• On civil engineering disasters-taliem-ir

    On civil engineering disasters and their mitigation

    تومان

    Civil engineering works such as buildings and infrastructure are the carriers of human civilization. They are, however, also the origins of various types of disasters, which are referred to in this paper as civil engineering disasters. This paper presents the concept of civil engineering disasters, their  characteristics, classification, causes, and mitigation technologies. Civil engineering disasters are caused primarily by civil engineering defects, which are usually attributed to improper selection of construction site, hazard assessment, design and construction, occupancy, and maintenance. From this viewpoint, many so-called natural disasters such as earthquakes, strong winds, floods, landslides, and debris flows are substantially due to civil engineering defects rather than the actual natural hazards. Civil  engineering disasters occurfrequently and globally and are the most closely related to human beings among all disasters. This paper emphasizes that such disasters can be mitigated mainly through civil engineering measures, and outlines the related objectives and scientific and technological challenges.

  • Atlas.of.Implant.Dentistry.and.Tooth-Preserving.[taliem.ir]

    Atlas of Implant Dentistry and ToothPreserving Surgery

    تومان

    A complication in its broadest sense can be defined as an infrequent and unfavourable evolution of a medical/dental treatment or as a circumstance/difficulty that complicates the outcome in implant dentistry (ID)/tooth-preserving surgery (TPS). With regard to ID/TPS, the dental surgeon as well as his/her assistant or personnel can be associated with complications of variable severity that reflect insufficient knowledge, inexperience, lack of surgical skills, disregard of established protocols as well as surgeon’s mistakes.  Knowledge in general can be described as a familiarity with someone or something, which can include facts,  information, description or skills acquired through experience or education. It can refer to theoretical or practical understanding of a subject. As far as ID/TPS are concerned, it is unlikely that a dental surgeon would consider these surgical procedures without overall knowledge about them. Insufficient knowledge as causative factor of complications and failures, however, mostly refers to the lack of information on the behaviour of certain materials applied and the reaction of host tissues to them or to specific manoeuvres within the surgical procedure. This factor can play a role both in novice and very experienced surgeons.

  • CYCLIC BEHAVIOUR OF STEEL BRACED FRAMES HAVING[taliem.ir]

    CYCLIC BEHAVIOUR OF STEEL BRACED FRAMES HAVING SHEAR PANEL SYSTEM

    تومان

    Seismic resisting structures are expected to maintain adequate stiffness during frequent but moderate  excitations on one hand, and to dissipate a large amount of energy under damaging earthquakes on the other hand. In this paper, a relatively new seismic resisting structural system, which satisfies stiffness and  energy dissipation requirements simultaneously, is numerically investigated using nonlinear finite element analysis procedure. In this system, earthquake energy is dissipated through large inelastic deformation  occurred within a shear panel. The shear panel acts as a ductile link beam connecting braces to the floor  beam. This paper aims to find out key issues influencing cyclic behaviour of frames braced by Shear Panel System (SPS), like Cross-sectional properties of SPS and link length. The results indicate that shear panel length significantly affects cyclic performance of this system. Use of shorter links results in more stiffness and at the same time more stable hysteretic behaviour and energy dissipation capacity. Finally, the paper  presents a mathematical model to evaluate lateral stiffness of braced frames braced having SPS.

  • CYCLIC BEHAVIOUR OF STEEL BRACED FRAMES HAVING[taliem.ir]

    CYCLIC BEHAVIOUR OF STEEL BRACED FRAMES HAVING SHEAR PANEL SYSTEM

    تومان

    Seismic resisting structures are expected to maintain adequate stiffness during frequent but moderate  excitations on one hand, and to dissipate a large amount of energy under damaging earthquakes on the  other hand. In this paper, a relatively new seismic resisting structural system, which satisfies stiffness and energy dissipation requirements simultaneously, is numerically investigated using nonlinear finite element  analysis procedure. In this system, earthquake energy is dissipated through large inelastic deformation  occurred within a shear panel. The shear panel acts as a ductile link beam connecting braces to the floor  beam. This paper aims to find out key issues influencing cyclic behaviour of frames braced by Shear Panel System (SPS), like Cross-sectional properties of SPS and link length. The results indicate that shear panel  length significantly affects cyclic performance of this system. Use of shorter links results in more stiffness and at the same time more stable hysteretic behaviour and energy dissipation capacity. Finally, the paper presents a mathematical model to evaluate lateral stiffness of braced frames braced having SPS.

  • Geomorphologic hazards for Vanyar Dam with emphasis on the[taliem.ir]

    Geomorphologic hazards for Vanyar Dam with emphasis on the reactivation of Tabriz fault, northwest Iran

    تومان

    Shahid Madani or Vanyar Dam is being construction on Aji Cahy River, to the north of Tabriz. It has been  built on the upper red formation of Miocene. This lithology generally consists of sandstones, conglomerates, clays, and gypsum. Salt domes are also located underneath the reservoir area behind the dam. The slopes beside the reservoir are not stable. Unexpected events, such as subsidence, could occur after the reservoir is filled causing destruction to infrastructure. However, the most serious event could be the infiltration of water into the Tabriz fault. This fault has not been reactivated for over 220 years and it is thought that the infiltration of water from the reservoir could cause the two sides of the fault plane to move. It is thought that the displacement of the fault could cause an earthquake of more than 6.5 on the Richter scale. To try and prevent this fault reactivating, filling of reservoir is proposed to be undertaken gradually.

