Experimental investigation on lateral impact response of concrete-filled double-skin tube columns using horizontal-impact-testing system

This paper presents an experimental investigation on the lateral impact performance of axially loaded concrete-filled double-skin tube (CFDST) columns. These columns have desirable structural and constructional properties and have been used as columns in building, legs of off shore platforms and as bridge piers. Since they could be vulnerable to impact from passing vessels or vehicles, it is necessary to understand their behaviour under lateral impact loads. With this in mind, an experimental method employing an innovative instrumented horizontal impact testing system (HITS) was developed to apply lateral impact loads whilst the column maintained a static axial pre-loading to examine the failure mechanism and key response parameters of the column. These included the time histories of impact force, reaction forces, global lateral deflection and permanent local buckling profile. Eight full scale columns were tested for key parameters including the axial load level and impact location. Based on the test data, the failure mode, peak impact force, impact duration, peak reaction forces, reaction force duration, column maximum and residual global deflections and column local buckling length, depth and width under varying conditions are analysed and discussed. It is evident that the innovative HITS can successfully test structural columns under the combination of axial pre-loading and impact loading. The findings on the lateral impact response of the CFDST columns can serve as a benchmark reference for their future analysis and design.

Review of vibration-based damage detection and condition assessment of bridge structures using structural health monitoring

As a part of vital infrastructure and transportation networks, bridge structures must function safely at all times. However, due to heavier and faster moving vehicular loads and function adjustment, such as Busway accommodation, many bridges are now operating at an overload beyond their design capacity. Additionally, the huge renovation and replacement costs always make the infrastructure owners difficult to undertake. Structural health monitoring (SHM) is set to assess condition and foresee probable failures of designated bridge(s), so as to monitor the structural health of the bridges. The SHM systems proposed recently are incorporated with Vibration-Based Damage Detection (VBDD) techniques, Statistical Methods and Signal processing techniques and have been regarded as efficient and economical ways to solve the problem. The recent development in damage detection and condition assessment techniques based on VBDD and statistical methods are reviewed. The VBDD methods based on changes in natural frequencies, curvature/strain modes, modal strain energy (MSE) dynamic flexibility, artificial neural networks (ANN) before and after damage and other signal processing methods like Wavelet techniques and empirical mode decomposition (EMD) / Hilbert spectrum methods are discussed here.

Trip to Sunshine Coast Queensland, September 2004 visit to bridge and foreshore

A trip was undertaken to look at concerns of Public Works and Main Roads Departments of Queensland. David Paterson and Wayne Ganther from CSIRO travelled to the Sunshine Coast with Alan Carse of Queensland Department of Main Roads and Michael Ball of Queensland Department of Public Works. We were also joined for part of the visits by Ed Bowers of QBuild which is a commercial unit of Public Works responsible for maintenance of Public Works. During the trip we visited a bridge on the David Low Way at Sunrise Beach near Noosa. This bridge was in a serve marine environment with high salt content in the concrete and corrosion of the galvanised guardrails and barriers. Also the foreshore at Coolum was visited and the use of stainless steel was examined. This is discussed in this report. Most problems stemmed from incorrect specification due to lack of awareness of the severity of the environment. The companion report Visit to Schools Report 2002-059-B No 7. covers the visit to four schools north of Caloundra.

A45 ICT curriculum design to bridge the gap between industry and academia

Building Information Model (BIM) software, collaboration platforms and 5D Construction Management software is now commercially available and presents the opportunity for construction project teams to design more cost effectively, plan construction earlier, manage costs throughout the life cycle of a building project and provide a central asset management register for facilities managers. This paper outlines the merits of taking a holistic view of ICT in curriculum design. The educational barriers to implementation of these models and planning tools are highlighted. Careful choice of computer software can make a significant difference to how quickly students can master skills; how easy it is to study and how much they enjoy learning and be prepared for employment. An argument for BIM and 5D planning tools to be introduced into the curriculum to assist industry increase productivity and efficiencies are outlined by the authors.

Comparison between ACI 440 and FIB 14 design guidelines in using CFRP for strengthening of a concrete bridge headstock

This paper compares and reviews the recommendations and contents of the guide for the design and construction of externally bonded FRP systems for strengthening concrete structures reported by ACI committee 440 and technical report of Externally bonded FRP reinforcement for RC structures (FIB 14) in application of carbon fiber reinforced polymer (CFRP) composites in strengthening of an aging reinforced concrete headstock. The paper also discusses the background, limitations, strengthening for flexure and shear, and other related issues in use of FRP for strengthening of a typical reinforced concrete headstock structure such as durability, de-bonding, strengthening limits, fire and environmental conditions. A case study of strengthening of a bridge headstock using FRP composites is presented as a worked example in order to illustrate and compare the differences between these two design guidelines when used in conjunction with the philosophy of the Austroads (1992) bridge design code.

