Co-creation,prevailing streams and a future design trajectory

Co-creation as a concept has won terrain over the past 10 years. In practice as well as in literature, co-creation is climbing the agenda in relation to contemporary opportunities and challenges within management, organisation design and change initiatives. This paper aims to build an overview of the literature on co-creation to explore what the existing literature relates to and indeed to pinpoint if any patterns or streams can be identified. The paper illustrates how the use of the concept of co-creation suggests a necessity for focusing further on specific co-creation-related issues and challenges of significance to business and society. The paper highlights new co-creation-related issues and challenges. Further, the paper crystallises an emerging design trajectory in theory and practice.     

CFRP confinement of bridge columns damaged by premature concrete deterioration: a case study in Texas

In 1998, the Texas Department of Transportation (TxDOT) identified two concrete distress mechanisms occurring on its bridge over Lake Ivie in the west central part of the state: alkali – silica reaction (ASR) and delayed ettringite formation (DEF), collectively referred to by TxDOT as premature concrete deterioration (PCD). The agency sponsored two research projects to investigate the problem. One focused on determining the remaining capacity of PCD-damaged concrete members with a case study of the Lake Ivie bridge and the other assessed treatments that could be applied to members with PCD damage. Based on findings of the study, TxDOT applied a system that waterproofed the damaged columns and then confined them using resin-bonded carbon fibre reinforced polymer (CFRP) fabric strips. This paper describes the efforts of TxDOT to mitigate PCD damage for its Lake Ivie bridge.     

Dynamical identification and modelling of steel–concrete composite high-speed railway bridges

In the last few years, the construction of new high-speed (HS) railways across Europe, as well as in many other countries, has required many different bridges and viaducts. Together with classical concrete solutions, new steel–concrete composite typologies have been developed, giving light and cheap structures. Despite these studies and applications, some concerns still remain about the definition of reliable models for the evaluation of their actual dynamical behaviour under HS train passage. In particular, the influence of many structural and non-structural components, such as cross-girders and ballast, are still not well recognised. In this paper, open problems related to the dynamical assessment and modelling of new steel–concrete four-parallel-girder and box-girder solutions are exposed and analysed. A suitable procedure, based on operational modal analysis, model updating and train–bridge interaction analysis is applied to two bridges, recently built in the new Italian HS network, in order to assess and verify their dynamic behaviour under operative conditions.     

Direct displacement-based assessment with nonlinear soil–structure interaction for multi-span reinforced concrete bridges

A practical and readily implementable seismic assessment procedure for multi-span reinforced concrete bridges is introduced in this paper. The procedure is based on an existing direct displacement-based assessment (DDBA) approach, and accounts for nonlinear dynamic soil–structure interaction (NLSSI) effects. Several simplified bridge structures lying on shallow foundations have been used as application examples. The validation has been done by comparing DDBA+NLSSI with the results of finite-element nonlinear time-history simulations by means of incremental dynamic analysis. Moreover, the influence of NLSSI on the assessment procedure has been evaluated by considering the same bridges with fixed base and with NLSSI effects. In spite of its simplicity that presently prevents its use for complex bridge structures, the proposed procedure is found to provide fast and reliable results, useful to give a first-level screening on a large set of bridges for highlighting the most critical situations, as well as to carry out fast parametric analyses to produce fragility curves in the framework of performance-based vulnerability/risk assessment.     

Application of sliding seismic isolator to building structures considering cost,performance and inspection: a case study

Seismic isolation system (SIS) of building structures can lead to reduction of the structural response to earthquake ground motion and improvement of structural safety. This paper introduces a sliding seismic isolator with mass energy regulator springs (SSIM) as a SIS type, and presents the application procedure of the SSIM to an existing building structure considering the probability that the SIS application leads to cost–benefit, the seismic performance evaluation of the building structure and the efficient SIS inspection after earthquakes. Based on a decision tree considering the probability of earthquake occurrence during the service of a building structure and functionality of the SIS against earthquakes, cost–benefit from installing a SIS is formulated, and, probability that the SIS application leads to cost–benefit is estimated. In the seismic performance evaluation, the fundamental period and structural response acceleration to the horizontal ground motion of the building with the SSIM are assessed. Furthermore, the efficient SIS inspection plan after earthquakes is investigated based on the acceptance sampling. The existing building structure, information and communications technology center of Syiah Kuala University located in Banda Aceh, Indonesia is applied for the case study.     

