Yuyun Tajunnisa

Graving Dock adalah sebuah tempat untuk membangun atau memperbaiki kapal. Struktur graving dock pada umumnya terdiri dari struktur dinding beton dan struktur pelat lantai beton. Struktur graving dock yang ditinjau saat ini sering mengalami kerusakan pada struktur pelat dan struktur dindingnya. Kerusakan yang terjadi pada pelat lantai dapat disebabkan karena umur dan material bangunan yang sudah lebih dari 50 tahun, sedangkan pada dinding graving dock dapat disebabkan karena terbuat dari pasangan bata yang ditunjang sloof yang berada di atas fondasi batu kali tetapi tidak menjadi satu kesatuan dengan fondasi tersebut. Hal itu berpotensi menyebabkan kerusakan berat dan dapat mengganggu aktivitas perbaikan kapal di graving dock. Untuk menghindari kerusakan berat, pada pengabdian masyarakat ini dilakukan perbaikan dan perkuatan pada struktur pelat lantai dan dinding graving dock. Langkah awal yang dilakukan adalah survei pendahuluan bertujuan untuk memperoleh data kondisi saat ini. Selanjutnya dilakukan analisis dan evaluasi terhadap struktur graving dock yang ada saat ini. Langkah terakhir yang dilakukan adalah desain perbaikan graving dock. Hasil desain perbaikan, didapatkan dimensi dan penulangan yaitu struktur dinding tebal 30 cm dengan tulangan D16-150, struktur dinding miring tebal 50 cm dengan tulangan D19-150, pelat lantai tengah tebal 60 cm dengan tulangan D19-150, dan pelat lantai tepi tebal 45 cm dengan tulangan D19-150.

This study investigates the shear behavior of reinforced concrete beams constructed with high-calcium fly ash-based Ultra-Low Carbon Concrete (ULCC) as a sustainable alternative to conventional Portland Cement Concrete (PCC). The objective is to assess ULCC’s structural performance under shear and its potential as a low-carbon substitute. Using a dry-mix method with dry activators, six beams (five ULCC, one PCC) of identical dimensions (150 × 250 × 1800 mm) were tested under four-point bending, with variations in shear reinforcement, flexural reinforcement, and shear span-to-depth (a/d) ratios. Digital Image Correlation (DIC) was employed to monitor crack propagation and strain development, while Finite Element Modeling (FEM) provided numerical validation. Results show that increasing shear reinforcement enhanced capacity by 12.05%, whereas higher (a/d) ratios decreased it by 22.63%; increased flexural reinforcement improved shear resistance by 31.27%. FEM closely matched experimental outcomes, with a load-deflection ratio of 1.01. ULCC outperformed PCC in shear capacity and exceeded ACI 318-19 predictions. The integration of DIC and FEM offers a comprehensive analysis framework, and the findings demonstrate ULCC’s viability as a structurally efficient, environmentally sustainable alternative for shear-critical applications.

The shear capacity of reinforced beam concrete was designed to resist the stirrup reinforcement, Vs, and by the concrete itself, Vc. Previous studies of geopolymer concrete show the mechanical properties of this proposed green concrete, yet the structural investigation is infrequently investigated. These studies mostly observed the impact of using alternative binder resources that affect the workability, setting time, compressive strength, split tensile strength, and drying shrinkage. Therefore, this study aims to observe the structural behavior of geopolymer concrete, precisely its shear capacity. Four geopolymer concrete beam types were designed to have shear failure mode when tested using a Universal Testing Machine by four-point load bending method. The results showed that geopolymer concrete has ductile behavior. Comparison between the Vu value of the test results with Vn calculation of nominal cross-sectional capacity according to standard concrete rules in an average of 2.11 higher than the nominal capacity conventionally calculated according to SNI. Two models of linear regression equations for concrete Vc values were created to explore this further. It was found that the presence of a constant increases the value of the coefficient of determination by up to 29% for the Vc equation in geopolymer concrete. In addition, cracking patterns observed with the DIC method using GOM Correlate software also showed that all the beam specimens had failure both in flexure and shear, even though they all are designed in a shear failure state.

