The paper presents the results of an extensive experimental dynamic testing and numerical modelling conducted on the bottom segment of an 81 m glass fibre reinforced polymer (GFRP) guyed tower. The 8.6 m bottom segment was made up of four 2.15 m sections, each of which consisted of three composite cells. The cells were inter-connected using sleeve joints and were bonded together to form an equilateral triangle having sides of 450 mm. The guyed tower was tested under dynamic loadings with and with out carrying a mass on its top to evaluate its vibration performance. A modal analysis was also carried out on the tower with and without mass on top. The damped natural frequency of the flexural mode obtained from finite element without mass on top had a frequency of 6.1 Hz. The natural frequency obtained from testing was 5.50 Hz. The difference of 10.9% happened due to the loss of pre-stress in the cables indicates a good agreement of the natural frequency obtained from the analysis and from the vibration tests. The natural frequency without having mass was 10.67% higher than with mass on the top. The results confirmed the validity of the developed theoretical model.

This work addresses the application of the Finite Element Method (FEM) in order to investigate the static behavior of tapered poles made of glass fiber reinforced polymer (GFRP). The theoretical model developed using the FEM was verified through comparison with an experimental procedure. More specifically, two poles made of glass fiber reinforced polymer (GFRP) were loaded as cantilever beams to failure at the Steel Structures Laboratory of the National Technical University of Athens (NTUA). The experimental poles were constructed using the filament winding method. The experimental results included load-deflection data at the point of loading as well as strain distribution near the fixed support. The results from the FEM closely matched the experimental results for deflection as well as for the ultimate load of the specimens. On the basis of these findings, the authors concluded that it is possible to use the FEM with confidence in the analysis and design of GFRP structures, such as utility line poles and wind turbine towers, without the high cost associated with experimentation.

The demand for a lightweight, reliable, and cost-effective construction material with free maintenance and great resistance to corrosion to replace steel communication towers has become more obvious in recent years. The paper explores the use of glass fibre-reinforced polymers (GFRP), as unconventional materials for the fabrication of lightweight communication guyed towers. The tower examined in this investigation had a uniform constant cross section of three identical cells bonded together to form an equilateral triangle with sides of 500 mm. The communication tower was analyzed using the finite element program ANSYS and was designed to satisfy both the ultimate limit state and the serviceability limit state requirements of the structural standards for antenna towers and antenna supporting structures, EIA/TIA Standard. The experimental work involved the testing of 9 m tower segment under static and dynamic loads and an extensive material testing to define the tower's material properties. This paper presents results from this research project.

Abstract Fixed‐wheel gates with wheels mounted on both sides that roll on roller path plates are used in both emergency intake gates and spillway gates in hydrogenerating stations. Environmental corrosion along with high wheel loads cause differences in the profile of the roller path surface. Combined with the relatively high torsional stiffness of the gate end girders, a condition of wheel load redistribution occurs where some wheels are relieved of load while others are loaded beyond their maximum design values. Failure of one wheel could jeopardize the overall operation of the gate. Furthermore, frequent operation of these gates result in changes in the stress profile in both wheels and roller paths that, potentially, could lead to failure. Currently, design guidelines for gate wheels and roller paths do not consider the fatigue life of these elements. Research‐based evidence is provided to support changes to these guidelines.

The article includes a comprehensive review of the design standards and specifications of ice accumulation used to design guyed structures and transmission lines. Both experimental and theoretical results are included. A total of 25 GFRP coupons were tested to failure to obtain material properties. The effects of icing, cable prestressing and the critical buckling stresses due to the extension and shear modes of failure on the design of multi-cell guyed towers are evaluated and discussed. The article evaluates the critical buckling stresses with reference to the percentage of fiber volume fractions and it provides a method to assess and control the design of guyed towers. Moreover, it provides a non-linear finite element model to analyze and set a design limit by predicting the maximum wind load profile that causes failure of the GFRP jointed guyed tower.

