JOURNAL OF STRUCTURAL AND CONSTRUCTION ENGINEERING
Year:2019 | Volume:6 | Issue:Special Issue 2 (27)|Papers Count:14

I am glad to announce publication of Volume 6, Special No. 2 (2019) of Journal of “ Structural and Construction Engineering” . Journal of “ Structural and Construction Engineering” publishes by Iranian Society of Structural Engineering (ISSE) which is one of the leading institutes in the region. ISSE’ s mission is to create an appropriate platform for the purpose of scientific, technical, research, educational communication, and scientific exchanges and competitions between researchers and specialists in structural engineering and related fields, and integration of the activities in the field of structural engineering and construction, the expansion of the frontiers of science and professional and public awareness in MEA region. To do so, ISSE established a leading journal and will publish it four times a year. Journal of “ Structural and Construction Engineering” provides a forum for a broad blend of scientific and technical articles to reflect the evolving needs of the structural engineering and construction communities in the region. The scope of “ Structural and Construction Engineering” encompasses, but is not restricted to, the following areas: structural engineering; earthquake engineering; structure-soil interaction; structural fire engineering; blast engineering; structural reliability/stability; life assessment/integrity; structural health monitoring; structural dynamics; experimental modelling; performance-based design, construction management. “ Structural and Construction Engineering” also publishes review articles, technical notes, and a diary on national and international events related to any aspect of structural engineering. “ Structural and Construction Engineering” has a continuous open call for papers. Backed by the reputation of the members of its Editorial Board, we will continue to push for excellence in the contents and quality of this journal. From now on, all published articles in JSCE will get Digital Objective Identifier (DOI) which is very important for indexing and etc. In addition, JSCE is an Open Access (OA) journal that is available online to the reader without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself. We also are proud to announce that Ministry of Science, Research and Technology of Iran gave grade A to JSCE (similar grade to ISSE) in the last year evaluation. I wish you enjoy reading this issue of “ Structural and Construction Engineering” and I invite you to contribute to the success of this journal by submitting your articles.

Tuned mass damper is a common tool in passive control, which is used in many structures. However, with all the proper features, its most important functional limitation is the weakness against broad band excitation. Various methods have been proposed to overcome this problem, among which using hysteretic damping of materials with nonlinear behavior is known effective. Among materials with nonlinear behavior, shape memory alloys have good features and large hysteresis loops. Hence, in this paper, using nonlinear stiffness and hysteretic damping of a shape memory alloy spring, linear stiffness and viscous damping of a common tuned mass damper are replaced. Then, the modified damper has been used to control responses of a single degree of freedom structure under harmonic loadings and the effect of the loading amplitude on the control of the structural responses was determined. Subsequently, the damper has been used to control seismic responses of single degree of freedom structures to compare its performance under broad band seismic loadings with the performance of conventional tuned mass dampers. Results of the analyses show that the characteristics of shape memory alloys can adequately control the impact of the loading amplitude on the performance of nonlinear mass dampers. Also, the presence of hysteretic damping can significantly improve control of seismic responses of single degree degrees of freedom structures compared to conventional tuned mass dampers, provided that dynamic properties of the nonlinear mass damper take their optimal values.

Concrete, as one of the main components of the manufacturing industry since the beginning of the process of production, operation and destruction, plays a major role in the creation of environmental pollution. Since more than 70% of the main body of concrete is aggregate, the promotion of culture and considerations based on the principles of sustainable development in design, construction and demolition process of concrete is of great importance. One of the basic principles of sustainable development is the importance of recycling. Recycling of damaged concrete in the last century has become one of the most important interests of researchers. So, after studying and recognizing their durability and mechanical properties (MP’ s), today in developed countries, the necessary relationships for the recognition of structural performance of these concretes is under construction. The purpose of this research is to investigate the results of research carried out in different countries in the field of recognition of the MP’ s of recycled concretes (RC’ s). More than 80 articles published in prestigious technical journals were examined and classified together in the six groups that the researchers considered in analyzing the MP’ s of RC’ s. The effect of each of these groups on compressive and tensile strengths and elasticity of concrete were studied. The results showed that the type, size and quality of recycled aggregates (RA’ s) are very effective in determining the level of replacement of recycled materials (RM’ s) in concrete. Curing conditions, water reducing and pozzolanic materials, although effective in improving the MP’ s of RC’ s, cannot reduce the adverse effects of increasing the replacement of RM’ s on the mechanical properties of concrete. Concerning the effect of age on the mechanical properties of RC’ s, it is common ground that some of these properties are similar to conventional ones.

