Journal of the Civil Engineering Forum

Revealing The Economic Viability Of Railway Investments (Case Study: Restoring Your Railway Programme, United Kingdom)

2024-05-31T13:10:32+07:00

The UK’s ”Restoring Your Railway” (RYR) programme aims to reopen abandoned railway infrastructure to foster local economic growth. However, since 2020, only 30% of RYR proposals have progressed, revealing challenges in the methodological approach, especially for projects introducing rail as a new mode. The current unimodal approach for estimating user benefits in such projects is considered inadequate. To address this, a Cost-Benefit Analysis (CBA) with improved methods for user benefit estimation has been conducted, compared with existing cases to determine if it results in a better Benefit-Cost Ratio (BCR). Historically, early appraisal methods relied on the Strategic Outline Business Case (SOBC), which took six months and incurred costs of approximately Rp. 1.5 billion. To expedite project delivery, sensitivity analysis explores circumstances under which RYR projects are socially justifiable across different Value for Money scenarios. Additionally, a comparative analysis is performed between the UK and Indonesian approaches. This study introduces a new CBA approach, focusing on user benefit estimation and conducting sensitivity analysis on key determinants. The mathematical CBA model, modified for the value of time and diversion factor, forms the basis for sensitivity analysis on BCR, travel time savings, capital and operational costs, diversion factor, and GDP growth. Testing the model against business cases reveals a 17-20% reduction in the required demand for the same BCR compared to conventional CBA approaches, suggesting the new method captures additional benefits related to mode shifts. Sensitivity analysis highlights circumstances under which railway projects are likely to deliver acceptable value for money, considering various BCR values. Total order indices show that operational costs contribute 40% to the model output, followed by capital costs and GDP growth rate at 29% and 25%, respectively. Surprisingly, the In-Vehicle Time (IVT) for trains has only a small contribution, ranging from 1.83% to 4%.

An Assessment Of Derelict Building Constructions Situated In Coastal Regions

2024-05-31T13:10:00+07:00

Reinforced concrete structures constructed in coastal areas in Indonesia often suffer damage before reaching their intended service life, with steel reinforcement corrosion being a major contributing factor. This study aims to investigate the use of concrete structures produced with simple methods and inadequate supervision in coastal regions. Reinforced concrete structures near the coast are susceptible to carbonation due to marine environmental factors, leading to reinforcement corrosion. The study was conducted on the Dande Dandere Market building, Tanakeke Island, Takalar Regency, South Sulawesi. The research method employed quantitative techniques, including surveys and structural testing. Visual inspections were conducted to identify the types of damage present in the building and estimate their causes. Structural testing involved both destructive and non-destructive tests. Concrete compressive strength testing was also conducted to assess the concrete sample’s compressive strength, along with carbonation testing to determine the acidity level of concrete due to the intrusion of salt compounds or carbonation formed within the concrete mass. The research findings indicate structural degradation in the market’s construction, occurring more rapidly than the intended lifespan of the building. Signs of structural degradation in the reinforced concrete construction include spalling of concrete cover on beams, supporting columns, and cantilever
slabs, as well as degraded reinforcement, with an average reduction in steel weight of 62.70% over six years, and an average weight loss of 0.103 grams per day. Therefore, efforts are needed to optimize the structural quality of the building through comprehensive repairs, starting from the foundation. However, for cost-efficient alternatives, it is recommended to use timber structural materials for new market construction. The use of timber in coastal buildings, which are vulnerable to marine influences, is more feasible as the presence of saltwater can inhibit wood decay caused by microorganisms.

Effects of Carbon Fiber on Mechanical Properties of Reactive Powder Concrete

2024-05-31T13:09:36+07:00

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 the
undamaged surface of carbon fiber. However, the implementation of both treatments on samples might produce RPC with good mechanical properties in flexure.