Humans are moving into urban areas at an accelerated pace. An increasing urban population fuels urban expansion and reduces nearby agricultural lands and natural environments such as forests, swamps, other water-pervious areas. Unsustainable development creates a disproportion between the growth of urban areas and the growth in urban population. The UN SDG indicator 11.3.1 specifically addresses the issue of the measurement of land-use efficiency. While the metric and methodology to estimate the indicator are straightforward, it faces problems of data unavailability and inconsistency. Vietnam has a record of tremendous economic growth that has translated into more urban settlements of size. Consequently, rural population movement into urban areas has led to many urban sustainable planning and development challenges. In the absence of previous work on estimating land-use efficiency in Vietnamese cities, this study makes the first attempt to examine land-use efficiency in Ha Long, one of the country’s fast-growing cities in recent decades. We mapped land use from high-resolution Landsat imagery (30 m) spanning multi-decadal observations from 1986 to 2020. An advanced machine learning approach, the Support Vector Machine algorithm, was applied to estimate the built-up area, which, by integration with census data, is essential for calculating SDG indicator 11.3.1. This study shows that the land-use efficiency metric was positive but small at the beginning of the considered period but increased in 2000–2020. These results suggest that before 2000, the urban land consumption rate in Ha Long was lower than the population growth rate, implying denser urban land use. The situation changed to the opposite when the urban land consumption rate exceeded the population growth rate in the past two decades. The study’s approach is applicable to regional and district levels to provide comparative analyses between cities or parts of a region or districts of the city. These analyses are valuable tools for assessing the impact of local urban and municipal planning policies on urban development.

This paper presents a reliability assessment of railway track buckling during extreme heatwave events. Monte Carlo simulation is used to estimate the probability of track buckling. The effects of important predictor parameters such as the effective buckling length and buckling modes of the rails, as well as the rail temperatures at the time of their installation and during the heatwave are taken into account in the simulation. The results show that the probability of the buckling of tracks during an extreme heatwave similar to the event that took place in Melbourne in January 2009 is about 2/100,000 on average, which is a good estimate of the number of the track segments that were actually observed to have buckled in the Melbourne railway network. This assessment demonstrates a science-based approach to reliability assessment for track buckling during heatwaves.

There has been growing recognition of the need for a more explicit consideration of material degradation effects in structural design. This article presents a procedure for the design of metal fasteners used in exposed timber structures that is suitable for use in modern reliability-based engineering design codes. The procedure is focused on the computation of the effective loss of structural section that is related to a specified service life. The fasteners are considered to be subjected to two types of corrosion: (1) the corrosion of exposed parts of the fasteners, where the corrosive agents are airborne salinity and pollution agents and (2) the corrosion of parts of the fasteners embedded in wood, where the corrosive agents are the wood acidity and preservatives. The corrosion of zinc and steel, and the effects of copper chrome arsenate preservative treatment are considered. The main design method, illustrated through a worked example in an Australian context, is applicable to most common types of mechanical joint in timber structures, but a special design procedure is required – and presented – for the shanks of bolts. The concept and format are applicable worldwide, when suitably modified according to local data and experience. Limitations and future research are suggested.

An experimental study is reported aimed at determining stiffness and strength of laterally loaded dowel-type fastener joints in Australian grown pine. Emphasis is on joints in Radiata pine lumber or glued-laminated (glulam) timber, and Slash pine lumber. Information was collected in a manner that makes it useful for load and resistance factor design. It was found that characteristic “one-fastener” design capacities of joints are most reliably based on the yield load rather than the ultimate load, and that for practical purposes behaviors of joints in Radiata pine and Slash pine can be regarded as identical.