ITB Journal
Not a member yet
5999 research outputs found
Sort by
Formula Empirik Periode Getar Fundamental Struktur Rangka Pemikul Momen Beton Bertulang di Indonesia
No full textAbstract
In dynamic analysis, the vibration period of a structure is recognized as a crucial factor that determines the structural response to earthquakes. The value of the structural vibration period is closely related to the stiffness and mass of a building, both of which are associated with the height and number of floors in the building. This study aims to establish a relationship between the structural vibration period, building height, and the number of floors in Indonesia. This research employs eigenvalue calculations to determine the structural vibration period. The vibration periods of 27 buildings with varying heights and numbers of floors are calculated, followed by statistical analysis to derive an empirical formula for the structural vibration period. The research findings indicate that the obtained vibration period data and resulting equation fall within the range of previous studies that employed direct measurement methods. Furthermore, this study proposes empirical formulas for the structural vibration period developed based on the lower bound of this research's data, offering estimates of conservative design earthquake forces.
Keywords: Vibration period, building height, number of floors, moment-resisting frame, concrete
Abstrak
Di dalam analisis dinamis, periode getar struktur diketahui menjadi faktor penting yang menentukan perilaku struktur terhadap gempa. Nilai periode getar struktur erat kaitannya dengan kekakuan dan massa bangunan, dimana keduanya berhubungan dengan tinggi dan jumlah lantai bangunan. Penelitian ini bertujuan mencari hubungan antara periode getar struktur dengan tinggi dan jumlah lantai bangunan di Indonesia. Penelitian ini menggunakan perhitungan nilai eigen untuk mendapatkan periode getar struktur. Sebanyak 27 bangunan gedung dengan ketinggian dan jumlah lantai yang bervariasi dihitung periode getarnya. Selanjutnya dilakukan analisis statistik untuk mendapatkan rumus empirik periode getar struktur. Hasil penelitian menunjukan bahwa data nilai periode getar dan persamaan yang dihasilkan berada dalam rentang data penelitian sebelumnya yang menggunakan metode pengukuran langsung. Selain itu, penelitian ini mengusulkan rumus empirik periode getar struktur yang dikembangkan berdasarkan batas bawah dari data penelitian ini untuk memberikan perkiraan gaya gempa desain yang konservatif.
Kata-kata kunci: Periode getar, tinggi bangunan, jumlah lantai, rangk a pem ik ul m om en, beton.Abstrak
Di dalam analisis dinamis, periode getar struktur diketahui menjadi faktor penting yang menentukan perilaku struktur terhadap gempa. Nilai periode getar struktur erat kaitannya dengan kekakuan dan massa bangunan, dimana keduanya berhubungan dengan tinggi dan jumlah lantai bangunan. Penelitian ini bertujuan mencari hubungan antara periode getar struktur dengan tinggi dan jumlah lantai bangunan di Indonesia. Penelitian ini menggunakan perhitungan nilai eigen untuk mendapatkan periode getar struktur. Sebanyak 27 bangunan gedung dengan ketinggian dan jumlah lantai yang bervariasi dihitung periode getarnya. Selanjutnya dilakukan analisis statistik untuk mendapatkan rumus empirik periode getar struktur. Hasil penelitian menunjukan bahwa data nilai periode getar dan persamaan yang dihasilkan berada dalam rentang data penelitian sebelumnya yang menggunakan metode pengukuran langsung. Selain itu, penelitian ini mengusulkan rumus empirik periode getar struktur yang dikembangkan berdasarkan batas bawah dari data penelitian ini untuk memberikan perkiraan gaya gempa desain yang konservatif.
Kata-kata kunci: Periode getar, tinggi bangunan, jumlah lantai, rangka pemikul momen, beto
PENENTUAN KADAR TOTAL FENOL, FLAVONOID, DAN PENAPISAN FITOKIMIA EKSTRAK ETIL ASETAT DAUN RAMBUTAN (NEPHELIUM LAPPACEUM L.)
