Current Issue : October - December Volume : 2013 Issue Number : 4 Articles : 7 Articles
This paper particularly addresses the market implementation of Fibre Reinforced Polymer (FRP) for bridges. It presents the\r\nconcept of demand and supply chain innovation as being investigated within two ongoing European collaborative research projects\r\n(FP7) titled Trans-IND and PANTURA. FRP has emerged as a real alternative structural material based on various sustainability\r\nconsiderations, among others the reduced life-cycle cost due to less maintenance needs, longer lifetime, and easiness to repair,\r\nreplace, or recycle the components. The Trans-IND research project aims to develop and demonstrate new industrialized processes\r\nto use FRP for civil infrastructure projects at a large scale. In order to be cost effective, a new value-chain strategy for the design,\r\nrealization, and maintenance of FRP bridges is required to replace the fragmented supply chain and the one-off approach to a\r\nconstruction project. This paper focuses on the development of new business models based on asset management strategy, which\r\ncovers the entire demand and supply chains. Research on new business models is supported by the insight into the market and\r\nregulatory frameworks in different EU countries. This is based on field surveys across the EU that have been carried out as a part\r\nof the Trans-IND and PANTURA collaborative research projects....
Considering facilities management (FM) at the early design stage could potentially reduce the efforts for maintenance during the\r\noperational phase of facilities. Few efforts in construction industry have involved facility managers into the design phase. It was\r\nsuggested that early adoption of facilities management will contribute to reducing the needs for major repairs and alternations that\r\nwill otherwise occur at the operational phase. There should be an integrated data source providing information support for the\r\nbuilding lifecycle. It is envisaged that Building Information Modelling (BIM) would fill the gap by acting as a visual model and a\r\ndatabase throughout the building lifecycle. This paper develops a framework of how FMcan be considered in design stage through\r\nBIM. Based on the framework, the paper explores how BIM will beneficially supportFMin the design phase, such as space planning\r\nand energy analysis. A case study of using BIM to design facility managers� travelling path in themaintenance process is presented.\r\nThe results show that early adoption of FM in design stage with BIM can significantly reduce life cycle costs....
This research study focuses on the actual performance of the flexible pavements and its relationship with the in-situ mechanistic\r\nand volumetric properties. The data required for the study were obtained using the Long Term Pavement Performance database.\r\nApproximately, 116 flexible pavement sections throughout United States were analyzed and discussed.The results indicated that the\r\ntemperature has a significant affect on the backcalculatedmodulus of the hot mix asphalt layer.However, no strong relationship was\r\nobserved between the hot mix asphalt backcalculated modulus and in situ air voids. It was found that fatigue life was a function of\r\ntensile strain at the bottomof hot mix asphalt layer, peak surface deflection, hot mix asphalt air voids and maximum specific gravity,\r\nand ambient air temperature. Similar relationships between the rut life, mechanistic and volumetric properties were established for\r\nwet-freeze and wet-no-freeze climatic zones.The sensitivity analysis revealed that the rut performance in wet-no-freeze sections is\r\nmainly affected by higher base and roadbed compressive stresses and strains. On the other hand, the performances in wet-freeze\r\nsections are highly depended on roadbed compressive strain and modulus ratio of subbase to roadbed....
A network of the feedforward-type artificial neural networks (ANNs) was used to predict the compressive strength of concrete\r\nmade from crude oil contaminated soil samples at 3, 7, 14, 28, 56, 84, and 168 days at different degrees of contamination of 2.5%,\r\n5%, 10%, 15%, 20% and 25%. A total of 49 samples were used in the training, testing, and prediction phase of the modeling in the\r\nratio 32 : 11 : 7. The TANH activation function was used and the maximum number of iterations was limited to 20,000 the model\r\nused a momentum of 0.6 and a learning rate of 0.031056. Twenty (20) different architectures were considered and the most suitable\r\none was the 2-2-1. Statistical analysis of the output of the network was carried out and the correlation coefficient of the training\r\nand testing data is 0.9955712 and 0.980097. The result of the network has shown that the use of neural networks is effective in the\r\nprediction of the compressive strength of concrete made from crude oil impacted sand....
The fatigue crack growth characteristics of structural steel and weld connections are analyzed using quantitative acoustic emission\r\n(AE) technique. This was experimentally investigated by three-point bending testing of specimens under low cycle constant\r\namplitude loading using the wavelet packet analysis. The crack growth sequence, that is, initiation, crack propagation, and fracture,\r\nis extracted fromtheir corresponding frequency feature bands, respectively.The results obtained proved to be superior to qualitative\r\nAE analysis and the traditional linear elastic fracture mechanics for fatigue crack characterization in structural steel and welds....
Themodel tuning through sensitivity analysis is a prominent procedure to assess the structural behavior and dynamic characteristics\r\nof cable-stayed bridges. Most of the previous sensitivity-based model tuning methods are automatic iterative processes; however,\r\nthe results of recent studies show that the most reasonable results are achievable by applying the manual methods to update the\r\nanalytical model of cable-stayed bridges. This paper presents amodel updating algorithm for highly redundant cable-stayed bridges\r\nthat can be used as an iterativemanual procedure.Theupdating parameters are selected through the sensitivity analysis which helps\r\nto better understand the structural behavior of the bridge.Thefinite elementmodel of Tatara Bridge is considered for the numerical\r\nstudies. The results of the simulations indicate the efficiency and applicability of the presented manual tuning method for updating\r\nthe finite elementmodel of cable-stayed bridges. The new aspects regarding effectivematerial and structural parameters andmodel\r\ntuning procedure presented in this paper will be useful for analyzing and model updating of cable-stayed bridges....
This paper provides a newgeneral stress-strain lawfor concrete confined by steel, fiber reinforced polymer (FRP), or fiber reinforced\r\ncementitious matrix (FRCM), obtained by a suitablemodification of the well-known Sargin�s curve for steel confined concrete. The\r\nproposed law is able to reproduce stress-strain curve of any shape, having both hardening or softening behavior, by using a single\r\nclosed-form simple algebraic expression with constant coefficients. The coefficients are defined on the basis of the stress and the\r\ntangent modulus of the confined concrete in three characteristic points of the curve, thus being related to physical meaningful\r\nparameters. It will be shown that if the values of the parameters of the law are deduced fromexperimental tests, themodel is able to\r\naccurately reproduce the experimental curve. If they are evaluated on the basis of an analysis-oriented model, the proposed model\r\nprovides a handy equivalent design model....
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