Constructional Defects Research Articles

Predicting Maximum Effective Temperatures and Thermal Gradients for Steel I-Girder in Canadian Climate Regions

The constant fluctuation of thermal loads on steel members, especially during construction, causes non-uniform distributions of temperatures, resulting in possible constructional and structural defects leading to unfavorable thermally induced responses and potential safety risks. The Canadian Highway Bridge Design Code (CHBDC) provides one thermal gradient variation profile without accounting for the differences in the geometrical parameters of the steel members and the variations in the climate regions of Canada. Therefore, in this study, three-dimensional finite element (FE) thermal simulations were conducted to investigate the maximum effective temperatures and positive vertical thermal gradients for different Canadian climate regions. Parametric studies were performed to conduct the FE thermal analysis using the thermal model validated in ANSYS. The comprehensive study results showed that Canada could be divided into two main zones for vertical thermal gradient calculations, meaning that one stationary thermal gradient profile cannot be applicable to all climate regions of Canada, as recommended by the CHBDC. Based on the FE thermal analysis results, empirical formulas as a function of the significant parameters were proposed to predict the maximum effective temperature and thermal gradient variations of the steel I-girder. The predicted maximum effective temperature and thermal gradient variation values were found to be highly correlated with the FE values with coefficients of determination R2 of approximately 0.97 and 0.98, respectively.

Математическое обоснование сопротивления движению автотранспорта в зависимости от состояния конструкции покрытия лесовозных дорог

The currently available methods for evaluating technical-operational characteristics and conditions of hauling roads are time- consuming. Although, they provide a sufficiently accurate description of the conditions of certain road components. Furthermore, they give the possibilities to identify ways for elimination of the constructional defects and determine the work extent to correct them. A peculiarity of forestry production is the simultaneous exploitation of a branching transport network with different types of subsidiary hauling roads, which depends on weather conditions, change of logging locations, traffic intensity, and other factors. Therefore, the available methods, which clarify the relationships between the traffic resistance and strength of the road construction, are poorly usable for rapid estimation of the technical and operational conditions in renovation planning. The purpose of the study is to improve the methodological fundamentals of traction-operational calculations for timber transportation according to the constructional state of the hauling roads. It has been determined that the calculation of the rolling resistance must include the factor of structural deformation. It is influenced by the modulus of elasticity for the surface structural materials. The resulting relationship makes it possible to increase the accuracy of traction-operational calculations at the project phase of the hauling road building. It can be included into the target function for comparing alternatives in the case of optional project planning. The mathematical aspect in the evaluation of the traffic resistance gives an opportunity to use this parameter as an indirect characteristic of the constructional strength of a road, as well as it can be a comprehensive qualitative indicator of the condition of a pavement. For citation: Prokopets V.S., Kozlov V.G., Skrypnikov A.V., Ponomareva N.G., Levushkin D.M., Borovlev Yu.A. Mathematical Justification of Vehicular Traffic Resistance in Relation to Structural Surface Conditions of Hauling Roads. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 2, pp. 106−120. (In Russ.). https://doi.org/10.37482/0536-1036-2023-2-106-120