The size of steel tubular guyed towers has become very big, expensive to transport and to erect in the field since a special crane equipment is needed for erecting the tower components. Moreover, steel is very susceptible to corrosion which causes loss of strength. The paper provides recommendations for the analysis, design and fabrication a lightweight multicells glass-fiber reinforced polymer (GFRP) guyed tower. The experimental work involved material testing, fabricating the tower and testing it with a secured mass of 163 kg, 1 kW vertical turbine, mounted on its top under static loading to evaluate the structural performance of the tower. A nonlinear finite element model was developed to analyze the tower holding a mass on its top. A superimposed failure envelope was developed to predict the tower's failure load using different failure theories. The deflections and stresses obtained from experimental testing compared well with the theoretical results; and therefore, validated the developed model.

A research study has been carried out to provide design guidelines for glass-fiber reinforced polymer (GFRP) guyed tower. Both material testing and theoretical analysis are involved. The tower examined in this study has 81 m in height with a uniform equilateral triangle cross section having sides of 450 mm. The tower supported by seven sets of guy wires oriented at 120 degrees, each set consisting of three guy wires. The tower was assumed to be supported at the base by means of a pinned connection to provide full moment release. The tower was analyzed using the finite element ANSYS software and was designed to satisfy both the ultimate and the serviceability limit state requirements of the CSA-S37-01 Standard. The guyed tower was analyzed in static to evaluate the tower strength failure using several advanced failure theories. Modal analysis and full dynamic analysis using CSA-37-01 Standard were extensively performed to evaluate the vibration performance and to obtain an accurate dynamic response of the full-scale tower. The paper presents the results obtained from material testing and from a finite element, ANSYS models developed for the static and dynamic analysis of the multi-cells 81 m lightweight-guyed towers. (C) 2018 Society for Computational Design and Engineering. Publishing Services by Elsevier.

The research was conducted to explore the use of advanced materials to design an 81 m FRP guyed tower. Theoretical and experimental works are involved. Several non-linear finite element models were developed to explore the effects of parameters such as cross-section dimensions, cable pre-stressing, and fiber volume fractions on the overall strength and stiffness of the tower. Experimental testing was performed to define the material properties. Results indicate that an increase of fiber volume fraction from 40.6 to 65% leads to a reduction of 13.5% in the deflection when tower cables were not pre-stressed and 22.9% when cables are pre-stressed.

The aim of this paper is to explore the potential use of advanced composite materials as an alternative material to conventional steel to design and fabricate a lightweight fiber reinforced polymer (FRP) guyed towers. Both theoretical and experimental testing are involved. The paper offers recommendations for the design of composite towers using various non-linear finite element models. It contains a comparative cost analysis between an 81 m composite and a steel guyed tower both designed to resist identical loading conditions. The paper results confirmed that FRP tower creates more economically viable alternatives and sustainable solutions to steel towers in the future. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.

A research project has been carried out at the University of Manitoba, Canada, to develop fibre-reinforced polymer (FRP) meteorological guyed towers. Both theoretical and experimental results are presented in this paper. The theoretical work involved the development of finite element models to analyze the structural behavior of an 81 m tower. The experimental work involved the testing of an 8.6 m long segment, representing the bottom segment of the 81 m guyed tower used in the analysis, under static and dynamic loading. This segment was constructed from three cells bonded together with epoxy resin to form an equilateral triangle shape. Each cell was fabricated using four layers of glass fibre matting for a total thickness of 5 mm with a sequence of [90 degrees/0 degrees/0 degrees/90] impregnated in epoxy resin. An extensive material testing program was also carried out to define the material properties for finite element analysis. The numerical results are compared with the experimental results to confirm the validity of the finite element models.