Developing within-company information and communication technologies (ICT) innovation diffusion networks : a study of three Australian major contractors

The innovation diffusion and knowledge management literature strongly supports the importance of communities of practice (COP) for enabling knowledge about how to use and adopt innovation initiatives. One of the most powerful tools for innovation diffusion is word-of-mouth wisdom from committed individuals who mentor and support each other. Close proximity for face-to-face interaction is highly effective, however, many organisations are geographically dispersed with projects being virtual linked sub-organisations using ICT to communicate. ICT has also introduced a useful facilitating technology for developing knowledge networks. This paper presents findings from a research program concentrating on ICT innovation diffusion in the Australian construction industry. One way in which ICT diffusion is taking place was found to be through within-company communities of practice. We undertook in-depth unstructured interviews with three of the major 10 to 15 contractors in Australia to discuss their ICT diffusion strategies. We discovered that in all three cases,within company networked communities of practice was a central strategy. Further, effective diffusion of ICT groupware tools can be critical in developing COP where they are geographically dispersed.

Hybrid cascade converter topology with series connected symmetrical and asymmetrical diode-clamped H-Bridge cells

A novel H-bridge multilevel PWM converter topology based on a series connection of a high voltage (HV) diode-clamped inverter and a low voltage (LV) conventional inverter is proposed. A DC link voltage arrangement for the new hybrid and asymmetric solution is presented to have a maximum number of output voltage levels by preserving the adjacent switching vectors between voltage levels. Hence, a fifteen-level hybrid converter can be attained with a minimum number of power components. A comparative study has been carried out to present high performance of the proposed configuration to approach a very low THD of voltage and current, which leads to the possible elimination of output filter. Regarding the proposed configuration, a new cascade inverter is verified by cascading an asymmetrical diode-clamped inverter, in which nineteen levels can be synthesized in output voltage with the same number of components. To balance the DC link capacitor voltages for the maximum output voltage resolution as well as synthesise asymmetrical DC link combination, a new Multi-output Boost (MOB) converter is utilised at the DC link voltage of a seven-level H-bridge diode-clamped inverter. Simulation and hardware results based on different modulations are presented to confirm the validity of the proposed approach to achieve a high quality output voltage.

Technology strategy and competitive performance in bridge construction

Pragmatic construction professionals, accustomed to intense price competition and focused on the bottom line, have difficulty justifying investments in advanced technology. Researchers and industry professionals need improved tools to analyze how technology affects the performance of the firm. This paper reports the results of research to begin answering the question, “does technology matter?” The researchers developed a set of five dimensions for technology strategy, collected information regarding these dimensions along with four measures of competitive performance in five bridge construction firms, and analyzed the information to identify relationships between technology strategy and competitive performance. Three technology strategy dimensions—competitive positioning, depth of technology strategy, and organizational fit—showed particularly strong correlations with the competitive performance indicators of absolute growth in contract awards and contract award value per technical employee. These findings indicate that technology does matter. The research also provides ways to analyze options for approaching technology and ways to relate technology to competitive performance for use by managers. It also provides a valuable set of research measures for technology strategy.

Board network characteristics and company performance in Sweden : the case of Gnosjö companies and their board members in southern Sweden

When managers of entrepreneurial companies typically talk about strategies, they first consider what products to make and secondly where to locate the business. The entrepreneurial companies locate in rural areas because of a wish to maintain a certain lifestyle, or because they can combine a resource available there with certain knowledge or interest that they have (Getz and Nilsson, 2004). In addition, many managers of entrepreneurial companies are confident in locating in a rural area, because there often is economic and social structure supportive of local corporate governance. The most central part of corporate governance is the board of directors. In an entrepreneurial company in a rural area, such members of boards are most likely to be individuals in dominant positions influential in the local economy.

Technology strategy and competitive performance : A study of bridge construction

Doctoral dissertation, Stanford University, California, 1993

Small, Medium, Large: Theatre Companies and Issues of Scale - A Case Study of a Medium-Sized Company

'Surviving but not thriving.' Tbat is the message about small to mediumsized companies that Ian McRae, Chair ofthe Theatre Board of the Australia Council, has been delivering since 2003. In the Theatre Board Assessment Meeting Report of 2007, McRae strongly urged renewed financial support for this most important sector given the significant decrease over the last 10 years and the consequent decrease in new Australian works being produced. Without such support his prediction is that'considerable damage could be done to the creative infrastructure across Australia resulting in a loss of artistic vibrancy down the track that could be very difficult to recover' (McRae, 2007:3).