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Predicting Nonlinear Behavior and Stress-Strain Relationship of Rectangular Confined Reinforced Concrete Columns with ANSYS

Duflow surface water hydrodynamic model has been applied using a case study from Nyando catchment in the western part of Kenya in Africa to simulate various extreme flood behaviours and their retardation levels by using selected structural measures as flood mitigation techniques. The objective of this case study was to establish a design flood recommendable for mitigation, and to identify the most cost effective flood mitigation structure. Various design flows are simulated against the different proposed structures hence, the optimal structure can be recommended when economical, social and environmental constraints are considered in the decision making process. The proposed four flood mitigation structures flood plain extension, embankment (dykes), channel by-pass, and green-storage were simulated for 20-year recurrence interval flood to determine their individual responses in storing excess water. The result shows that building a green-storage is the best and optimal structure for flood mitigation.

Effects of Confinement on Interaction Diagrams of Square Reinforced Concrete Columns

The key in developing a strategy for management of non-revenue water (NRW) is to gain a better understanding of the reasons for NRW and the factors which influence its components. The components of NRW can be determined by conducting a water balance analysis. The International Water Association (IWA) provides a water balance calculation that gives guidance to estimate how much is lost as leakage from the network (physical losses), and how much is due to non physical losses. Further, IWA has established the Infrastructure Leakage Index (ILI), a performance indicator for comparisons of leakage management in water supply systems. This paper introduces ILI and reasons why it is a more appropriate approach to use than the percentage of system input volume.This paper reviews the applicability of nine selected expressions in determining the equivalent value of the Manning coefficient of roughness. For this purpose, a prismatic 4m-long and 0.05m-wide trapezoidal-shape channel was constructed, namely the homogeneous channel and the composite channel. The homogeneous channel had the same surface lining, whereas the composite channel had two different surface linings. Four different lining materials were considered: plaster, small, medium, and large-sized aggregates. The homogeneous channel showed a reliable Manning coefficient prediction, provided that a uniform flow was achieved. The roughness of the composite channel can be predicted accurately by the nine expressions; the average was 0.96, with standard deviation of 11.13%. Out of the nine expressions, the expression that considers wet-perimeter as its main parameter showed the best estimate. The error was about 2% with standard deviation of 5.15%. This can be actually traced back to the limited width of the test channel, thereby increasing the role of wet perimeter.This paper presents an experimental and analytical research conducted to study the in-plane behavior of reinforced concrete (R/C) frames in-filled with lightweight materials. The tests were performed on two single bay, single story in-filled frame specimens with 1⁄2 scale models. One of the test specimens was in-filled with lightweight materials, i.e. autoclaved aerated concrete (AAC) blocks, and the other, used as the comparison, was in-filled with clay brick materials. The loading used in the tests was in the form of cyclic in-plane lateral loads, simulating earthquake forces. Behavior of the frame structures was evaluated through the observed strength and deformation characteristics, the measured hysteretic energy dissipation capacity and the measured ductility. The experimental results show that the R/C frame in-filled with AAC blocks exhibited better performance under in-plane lateral loads than that in-filled with conventional clay bricks. In the analytical work, the performance of some analytical models available in the literature was evaluated in simulating the experimental results

Spline Nonparametric Regression Analysis of Stress-Strain Curve of Confined Concrete

Note from the Editor: The ability to forecast maximum water depth during maximum discharge of a design flood is very important in designing flood protection scheme along the river reach. This paper explains the use of ISIS Flow, a one-dimensional hydrodinamic computer modelling for river flood forecasting. The computer simulations produced detailed information from each node including the maximum water depth during maximum discharge, thus it can be expected that an economical flood protection structure can be produced.Variable Message Sign (VMS) is especially recommended for congested flow conditions. The aim of this study is to investigate how drivers in a large city in a developing country with many specific geometric and traffic conditions and also specific driver behaviour, use VMS in aid of choosing route for their inter-city trips. Furthermore, to explore the impact of the use of the information on increasing traffic performance measures. A case study was carried out in Bandung, Indonesia. Microscopic traffic simulations were used in this study to evaluate traffic performance measures. The results of the evaluation found that VMS has insignificant impact on drivers’ route choice behaviour. The results indicated that drivers in Bandung rely much on their experience of traffic conditions commonly occur in the city and demonstrated that VMS has no significant impact to increase traffic performance, but has better impact on the roads with higher number of alternative roads.Due to enormous uncertainties in confinement models associated with the maximum compressive strength and ductility of concrete confined by rectilinear ties, the implementation of spline nonparametric regression analysis is proposed herein as an alternative approach. The statistical evaluation is carried out based on 128 large-scale column specimens of either normalor high-strength concrete tested under uniaxial compression. The main advantage of this kind of analysis is that it can be applied when the trend of relation between predictor and response variables are not obvious. The error in the analysis can, therefore, be minimized so that it does not depend on the assumption of a particular shape of the curve. This provides higher flexibility in the application. The results of the statistical analysis indicates that the stress-strain curves of confined concrete obtained from the spline nonparametric regression analysis proves to be in good agreement with the experimental curves available in literatures.