Inspection and evaluation methods on dynamic performance of highway bridges under moving vehicular loads

This paper is concerned with the inspection and evaluation methods on dynamic performance of highway bridges under moving vehicular loads. The background and development process of the existing specifications are stated and discussed. Up to now, four specifications or drafts for approval related to dynamic performance inspection and evaluation have been published. The deficiencies of the existing specifications are discussed and the differences among them are compared, including dynamic loading test methods, data processing, and evaluation criteria. Finally, some key research topics about the inspection and evaluation methods on dynamic performance of highway bridges are proposed.     

Laboratory measurement of hydraulic conductivity functions of two unsaturated sandy soils during drying and wetting processes

The importance of applying unsaturated soil mechanics to geotechnical engineering design has been well understood. However, the consumption of time and the necessity for a specific laboratory testing apparatus when measuring unsaturated soil properties have limited the application of unsaturated soil mechanics theories in practice. Although methods for predicting unsaturated soil properties have been developed, the verification of these methods for a wide range of soil types is required in order to increase the confidence of practicing engineers in using these methods. In this study, a new permeameter was developed to measure the hydraulic conductivity of unsaturated soils using the steady-state method and directly measured suction (negative pore-water pressure) values. The apparatus is instrumented with two tensiometers for the direct measurement of suction during the tests. The apparatus can be used to obtain the hydraulic conductivity function of sandy soil over a low suction range (0–10 kPa). Firstly, the repeatability of the unsaturated hydraulic conductivity measurement, using the new permeameter, was verified by conducting tests on two identical sandy soil specimens and obtaining similar results. The hydraulic conductivity functions of the two sandy soils were then measured during the drying and wetting processes of the soils. A significant hysteresis was observed when the hydraulic conductivity was plotted against the suction. However, the hysteresis effects were not apparent when the conductivity was plotted against the volumetric water content. Furthermore, the measured unsaturated hydraulic conductivity functions were compared with predictions using three different predictive methods that are widely incorporated into numerical software. The results suggest that these predictive methods are capable of capturing the measured behavior with reasonable agreement.     

Determination of Myricetin in Medicinal Plants by High-Performance Liquid Chromatography

The concentrations of myricetin in medicinal plants such as Rosa canina L. (rosa hip), Terebinthina chica L. (terebinth), Urtica dioica L. (nettle), and Portuca oleracea L. (purslane) were determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS). The aglycones of myricetin were extracted using methanol–ascorbic acid– hydrochloric acid, methanol–hydrochloric acid, and methanol, separated within 5 min, and individually quantitated in the positive ionization mode using optimized conditions for HPLC-MS. Methanol–ascorbic acid–hydrochloric acid was the optimum extraction solvent. The myricetin concentration in the plants were between 3 and 58 mg kg^?1, with a limit of quantification equal to 0.1 mg L^?1.     

Characterization of the Capacitance of a Rotating Ring–Disk Electrode

The use of rotating ring–disk electrodes as generator-collector systems has so far been limited to the detection of Faradaic currents at the ring. As opposed to other generator-collector configurations, non-Faradaic detection has not yet been carried out with rotating ring–disk electrodes. In this study, a.c. perturbation based detection for measurement of the ring impedance is introduced. By using a conducting polymer-modified disk electrode in combination with a bare gold ring as a model, it is shown that the measured ring capacitance correlates with the polarization of the polymer film, most probably due to counter-ion exchange. A method of calculating the ring capacitance based on a small-signal sinusoid perturbation is described and the most important instrumental limitations are identified.