Full text linkMedicinal plants are included in the abundant biodiversity heritage in Indonesia, including the South Kalimantan region, which still uses many plants in medicine. Rambutan (Nephelium lappaceum L.) is a plant known to contain phenolic compounds and flavonoids that have potential as therapeutic agents. This study was conducted to analyze the total phenol and flavonoid levels by UV-Vis spectrophotometric method and phytochemical screening. Extraction was carried out on rambutan leaves using the soklet method with ethyl acetate solvent. The results of phytochemical screening showed that the ethyl acetate extract of rambutan leaves contained phenol compounds, flavonoids, alkaloids, tannins, saponins, steroids, and triterpenoids. Determination of total phenol content was measured using Folin-Ciocalteu reagent with standard gallic acid comparison solution, while determination of total flavonoid content was measured using AlCl3 reagent with standard quercetin comparison solution. The total phenol content obtained from the ethyl acetate extract of rambutan leaves was 437.69 mgGAE/gram (43.76%), while the total flavonoid content was 81.490 mgQE/gram (8.14%). Based on the results of the study, it can be concluded that the ethyl acetate extract of rambutan leaves contains significant total flavonoid and phenol levels and contains secondary metabolite compounds so that it has the potential to be used in medicine.Tanaman obat termasuk kedalam warisan keanekaragaman hayati yang melimpah di Indonesia, termasuk wilayah Kalimantan Selatan masih banyak menggunakan tanaman dalam pengobatan. Rambutan (Nephelium lappaceum L.) adalah tanaman yang dikenal memiliki kandungan senyawa fenolik serta flavonoid yang berpotensi sebagai agen terapi pengobatan. Penelitian ini dilakukan untuk menganalisis kadar total fenol dan flavonoid dengan metode spektrofotometri UV-Vis dan penapisan fitokimia. Ekstraksi dilakukan pada daun rambutan menggunakan metode soklet dengan pelarut etil asetat. Hasil penapisan fitokimia menunjukkan bahwa ekstrak etil asetat daun rambutan mengandung senyawa fenol, flavonoid, alkaloid, tanin, saponin, steroid, dan triterpenoid. Penetapan kadar total fenol diukur menggunakan reagen Folin-Ciocalteu dengan standar larutan pembanding asam galat, sedangkan penetapan kadar total flavonoid diukur menggunakan reagen AlCl3 dengan standar larutan pembanding kuersetin. Kadar total fenol yang diperoleh dari ekstrak etil asetat daun rambutan sebesar 437,69 mgGAE/gram (43,76%), sementara kadar total flavonoid adalah 81,490 mgQE/gram (8,14%). Berdasarkan hasil penelitian, dapat disimpulkan bahwa ekstrak etil asetat daun rambutan mengandung total kadar flavonoid dan fenol yang cukup signifikan dan mengandung senyawa metabolit sekunder sehingga berpotensi untuk digunakan dalam pengobatan
Participatory Action For and Through Ecological Integrity: Toroidality as a Circular Design Model
Full text linkThe ecological crisis corrupts natural cycles, damages networks of organisms, and disrupts the ecosystem equilibrium. In response to the ecological crisis, the concept of circularity proposes reformative actions. However, these actions are insufficient to reverse the crisis and achieve ecological integrity because they are non-holistic and based on human concerns and priorities. A more inclusive and integrative mindset is necessary for better-functioning circular processes. In this regard, this research presents a theoretical framework for an alternative circular design model – Toroidality – which is driven by collective knowledge and participatory action. Toroidality functions through the integrative capacity of collective knowledge and collaboration among human and non-human stakeholders in the ecosystem. Based on the intertwined cycles of collective knowledge and collective value-creation, Toroidality becomes a self-feeding circular design model. Through its four-phased circular design processes, Toroidality claims to generate solutions that have regenerative capacities. This article clarifies the conceptual background, theoretical framework and complementary notions to present the fundamentals of Toroidality. After this initial explanatory article, the dynamics of the phases and interactions among the stakeholders are aimed to be explored and reported in the following research, through a real-life case study
Grassroots Representation or Pro Forma Exercise? Cooperation and Participation in the Revitalization of Polish Municipalities
Full text linkThis article explores a participatory approach to revitalizing degraded urban areas. The study examined whether revitalization committees in Poland serve as platforms for cooperation among various stakeholders and to assess local authorities’ views on the importance of individual stakeholders in the revitalization process. This article presents the concept of sustainable revitalization as a response to urban crises and discusses the dilemmas and challenges associated with the participatory approach to planning and implementation.