A depth camera or 3-dimensional scanner was used as a sensor for traditional methods to quantify the identified concrete spalling damage in terms of volume. However, to quantify the concrete spalling damage automatically, the first step is to detect (i.e., identify) the concrete spalling. The multiple spots of spalling can be possible within a single structural element or in multiple structural elements. However, there is, as of yet, no method to detect concrete spalling automatically using deep learning methods. Therefore, in this paper, a faster region-based convolutional neural network (Faster R-CNN)-based concrete spalling damage detection method is proposed with an inexpensive depth sensor to quantify multiple instances of spalling simultaneously in the same surface separately and consider multiple surfaces in structural elements. A database composed of 1091 images (with 853 x 1440 pixels) labeled for volumetric damage is developed, and the deep learning network is then modified, trained, and validated using the proposed database. The damage quantification is automatically performed by processing the depth data, identifying surfaces, and isolating the damage after merging the output from the Faster R-CNN with the depth stream of the sensor. The trained Faster R-CNN presented an average precision (AP) of 90.79%. Volume quantifications show a mean precision error (MPE) of 9.45% when considering distances from 100 cm to 250 cm between the element and the sensor. Also, an MPE of 3.24% was obtained for maximum damage depth measurements across the same distance range.

In this paper, the performance of a proposed geothermal energy pile system for the energy demand of an institutional building is investigated. The building studied in this research is situated in the Fort-Garry campus of the University of Manitoba in the southernmost portion of Winnipeg (MB) in Canada. In an urban area, underground temperatures are substantially higher than the surrounding rural areas due to the buildings heat leakage to their underneath ground. In this study, this heat loss is harvested through geothermal piles and rejected to the building for the HVAC system utilization. The underground thermal imbalance, which is the most common problem encountered while utilizing the geothermal energy in cold regions, is extensively studied. It is concluded that despite the heat leakage through the basement enclosure, thermal balance of the soil, in case of supporting the total energy demand of the building by geothermal piles, cannot be met. The application of some auxiliary heat sources is proposed. Finally, the amount of energy harvested from the ground is calculated by maintaining the thermal balance of the soil and preventing the freezing at the soil-pile interface which affects adversely the structural performance of geothermal piles.

Structural health monitoring has become an outstanding tool to perform structural condition assessments, once performed solely by trained experts. In this study, a methodology utilizing an inexpensive depth sensor to detect and quantify volumetric damages within concrete surfaces is proposed. To allow automatic damage detection, a Faster Region-based Convolutional Neural Network (Faster R-CNN)-based method is implemented. A database of 444 images with resolution of 853 x 1440 pixels annotated for concrete spalling is developed. The network is modified, trained and validated using the proposed database. Damage quantification is automatically performed using the depth data output by the sensor. The surface of the analyzed element is extracted by merging the bounding boxes output by the Faster R-CNN onto the depth map. A polystyrene test rig containing damage simulations of known volume was utilized to test the accuracy of volume calculation. In addition to that, a concrete beam was also used to test the entire system. The Faster R-CNN yielded an average precision (AP) of 77.97% for damage detection. Damage quantification routine presents error of 9.45% in volume quantification of samples located within 100 cm and 250 cm away from the sensor plane. On top of that, maximum depth measurements of damages show a mean precision error (MPE) of 3.24% considering the same distance range. The implemented method allows for damage segmentation and quantification regardless of the distance between the sensor and the analyzed element.

A study examining the relationship between housing conditions, respiratory health, and school absenteeism was conducted in the city of Winnipeg in Manitoba, Canada. As part of this study, a survey was completed by 3,424 parents of children in grades 3 and 4 to determine the a) relationship between self-reported visible mold in homes and tested airborne mold; b) relationships of self-reported visible mold, tested airborne mold, and asthma and/or persistent colds; c) school absenteeism rates due to asthma and/or persistent colds; and d) children's socioeconomic status (SES) and incidence of asthma and/or persistent colds. In addition, a complete inspection of a subset of 715 homes was conducted, including the collection of over 1,400 indoor and 500 outdoor air samples for mold analysis. Results indicate a significant association between self-reported visible mold and airborne mold. Additionally, a significant association was found between Cladosporium levels from air samples (the most common genus type found) and children's asthma in combination with persistent colds. Children with persistent colds in combination with asthma miss significantly more school than children who have only asthma or only persistent colds. Children from poorer families reported more persistent colds than children from high-income families. No association was found between income and asthma. Furthermore, SES was not a significant factor for number of school days missed.

