binding of carbon fiber. Flexural and compressive tests used samples with dimensions of 40 x 40 x 160 mm were tested in accordance with BS-EN-196-1:2011, which allows to use one of the two broken pieces from the flexural test as the sample. The microstructure surrounding carbon fiber and paste was qualitatively compared using Scanning Electron Microscopy (SEM) in the secondary electron detector mode. Samples were subjected to static pressure at 8 MPa after 1 hour of pouring and heat curing at 240 °C in a dry oven after demolding. Results show that the presence of carbon fiber increased the flexural strength of RPC by up to 28.85% for samples without treatments and up to 14.32% for samples with both treatments. Although carbon fiber increased toughness by 20% and flexural modulus by 6%, it had no effect on the failure mode after reaching the peak load, which remained brittle. On the other hand, the presence of carbon fiber had little effect on compressive strength. Despite the pressure and heat, curing treatments had no effect on enhancing the adhesion between carbon fiber and cement paste, which was indicated by theundamaged surface of carbon fiber. However, the implementation of both treatments on samples might produce RPC with good mechanical properties in flexure.

Increasing The Strength of Cellular Lightweight Concrete Bricks with The Addition of Bamboo Fiber Magnolia, An-Nisa; Akmal, Jamiatul; Martinus, Martinus; Savetlana, Shirley; Helmi, Masdar
Jurnal Rekayasa Proses Vol 18 No 2 (2024): Volume 18, Number 2, 2024
Publisher : Jurnal Rekayasa Proses

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.15320

This research aims to obtain technology for improving the quality of CLC (Celullar Lightweight Concrete) bricks to be equivalent to AAC (Autoclaved Aerated Concrete). This is a response to the rapid development, especially in the property sector, which is followed by the increasing need for bricks as the main material for building walls. CLC bricks are an alternative product other than red bricks that have the potential to pollute the environment because in the production process there is burning. The problem is that the quality of CLC bricks is relatively lower compared to AAC bricks. The method is to add bamboo fiber as a reinforcement and optimize the elements. The design of the experiment was made using the Taguchi Method, but preliminary experiments had previously been carried out to predict the percentage of elements. The research includes manufacturing process technology and quality testing on samples. Bamboo fiber-reinforced CLC bricks are obtained with an optimal composition of 0.5% fiber and a ratio of cement mass to sand mass of 1:1.6. This sample has a compressive strength of 1.1235 MPa and a bending strength of 1.1723 MPa. From this composition, samples were obtained with an average compressive strength of 1.1285 MPa and an average bending strength of 1.3551 MPa. Thus, it can be concluded that the addition of fiber can increase the strength of CLC bricks to be equal to or stronger than AAC bricks on the market.

Perancangan Sistem E-Commerce MotoPart Berbasis Web dengan Metode Waterfall Masdar Helmi; Ahmad Wahyudi; Bagus Rifai; Luthfi Ardeansyah R
Jurnal ilmiah Sistem Informasi dan Ilmu Komputer Vol. 5 No. 1 (2025): Jurnal ilmiah Sistem Informasi dan Ilmu Komputer
Publisher : Lembaga Pengembangan Kinerja Dosen

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55606/juisik.v5i1.1435

This research aims to develop MotoPart, an online marketplace application specifically designed to meet the demand for motorcycle spare parts in Indonesia. The background to the development of this application is the high demand for motorcycle spare parts along with the increasing number of two-wheeled vehicles, as well as various problems still frequently encountered in conventional distribution systems. These problems include limited access to genuine products, inefficiencies in the transaction process, and limited information regarding product availability. MotoPart was developed with the main goal of facilitating digital spare part buying and selling transactions that are easier, safer, and more efficient, as well as building an active, trusted, and integrated automotive ecosystem. In this research, a comprehensive system requirements analysis was conducted, covering functional requirements such as user registration and authentication, product management by sellers, a product search and filter system, a shopping cart feature, digital payments, delivery services, a user review system, notifications, transaction management, and an admin panel for monitoring. Meanwhile, non-functional requirements were also outlined to ensure system performance and reliability, including the required hardware and software specifications. The system design was carried out using a Data Flow Diagram (DFD) approach, starting from the context diagram to level 1 to illustrate the data flow and processes that occur. Furthermore, the database design was designed in detail with tables such as users, products, orders, and order items, to support systematic data management. With the development of MotoPart, it is hoped that it can provide solutions to obstacles in spare parts distribution, guarantee product authenticity, and become part of the digital transformation in the Indonesian automotive sector.