Although the total collapse of buildings under earthquake occurs less but the incidence in recent decades and the possibility of its re-occurrence in the future has made research inevitable in this field. Several numerical and laboratory studies have been carried out on the seismic collapse of the structures. The most common model considering the strength and stiffness deterioration of the structural elements under earthquake is the Ibarra-Madina-Krawinkler three-linear behavioral model that in the case of steel structures, its parameters is presented via performing a large number of laboratory connection tests by the other researchers. The behavioral models resulted from laboratory tests are usually accompanied by a fitting mathematical model with many errors, i. e., the existence of uncertainty in laboratory behavior models is the fundamental challenge of their practical application. In this research, a 5-story steel structure has been designed with intermediate moment resisting frame in accordance with the internal codes. The effect of strength and stiffness deterioration of structural elements is performed based on the Ibara-Madina-Krawinkler behavioral model. Incremental dynamic analysis was carried out under the proposed 50 pairs of earthquake records proposing FEMA P 695 instruction and the fragility curves of its collapse capacities have been developed considering the uncertainty in the yielding moment and the capping moment of the elements and the ultimate rotation capacity of the elements. The results show that among the studied parameters, the uncertainty in the capping moment parameter has the greatest effect on structural collapse capacity and it can change to 19. 2% the collapse probability. Uncertainty of the ultimate rotation capacity compared to the other parameters played a small role in structural collapse capacity and has changed the collapse probability up to 5. 2 %.

In the production of heavy concrete, instead of typical aggregates, heavy aggregates or steel spalls, cast iron or lead is used; The use of such concrete is to prevent the emission of radiation such as X and gamma; Basically, this kind of concrete is used in structures related to nuclear facilities, and hospitals; Heavy concrete, is a concrete that has a substantially higher specific gravity than concrete with typical aggregates; Heavy concrete is usually produced using heavyweight aggregates and is especially used as a protective shield against radiation; The specific gravity of heavy concrete is about 1. 5 to 2. 5 times the typical concrete weight. The aim of this paper is to investigate the linear attenuation coefficient and compressive strength parameters of cube samples made from heavy concrete, with typical aggregate, barite aggregate, bismuth powder, microsilica powder, and concrete superlubricant additive compounds; and compare the results of these samples withbuilt control sample result. The results show that the linear attenuation coefficient parameterof built concrete samples, relates to cesium 137 gamma rays, directly correlates with the percentage of compounds used in the manufacture of samples, ie, the percentage of typical aggregate, barite aggregate, bismuth metal and microsilica powder, but this is not the case with the compressive strength parameter of concrete.

Preventing brittle fracture in the connection welds of the steel members is one of the most important issues in the performance of steel structures. Bitter experiences of Northridge earthquake in the case of “ demand critical” welds such as complete-joint-penetration (CJP) groove welds in the connections of steel moment frames forced researchers to conclude that for preventing decrease in ductility and preventing brittle fracture of welds, it should be that impact toughness of welds must be provided at the determined temperature. Seismic Requirements of AISC and following of it the 10 th topic of Iranian national building Requirements for the mentioned welding recommends Charpy-v-notch toughness at the determined Test temperature. In this research, to ensure impact toughness of preformed welds in the common conditions of Iran, the Charpy Test in the specimens of multiple thicknesses and common electrodes has been done with Shielded Metal Arc Welding (SMAW) and Submerged Arc Welding (SAW) and the conclusions of them compared with the 10 th topic requirements. It has been shown that impact toughness of groove weld in SMAW process with E6013 electrode and groove weld in SAW process doesn’ t matched with requirements of present Codes, but for other electrodes there was no contradiction.

Considering the necessity of developing the road network, bridges as infrastructures, play a key role in helping and sustaining vital activities in the recovery phase after natural disasters and events. So, In Khorasan Razavi province, with regard to climatic conditions on the one hand, and the presence of corrosive agents in the soil profile of many areas, as well as seasonal rivers with high water salinity, on the other hand, many concrete structures of roads such as bridges, culverts and concrete foundations are subject to corrosion and degradation. Therefore, the present study aimed to prioritize the restoration and reconstruction of important concrete bridges in the main roads of Khorasan Razavi province. This prioritization provides the possibility of allocating the annual budget necessary for the maintenance and utilization of concrete bridges of the roads in this province. In this research, 52 concrete bridges with a length of more than 15 meters in different parts of Khorasan Razavi province were studied under precision field observations after geotechnical studies, review of design procedure and as-built maps and after weighing the failure criteria according to the expert opinion, concrete bridges that requiring repair and Rehabilitation were prioritized using Analytical Hierarchy Process (AHP) with Expert Choice software and finally 10 bridges with the highest priority were identified. In line with this research, the results show that the most important and influential criterion in prioritizing the restoration and reconstruction of concrete bridges is the general characteristics of the bridge site with a priority index of 0. 115 and the least effective criterion in this field is creating green area which leads to deterioration of foundation materials near footing, with priority index of 0. 014. At the end, results of the sensitivity analysis based on performance for prioritization criteria of the bridges needed restoration and reconstruction showed that the bridge importance criterion has the most sensitivity in prioritizing the restoration and reconstruction of large concrete bridges located in the main roads of Khorasan Razavi province.

