Structural Engineering

This paper discusses about the detection of damages present in the steel plates using nondestructive vibration testing. A simple experimental model has been developed to hold the steel plate complying with the simply supported boundary condition. Vibration patterns from the steel structure are captured based on the impact testing using a simple protocol. The vibration signals in normal condition of the steel plate are recorded. The damages of size 512 m to 1852 m are simulated manually on the steel plate using drill bits. The vibration signals in the fault condition of the steel plate are collected. The captured vibration signals are preprocessed and time domain based feature extraction algorithms are developed to extract features from the vibration signals. The conditions of the steel plate namely healthy and faulty are associated with the extracted features to establish input output mapping. A feed-forward neural network is modeled to classify the condition. The neural network parameters are adjusted to train the network. The performance of the network is calculated using Falhman criterion.

In this paper the influence of a surface fatigue crack on vibration behaviour of tee-welded plates was studied and results compared to the influence of machined through-thickness cuts on the dynamic response of cantilever beams. Comparison of experimental data with two and three dimension finite element modelling results was also carried out and discussed. Detection threshold using natural frequencies shift was found and compared to literature. The influence of naturally grown fatigue cracks on the oscillation frequencies was analysed and compared to two and three-dimensional numerical modelling results. An experimental detection threshold was found using the variation of the first mode natural frequencies. The power density spectra of the acceleration signals were analysed. Crack shape was found important for the detection threshold of the method. It was found that small size semicircular fatigue cracks do not noticeably modify the beam natural frequency but generate integer harmonics of the vibration modes that provoked stresses at the samples surface affected by the crack. The harmonics found were found to be generated by the breathing behaviour of the fatigue crack. A detection threshold using this spectral analysis was found to be lower than those found by using frequency shifts. The results obtained showed the ability of the experimental technique to detect cracks from a size of 0.6% of the cross section area, at 55% of the fatigue lifespan, 35% earlier than the other method studied.

This is a doppler device, based on heterodyning with a laser source. Its features include a very large DoF and dynamic range. • Spherical projectiles, 14 mm. • Projectiles could be observed through cavity • From V(t) integrate to get V(x) or differentiate to get dV/dt.

A-Wall systems are a combination of deep foundations and, in some cases, tiebacks used to provide lateral support to an unstable ground mass. Determination of the lateral and vertical forces acting on an A-Wall system can be a complex endeavor. As the unstable soil mass tends to move past and through the A-Wall system, forces are generated between the A-Wall elements and the soil. These forces provide support to the ground mass. If the A-Wall is correctly designed, the forces will increase as the soil moves until a maximum is attained at which ground movement ceases and the system reaches equilibrium. Design of an A-Wall thus requires Soil-Structure Interaction (SSI) analyses that provide a solution that meets force and moment equilibrium as well as compatibility of displacements. The individual elements of the A-Wall are designed based on a structural analysis utilizing the estimated forces. This paper describes the philosophy of design of A-Walls. It also contains a detailed description of design steps based on the use of a commercially available computer program that allows determination of soil forces against a deep foundation element installed through a mass of moving soil. An iterative method is presented to find a solution to the A-Wall problem that meets equilibrium and compatibility and considers material nonlinearity of soils and A-Wall components, as well as geometric nonlinearity of the deep foundation elements. Two case histories are presented.

Structural Health Monitoring (SHM) of aerospace structures has received significant interest as a core component of Condition Based Maintenance (CBM). This paper examines the possibility of using an ultrasonic guided wave system for damage detection in thin metallic plates. Acousto-Ultrasonic methods based on high frequency structural vibrations using piezoelectric transducers (PZT) have been developed to perform damage detection on thin metallic structures.The fundamentalLamb wave modes (AO&SO) travel into the structure and are reflected by the structural boundaries, discontinuities, and damage.Thus the presence of defect in the structure can be determined by studying their propagation and reflection. Laboratory level experiments have been carried out on thin Aluminum plates with angular, horizontal and vertical defect. This study provides significant insight into the problem of identifying localized damages in the structure using PZT and dispersion of signal after they interact wi...