Stress-Strain Behavior of Steel Fiber-Reinforced Concrete Cylinders Spirally Confined with Steel Bars

The compressive strength of concrete according to certain codes can be based on the compressive strength of unconfined plain standard concrete cylinders tests at the age of 28 days. In this paper, the standard concrete cylinders were spirally confined with steel bars and with/without hooked-end steel fibers. The influence of the use of hooked-end steel fiber in spirally confined concrete with various pitches was investigated. It can be seen that the use of hooked-end steel fiber contributes significantly in improving both compressive strength and ductility of concrete. The compressive strength and ductility of steel fibered concrete also increase with the reduction of the spiral’s pitch.

FE modelling of fiber reinforced elastomeric isolators (FREI): Mesh verification and validation

Seismic isolation is an effective technical solution to reduce the vulnerability of new and existing structures. It can mitigate the negative impact of an earthquake by shifting the period of the structure in that range of the spectrum where the spectral acceleration is low. A well known and relatively cheap seismic isolation device is the so-called elastomeric isolator. The fabrication cost of such isolator can be reduced by the utilization of fiber lamina instead of steel. In this work, finite element (FE) modeling of fiber reinforced elastomeric isolators is discussed. In numerical modelling, the main characteristic of elastomeric materials is the hyperelasticity, which can be taken into account in the commercial FE code that was used in the present study (namely ABAQUS). In this paper, an interesting issue highlighted is the mesh verification on FE models of an elastomeric material embedded into a seismic isolator.Seismic isolation is an effective technical solution to reduce the vulnerability of new and existing structures. It can mitigate the negative impact of an earthquake by shifting the period of the structure in that range of the spectrum where the spectral acceleration is low. A well known and relatively cheap seismic isolation device is the so-called elastomeric isolator. The fabrication cost of such isolator can be reduced by the utilization of fiber lamina instead of steel. In this work, finite element (FE) modeling of fiber reinforced elastomeric isolators is discussed. In numerical modelling, the main characteristic of elastomeric materials is the hyperelasticity, which can be taken into account in the commercial FE code that was used in the present study (namely ABAQUS). In this paper, an interesting issue highlighted is the mesh verification on FE models of an elastomeric material embedded into a seismic isolator.

Desain Modifikasi Apartemen One East dengan Menggunakan Precast Dual System Sesuai dengan Peraturan ACI 318M-14

Beton pracetak merupakan metode yang digunakan pada perancangan bangunan selain cara pengecoran dengan metode konvensional. Seiring dengan perkembangannya, metode pracetak kini semakin banyak digunakan. Tingkat kecepatan pembangunan dan kontrol kualitas merupakan keunggulan utama metode pracetak. Perencanaan Gedung Apartemen One East Surabaya pada kondisi sebenarnya dirancang menggunakan metode konvensional dengan ketinggian 33 lantai dan 3 buah basement. Dalam tugas akhir ini, gedung tersebut akan dilakukan perancangan menggunakan metode pracetak. Pemilihan metode pracetak didasari oleh kecepatan pelaksanaan, kontrol kualitas mutu yang tinggi, ramah lingkungan, serta pengurangan jumlah tenaga kerja. Metode pracetak diterapkan pada elemen-elemen struktur primer, seperti pelat, balok, tangga, kolom dan shearwall. Dalam perencanaan struktur pada tugas akhir ini, metode menggunakan peraturan seperti perencanaan beton secara konvensional sesuai dengan SNI 2847:2013, PCI Handbook dan beberapa referensi lainnya. Selain perencanaan elemen struktur sendiri, perlu dilakukan perencanaan sambungan untuk menyambungkan elemen-elemen tersebut. Metode penyambungan yang digunakan berdasarkan dari beberapa sumber seperti, produk dari Peikko Group, dan jurnal “Horizontal Connection for Precast Concrete Shear Wall Subjected to Cyclic Deformations”. Analisis perhitungan sambungan pada balok berdasarkan pada kekuatan aksial sambungan yang dibandingkan dengan kekuatan tulagan setelah mengalami leleh serta panjang penyaluran. Untuk analisa kekuatan sambungan pada kolom dan shearwall, digunakan peraturan ACI 318M-14 dimana nilai ϕSn ≥1,4 Se sedangkan ϕMn ≥0,4 Mpr.