The present paper proposes a new control strategy to mitigate windinduced vibrations of tall TV towers. Based on the proposed idea, a part of the main structure of the tower is isolated and regarded as a dynamic vibration absorber. In order to investigate the effectiveness of the proposed system, the 310-m tall Nanjing TV tower in China, which has two observation decks at the heights 180 m and 240 m, is studied. The wind-induced responses are obtained for the following cases: uncontrolled structure; controlled structure equipped with the TMD system; and the controlled structure with an isolated substructure at the upper observation deck level. The structure is modelled as a multi-degreeof-freedom (MDOF) lumped mass vertical cantilever beam. The TMD system and the isolated substructure are modelled as a lumped mass connected to the upper observation deck by a parallel stiffness and damper system. All the calculation works related to the frequency-domain analysis, optimizing the system, simulating the wind velocity, and the timedomain analysis are carried out using the MATLAB software. The results indicate that the proposed self-control structural system has higher vibration control capacity than the TMD system. The proposed system can effectively reduce the acceleration response of the structure and improve occupant comfort during critical wind speed. In the proposed system, since a part of the main structure performs as a vibration absorber, it is not required to assign a valuable space of the observation deck for the installation of an additional mass damper and the corresponding clearance to accommodate its large strokes.

In the present study, seismic analysis of concrete gravity dams strengthened by asphalt buttressing is presented for improving the seismic behavior of the Koyna dam in India subjected to Koyna ground motion. Fluid-Structure interaction is modeled including water compressibility and reservoir bottom absorption. The foundation is considered as rigid. A three-dimensional fixed smeared crack model is used to consider the nonlinear behavior of mass concrete. The analysis is carried out in the time domain by Newmark time integration scheme. Linear and nonlinear behavior of dam models subjected to horizontal and vertical components of selected record have been analysed. In order to investigate the effects of asphalt buttressing on the interface of dam and asphalt, the contact surface is defined using joint elements with a thickness of zero. The results of the analyzes confirm that the asphalt buttressing can improve the stability of the dam due to the pressure applied to the dam in counteracting the hydrostatic and hydrodynamic forces, Also the significant effect of asphalt Buttressing on the optimal distribution of stresses in the entire body of the dam as well as the prevention of stress concentration and reduction of fracture in the upper body near the dam crest show so that the crack at the lower section of the dam and at the interface of the dam and foundation is partially developed with a slower rate, and the cracking at the upper part near the crown of the dam does not spread to the upstream body of the dam and does not cause a total failure. Overall, it can be said that asphalt buttressing can improve the seismic stability of gravity dams by exerting pressure on the dam in opposition to hydrostatic and hydrodynamic loads.

In the present Experimental research, the behavior of exterior RC beamcolumn connections subjected to cyclic loading is studied using steel and shape memory alloy (SMA) reinforcing bars. In this research, 8 specimens of exterior RC beam-column connections were tested in which four specimens included SMA reinforcing bars and the remaining four specimens included steel bars. The confinement of beam longitudinal bars was different in the connections. Also, two types of concretes were used with the strengths 30 and 45 MPa, respectively. The specimens were tested under cyclic loading. The results of the research show that the specimens with SMA reinforcing bars can return to their initial shape after tolerating large displacements. In these specimens, the energy dissipation is satisfactory and the decrease in the residual deformation is significant. According to the superelastic behavior of the SMA reinforcing bars, the width of cracks is not significant in the connection core and cyclic loading reduced the cracks in the connection core. As the cyclic loading increased, bending failure occurred in the beam outside of the connection core. As the concrete strength and confinement value increased, bending failure still occurred in the beam outside of the connection core. In the beam-column connection with steel bars, shear failure occurred in the connection core. However, as the concrete strength and confinement increased, bending failure occurred in the beam outside of the connection core. Plastic hinge length in the connecting beams were calculated in the specimens with SMA and steel bars by empirical equations and compared with the test results. It was shown that Paulay and Priestley equations were suitable to be used for concrete connections with different bars.

