An improved computational method in structural dynamics

Purpose – In structural, earthquake and aeronautical engineering and mechanical vibration, the solution of dynamic equations for a structure subjected to dynamic loading leads to a high order system of differential equations. The numerical methods are usually used for integration when either there is dealing with discrete data or there is no analytical solution for the equations. Since the numerical methods with more accuracy and stability give more accurate results in structural responses, there is a need to improve the existing methods or develop new ones. The paper aims to discuss these issues. Design/methodology/approach – In this paper, a new time integration method is proposed mathematically and numerically, which is accordingly applied to single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems. Finally, the results are compared to the existing methods such as Newmark’s method and closed form solution. Findings – It is concluded that, in the proposed method, the data variance of each set of structural responses such as displacement, velocity, or acceleration in different time steps is less than those in Newmark’s method, and the proposed method is more accurate and stable than Newmark’s method and is capable of analyzing the structure at fewer numbers of iteration or computation cycles, hence less time-consuming. Originality/value – A new mathematical and numerical time integration method is proposed for the computation of structural responses with higher accuracy and stability, lower data variance, and fewer numbers of iterations for computational cycles.

An empirical study of capability development within product innovation projects

The objective of this paper is to develop insights into firms’ strategic capability development processes within product innovation projects. In particular, the research aims at investigating the interactions among product innovation, knowledge processes, and capability development within firms. Building on qualitative data from the auto-industry, our analysis reveals that across four product innovation projects, the case company developed architectural knowledge and capability. Findings reveal that, along with changes at each level of product architecture, “design knowledge” and “design capability” have been developed at the same level of product architecture, leading to capability development at that level. Furthermore, findings suggest that such capability transformation resulting from knowledge and capability creation over the course of case projects leads to modularization of product architecture. Overall, the research contributes to identifying and emphasizing the role of micro processes in capability development and renewal, which in turn enhances our understanding of strategic capability development processes.

Field performance of in-service cast iron water reticulation pipe buried in reactive clay

Field monitoring is an important means for understanding soil behaviour and its interaction with buried structures such as pipeline. This paper details the successful instrumentation of a section of an in-service cast iron water main buried in an area of reactive clay where frequent water pipe breakage has been observed. The instrumentation included measurement of pipe strain; pipe water pressure and temperature; soil pressure, temperature, moisture content and matric suction, as well as the meteorological conditions on site. The data generally indicated that changes in soil temperature, suction and moisture content were directly related to the local climatic variations. The suction and moisture content data indicated that the soil profile at the site down to around 700 mm, and probably down to 1000 mm, is affected by changes in surface weather, while soil conditions below this depth appear to be more stable. Analysis of pipe strain indicated that the pipe behaves like a cantilever beam, with the top experiencing predominantly tensile strains during summer. Subsequently, these trends reduce to compressive strains as soil swelling occurs due to increase of moisture content with the onset of winter.

Numerical modeling of thin steel roof battens under wind uplift loads

Extreme wind events such as tropical cyclones, tornadoes and storms are more likely to impact the Australian coastal regions due to possible climate changes. Such events can be extremely destructive to building structures, in particular, low-rise buildings with lightweight roofing systems that are commonly made of thin steel roofing sheets and battens. Large wind uplift loads that act on the roofs during high wind events often cause premature roof connection failures. Recent wind damage investigations have shown that roof failures have mostly occurred at the batten to rafter or truss screw connections. In most of these cases, the screw fastener heads pulled through the bottom flanges of thin steel roof battens. This roof connection failure is very critical as both roofing sheets and battens will be lost during the high wind events. Hence, a research study was conducted to investigate this critical pull-through failure using both experimental and numerical methods. This paper presents the details of numerical modeling and the results.

Emerging issues for road construction and maintenance – A futuristic view

In the coming decades the design, construction and maintenance of roads will face a range of new issues and as such will require a number of new approaches. In particular, road authorities will be required to consider and respond to a range of issues related to climate change, and associated extreme weather events, such as the extensive flooding in January 2011 in Queensland, Australia Figure 1). Coupled with diminishing access to road construction supplies (such as aggregate), water scarcity, and the potential for increases in oil and electricity prices, this range of challenges bear little resemblance to those previously faced. In Australia, state and federal authorities face further pressures given the variety of needs resulting from the country's geographical and population diversity, expansive road networks, road freight requirements and relatively small population base.