Low cost friction seismic base-isolation of residential new masonry buildings in developing countries: A small masonry house case study

A Finite element model was established to examine performance of a low-cost friction base-isolation system in reducing seismic vulnerability of rural buildings. This study adopts an experimental investigation of the isolation system which was conducted in India. Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ in static and dynamic friction coefficient obtained through previous research. The FE model was performed based on a macroscopic approach and the masonry wall is assumed as an isotropic element. In order to observe structural response of the masonry house, elastic and plastic parameters of the brick wall were studied. Concrete damage plasticity (CDP) model was adopted to determine non-linear behavior of the brick wall. The results of FE model shows that involving these friction isolation systems could much decrease response acceleration at roof level. It was found that systems with marble-marble and marble-geosynthetic interfaces reduce the roof acceleration up to 50% comparing to the system without isolation. Another interesting result is there was no damage appearing in systems with friction isolation during the test. Meanwhile a severe failure was clearly visible for a system without isolation.A Finite element model was established to examine performance of a low-cost friction base-isolation system in reducing seismic vulnerability of rural buildings. This study adopts an experimental investigation of the isolation system which was conducted in India. Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ in static and dynamic friction coefficient obtained through previous research. The FE model was performed based on a macroscopic approach and the masonry wall is assumed as an isotropic element. In order to observe structural response of the masonry house, elastic and plastic parameters of the brick wall were studied. Concrete damage plasticity (CDP) model was adopted to determine non-linear behavior of the brick wall. The results of FE model shows that involving these friction isolation systems could much decrease response acceleration at roof level. It was found that syst...

Evaluasi Gedung Mnc Tower Menggunakan Sni 03-1726-2012 Dengan Metode Pushover Analysis

Pembaruan SNI 03-1726-2002 menjadi SNI 03-1726-2012 membuat perbedaan perancangan gedung MNC Tower terhadap beban gempa berubah. Perancangan gedung MNC Tower menggunakan SNI 03-1726-2002 perlu dievaluasi kembali akibat beberapa perbedaan antara peraturan lama dengan yang baru diantaranya perubahan nilai area repon spectrum percepatan menjadi 15 area spectrum dari 6 area spectrum kemudian di SNI 1726 2002 hanya diperhitungkan respon percepatan gempa periode pendek dibandingkan dengan SNI 1726 2012 yang memperhitungkan periode pendek dan periode 1 detik Kenaikan nilai R untuk sistem SRPMK dari 8.5 menjadi 8 yang akan mengubah percepatan respon gempa dan periode yang mengakibatkan perbedaan rancangan ketahanan struktur gedung pada gempa bumi. Perbedaan isi dalam SNI 03-1726-2002 dengan SNI 03-1726-2012 menjadi focus tugas akhir ini dimana dalam mengetahui kelayakan gedung dalam menerima beban gempa yang terbarukan digunakan metode Pushover Analisis yang merupakan sebuah analisa static nonlinier berdasarkan Performance Base Design yang pada intinya adalah mencari kapasitas struktur suatu bangunan. Peraturan pushover anisis mengambil acuan dari ATC 40 (Seismic Evaluation and Retrofit of Concrete Buildings, Redwood City, California, USA) dan menggunakan bantuan program softwear 2000 dalam mengevaluasi gedung MNC Tower. Perkuatan struktur direkomendasikan dengan beberapa metode jika hasil akhir evaluasi gedung mengalami kelelehan dibeberpa elemen.

A REGIONAL REFINEMENT FOR FINITE ELEMENT MESH DESIGN USING COLLAPSIBLE ELEMENT

A practical algorithm for automated mesh design in finite element analysis is developed. A regional mixed mesh improvement procedure is introduced. The error control, algorithm implementation, code development, and the solution accuracy are discussed. Numerical example includes automated mesh designs for plane elastic media with singularities. The efficiency of the procedure is demonstrated.In this paper, existing innovation models are reviewed. The influence of technology and market-driven schools of thought on the creation and diffusion of innovation is examined. Incremental vs. radical models and autonomous vs. systemic models are considered in the context of the construction industry. The concept of “technology adoption life cycle” is investigated to understand better the acceptance of new technology by key parties. A new model of innovation is proposed. In this model, the transformation process of invention into adoption flows through a cyclical mechanism encompassing six phases: 1) need, 2) creation, 3) invention, 4) innovation, 5) diffusion, and 6) adoption. This model clearly shows the interaction of the three most influential domains: users, changes, and the environment. The model also takes into consideration the influence of technology and market-driven forces on the creation and diffusion of innovation. As a consequence of their particular function in the construction activity, construction management firms should perform as catalysts in the generation and diffusion of technological advances in the construction industry.