A numerical investigation for the stresses and displacements of a two-dimensional elastic problem with mixed boundary conditions is reported in this paper. Specifically, it is on the analysis of stresses at the fixed end of deep cantilever beams, subjected to uniformly distributed shear at the free end. An ideal rnathematical model, based on a displacement potential function, has been used to formulate the problem. The solutions are presented in the form of graphs. Results are compared with the elementary solutions and the discrepancy appears to be quite noticeable, specifically at the fixed end. The present solution shows that the fixed end of a short cantilever beam is an extremely critical zone and the elementary theory of beams completely fails to predict stresses in this zore.

Concrete structures are subject to aging depending on a number of factors particular local environmental issues. The current non-destructive testing practice only provides limited localized samples of concrete strength and can not give values for the entire structure and its performance. Ambient vibration monitoring technologies have developed rapidly and are now able to quantify the performance not only for static load cases but also for dynamic actions like earthquakes. Experience has shown that in average concrete structures show higher capacities than anticipated through conventional assessment methods. Nevertheless one of the major targets of a detailed monitoring campaign is to find out deficiencies and particular weak structures, which might collapse in an earthquake event. The combination of multiple non-linearities enables profound assessment of the earthquake resistance. The methodology has started to enter the practice of earthquake assessment and the improvement of mitigation strategies.

The present study focused on an experimental determination of damping ratio of a multi-storey building subjected to aerodynamic loadings. It used the methods of model construction, wind tunnel and dimensional analysis for the investigation. Although, the wind tunnel and dimensional analysis were successfully used in the past and in different ways by many Scholars and Engineers to investigate the problem of wind effects on buildings; but such solutions or efforts, did not include the influence of the building deflection (δ). The results of the study show that depending on the phase of the force with respect to motion, self-excited forces can be associated with the displacement, the velocity or acceleration of the structure. Due to the influence of these associations, these forces can be thought of as "aerodynamic contributions" to stiffness, damping and mass, respectively. The building deflection is therefore, considered to be an important structural quantity which affects structural quantities such as forces, moments, velocity and acceleration which severely affect the human perception criteria of occupants using multi-storey buildings. The damping ratio also proved to have been influenced by dependent variables such as stiffness, amplitudes of vibration, H/B ratio, Strouhal and L o numbers at a basic wind speed of 52.5 ms -1 . Therefore, it can also be inferred that the relationship in the variations of the values of H/B ratio and L o number are inversely proportional to the values of the Strouhal numbers and damping ratio along the model height. Whereas, the amplitude of the vibrations progressively increased, while, a critically damped model and its stiffness decrease with increase in model height. All these are likely to provide wider areas of applicability in structural analysis and in particular, experimental use of wind tunnel for structural modeling and similitude.

The arch is a very efficient load bearing structure, especially when its shape is affine to the funicular of forces. However, if live loads are predominant as compared to permanent uniformly distributed gravity loads, the arch will be subjected to substantial bending moments, thus losing a great part of its structural efficiency. In traditional arch bridges with hangers arranged in a vertical manner, asymmetrical loads would cause a substantial deviation of the pressure line from the axial line of the arch. In this paper, an innovative concept for timber arch bridges is introduced where V-shaped hangers, rather than vertical hangers, are used. The adoption of V-shaped hangers significantly contributes to the reduction of the eccentricity between the pressure line and the axial line of the arch, thus decreasing the magnitude of bending moments in the arch. The paper discusses the advantages of using V-shaped hangers as an alternative to vertical hangers, both in terms of statics, in-plane stability and dynamic efficiency. Moreover, the design and the recent construction of a parabolic three-hinged arch made of timber, with a steel V-shaped hanger is thoroughly discussed in the paper.