Understanding how respiratory health risks are associated with poor housing is essential to designing effective strategies to improve children's quality of life. The objective of the study described in this article was to determine the relationship between respiratory health and housing conditions. A survey was completed by 3,424 parents of children in third and fourth grade in Winnipeg, Manitoba, Canada. An engineering audit and air samples were also taken in the homes of a subset of 715 homes. Results showed that a child's respiratory health is significantly associated with self-reported visible mold in the home and that a significant association existed between occupant-reported visible mold and tested airborne mold. Findings highlight the need for clearer standards of acceptable CFU/m3 limits for mold genera that are applicable to homes. In the absence of such guidelines, problems associated with indoor mold will continue to impact the health of residents, despite growing evidence of the adverse effects from mold exposure.

The present paper deals with the results from a theoretical and an experimental research program on the development of composite meteorological towers. The theoretical work consisted of developing various models to analyze an 81 m tower using the finite element program ANSYS and to design this tower in accordance with the Canadian Standard CSAS037. The composite tower developed for this application had a triangular shape comprised of three identical cells jointed together to form an equilateral triangle, each side measuring 450 mm. The cells were designed to be fabricated through the filament winding method using a collapsible mandrel designed and fabricated specifically for this project. Unfortunately, the filament winder was not available at the time and the cells were fabricated using four layers of unidirectional glass fibre mats with a sequence [90, 0, 0, 90] and a weight of 1285g/m. Each layer was saturated with a mixture of 105 epoxy resin and 205West System hardener. The mechanical properties of the composite layers were obtained through testing of several coupons. Various parameters were investigated theoretically, including: the effect of three different laminates that contained a variety of stacking sequence of laminae orientations; various thicknesses for each laminate; the effects of fibre volume fractions; and, various sizes and location of guy cables. An 8.6 m tower segment was tested under static and dynamic load to verify the theoretical model. In addition, a comparative analysis was carried out between an 81 m composite tower and a steel tower both designed to resist identical loading conditions. The test results confirmed the validity of the theoretical model.

This paper presents results from a research project carried out at the University of Manitoba, Winnipeg, Canada, in collaboration with the National Technical University of Athens, Greece, which examines the potential of manufacturing fibre-reinforced polymer (FRP) lattice tower segments using the filament winding process. Both theoretical and experimental work has been carried on a tower 8534mm long segment that consists of four identical parts 2134mm long each, fabricated and tested under static and dynamic loading conditions. It has been found that the experimental results correlate well with theoretical findings from FEM analyses. The dynamic properties of the tower segment were also verified through a single degree-of-freedom analytical model.

An extensive research project is currently being carried out at the University of Manitoba, Canada, involving the development of glass fiber-reinforced polymer (GFRP) wind turbine towers. The towers consist of multi-cell segments, each segment constructed from eight filament wound cells jointed together with resin applied over their interface. The present paper mainly addresses the static and dynamic characteristics, such as failure static loads, modes of failure, fundamental frequencies and periods of such segmented composite towers. Both experimental and numerical results are presented. The experimental investigation involved the testing of two jointed scaled towers. These specimens had a total height of 4.88-m (16-ft) and were tested as cantilevers under static and dynamic loading. The testing was conducted at the W.R. McQuade Structural Engineering Laboratory of the University of Manitoba. Finally, finite element models were developed to analyze the structural behavior, static and dynamic, of single and multi-cell composite segments and towers. The results from the finite element models under static loading were validated through comparison with the experimental results.

A survey designed to determine the relationship between respiratory health and housing conditions was completed by 3,423 parents of 9-year old children in Winnipeg, Canada. Air samples were taken in 715 homes and an engineering audit of each residence was conducted including measurements of relative humidity, temperature, and moisture content of walls. Results indicate that: (a) Self-reported visible mould in the home is a significant independent predictor of persistent colds alone as well as of asthma in combination with persistent colds in children; (b) over 64% of homes have mould CFU levels of >= 100/m(3) -- the most common genus type being Cladosporium; (c) self-reported presence of visible mould in the home is significantly associated with measured CFU mould counts : >= 100/m(3); (d) presence of Cladosporium is significantly associated with childhood asthma in combination with persistent cold symptoms;.(e) measurements of relative humidity and/or air temperatures are not reliable indicators of high mould CFU counts.