To gather opinions from local authorities on the functioning of revitalization committees and other advisory bodies that include revitalization stakeholders, quantitative research was conducted in 573 Polish municipalities. The online survey questionnaire was addressed to mayors or heads of villages and their deputies. The research results indicate that the permanent involvement of stakeholders in revitalization is not common among Polish municipalities. Although local leaders highly rated the importance of partnerships and local cooperation in revitalization and reported no difficulties in establishing revitalization committees, these committees operated in only 27% of the surveyed municipalities. The established revitalization committees are characterized by both administrative and social functions, predominantly comprising local government officials, local authorities, and NGO representatives. Business communities, vulnerable groups, and institutions addressing socio-economic issues in the revitalized areas are relatively underrepresented in these committees. A key finding of the study is the mismatch between the high importance assigned by local leaders to certain stakeholder groups and the limited presence of these groups in the composition of revitalization committees
Analisis Kerentanan Seismik pada Jembatan Beton Bertulang Eksisting dengan Kolom Pendek: Tinjauan Terkini
Full text linkAbstrak
Struktur jembatan beton bertulang eksisting yang direncanakan berdasarkan peraturan lama umumnya belum mempertimbangkan konsep perencanaan tahan gempa dan belum mengaplikasikan detailing seismik yang memadai. Hal ini menjadi perhatian bagi jembatan eksisting dengan kolom pendek yang memiliki aspek rasio (a/h) di bawah 2.5 dan berpotensi mengalami mekanisme keruntuhan geser atau geser-lentur. Mekanisme keruntuhan tersebut mengakibatkan performa struktur jembatan akibat gempa memiliki tingkat ketidakpastian yang tinggi. Analisis kerentanan seismik pada struktur jembatan eksisting dapat dilakukan dengan mengembangkan kurva kerentanan menggunakan incremental dynamic non-linear time history analysis yang mampu menghasilkan nilai probabilitas kerusakan pada berbagai intensitas gempa. Penelitian terdahulu umumnya mengembangkan kurva kerentanan berdasarkan idealisasi perilaku sendi plastis pada kolom jembatan yang mengalami mekanisme keruntuhan lentur akibat beban gempa. Studi ini menyampaikan tinjauan terkini (state-of-the-art) yang meliputi penelitian struktur jembatan beton bertulang dengan kolom pendek, khususnya yang perilaku keruntuhannya tidak didominasi oleh mekanisme lentur. Tinjauan ini juga mengusulkan kerangka kerja untuk penilaian risiko seismik dan pengembangan kurva kerentanan yang lebih sesuai untuk struktur jembatan dengan kolom pendek. Hasil tinjauan ini dapat memberikan gambaran yang lebih jelas mengenai risiko seismik yang dihadapi oleh jembatan dengan kolom pendek, serta menunjukkan potensi penelitian lanjutan yang dapat dilakukan untuk pengembangan kurva kerentanan yang lebih akurat dan relevan.
Kata-kata Kunci: Analisis kerentanan seismik, jembatan beton bertulang eksisting, kolom pendek, kurva kerentanan, mekanisme keruntuhan geser
Abstract
Existing reinforced concrete bridge structures designed based on older regulations often do not consider seismic design concepts and lack adequate seismic detailing. This issue is particularly concerning for existing bridges with short columns and aspect ratio (a/h) below 2.5, which has the potential of shear or flexural-shear failure mechanisms. These failure mechanisms result in a high level of uncertainty in the seismic performance of bridge structures.Seismic fragility analysis of existing bridge structures can be performed by developing fragility curves using the incremental dynamic non-linear time history analysis method, which is capable of providing damage probability for various levels of seismic intensity. Previous studies typically developed fragility curves based on idealized plastic hinge behavior in bridge columns subjected to flexural failure mechanisms.This study presents a state-of-the-art review of reinforced concrete bridge structures with short columns, especially those whose failure behavior are not dominated by flexure mechanism. This review also proposes a framework for seismic risk assessment and for the development of more suitable fragility curves for bridge structures with short columns.The findings of this study can provide an understanding of the seismic risk in bridges with short columns, while also highlighting the potential for future research to develop more accurate and relevant fragility curves.