Pengaruh Substitusi Bahan Penyusun Beton Menggunakan Abu Ketel dan Limbah Genteng Terhadap Kuat Tekan Beton Safari, Azka Muhammad; Irianti, Laksmi; Helmi, Masdar; Husni, Hasti Riakara
Teras Jurnal : Jurnal Teknik Sipil Vol. 15 No. 1 (2025): Volume 15 Nomor 1, Maret 2025
Publisher : UNIVERSITAS MALIKUSSALEH

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/tj.v15i1.1198

Abstrak Hasil dari pembakaran limbah kelapa sawit menghasilkan abu ketel yang dapat dimanfaatkan sebagai bahan pozzolan. Limbah genteng juga dimanfaatkan sebagai substitusi dari agregat kasar. Pembuatan benda uji kubus 15cm x 15cm x 15cm untuk diuji kuat tekan pada umur 3, 7, 14, dan 28 hari, dengan variasi pada bahan penyusunnya 5% abu ketel terhadap berat semen dan 5%, 10%, 15%, dan 20% limbah genteng terhadap berat agregat kasar. Kuat tekan terbesar pada umur 28 hari untuk beton dengan substitusi hanya limbah genteng terdapat pada variasi 5% (G5) dengan kuat tekan 34,86 MPa. Substitusi 5% abu ketel untuk semen pada G5, kuat tekan beton mengalami peningkatan yang cukup signifikan menjadi 37,45 MPa. Hasil kuat tekan pada benda uji dengan kadar limbah genteng lain seluruhnya mengalami peningkatan kuat tekan setelah dilakukan substitusi 5% abu ketel pada semen. Sehingga subtitusi 5% abu ketel dapat meningkatkan kuat tekan pada beton dengan substitusi limbah genteng. Kata kunci: Abu ketel, limbah genteng, kuat tekan Abstract The combustion of palm oil waste produces boiler ash, which can be used as pozzolanic material. Tile waste is also used as a substitute for coarse aggregate. A 15cm x 15cm x 15cm cube specimen was produced to test the compressive strength at 3, 7, 14 and 28 days with variations in the constituents 5% boiler ash by weight of cement and 5%, 10%, 15% and 20% tile waste by weight of coarse aggregate. The highest compressive strength at 28 days for concrete with only tile waste substitution found in the 5% variation (G5) with a compressive strength of 34.86 MPa. Substituting 5% boiler ash for cement in G5, the compressive strength increased to 37,45 MPa. The compressive strength of other variations of tile waste increased after 5% substitution of boiler ash in cement. Therefore, 5% boiler ash substitution can increase the compressive strength of concrete with tile waste substitution. Keywords: boiler ash, tile waste, compressive strength

Pemanfaatan Limbah Industri Berupa Abu Ketel dan Silica Fume Untuk Peningkatan Kuat Tekan Beton Irianti, Laksmi; Helmi, Masdar; Widyawati, Ratna; Abdullah, Habib Ilham; Hidayatullah, Hadi
Teras Jurnal : Jurnal Teknik Sipil Vol. 15 No. 2 (2025): Teras Jurnal (September)
Publisher : UNIVERSITAS MALIKUSSALEH

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/tj.v15i2.1247

Abstrak Pembangunan infrastruktur di Indonesia mengalami kemajuan signifikan. Penelitian ini mengeksplorasi penggunaan abu ketel dan silica fume dalam beton sebagai alternatif berkelanjutan. Variasi percobaan mencakup penambahan dan penggantian sebagian semen dengan abu ketel dan silica fume. Hasil menunjukkan bahwa campuran dengan kandungan abu ketel dan silica fume memiliki slump yang lebih rendah, namun meningkatkan kuat tekan pada umur 28 dan 56 hari. Proporsi optimum sebagai bahan tambah adalah 5% abu ketel dan 5% silica fume dengan peningkatan kuat tekan dari 28 hari ke 56 hari sebesar 9,42 MPa sedangkan sebagai bahan pengganti sebagian semen adalah 85% semen, 5% abu ketel, dan 10% silica fume, mencapai kuat tekan beton kubus sebesar 28,93 MPa pada umur 28 hari dan 30,67 MPa pada umur 56 hari. Penelitian ini memberikan wawasan tentang potensi penggunaan limbah kelapa sawit dan sisa industri sebagai bahan tambahan dalam industri konstruksi untuk mendukung pembangunan berkelanjutan. Kata kunci: Abu Ketel, Silica Fume, Kuat Tekan Beton Abstract Infrastructure development in Indonesia has experienced significant progress. This research explores the use of palm kettle ash and silica fume in concrete as a sustainable alternative. Experimental variations include adding and replacing some of the cement with palm kettle ash and silica fume. The results showed that the mixture containing palm kettle ash and silica fume had a lower slump, but increased compressive strength at the ages of 28 and 56 days. The optimum proportion as an additive is 5% palm kettle ash and 5% silica fume with an increase in compressive strength from 28 days to 56 days of 9.42 MPa while as a partial replacement material for cement it is 85% cement, 5% palm kettle ash and 10% silica fume, reaching a compressive strength of cube concrete of 28.93 MPa at 28 days and 30.67 MPa at 56 days. This research provides insight into the potential for using palm oil waste and industrial residue as additional materials in the construction industry to support sustainable development. Keywords: Palm Kernel Ash, Silica Fume, Compressive Strength of Concrete

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