THE KNOWLEDGE OBTAINED FROM THE MAIN INSPECTIONS OF PEDESTRIAN BRIDGES IN PREŠOV

The maintenance and inspection of bridges is often a neglected component of necessary technical bridge care. One of the factors contributing to this can be the insufficient financial resources available for repairs under town and municipality administration where financial resources may be restricted. The most severe problem is the underestimation of the importance of bridge inspections. Preventive measures, in the form of regular inspections, can reveal structural issues caused by constructional defects during production or by changing external conditions. We can nevertheless still prioritize and effectively use financial resources for repairs. The knowledge obtained during inspections is an essential part of the draft process for new bridges and lessons learned on maintaining them effectively. This study sums up the most severe faults on selected pedestrian bridge structures and provides findings acquired during the inspections. This article presents findings from the inspection of pedestrian bridges in Prešov, Slovak Republic: Segmental pedestrian bridge next to the University of Prešov; Pedestrian bridges over the railway line in the direction of Rusínska ‒ Lesík Delostrelcov; Pedestrian bridge over the Torysa river on Mukačevska street. Main inspections have been carried out in the first half of 2021 by the company ProPonti s.r.o, in cooperation with the Department of Concrete Structures and Bridges (KBKM) STU Bratislava. Based on the executed main inspections, we can sum up the main following findings: immediate grouting and repassivation of the prestressing reinforcement can prevent a significant shortening of the service life, despite substantial manufacturing error; in the case of segmental constructions, a detailed inspection of the interior of the chambers as well as the condition of the prestressing reinforcement located in cement mortar is needed on a regular basis; for all types of structures, it is important to monitor the function of the bridge´s drainage system and any water penetration manifested by wet stains and efflorescence. Such problems must be solved immediately and will, in turn, significantly reduce the contamination of concrete with salts, greatly extending the service life of the bridge.

Progressive collapse of a steel structure under expected snow loads

The structural design process has many vital roles in preventing the collapse of structures and should be conducted according to national obligatory standards. However; structural failures or even catastrophic collapses based on improper design, underestimated design loads, unexpected extreme loads, and improper erection are reported worldwide on large-span structures. A steel structure of the factory partially collapsed under expected snow loads in the western part of Turkey was investigated in this study. The possible reasons for the collapse of the system were examined by visual inspections and analytical results. The load-carrying capacities of the main girders and purlins were determined using the buckling analyses of the structural member. The nonlinear geometric analysis of the entire steel structural system was defined to evaluate the vertical load-carrying capacity of the main girder. The progressive collapse mechanism of the system was determined. The obtained results indicate that the snow load is not the main reason for the collapse and mistakes in the project design, constructional defects and inadequate capacity of structural elements are the primary reasons behind the collapse.

Apartment quality during warranty period of building

The article studies process of optimization of cost management structure for improving quality of constructional works in apartment. Property owner has the right to demand the apartment quality during the warranty period. Article 756 of the Civil code of the Russian Federation indicates the limit warranty period as 5 years. Constructional defects can be divided into two categories: general construction and engineering system defects. There are 3 methods, which are applicable to the assessment of apartment quality: ABC, target-costing and life-cycle cost analysis. It is essential to identify the parameters, which can decrease service costs and quantity of defects. Three models of apartment with different conditions are compared. Considering such parameters as the number of defects, the presence of delay in the execution of application, financial loss, presence of repeated complaint from owner, the formula of quality assessment is proposed. New equation allows assessing the quality of the apartment and defining variables, which can influence on it.

Large-scale engineering geomorphological mapping as an additional tool in the assessment of earthworks for transport infrastructure

Although large-scale engineering geomorphological mapping is an important method in site investigations for new traffic route construction projects, it has only a very modest place in transport infrastructure maintenance management. It should be seen as an useful additional tool in the engineering stability assessment of earthworks, which is currently based on geotechnical and geophysical investigation methods. The geomorphologist must map all geomorphological features and constructional defects that impair the stability of an earthwork and its surroundings. For the application to man-made landforms existing geomorphological map legends have to be extended to constructional symbols.

Revisiting Constructional Defects of Constructivism in IR

Abstract Early Wendtian and Habermasian constructivism in IR displayed a number of traits that were inconsistent with constructivist sociological theory. These included state-centrism and actorhood, a voluntarist and intentionalist conception of agency, the limited focus on the problems of anarchy and cooperation, a partial insistence on causal models, a conception of the problem of order in terms of normative integration, the dissociation of norms and power, and the lack of a theory of socialisation (accounting for the formation of identities and interests). Focusing on Wendt’s seminal Social Theory of International Politics as well as exemplary formulations of Habermasian constructivism, this paper examines to extent which these early constructional defects of mainstream constructivism in IR were fixed or persist in its mature formulations. The conclusion of the paper reflects on broader challenges to (and opportunities for) constructivism deriving from a changing disciplinary and political context. Where early constructivist scholarship largely wrestled with the neo-neo synthesis and the political context of the end of the Cold War, contemporary constructivist scholarship is well advised to engage with the practice (and material) turns and to address postcolonial challenges and the reality of a post-Western world. Keywords : constructivism, agency, anarchy, socialisation, practice theory ----- Bibliography: Jaeger, Hans-Martin: Revisiting Constructional Defects of Constructivism in IR, ERIS, 3-2016, pp. 14-26. https://doi.org/10.3224/eris.v3i3.27339

Crossed-brain representation of verbal and nonverbal functions.