Keywords: Seismic fragility analysis, existing reinforced concrete bridges, short columns, fragility curves, shear failure mechanismsAbstrak
Struktur jembatan beton bertulang eksisting yang direncanakan berdasarkan peraturan lama umumnya belum mempertimbangkan konsep perencanaan tahan gempa dan belum mengaplikasikan detailing seismik yang memadai. Hal ini menjadi perhatian bagi jembatan eksisting dengan kolom pendek yang memiliki aspek rasio (a/h) di bawah 2.5 dan berpotensi mengalami mekanisme keruntuhan geser atau geser-lentur. Mekanisme keruntuhan tersebut mengakibatkan performa struktur jembatan akibat gempa memiliki tingkat ketidakpastian yang tinggi. Analisis kerentanan seismik pada struktur jembatan eksisting dapat dilakukan dengan mengembangkan kurva kerentanan menggunakan incremental dynamic non-linear time history analysis yang mampu menghasilkan nilai probabilitas kerusakan pada berbagai intensitas gempa. Penelitian terdahulu umumnya mengembangkan kurva kerentanan berdasarkan idealisasi perilaku sendi plastis pada kolom jembatan yang mengalami mekanisme keruntuhan lentur akibat beban gempa. Studi ini menyampaikan tinjauan terkini (state-of-the-art) yang meliputi penelitian struktur jembatan beton bertulang dengan kolom pendek, khususnya yang perilaku keruntuhannya tidak didominasi oleh mekanisme lentur. Tinjauan ini juga mengusulkan kerangka kerja untuk penilaian risiko seismik dan pengembangan kurva kerentanan yang lebih sesuai untuk struktur jembatan dengan kolom pendek. Hasil tinjauan ini dapat memberikan gambaran yang lebih jelas mengenai risiko seismik yang dihadapi oleh jembatan dengan kolom pendek, serta menunjukkan potensi penelitian lanjutan yang dapat dilakukan untuk pengembangan kurva kerentanan yang lebih akurat dan relevan.
Kata-kata Kunci: Analisis kerentanan seismik, jembatan beton bertulang eksisting, kolom pendek, kurva kerentanan, mekanisme keruntuhan geser
Abstract
Existing reinforced concrete bridge structures designed based on older regulations often do not consider seismic design concepts and lack adequate seismic detailing. This issue is particularly concerning for existing bridges with short columns and aspect ratio (a/h) below 2.5, which has the potential of shear or flexural-shear failure mechanisms. These failure mechanisms result in a high level of uncertainty in the seismic performance of bridge structures.Seismic fragility analysis of existing bridge structures can be performed by developing fragility curves using the incremental dynamic non-linear time history analysis method, which is capable of providing damage probability for various levels of seismic intensity. Previous studies typically developed fragility curves based on idealized plastic hinge behavior in bridge columns subjected to flexural failure mechanisms.This study presents a state-of-the-art review of reinforced concrete bridge structures with short columns, especially those whose failure behavior are not dominated by flexure mechanism. This review also proposes a framework for seismic risk assessment and for the development of more suitable fragility curves for bridge structures with short columns.The findings of this study can provide an understanding of the seismic risk in bridges with short columns, while also highlighting the potential for future research to develop more accurate and relevant fragility curves.