  • Investigation of the cracking of CFRD face plates[taliem.ir]

    Investigation of the cracking of CFRD face plates

    تومان

    The primary goal of this study was to examine the cracking behavior of the face plate of a CFRD over its life cycle. Analyses of the  construction stage, impounding, long-term deformation and earthquake loading were conducted in sequential phases using a 2-D plane-strain model with the appropriate nonlinear constitutive relationships for the dam constituents. The state of stress and the cracking behavior of the plate were found to be substantially different in the short and long term. Earthquake loading appears to be a critical load condition for the face plate; cracking increased significantly after ground shaking.

  • Investigation of the cracking of CFRD face plates[taliem.ir]

    Investigation of the cracking of CFRD face plates

    تومان

    The primary goal of this study was to examine the cracking behavior of the face plate of a CFRD over its life cycle. Analyses of the construction stage, impounding, long-term deformation and earthquake loading were conducted in sequential phases using a 2-D plane-strain model with the appropriate nonlinear constitutive  relationships for the dam constituents. The state of stress and the cracking behavior of the plate were found to be substantially different in the short and long term. Earthquake loading appears to be a critical load  condition for the face plate; cracking increased significantly after ground shaking.

  • Paleoseismicity and new seismicity studies in Azerbaijan and the[taliem.ir]

    Paleoseismicity and new seismicity studies in Azerbaijan and the necessity for seismic zonation

    تومان

    Azerbaijan is the site of convergent plate collisions along the Alpine-Himalayan active mountain belt. Brittle faults in the Azerbaijan area are mostly Cenozoic in or younger. The data presented demonstrate clearly that geological structures are commonly repeated at all scales from outcrop to regional. In order to forecast  earthquake activity we need to determine the past history of faults. A fault that is active is likely to move again. The great earthquakes of 6 May 1930 at 22 h 34 m. 24s (GMT) with M = 7.3 (the Salmas Earthquake), of 4 January 1780 with M = 7.7 (the Tabriz Earthquake) and of 21 June 1990 at a few minutes after  midnight (local time) with a magnitude 7.4 (the Zanjan-Roudbar Earthquake) and located about 320 km NE of Tabriz, caused about 40 to 50 thousand deaths. 60000 were injured and 50000 to 60000 made  homeless. These earthquakes have ruptured progressively from east to west. Consequently, there is a  probability of a large earthquake occurrence in the North Tabriz Fault (NTF) and the central part of Tabriz to Khoy-Salmas fault. The average recurrence interval is estimated to be 250-300 years; more than 60-80 destructive earthquakes have been described in the 1000-1200 years in the history of Azerbaijan. Therefore, as there is a likelihood of large and dangerous earthquakes in Tabriz, micro-seismic zonation of the Tabriz and other seismic regions of Azerbaijan should be included in future construction planning of the country and it will be effective for the macroeconomic and industrial planning of the country.

  • Random vibration analysis of long-span structures subjected to spatially[taliem.ir]

    Random vibration analysis of long-span structures subjected to spatially varying ground motions

    تومان

    On the basis of the pseudo-excitation method (PEM), a random vibration methodology is formulated for the seismic analysis of multi-supported structures subjected to spatially varying ground motions. The ground  motion spatial variability consists of the wave passage, incoherence and site–response effects. Advantages of this method are that less computation effort is required and that the cross-correlations both between normal modes and between excitations are automatically included. Random seismic responses of a realistic long-span bridge due to the wave passage, incoherence and site–response effects are extensively investigated. It is shown that all these effects have significant influence on the seismic response of the structure.

  • Training, motivation, and performance The case of human[taliem.ir]

    Training, motivation, and performance: The case of human resource management in construction projects in Mashhad, Iran

    تومان

    An enterprise’s productivity is closely correlated with its people and strategies; therefore, a forceful human resource management system is the most valuable asset of the current century construction companies. Purpose/design/methodology/approach: Based on a combination of literature review and questionnaire surveys, this paper explores the execution of construction workers training and motivation methods in HRM practices by the survey respondents’ companies and the effects on the companies’ performances. The research was conducted by sending 120 sets of questionnaires to the nominated companies and firms in Mashhad, Iran. A quantitative research approach was adopted requiring the development and dissemination of a questionnaire survey. The analysis method in this research is mainly descriptive and the type of investigation is co-relational study. Findings: The research exposes some barriers in the training and motivation of the construction workers and provides solutions for the government and companies in Iran. Also, it reveals the effects of unskilled labour on the quality of construction projects in Mashhad. Research limitations/implications: Future research should be under taken to address how companies and governments adapt to and shape the environmental and organizational settings in such a way that the context optimally stimulates workers motivation and participation in training courses and effects on increasing the quality of construction.