The current design philosophy for buildings located in zones with high seismic risks is that the buildings must have sufficient strength and stiffness to remain elastic and serviceable under moderate but frequently occurring earthquakes and to have sufficient ductility to prevent collapse under extreme earthquake loading. Conventional structural steel framing systems such as moment resisting frames (MRFs), concentrically braced frames (CBFs), and eccentrically braced frames (EBFs), are extensively used in seismically active areas. Each of the previously mentioned structural systems has different advantages and disadvantages. In this study, response modification factor of ordinary inverted V-braced frames and specially inverted V-braced frames are evaluated, result confirm that the proposed height for buildings with ordinary inverted braced frames in the ASCE7, can be increased up to 10. 7 meter. In addition, results indicate that by using ordinary inverted V-bracing systems in buildings their height can be increased up to 6 stories or 20 meters. Using special inverted V-braced systems can have saving about 0 to 30 present on used materials for frames from 1 story to 16 stories. According to the results of this study, the response modification factor proposed by Iranian seismic design code (2800 standard fourth edition), (R=5. 5), is more logical than the one which is proposed by ASCE7, (R=6). Unfortunately, in special inverted V-braced frames, and when the story of the frames increases up to 12 stories, expected ductility demand cannot be achieved, so as a result, for frames that are more than 12 stories tall, lower response modification factor should be used. In addition, frames taller than 12 story height don’ t experience specified target displacement and collapse before getting to preferred mechanism. This phenomenon shows the necessity of using different response modification factor for frames taller than 12 stories.

Controlling the behavior of frame building is very common these days. This goal is achieved by changing the structural behaviors through applying forces to the frames. Recently, extensive studies have been carried out in the field of structural control related to the earthquakes. All studies conducted in this area can be divided into two groups. The first category is devoted to the control devices. Since accuracy and sensitivity of required equipment play an important role, some industries are trying to build better and more robust instruments. The key subject of the second group of researchers is developing new control algorithms. These approaches need some innovations. The purpose of this study is to minimize the structural response against earthquake utilizing two actuators. The purpose of this study is to minimize the structural response against earthquake utilizing two actuators. The relationship between the control forces of the actuators was so arranged that the first mode force becomes zero. In order to minimize the structural responses, the genetic algorithm was used. The controlling system, which is exploited in this paper, is a closed circle. In addition, the neural network was employed to predict the earth acceleration. The authors selected a kind of the neural network to have compatibility with earthquake acceleration variation. To achieve this, the number of the neurons in layers should be varied. The comprehensive experimental numerical results for a variety of earthquakes and structures indicated that the suggested method is very effective. However, the present study drawback is in decreasing the responses of tall frames.

Today, with the increasing spread of high constructions, as a development symbol, the need for selecting robust and suitable system for bearing optimally loads from earthquakes and wind and with high energy absorption power, has been significantly considered. Steel plate shear walls have been used over four decades as an efficient lateral resistance system. This paper analyzed the over strength factor, Ductility Factor and behavior factor of these system. For this, 7, 15 and 30 floors frames possessing one or two steel plate shear wall spans, have been analyzed in non-linear static, linear dynamic or increasingly dynamic analysis (IDA). For considering inherent uncertainty of earthquake, it was used of increasingly dynamic analysis and 7 records of the strongest earthquakes have been ever occurred were selected. The results showed that the behavior factor of this system in limit form for high construction is 8 and for short and middle construction is about 9.

Nowadays, Strengthening of existing structures was conducted by FRP wrapping in Iran in order to increase capacity and ductility particularly for columns resulting in an increase in the strength of concrete and improve structure behaviour. In this study, RC strengthened (with FRP) and un-strengthened buildings with 3, 5, 10 & 15 stories and 1 to 5 bay were considered. By performing linear and non-linear static analyses, seismic parameters such as acceleration and spectral displacement, damping and effective period of structure in performance points and capacity curves were discussed. The results indicated that the confinement of beams and columns of RC structures with CFRP sheets will improve the absorption and dissipation energy of structure and the stiffness and initial gradient of retrofitted structure with CFRP were about 1. 5 to 2. 5 times of those of original un-strengthened structure. And also via strengthening of structure with CFRP sheets, the spectral acceleration was increased and the spectral displacement, damping ratio and effective period were decreased, resulting in increasing seismic loading capacity. However, the structure retrofitted by CFRP with 3-stories, 4 bays showed the best performance in the term of stiffness, more spectral acceleration and spectral displacement and less effective period, but in the term of damping and energy absorption the best performance was for the structure with 10stories, 4 bays.