Keywords: Seismic fragility analysis, existing reinforced concrete bridges, short columns, fragility curves, shear failure mechanism
An Isolation Model for Tuberculosis Dynamics with Optimal Control Application
Full text linkTuberculosis (TB) remains a persistent global health challenge, worsened by asymptomatic carriers who contribute to undetected transmission. An SIQR mathematical model that classifies infected individuals into symptomatic and asymptomatic classes, with isolation as the primary intervention, is formulated in this study. We establish the positivity and invariant region to ensure epidemiological relevance and derive the basic reproduction number, R0, as a threshold for disease persistence. The model analysis reveals that the diseasefree equilibrium is both locally and globally asymptotically stable if R0 < 1, while an endemic equilibrium also exists if R0 > 1. The key parameters influencing transmission dynamics are identified through sensitivity analysis. Furthermore, an optimal control framework is formulated using the Pontryagin’s maximum principle to assess the efficacy of isolation in reducing disease burden while minimizing associated costs. Numerical simulations demonstrate that well-implemented isolation significantly curtails TB spread, highlighting its potential as a targeted intervention
The Relationship between Self-efficacy and Goal setting in Student Sepak Takraw Athletes in Indonesia
Full text linkSelf-efficacy and goal setting were psychological factors that influenced athletes in improving sports performance. This study aimed to determine the relationship between self-efficacy and goal setting in student Sepak Takraw athletes in Indonesia. The instruments used were the Athlete Self-Efficacy Scale (ASES) (Koçak, 2020) and the Self-Audit Questionnaire for Goal Setting (Wilson & Dobson, 2008). Data collection was carried out using the convenience sampling technique. The study involved 156 Sepak Takraw athletes aged 12-18 years. Descriptive statistical analysis was used to describe the levels of self-efficacy and goal setting among Sepak Takraw athletes, while Spearman correlation analysis was conducted to examine the relationship between the two variables. The results indicated that 66.03% of athletes had a moderate level of self-efficacy, while goal setting was also categorized as moderate, with a percentage of 75.64%. The relationship between self-efficacy and goal setting showed r = 0.638 (p < 0.001), indicating a significant relationship with a strong correlation between these two variables in student Sepak Takraw athletes in Indonesia. The findings of this study can be applied in training programs by optimizing self-efficacy and goal setting, such as implementing the SMART method (Specific, Measurable, Achievable, Relevant, Time-bound) as a strategy to enhance athlete performance.Self-efficacy berpengaruh bagi seorang atlet untuk melihat seberapa yakin dan percaya atlet terhadap kemampuan dirinya sendiri guna menyelesaikan suatu tugas olahraga. Tugas seorang atlet pelajar selain sekolah adalah melakukan latihan rutin yang perlu adanya penyelarasan tujuan di usia atlet yang masih muda. Goal setting diterapkan untuk membantu atlet mampu merancang serta merumuskan suatu tujuan sehingga dapat meningkatkan self-efficacy yang dimilikinya. Penelitian ini bertujuan untuk mengetahui hubungan antara self-efficacy dengan goal setting pada atlet Sepak Takraw pelajar di Indonesia. Penelitian ini menggunakan instrument Athlete Self-efficacy Scales (ASES) (Koçak, 2020) untuk mengukur tingkat self-efficacy sedangkan untuk goal setting menggunakan kuesioner self-audit for goal setting (Wilson & Dobson, 2008). Proses pengumpulan data dilakukan dengan teknik convenience sampling, kuesioner disebarkan menggunakan google form. Jumlah partisipan pada penelitian ini 156 atlet sepak takraw dengan rentang usia 12 hingga 18 tahun. Penelitian ini menggunakan statistik deskriptif untuk menggambarkan tingkat self-efficacy dan goal setting atlet sepak takraw, serta analisis korelasi Spearman untuk melihat hubungan antara kedua variabel. Hasil penelitian menunjukkan tingkat self-efficacy dan goal setting pada atlet sepak takraw pelajar di Indonesia dalam kategori sedang. Serta hubungan antara self-efficacy dan goal setting sebesar 0,638<0,001 dimana terdapat hubungan yang signifikan antara self-efficacy dan goal setting pada atlet sepak takraw pelajar di Indonesia
The Influence of Positive Self-Talk on Decision-Making of Young Futsal Athletes