A 74-year-old, left-handed man presented with a rapidly evolving loss of strength in his right leg associated with difficulty in walking. MR images disclosed an extensive left hemisphere tumor. A neuropsychological examination revealed that language was broadly normal but that the patient presented with severe nonlinguistic abnormalities, including hemineglect (both somatic and spatial), constructional defects, and general spatial disturbances; symptoms were usually associated with right hemisphere pathologies. No ideomotor apraxia was found. The implications of crossed-brain representations of verbal and nonverbal functions are analyzed.

Colonial Ambition, Common Sense Thinking, and the Making of Takoradi Harbor, Gold Coast

AbstractThroughout the 1920s, British officials in London and Accra dedicated considerable time and bureaucratic energy to the planning and construction of Takoradi harbor, an ambitious project that, they expected, would revolutionize the Gold Coast’s economic prospects. But by 1930, their efforts had created a structure beset with constructional defects, considerable flaws, and financial shortcomings. This article seeks to explain the sizeable gap separating Takoradi-envisioned from Takoradi-realized by examining the massive paper record compiled during the harbor’s planning and construction. Demonstrating that the structure was born largely from illusion, affect, and a particular version of “common sense” thinking, it encourages historians to not only give further attention to the detailed, and often overwhelming, corpus of blueprints, reports, and correspondence that such projects engendered, but to use them to reflect upon the ways in which colonial statecraft actually sought to limit, rather than expand, the knowledge it had at its disposal.

Long-term neuropsychological development in single-suture craniosynostosis treated early

The authors evaluated the results of complete cognitive function examinations in a series of 65 adolescents who had undergone surgery for sagittal or unicoronal craniosynostosis when they were younger than 1 year old. Each of the 65 study participants was evaluated individually. The neuropsychological assessment, consisting of a battery of tests tailored to the patient's age, cognitive level, and level of cooperation, was conducted in 2 separate sessions on the same day. The main outcome measures included fine motor skills, language, visual motor spatial and visual perceptual skills, working and visual memory, attention, executive function, and verbal fluency. Thirty-five children (mean age 13.4 years) were affected by sagittal synostosis and 30 (mean age 14.9 years) by unicoronal synostosis (16 right-sided, 14 left-sided). The mean age at surgery was 7.2 months. All of the children had begun school at a normal age and attended regular classes. Seven percent of those with sagittal craniosynostosis demonstrated visuospatial and constructional ability defects with associated visual memory recall deficits; 17% also exhibited selective and sustained attention deficits. Approximately one-third (30%) of the children with anterior plagiocephaly had processing and planning speech deficits. Data in this study support the hypothesis that children with sagittal or unicoronal craniosynostosis, although they undergo early surgical treatment, may still manifest lower than average results at long-term selective neuropsychological evaluations.

Joint Sealing Systems for Pavements—A New Approach Towards a Performance Related Evaluation of Capability and Durability