Since the reports of promising creep properties of MARBN alloys (a short name for MARtensitic 9Cr steel strengthened by Boron and Nitrides), nearly two decades ago, significant effort has been input in examining the base alloys, development and validating of the matching filler metals. One of the main targeted applications of MARBN alloys is the castings for thermal power plant turbine components. These applications will involve repair welding of castings and joint welding between castings and other structures, such as joints between casted valves and steam pipe works, etc. For weld joints with satisfactory microstructure and properties, there are practical needs for developing appropriate welding procedures and post weld heat treatment (PWHT) parameters. Particularly, a relatively lower PWHT peak temperature, i.e. 735°C, is preferred for the fabrication of casting components. Within the UK collaborative projects, IMPLANT, a detailed investigation has been carried out to the matchin...

In surface mines, bench blasting is a typical way of excavating hard rock mass. Although a significant development has taken place in explosive technology but still only a part of the energy is used to excavate and a large proportion of energy is wasted away and creates a number of nuisances. Backbreak, massive rock fragmentation, and high-intensity ground vibration are all symptoms of improper blasting. As a result, production costs increase significantly while productivity decreases. The blasting outcomes are affected by a variety of factors, which may be classified into three categories: rock properties, explosive properties, and blast geometry. Consequently, it is necessary to examine the effect of these parameters on bench blasting. So, in this study, a sensitivity analysis has been performed on various blast design parameters using the Taguchi method to study the influence of blast design parameters on blast vibration, backbreak, and rock fragmentation. A total of 32 experiments have been designed and numerical modeling was also carried out, using LS DYNA software to simulate the blast results. It was found that the blast hole diameter is the most important factor influencing the blasting outcomes. However, the number of rows in a blast affects backbreak almost slightly more than the hole diameter, but blast vibrations and the surrounding rock damage strongly depend on the hole diameter. Furthermore, rock blast geometry significantly affected rock blast vibration and damage compared to explosive properties. However, both blast geometry parameters and explosive properties play a significant role in backbreaking. • The Taguchi method has been applied to study the influence of various blast design parameters on blast vibration, back break, and rock fragmentation. • According to sensitivity analysis, it was observed that the hole diameter is the most important parameter that affects blasting results. • In large diameter holes, the energy released by explosives is greater than the small diameter holes and due to that, a higher PPV occurred. As a

In surface mines, bench blasting is a typical way of excavating hard rock mass. Although a significant development has taken place in explosive technology but still only a part of the energy is used to excavate and a large proportion of energy is wasted away and creates a number of nuisances. Backbreak, massive rock fragmentation, and high-intensity ground vibration are all symptoms of improper blasting. As a result, production costs increase significantly while productivity decreases. The blasting outcomes are affected by a variety of factors, which may be classified into three categories: rock properties, explosive properties, and blast geometry. Consequently, it is necessary to examine the effect of these parameters on bench blasting. So, in this study, a sensitivity analysis has been performed on various blast design parameters using the Taguchi method to study the influence of blast design parameters on blast vibration, backbreak, and rock fragmentation. A total of 32 experimen...

Metode Direct Displacement Based Design (DDBD) atau Metode Perpindahan Langsung sebagai metode alternatif dalam desain bangunan gedung tahan gempa. Menurut P., Yosafat, 2007, karena gaya geser dasar yang dipakai dalam perencanaan adalah gaya geser dasar pada saat leleh pertama, maka diasumsikan gaya geser dasar ultimit metode DDBD dikoreksi dengan cara membaginya dengan faktor kuat lebih total struktur yang pada saat itu sesuai SNI 1726-2002. Makalah ini membahas kinerja struktur hasil dari analisis metode DDBD dengan dan tanpa faktor kuat lebih menurut SNI 1726-2019 pada gedung bertingkat beton bertulang yang diterapkan pada gedung bertingkat 5 (empat) lantai 3D di Kota Ternate. Hasil perbandingan antara struktur yang didesain dengan Metode DDBD dengan dan tanpa faktor kuat lebih menunjukkan bahwa Metode DDBD dengan gaya geser rencana tanpa dibagi dengan faktor kuat lebih menghasilkan respon struktur yang lebih baik yaitu terjadinya mekanisme kelelehan pada balok. Dengan demikian s...