Full text linkFutsal sports have very fast and dynamic game characteristics that require players to move quickly and dynamically on the field. During the match, the psychological changes of futsal athletes must change due to several factors such as stress, Concentration Stress, and mental pressure. Therefore, one of the mental skills that can be used when several of these factors occur is to use Positive Self-Talk skills. This study aims to determine the positive influence of self-talk on the decision- making of young futsal athletes. The method used is an experiment with a quantitative approach and one-group pretest-posttest design. The sample consisted of 12 futsal extracurricular students of SMAN 11 Bandung with a total sampling technique. The instrument used was the Decision Style Questionnaire (DSQ). The results showed there is a significant effects positive self-talk on decision-making of young futsal athletes. These findings suggest that positive self-talk is effective in improving decision-making in young futsal athletes. It is recommended that coaches incorporate mental self-talk training into training programs and that further research be conducted with a larger sample size and exploration of other types of self-talk
Prediksi Model Zonifikasi Wilayah Peri-urban Kota Bandung Bagian Timur
Full text linkUrbanization pressure has driven the expansion of Bandung's urban area to the East, especially in Cileunyi, Rancaekek, and Jatinangor Districts. As a peri-urban area of Bandung City, which is a transition zone between urban and rural areas, the challenges of its development are increasingly complex, especially since the area has physical limitations but does not hinder land conversion. This study aims to predict land cover changes and zonification models in the Eastern peri-urban area of Bandung City using the Cellular Automata Markov model. The results indicated that urban growth in the peri-urban area of Bandung City, especially in Cileunyi District, occurred significantly, forming an urban-rural frame zone (zobikodes). This pattern indicates strong competition between development interests and environmental conservationefforts. This transformation indicates that urbanization in the peri-urban area is not only triggered by population growth but also by economic dynamics, accessibility, and spatial planning policies that have not been fully able to control urban sprawl. The conclusion of this study confirms that without stricter and evidence-based policy interventions, uncontrolled urban expansion risks accelerating environmental degradation, reducing ecological resilience, and threatening the sustainability of agricultural land. Therefore, the resulting zonification models can be the basis for formulating a more adaptive and sustainable spatial planning strategy to balance economic growth with environmental preservation in the peri-urban areas of Eastern Bandung City.Tekanan urbanisasi telah mendorong ekspansi wilayah perkotaan Bandung ke wilayah Timur, terutama di Kecamatan Cileunyi, Rancaekek, dan Jatinangor. Sebagai wilayah peri-urban Kota Bandung yang menjadi zona peralihan antara kawasan perkotaan dan perdesaan, tantangan pengembangannya semakin kompleks, wilayah tersebut memiliki keterbatasan secara fisik namun tidak menghambat terjadinya perubahan tata gunalahan. Penelitian ini bertujuan untuk memprediksi perubahan tutupan lahan dan pola zonifikasi di wilayah peri-urban Kota Bandung bagian Timur dengan menggunakan model Cellular Automata Markov. Hasil penelitian menunjukkan pertumbuhan perkotaan di wilayah peri-urban Kota Bandung, khususnya di Kecamatan Cileunyi, terjadi secara signifikan membentuk zona bingkai kota-desa (zobikodes). Hal ini mengindikasi adanya persaingan kuat antara kepentingan pembangunan dengan upaya pelestarian lingkungan. Model zonifikasi yang dihasilkan dapat menjadi dasar bagi perumusan kebijakan tata ruang yang lebih efektif untuk mengendalikan urban sprawl dan menjaga keseimbangan ekologis di wilayah peri urban
The Impact of Convective Available Potential Energy (CAPE) on Spatio-Temporal Variations of Indonesian Extreme Rainfall
Full text linkAtmospheric instability frequently influences the distribution of precipitation and is closely associated with atmospheric dynamics and thermodynamics. An increase in convective available potential energy (CAPE) has the potential to result in the development of convective clouds, which could contribute to extreme rainfall. This study used rainfall data from Asian Precipitation–Highly Resolved Observational Data Integration Towards Evaluation (APHRODITE) and CAPE data from the European Centre for Medium-Range Weather Forecasts. We defined extreme rainfall trends by applying the Expert Team on Climate Change Detection and Indices (ETCCDI), which include the number of days with precipitation greater than the 95th percentile (R95P), consecutive dry days (CDD), consecutive wet days (CWD), the number of days with precipitation greater than 10 mm (R10mm), the number of days with precipitation greater than 20 mm (R20mm), and the Simple Daily Intensity Index (SDII). Using Mann-Kendall statistics, we found that the trend of extreme rainfall in Indonesia from 1983 to 2007 was predominantly characterized by the extreme category, as indicated by the increasing CDD indices. During the MAM-SON seasons, the CAPE had a substantial contribution to the extreme rainfall in Indonesia. The CAPE exhibited a significant positive (negative) correlation with the CWD and R10mm (CDD) indices