Reducing environmental pressures of road building

Although road construction and use provides significant economic and social benefits its environmental impact is of growing concern. Roads are one of the greatest greenhouse gas contributors both directly through fossil energy consumed in mining, transporting, earthworks, and paving work, along with in-direct emissions from road use by vehicles. This discussion paper will outline opportunities within the Australian context for reducing environmental pressure in road building and consider the future environmental impacts of road projects.

Skilling up for a low-carbon future: Vocational education and training

Given the need for both short and long-term training for sustainability discussed in the first of this three-part series (ECOS 158, pp 22–24), it is clear that the vocational education and training sector will play a major role in building capacity for our nation over the next five years.

Understanding pressures on the future of roads: A sustainable built environment National Research Centre Discussion Paper

According to the Australian Government, when combined with expected population growth and internal migration, expected changes in temperature and rainfall are expected to increase road maintenance costs by over 30 percent by 2100. This presents a significant future economic risk, in response, this paper will discuss the potential for roads to improve their resilience to the impacts of climate change and other key pressures. The paper will also highlight how such measures can inform state and national main road infrastructure planning and reduce future associated risks and costs.

Tuning in to a deeper wisdom

In 2005, natural sequence farming founder Peter Andrews was featured on ABC TV’s Australian Story, since voted one of the top five episodes of the last 10 years. His book Back from the Brink is a national bestseller. Why are Andrews’ ideas attracting so much attention?

The future of roads: How road agencies are facing a conflicted future

Although road construction and use provides significant economic and social benefits, its environmental impact is of growing concern. Roads are one of the greatest greenhouse gas contributors, both directly through fossil energy consumed in mining, transporting, earthworks and paving work, and through the emissions from road use by vehicles. Further,according to the Australian Government, when combined with expected population growth and internal migration,expected changes in temperature and rainfall are expected to increase road maintenance costs. This discussion paper will outline opportunities within the Australian context for reducing environmental and carbon pressure from road building, and provide a framework for considering the potential pressures that will affect the resilience of roads to the impacts of climate change and oil vulnerability.

Understanding the performance of green commercial buildings: a Sustainable Built Environment National Research Centre (SBEnrc) briefing report

Efforts to reduce carbon emissions in the buildings sector have been focused on encouraging green design, construction and building operation; however, the business case is not very compelling if considering the energy cost savings alone. In recent years green building has been driven by a sense that it will improve the productivity of occupants,something with much greater economic returns than energy savings. Reducing energy demand in green commercial buildings in a way that encourages greater productivity is not yet well understood as it involves a set of complex and interdependent factors. This project investigates these factors and focuses on the performance of and interaction between: green design elements, internal environmental quality, occupant experience, tenant/leasing agreements, and building regulation and management. This paper suggests six areas of strategic research that are needed to understand how conditions can be created to support productivity in green buildings, and deliver significant energy consumption reductions.

Education critical to going beyond business as usual

As government and industry grapple with 21st century challenges, building the capacity to look at complex problems through fresh eyes is critical.

The future of roads: Reducing environmental pressures and the management of carbon

Although road construction and use provides significant economic and social benefits, its environmental impact is of growing concern. Roads are one of the greatest greenhouse gas contributors, both directly through fossil energy consumed in mining, transporting, earthworks and paving work, plus the emissions from road use by vehicles. Further, according to the Australian Government, when combined with forecast population growth, internal migration and changes in temperature and rainfall, these are expected to increase road maintenance costs. This discussion paper outlines opportunities within the Australian context for reducing environmental and carbon pressure from road building, and provides a framework for considering the potential future pressures that will affect the resilience of roads to the impacts of climate change and oil vulnerability. Seven strategic areas are outlined for further investigation, including a guide to carbon management for road agencies covering planning, funding, procurement, delivery and maintenance of roads.

Reducing the environmental impact of road construction

The practice of road construction and maintenance is inherently lean and efficient; a result of the economic benefits that are gained by minimizing wasted resources. In this age of conservation and environmental management, the inbuilt sustainability of existing road construction practices is being developed and extended to produce variety of environmentally sustainable options. A new concept of a “sustainable road” has emerged through both academia and industry, and is defined to be a road that is: - constructed to reduce environmental impacts; - designed to optimise the alignment (vertical and horizontal including considerations of ecological constraints and operational use by vehicles); - resilient to future environmental and economic pressures (e.g. climate change and resource scarcity); - adaptable to changing uses including increased travel volumes, greater demand for public and active (cycling and walking) transport, and; - able to harvest the energy to power itself.