Metode Direct Displacement Based Design (DDBD) sebagai metode alternative dalam desain bangunan gedung tahan gempa. Beberapa kegagalan bangunan disebabkan karena mekanisme softstory atau lantai lemah. Hal ini disebabkan karena perbedaan kekakuan lantai yang lebih rendah dibanding lantai yang lain. Makalah ini membahas tentang penerapan metode DDBD pada gedung bertingkat 4 (empat) lantai beton bertulang di Kota Ternate yang memiliki ketidakberaturan vertikal tipe 1a menurut SNI 1726-2012. Hasil analisis menunjukkan bahwa metode DDBD memberikan level kinerja lebih tinggi dari desain rencana.

The strength of reinforced concrete members can be enhanced by using the externally bonded reinforcement (EBR) and near-surface mounted (NSM) methods. However, very few studies have adopted the NSM method for torsional strengthening. Although previous studies have reported the efficacy of using epoxy-resin-bonded NSM steel bars in increasing the flexural and shear strength of RC beams, no study has examined the use of steel bars and epoxy adhesives for torsional strengthening. Therefore, this study investigates the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with NSM steel bars (Ø10 mm) in different configurations. The practical part of this investigation consisted of seven cast and tested beams of 150 × 250 × 2000 mm dimensions. One beam was reference, which is not strengthened; meanwhile, all the other beams were strengthened with two U-shape-welded NSM steel bars. During the testing process, the twist angle at t...

Many researchers worldwide have extensively used fibre-reinforced polymer (FRP) strengthening materials and near-surface mounted (NSM) to enhance the shear and flexural strengths of reinforced concrete (RC) beams. However, studies on torsional strengthening are limited. Although a few studies have focused on torsional strengthening, none of them simultaneously investigated torsion with shear and/or bending moment. This study aims at demonstrating the behaviour of RC beams strengthened with FRP sheets (strips) with different configurations and NSM steel bars with different spacing that was subjected to combined actions of torsion and bending moment and making a comparison between them. Seven beams with a dimension of 15 × 25 × 200 cm were casted. One of the beams was not strengthened; three of them were strengthened with carbon FRP, and the others were strengthened with NSM steel bar. The angle of twist at torque intervals, first cracking torque, ultimate torque, and ultimate twist a...

This paper presents a matrix-based procedure to characterize the specific stiffness properties of 2D lattice materials with any arbitrary cell topology. Unlike previous works, the current study automates the analysis process to include lattice materials whose unit cell has elements extending between adjacent cells and thus intersecting their envelopes. The main challenge in the analysis of this periodic lattice structures is that the unit cell does not have the full information concerning its nodal kinematic and static periodicity. For this reason, we introduce the Dummy Node Scheme, which enables the analysis of lattice material with any cell topology. The lattice material is modelled here as a pin-jointed infinite micro-truss structure. The results of the determinacy analysis are used to distinguish between the bendingdominated and the stretching-dominated behaviours of the material. The Cauchy Born Hypothesis is used to homogenize the lattice material properties by formulating the microscopic lattice nodal deformations in terms of the material macroscopic strain field. This formulation, in turn, is used to express the microscopic element deformations in terms of the macroscopic strain field, from which the material macroscopic stiffness properties are derived. In this process, the Dummy Node Scheme is a necessary step to construct the nodal periodicity within the unit cell, which is used to apply the Cauchy Born kinematic boundary condition to the nodal deformation wave functions. The procedure introduced in this paper is applied to 10 lattice topologies, five of which have unit cells with a square Bravais lattice symmetry and the other five have unit cells with a hexagonal Bravais lattice symmetry. Finally, charts representing the relative elastic moduli of the lattice material versus its relative density are developed. These charts assist the selection of the best topology of a stretching-dominated lattice material for a given application that requires a material with specific stiffness properties.