Desa Sumberrejo menghadapi dua permasalahan utama yakni, akses jalan yang buruk dan dampak limbah dari PLTU Paiton. Akses jalan yang tidak layak memerlukan renovasi, sementara limbah Fly Ash dan Bottom Ash (FABA) dari PLTU menyebabkan masalah lingkungan dan kesehatan. PLTU Paiton menghasilkan 75% fly ash dan 25% bottom ash dari pembakaran 250 ton batu bara per jam, yang berdampak pada kerusakan hasil panen serta berpotensi menimbulkan masalah kesehatan. Meskipun demikian, uji karakteristik FABA menunjukkan bahwa limbah ini termasuk dalam kategori Limbah Non B3 Terdaftar dan aman digunakan sebagai pengganti semen dalam pembuatan paving block. Penggunaan FABA dalam paving block dapat meningkatkan kekuatan, mengurangi konsumsi air, dan berdampak positif bagi lingkungan. Rencana optimalisasi pemanfaatan FABA mencakup sosialisasi dan pendampingan kepada masyarakat Desa Sumberrejo untuk mengolah limbah menjadi paving block. Inisiatif ini dapat memberikan pengetahuan untuk mengatasi masalah akses jalan, meminimalisasi dampak FABA, dan meningkatkan perekonomian desa. Studi lebih lanjut diperlukan untuk memahami karakteristik FABA, terutama terkait konduktivitas panas sinar matahari. Dengan upaya ini, Badan Usaha Milik Desa Sumberrejo (BUMDes) dapat memanfaatkan limbah PLTU secara berkelanjutan, meningkatkan produktivitas, dan menjaga lingkungan serta kesehatan masyarakat.

The performance of roof insulation such as polyurethane decreased due to problems such as insufficient absorption and poor thermal insulation performance, especially during rainstorms. The aims of this study are to investigate the physical property and its potential reinforced material such as rigid polyurethane doped with treated and untreated bamboo fiber composite (RPU-BF) at different ratios of 0, 25, 30, 35, and 40% of bamboo fibers as an insulation material for roof applications. The bamboo fibers were treated by using silane coupling agent treatment. The rigid polyurethane composite samples were prepared and then laminated bamboo fiber to overcome the sound problem in roofs. The physical characterization was investigated by Water Contact Angle (WCA), the morphological by Scanning Electron Microscopy (SEM), Thermo-gravimetric Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR) Analysis. The results showed that the treated bamboo fiber had a 192.5° water contact angle as a super hydrophobic property due to the presence of the chemical bonds Si-O-Si and Si-O-C in the silane coupling agent treatment. The morphology showed that 30% ratios of RPU-BF-T30 give the smallest pore diameter size. The peak of thermal degradation temperature of untreated and treated bamboo fiber was increased from 320°C to 350 °C with a weight loss of 80% to 50%. The treated bamboo fiber exhibited peaks at 3010–3040 cm-1 were associated with stronger Si-O-Si bonding, indicating the formation of new chemical bonds between bamboo fiber and silane coupling agent due to the ester bond from the cellulose, lignin, and hemicellulose. Thus, there was a similar trend peak in the functional chemical group in the FTIR spectrum of the RPU-BF composite. This result shows that RPU-BF composite had the potential of the optimum ratio of bamboo fiber as an insulation material for local communities and beneficial to the bamboo industry.

Performance of High-Damping Rubber Bearings for Seismic Isolation – Case Study of Nayumi Sam Tower Malang Apartment

The development of 3D Printing machine technology as a printing tool that uses an additive manufacturing method system with the aim of producing a three-dimensional (3D) object or object according to the default digital design file. 3D Printing was created to facilitate construction work, with 3D Printing construction work becoming lighter because this tool saves time, and costs, and reduces the risk of work accidents. With 3D Printing, work runs quickly and avoids problems in the development process. In the last few decades, many developed countries have used 3D Printing technology in making buildings. The 3D printing process basically consists of three different stages namely, data preparation, material preparation and transfer to the printer, and the printing stage. In the data preparation stage, the components are designed as 3D CAD models, then converted to STL (Stereolithography) format and sliced with the desired layer depth. The preparation of concrete involves mixing and placing it into a container. Once fresh concrete has been placed into the container, it can be channeled smoothly through a pump-pipe-nozzle system to print self-compacting concrete filaments, which build structural components layer by layer. The material used in this 3D printing method was Portland cement where this cement is easy to find among the public. Portland cement itself is the cement that is commonly used as a basic material for making concrete, plaster, mortar, and non-specialized mortar. In addition, fly ash and silica fumes are also added as a mixture. The addition of silica fumes increases the compressive strength of concrete. Furthermore, the addition of fly ash to the concrete has the effect of reducing drying shrinkage; but reducing the compressive strength of the concrete. In this study, the author focuses on the workability of 3D Printing concrete materials, and the impact of the material was added with additional type C fly ash and silica fume, namely flowability. The result is a concrete mix design that has good flowability value to be applied to the 3D Printing method