Abstract Joint sealants influence decisively the performance and service life of pavements although they account for only a small fraction of the total investment. Motivated by the damages observed and the resulting, increasing maintenance efforts, the Federal German Government recognizes the need for performance-evaluated joint sealing systems with improved capability (fitness-for-purpose) and durability. A literature study showed that an identification of the actual mechanical system behavior under realistic loads as well as a prediction regarding the durability (fatigue, climatic effects) of joint sealing systems are either completely lacking in most of the relevant evaluation methods or have only been incompletely addressed previously. Furthermore an imbalance between commonly used test methodologies and the actual development status of modern modified sealing materials exists, i.e., the current test methods are not effective in evaluating the performance of tailor-made products. In this paper, the authors suggest a methodology to overcome the present situation. In contrast to the existing, predominantly empirical evaluation and selection of joint sealing materials and systems for pavements, the new approach is defined by verified performance under relevant and superimposed loads. This new approach is expected to allow a more engineered joint design. In addition to the adaptation of performance-oriented material identification tests, a special focus was placed on the development and installation of a complex test facility for the investigation of the service capability and durability of joint sealing systems in building constructions in general. This paper presents an attempt at the realization of this approach for pavement joints with the help of our new joint sealant test equipment utilizing a specific, adapted load function, which comprises cyclic movements (slow and fast acting), as well as crucial climatic exposures. The test data and its interpretation are discussed. For example, the actual mechanical behavior of the various joint sealing systems as well as the relevant maximum loading of cohesive and adhesive bonds can be deduced and used to differentiate between systems. Furthermore, information gained allows discrimination of products within the various joint sealing systems. The test results will also enable numerical simulations, e.g., of different joint designs or materials by finite element analysis. The fatigue behavior is detected by analysis of cycle-dependent changes of the mechanical system characteristics. The evaluation methodology further allows investigation of the degradation mechanisms of specific system failures and, thus, enables service life prediction by reproducing the performance of the complete system under realistic conditions. Constructional defects and material flaws can be activated and detected by the performance-related test methodology, thus identifying possible corrections to material selection and application procedures. The potential of the proposed evaluation methodology is discussed for several thermoplastic and reactive joint sealing systems.

Experimental Investigation of the Electromagnetic Signal Attenuation Characteristics of the Partial Discharge Laboratory at Jadavpur University

Electromagnetic interference is becoming an increasing concern, because of the high intensity of surrounding electromagnetic waves, mainly arising from communication signals and also due to widespread use of equipment that operates at radio frequencies. As a consequence, sensitive data acquisition equipment suffers from erroneous results. Operating such instruments in a suitable shielded environment can significantly reduce this electromagnetic interference. But to achieve good shielding in practice, construction-related problems are to be faced, especially in large spaces, where a single metal plate cannot cover the whole area. Unless special care is taken, electromagnetic waves can penetrate through the gap in the joints and defects like drill holes reducing the shielding effectiveness. Also, a single layer of shielding is not always effective as the quality deteriorates drastically even due to minor constructional defects as mentioned above. This paper describes real-life experiences, step-by-step, in the shielding of a spacious insulation diagnostic laboratory (with a target of at least 55 dB signal attenuation), firstly using a good conducting material, using two different methods for joining the sheets, and ultimately constructing a second layer of shielding using a magnetic material. To study the attenuation behavior of the laboratory with respect to electromagnetic waves, a device for the relative measurement of surrounding electromagnetic signal strength is developed. The signal levels are measured initially outside and then at different places inside the shielded laboratory. The results presented in this paper show (1) the variation of attenuation characteristics inside the shielded laboratory due to different methods adopted for joining the shielding sheets using a good conducting material, (2) the effect of a second shielding layer in the form of a box that was constructed using a magnetic material and placed inside the laboratory and (3) the improvement in attenuation behavior after the actual construction of the second layer of shielding using a magnetic material.

Beyond memory impairment: cognitive changes in Alzheimer's disease.

In addition to memory impairment, deficits in other cognitive processes are common in the advanced stages of Alzheimer's disease (AD). The diagnosis of AD does not consider the relative prevalence of deficits in cognitive areas other than memory. We report on the prevalence of aphasia, apraxia, and other cognitive changes in individuals from a large representative sample of elderly Canadians. The proportion of these symptoms and the relevant neuropsychological test performance were compared in a group of 749 people over 65 years in age with AD and a control group of 563 people without cognitive impairment. Agnosia was less common in both groups than were deficits in complex visuomotor tasks, abstract thinking, aphasia, and constructional defects. The occurrence of all symptoms increased, and levels of performance on relevant neuropsychological tests decreased, with severity of Alzheimer disease. The tests did not, however, distinguish between possible and probable AD. Both these diagnostic groups showed similar levels of performance, which suggests that this distinction is not clinically meaningful.