Most of the structural designer do not consider masonry infill walls during design process due to a lack of modeling guidelines in design standards and are treated as non-structural elements. In fact, the interaction effect between bounding frames and infill masonry is a complicated issue in nonlinearity of structures. The current seismic codes indirectly incorporate the nonlinear response of structure through linear elastic approach by considering the response reduction factor 'R' without comprising infill. In this context, this study evaluates the response reduction factor of existing engineered designed RC frame structures that are designed based on Indian standard codes. For this, three existing RC buildings were selected and performed non-linear pushover analysis. The structural response was examined in terms of natural period, base shear, strength, stiffness, ductility and response reduction factor. The results specify that the buildings with infill walls significantly influence on 'R' value of structures. Additionally, study shows that the variation of 'R' value mainly depends on the percentage of infill inclusion.

A magic cricket bat is the bat in which the weight of bat is increased at the point of percussion. Just by increasing the weight at the centre of percussion one can hit the ball very well, and for same effort the ball can drop/ travel more distance.

We formulate and solve data-driven aerodynamic shape design problems with distributionally robust optimization (DRO) approaches. Building on the findings of the work [13], we study the connections between a class of DRO and the Taguchi method in the context of robust design optimization. Our preliminary computational experiments on aerodynamic shape optimization in transonic turbulent flow show promising design results.

Development of vibration controlled high-rise RC building with low stiffness at lower stories using shear-wall and oil-dampers Part 1 Tsubasa TANI, Ryota MASEKI, Hiroshi HIBINO and Izuru TAKEWAKI A new structural control system using shear-walls with a pin connection at the bottom is proposed for vibration control of high-rise RC buildings. A laminated rubber is adopted at the bottom of the shear-wall as a rotary bearing. However it is not connected to the base concrete to reduce the tensile deformation of the rubber. In this study, two kinds of loading tests and FEM analysis are conducted to clarify the behavior of the unconnected laminated rubber. It is shown that the laminated rubber has a high durability against the rotary deformation in spite of the existence of axial load, and the tensile deformation of the rubber is effectively decreased due to the bending deformation of the flange. A slight change of horizontal and vertical stiffnesses was observed after the tests.

The purpose of this paper is to disclose the fundamental proper 【 ies of a new selsmic retrofitting method of connecting an existing bui且 ding with an a 〔 ljacent outer frarne by viscous dampe 【s ． The mass ratio and stiffness ratio of the outer frame to the buUding a 【 e introduced as the key parameters fer representing the dynamic propenies of such retrofitting system ． The damping ratiQ evalua 忙 ed undcr the assumpdon that the outer me is rigid is凵 sed to express a quantity of damping of the add に d connecting dampeτs ． h is shQwn that the stiffness ratio and the damping ratio defined above play a cent 瓰 l role in 山 e seismic response reduction by the proposed retrofitting method ， The approximate formlllas of the response reduction ratio and the 皿 aximum damping f( )rce of the connecting darnpers are propt )sed and are yalidated by numedcal examples ． It is conc ］ uded that the propOsed method is an effective seismic retrofitting rnethod fc )r existing buildings ，

The double impulse input is introduced as a substitute of the fling-step near-fault ground motion and a closed-form solution of the elastic-plastic response of a structure with viscous damping under the 'critical double impulse' is derived. Since only the free vibration appears under such double impulse, the energy approach plays an important role in the derivation of the closed-form solution of a complicated elastic-plastic response with viscous damping. The quadratic-function approximation for the damping force-deformation relationship is introduced. The validity and accuracy of the proposed theory are investigated through the comparison with the response analysis to the corresponding one-cycle sinusoidal input.

