Current Issue : July-September Volume : 2025 Issue Number : 3 Articles : 5 Articles
Corrosion in steel girder ends, progressing from localized thinning of the web and the lower flange to severe perforation in severe cases, can significantly affect structural integrity. This study evaluates the effects of severe corrosion, including web–lower flange disconnection and transverse flange perforation combined with web damage, on the residual shear strength of steel girder end web panels through experimental and numerical methods. Results indicate that when only the web is affected, post-buckling strength starts to decline by corrosion damaging the plastic hinge on the tension flange, disrupting the tension field action. Conversely, in cases involving simultaneous web and lower flange damage, localized yielding at fracture points near the flange damage leads to the abrupt rotation of the tension field inclination angle, causing an earlier and more pronounced decline in post-buckling strength compared to web-only damage scenarios....
Large-span precast prestressed concrete box girders have been widely used in bridge construction near or across the sea. However, this would easily lead to a hydration heat problem, including large initial tensile stress and concrete cracks during the stage of concrete pouring. A 5 m long segment of the prestressed concrete box girder for the Hangzhou Bay Cross-Sea Railway Bridge was continuously monitored to investigate the hydration heat effect on the long-span concrete box girder during the pouring stage of construction. The initial temperature variation and stress distribution of the concrete in the segment were analyzed through finite element analysis based on the experimental data and temperature monitoring results. A suitable concrete pouring and maintenance plan for the box girder was proposed after the comparison of several construction schemes. The results indicate that the primary cause of initial tensile stress is the temperature difference between the inner and outer surfaces of the long-span precast concrete box girder. By adding some ventilation inside the box girder with suitable maintenance measures, the initial tensile stress in the concrete can be effectively reduced, thus mitigating the risk of early cracking....
Somalia’s construction sector grapples with systemic challenges threatening building safety, including fragmented regulations, unskilled labor, and substandard materials. Using a mixed methods approach, this study analyzes survey responses from 50 professionals and insights from 15 stakeholders to identify key structural challenges. Key findings reveal that 95% of respondents attribute safety risks to the lack of unified building codes, 85% report poor-quality concrete, and 70% cite high material costs as a barrier to compliance. Interviews with engineers, architects, contractors, and academics confirm that financial constraints, outdated training methods, and inadequate risk management exacerbate these issues. Recommendations include adopting Somalia-specific building codes, establishing a National Construction Authority, and prioritizing vocational training. This study underscores the urgency of systemic reforms to mitigate collapse risks and foster resilient infrastructure....
Understanding the mechanism of strength degradation in fiber-reinforced soils under freeze–thaw conditions is critical for expanding their engineering applications. In this study, shear tests were conducted on fiber-reinforced soil subjected to 0, 1, 5, 10, 20, and 30 freeze–thaw cycles to investigate variations in shear strength. The mechanisms driving these variations were analyzed through soil shear tests, fiber tensile tests, and fiber pull-out tests, all conducted under identical freeze–thaw conditions. The results indicated that fiber inclusion significantly enhances the shear strength of soils exposed to freeze–thaw cycles. However, the shear strength decreases exponentially as the number of cycles increases. The strength of fiber-reinforced soil is primarily due to the soil strength, fiber strength, and strength of the fiber–soil interface. All three components exhibit an exponential reduction under freeze–thaw conditions, contributing to the overall exponential decrease in the strength of fiber-reinforced soil....
Currently, the demand for environmental sustainability options in the construction industry is increasing, especially those related to the correct use of water. The aim of this work is to study different sustainable alternatives that minimize the use of water in cured hydraulic concrete, analyzing the effect of curing on hydration, microstructure, and compressive strength of hydraulic concrete exposed to different curing techniques: Manual Curing, Standard Curing, Vinipel, and Uncured. An experimental study was conducted using 180 cylindrical hydraulic concrete specimens, which were compression-tested at 7, 28, and 56 days. A Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer analysis was carried out to examine the microstructural and compositional changes under the different curing techniques. The results indicate that the Vinipel technique is the best alternative, showing a compressive strength of 35 MPa after 56 days of curing. In general, Vinipel > Standard Curing > Manual Curing > Uncured is the order of strength from highest to lowest. The formation of hydration products was observed in all curing techniques. The presence of ettringite, complementing by abundant portlandite in Vinipel, shows the dominance of an important product in the strength of concrete. The best strength capacity under load and the lowest percentages of vacuum are likely to be favorable for the durability of the processes....
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