Evaluation of septic tanks performance in some parts of Mosul City in Iraq

Abstract Septic tanks are still a common method of treatment and disposal of domestic wastewater in many parts of the world. Their removal efficiency of potential pollutants depends on many parameters. In Mosul city and due to the absence of the sewerage system, dwellings are provided with individual septic tanks. An investigation of these tanks showed a good percent removal of pollutants. Some constructional defects and faulty location of some arrangements had affected tank performances. Soil type necessitated rapid desludging or effluent overflow which might affect the environment. An oversizing of the tanks might cause some constructional danger. Besides, it added an overburden cost to the owner. The study set some recommendations to uprate tank performance and ascertained the importance of providing the city with sewerage system.

Construction Faults in Housing Located in a Mining Town in North Western Australia

The purpose of this paper is to identify the many technological faults evident in the housing stock of a mining town in North Western Australia. The research programme, of which this paper is a part, includes a brief to draw up recommendations for the restoration and making good of constructional defects with the aim of reducing recurrent maintenance costs. Defects such as those described can be attributed mostly to a lack of awareness of the problems associated with building in hot dry regions and to the inappropriateness of the finished building to the lifestyle of its occupants.

10MV医療用直線加速器からの漏洩放射線について : 第1報 使用室迷路からの異常漏洩とその原因

As the result of the survey of leakage X-ray from the treatment room, unusual high leakage value is found at the entrance to the treatment room. The leakage values at the other measurement locations are less than those expected from a shielding calculation. Layout of the treatment room is an ordinary construction, and no constructional defects are found. As a consequence of tracing the origin of this unusual leakage, it is concluded that neutrons produced in Linac leak from the treatment room through that the maze, and that the main contribution to the measured leakage radiation is that from neutron capture γ-ray in materials composing the maze, the door etc.. For the purpose of reducing the unusual leakage, a reconstruction of the room is performed by reducing an open area at the part of the entrance from the main room to the maze. At the entrance to the treatment room, initial measured X-ray dose equivalent rate is 5.8 mrem/h in the condition of the beam direction vertically downward, the fully closed field and output 4.65 Gy/min, but, after the reconstruction, its value reduces to 1.8 merm/h and measured neutron dose equivalent rate is 3.9 mrem/h in the same condition. The X-ray and neutron leakage values in the fully opened field are less than the above values. From X-ray leakage values before and after the reconstruction, it is deduced that initial neutron leakage dose equivalent rate is about 12 mrem/h in the fully closed field. When a treatment room to set up a Linac with the accelerative energy exceeding 10 MV is designed, it is suggested from the above facts that some plans to reduce neutron leakage through the maze must be taken into consideration. Also, in survey of leakage radiation from the treatment room, not only X or γ-ray but neutron survey is demanded.

Isolation of Anatomical Brain Mutants of Drosophila by Histological Means

Abstract Due to its small size Drosophila melanogaster can conveniently be used in screening experiments for anatomical brain mutants. A simple method has been designed which allows to process up to 20 identifiable flies as a single preparation in a standard histology routine. Anatomical brain mutants are very frequent. Over 60 mutants were obtained from the inspection of about 3000 brains. So far genetic variations of brain structure fall into 4 classes: (1) “low fidelity” mutants in which brains are less precisely built; (2) “brain shape” mutants with globally or partially reduced brains; (3) “architectonic” mutants which show constructional defects mainly in the repetitive structures of the brain and (4) “vacuolar” mutants with globular “holes” in certain areas of the brain. These mutant classes obviously reflect different aspects of brain development like cell pro­liferation (2), “wiring” (3) and cell death (4). Some of the mutants may prove to be useful in anatomical, physiological or genetic brain research.