Due to the spatial variations of the strong ground motions and Near-Field (N-F) effects, significant and unexpected damages have been observed in long-span bridges during past earthquakes. One of the outstanding characteristics of N-F motions is the forward directivity effect seen as a single, intense, long period pulse at the beginning of velocity records in the fault-normal direction. To better understand the effect of this pulse and the wave passage effect of spatially correlated motions on the seismic response of long-span bridges in comparison with these bridges' response to the far-field earthquakes, a comprehensive case study has been done in three parts on the finite element model of a long-span bridge: 1) Uniform excitations of the model bridge with forward directivity pulses and the original records; 2) Asynchronous excitations with different shear wave velocities for impulsive part of the inputs; and 3) Comparison of the wave passage effect of two sets of near-field and far-field strong ground motions (SGMs) on the seismic response of the model bridge. The results show that the wave passage effect of forward directivity N-F pulses can have significant influence on the bridge nonlinear response, and it becomes more evident in the soft soils causing severe seismic demands. Even in the case of rock sites, ignoring this effect can result in under-designed piers. Besides, comparison of the near-field and far-field SGM excitations effect on the bridge response indicates that although in uniform excitations both sets cause approximately the same displacement response values, in the case of asynchronous inputs, the N-F records can produce larger ductility demands.

This paper reports the behavior of I-shaped fiber reinforced concrete (FRC) beams flexurally reinforced with prestressed steel and glass fiber reinforced polymer (GFRP) bars. The use of steel fibers aims to enhance the durability of pre-fabricated concrete structures by partially or completely replacing steel stirrups. In addition, GFRP and steel bars/tendons are combined as flexural reinforcement, creating a hybrid reinforcement system. GFRP bars are immune to corrosion and are positioned with minimum concrete cover, while steel reinforcement has adequate concrete cover thickness to minimize its risk to corrosion and ensure the required flexural capacity in a fire occurrence. Nonlinear finite element analysis (NLFEA) software was utilized for a critical analysis on the use of smeared crack model for predicting the behavior of this type of beams, including deflection, crack pattern, load-carrying capacity, and failure modes.

Wind turbine support towers at heights in excess of 90m are nowadays being formed in steel, concrete and hybrid concrete and steel structures. As is the case for all towers of this height, the towers will be assembled using a number of segments, which will be connected in some way. These local connections are to be viewed as areas of potential local weakness in the overall tower assembly and require care in terms of design and construction. This work concentrates on identifying local damage which can occur at an interface connection by either material or bolt/tendon failure. Spatial strain patterns will be used to try to identify local damage areas around a 3dimensional tower shell. A Finite Element (FE) model will be assembled which will describe a hybrid tower as a continuum of four-noded, two-dimensional Reisser-Mindlin shell elements. In order to simulate local damage, an element around the circumference of the tower interface will be subjected to a reduced stiffness. Strain patterns will be observed both in the undamaged and damaged states and these signals will be processed using a Discrete Wavelet Transform (DWT) algorithm to investigate if the damaged element can be identified.

Railway infrastructure maintenance is essential in implementing the transportation system. Most of these railway bridges have suffered gradual deterioration over time. Predictive structural health monitoring (SHM) is required by installing instrumentation sensors on railway bridges to determine the condition of the railway bridge infrastructure at the site. This research aims to analyze and assess the existing condition of steel railway bridges to understand the load-deformation characteristics, bearing capacity, and dynamic response of the structure. This paper describes a valuable method for assessing the condition of steel railway bridges during operation. This paper presents a direct analysis of the steel railway bridge structure, with a span of 40.00 meters, a width of 4.40 meters, and a height of 6.60 meters. The steel structure railway bridge is modeled in 3D in detail, and numerical analysis is carried out using finite element analysis based on input parameters obtained from manual field measurements and instrumentation sensors. The expected result of the development of this SHM System is to know the performance of the steel railway bridge structure in real-time via the dashboard display. The results showed that the carrying capacity of the railway bridge was in a relatively safe condition. This case study may help practice engineers and researchers in future research. It can be a valuable reference for future research in developing and applying such a system to a typical case.

In Referring to the government programs on the increasing speed of the Jakarta-Surabaya express train in 2017, problems arise in the field, namely the potential increase in freight transportation via the railway line where an increase in loading is required on the railway especially for the existing bridge. This Research was implemented by increasing of the loading of the standard PM 60/2012 bridge to be compared with the EN1991: 2/2003 standard. This research analyzed the increase in structural strength of the 30m span steel bridge of the BH 182 constructed in Operational Region 2 Bandung as a results of loading adjustment from PM 60/2012 to EN 1991:2/2003.This paper explained an effect caused by increasing load on railway bridges with similar span and materials on normal plane, shear plane, moment and deflection. Structural analysis and calculation was performed by means of SAP2000 software. Results of analysis showed that standard equalization of EN 1991:2/2003 caused increasing ...

The railway bridge in Indonesia, with a width of 1067 mm, was built in 1878, so that maintenance modules are needed to repair or to replace of construction modul at regular intervals. Implementation of maintenance and repairs refers to the Minister of Transportation Regulation No. 60 of 2012. Problems were encountered in the field at the BH182 Daop 2 railway bridge in Bandung due to lowering structural strength. Therefore, it was necessary to repair the bridge module with a new bridge design. The purpose of this study is to analyse and to calculate strength of the structure and to determine effectiveness of the use of construction materials on 2 alternative bridge construction selection with the type of “I" girder and the type of “Warren" Truss. Design implementation method used is to utilize Midas Civil Structure software. The loading used for railway bridges is grouped into three load groups, namely the girder's self-weight, additional dead load, and live load. A...

Penelitian ini dilatarbelakangi oleh keinginan penulis untuk mengetahui efektivitas teknik show not tell dengan memori otobiografi dalam pembelajaran menulis cerita pendek. Tujuan penelitian ini adalah menguji keefektifan teknik show not tell dengan memori otobiografi dalam pembelajaran menulis cerita pendek dan memberikan alternatif teknik pembelajaran menulis cerita pendek di sekolah. Teknik show not tell memiliki prinsip “menggambarkan bukan memberitahukan”, yaitu mengubah “kalimat-kalimat memberitahu” menjadi “paragraf-paragraf menggambarkan’. Memori otobiografi merupakan memori jangka panjang yang dimiliki setiap manusia, di dalamnya terkait dengan histori masa lalu seseorang. Pada penelitian ini, memori otobiografi yang akan digunakan terkait dengan peristiwa penting dalam hidup siswa. Sampel dalam penelitian ini berjumlah 29 siswa pada kelas eksperimen dan 30 siswa pada kelas kontrol yang diambil secara purposive sampling. Metode yang digunakan dalam penelitian ini adalah met...

The delivery of electricity to widely dispersed communities across the open steppe grasslands of Mongolia depends on medium-voltage (10–35 kV) distribution lines, often carrying power over substantial distances. Previously utilizing wooden supports, upgraded and new distribution lines are now designed to be cheaper, using steel-reinforced concrete poles with galvanized steel crossarms that can carry an electrical charge to the ground. Consequently, any bird that perches on these poles and simultaneously touches a conducting cable can be electrocuted, which is a significant risk for medium to large-sized birds at 10 kV and 15 kV lines utilizing pin-insulators. Surveys and monitoring of these dangerous power lines revealed that raptor electrocution rates were high, especially in areas with abundant prey, and widespread across steppe habitats. With around 3,500 km of hazardous lines in the Mongolian steppe zone, it was estimated around 18,000 raptors, including 4,000 Saker Falcons, wer...