Effects of internal discharges on prospective life and overvoltage-withstand behaviour of e.h.v. oil-impregnated paper bushings

The paper gives the results of an experimental laboratory investigation of model bushings, with the object of predicting the behaviour of full-scale e.h.v. oil-impregnated paper bushings operating at a radial a.c. stress of 3kV r.m.s./mm. One of the aims was to determine whether discharges of up to 5pC in full-scale bushings might damage the insulation during prolonged periods in service, and so reduce the prospective life. Frequency-accelerated life tests were made on over 90 model bushings, some of which were constructed according to accepted manufacturing methods, whilst others contained defects of various kinds. It was found that, while the initial-discharge magnitude is a good indication of air trapped in the windings in a region of high electric stress, it is not a good guide to the prospective life of the bushings. The most critical factor is the ability of the oil to dissolve any trapped gas. If the trapped gas dissolves, bushings working at a stress of 3kV r.m.s./mm will have a low discharge level and a long life, provided they have no constructional defects. If not, the discharge magnitude may fall at first, but will then rise steadily until breakdown occurs after 12–20 years. A further aim of the investigation was to determine the extent to which either permanent damage or temporary impairment of the dielectric properties could be caused by overvoltages in the range 7–16kV r.m.s./mm, applied for periods of 1–50min. The effects of impulse stresses up to 19kV peak/mm were also studied. It was found that a sensitivity of about 0.1pC would be required to detect the discharge resulting from the gas generated during a normal overvoltage test on a well made 400kV bushing, but that much larger quantities of gas produced in this way would dissolve in the oil within a few days, and the bushing would then return to a discharge-free condition, without apparent physical damage. Where a quantity of air was trapped in the winding during manufacture, it was shown that a discharge level of 30pC at working voltage in a 400kV bushing having a moisture content not greater than 1% would not involve a risk of degradation by a single overvoltage test having a duration of 1 min at a stress of 14kV r.m.s./mm.

THE GEOMETRICAL THEORY OF THE CAMERA AND ITS APPLICATION IN PHOTOGRAMMETRY

AbstractThe conventional treatment of lens theory in photogrammetric textbooks is based upon over‐simplified notions of how an objective functions. Modifications to take account of distortion inevitably lead to the introduction of an arbitrary parameter, the calibrated principal distance, which prevents the adoption of universal specifications for cameras and leads to confusion about the meaning of lens distortion. This paper sets out a treatment that confines itself to the geometrical characteristics of the picture and, with one minor exception (Appendix 3), avoids discussion of the mechanism of image formation. This enables a logical theory to be built up, independent of arbitrary parameters and the design of particular lenses, and, furthermore, allows constructional defects and errors of observation in calibration to be included naturally.The paper falls into two parts, camera calibration and the problem of internal orientation, the successful solution of which is the ultimate object of calibration. The paper ends with a general treatment of transformation printers.

Tractor Transport in the Soviet Arctic

Mechanical transport was first used by the author of this article at the time of the investigation of the Norilsk mining field (Lat. 69° 20′ N., Long. 88° 8′ E.) in 1925 for the purpose of taking goods from the port of unloading to the village of Dudinsk on the River Yenisei over a distance of 85 km. across tundra. At that time the tractor industry had only just come into being in the Soviet. Special machines for cross-country freight did not exist, so imported caterpillar tractors of the Reno make were used, drawing sledges freighted up to five tons. Certain constructional defects in the machines, and particularly in the sledges, as well as lack of experience in the work, combined to make the results far from satisfactory at this stage. At the end of the winter we had only succeeded in making one full journey and had transported only ten tons of profitable cargo on three machines. Nevertheless, this first experiment was valuable in that it demonstrated that, given mechanical improvement, the tractors might revolutionise polar transport. In this case, for instance, three machines had transported rapidly a cargo which would have required a caravan of two hundred and forty reindeer. It was ascertained also by this trial that caterpillar tractors of this type were suitable only for work in the vicinity of a base on smooth and hard roads. For transport over long distances in new and soft snow they were less satisfactory.