Received January 01, 2015; Accepted April 06, 2015 Abstract: Concrete such a composite material is practically more presented material in engineering structures. Development trends for high rise Building or structures, modern skyscrapers request the different workability of fresh concrete to cast in properly way and to achieve the requested results. The many of factors such are: highest of the cast concrete, sections of concrete elements, request the concrete with more plasticity and higher class of consistency, the smaller size of aggregate, the compacted process, etc. The fulfilling the previous condition, using the Self Compacted Concrete is one of the aims in this paper. Based on the requests, and also the behaviour of concrete in short and long term period , the presented experimental data provide the necessary information’s for different results in comparing the conventional and using the SCC. The results based on the experiment in this paper present the difference in some of ...

A laboratory-based experimental study with well defi ned but artifi cial boundary conditions, which utilises constituent construction materials that replicate the material properties of masonry found in historic URM buildings, is currently addressing this need. The purpose of this study is to investigate the performance of near-surface mounted (NSM) carbon fi bre reinforced polymer (CFRP) strips as a seismic retrofi t solution for out-of-plane lateral loading of the walls in URM buildings. In addition, fi ve retrofi tted URM walls located in four different buildings were tested in-situ by applying outof-plane loading, to complement the laboratory-based study. Testing confi rmed that the NSM CFRP retrofi t technique is an excellent minimally-invasive and cost effective option for seismic strengthening of URM buildings. Provisional details of the design methodology for the NSM CFRP retrofi t technique, and laboratory and in-situ test results are reported. Two recent projects that implemented the NSM CFRP technique are also briefl y presented.

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Accurately measured strains are critical when investigating the application of Fiber Reinforced Polymer (FRP) materials, but traditional mechanical strain measurement methods have several critical drawbacks related to the installation process and the recording capabilities of the devices. FRP materials typically used in the civil engineering field feature large asymmetries and heterogeneity originated from the manual installation procedures, as opposed to the highly controlled FRP fabrication methods used in other fields that result in more homogeneous materials. The feasibility of using an optical full-field Digital Image Correlation (DIC) technique for measurement of strain fields on FRP materials used in the civil engineering industry has been investigated and the level of error in the DIC method when using more traditional methods was determined. The main advantage of using DIC over more traditional methods, which is the capacity of DIC to measure full field strains instead of strains at isolated points, has been demonstrated by providing exemplar measurements of various specimens of FRP materials. The reported strain fields are examples of what was obtained during an experimental campaign to understand the behavior of FRP anchors and other materials. The main conclusions drawn from the observation of those strain fields are discussed.

Self-centering precast concrete walls have been found to provide excellent seismic resistance. Such systems, however, typically exhibit low energy dissipation, requiring supplementary dissipating components to improve their seismic performance. An economical option is to use mild steel shear connectors as energy dissipating elements. The design of steel shear connectors for a new precast wall system was undertaken using finite element analyses. Of the different types studies, an oval shaped connector (or O-Connector) was found to provide the most suitable response, with stable force-displacement behavior and large displacement capacity. An experimental test program was conducted to verify the performance of two different O-Connector designs, confirming the expected excellent response with sufficient energy dissipation. The experimental data demonstrated excellent correlation with the finite element model developed. The O-Connector has since been incorporated into a large scale PreWEC test specimen, behaving as expected and providing an excellent connector for the system.

Reinforced concrete frames with masonry infill walls are popular form of construction all over the world as well in seismic regions. While severe earthquakes can cause high level of damage of both reinforced concrete and masonry infills, earthquakes of lower to medium intensity sometimes can cause significant level of damage of masonry infill walls. Especially important is the level of damage of face loaded infill masonry walls (out-of-plane direction) as out-of-plane load cannot only bring high level of damage to the wall, it can also be life-threating for the people near the wall. The response in out-of-plane direction directly depends on the prior inplane damage, as previous investigation shown that it decreases resistance capacity of the infills. Behaviour of infill masonry walls with and without prior in-plane load is investigated in the experimental campaign and the results are presented in this paper. These results are later compared with analytical approaches for the out-of-plane resistance from the literature. Conclusions based on the experimental campaign on the influence of prior in-plane damage on the out-of-plane response of infill walls are compared with the conclusions from other authors who investigated the same problematic.