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CONTENTS
Volume 4, Number 4, October 2019
 

Abstract
Rehabilitation and retrofitting of structures designed in accordance to standard design codes is an essential practice in structural engineering and design. For steel structures, one of the challenges is to strengthen the panel zone as well as its analysis in moment-resisting frames. In this research, investigations were undertaken to analyze the influence of the panel zone in the response of structural frames through a computational approach using ETABS software. Moment-resisting frames of six stories were studied in supposition of real panel zone, different values of rigid zone factor, different thickness of double plates, and both double plates and rigid zone factor together. The frames were analyzed, designed and validated in accordance to Iranian steel building code. The results of drift values for six stories building models were plotted. After verifying and comparing the results, the findings showed that the rigidity lead to reduction in drifts of frames and also as a result, lower rigidity will be used for high rise building and higher rigidity will be used for low rise building. In frames with story drifts more than the permitted rate, where the frames are considered as the weaker panel zone area, the story drifts can be limited by strengthening the panel zone with double plates. It should be noted that higher thickness of double plates and higher rigidity of panel zone will result in enhancement of the non-linear deformation rates in beam elements. The resulting deformations of the panel zone due to this modification can have significant influence on the elastic and inelastic behavior of the frames.

Key Words
double plates; lateral drift; moment-resisting frames; panel zone; rigidity; rigid zone factor; steel structure

Address
Masoud Abedini, Sudharshan N. Raman, Azrul A. Mutalib: Smart and Sustainable Township Research Centre (SUTRA), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
Ebrahim Akhlaghi: Islamic Azad University, Mahshahr

Abstract
Among the themes related to earthquake countermeasures at construction sites, those for tower cranes are particularly important. An accident involving the collapse of a crane during the construction of a skyscraper has serious consequences, such as human injury or death, enormous repair costs, and significant delays in construction. One of the causes of deadly tower crane collapses is the destruction of the site joints of the tower crane mast. This paper proposes a new design method by static elastoplastic finite element analysis using a supercomputer for the design of the end plate–type tensile bolted joints, which are generally applied to the site joints of a tower crane mast. This new design method not only enables highly accurate and reliable joint design but also allows for a design that considers construction conditions, such as the introduction of a pre-tension axial force on the bolts. By applying this new design method, the earthquake resistance of tower cranes will undoubtedly be improved.

Key Words
computer simulation, tower crane, FEM, bolted tensile joints, joint design

Address
Yoshitaka Ushio, Yasuyuki Nagano: Graduate School of Simulation Studies, University of Hyogo 7-1-28 Minatojima-Minamicho, Chuo-ku,
Kobe 650-0047, Japan
Tomoharu Saruwatari : Engineering Technology Div. JSOL Corporation 2-2-4 Tosabori, Nishi-ku, Osaka, 550-0001, Japan

Abstract
Multiple Inputs and Multiple Outputs (MIMO) Fuzzy logic model is developed to predict the engine performance and emission characteristics of pongamia pinnata biodiesel with hydrogen injection. Engine performance and emission characteristics such as brake thermal efficiency (BTE), brake specific energy consumption (BSEC), hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2) and nitrous oxides (NOX) were considered. Experimental investigations were carried out by using four stroke single cylinder constant speed compression ignition engine with the rated power of 5.2 kW at variable load conditions. The performance and emission characteristics are measured using an Exhaust gas analyzer, smoke meter, piezoelectric pressure transducer and crank angle encoder for different fuel blends (Diesel, B10, B20 and B30) and engine load conditions. Fuzzy logic model uses triangular and trapezoidal membership function because of its higher predictive accuracy to predict the engine performance and emission characteristics. Computational results clearly demonstrate that, the proposed fuzzy model has produced fewer deviations and has exhibited higher predictive accuracy with acceptable determination correlation coefficients of 0.99136 to 1 with experimental values. The developed fuzzy logic model has produced good correlation between the fuzzy predicted and experimental values. So it is found to be useful for predicting the engine performance and emission characteristics with limited number of available data.

Key Words
biodiesel; fuzzy logic; hydrogen; injection; emission

Address
Department of Mechatronics, Bannari Amman Institute of Technology, Sathyamangalam-638401, India

Abstract
This paper proposes a new approach to model the screw joints of integrated ceilings via the finite element method (FEM). The simulation models consist of the beam elements. The screw joints used in the main bars and cross bars and in the W bars and cross bars are assumed to be rotation springs. The stiffness of the rotation springs is defined according to the technical standards proposed by the National Institute for Land and Infrastructure Management of Japan. By comparing the results of the sheer tests and the simulation models, the effectiveness and efficiency of the simulation models proposed in this paper are verified. This paper indicates the possibility that the seismic performance of suspended ceilings can be confirmed directly via beam element models using FEM if the stiffnesses of the screw joints of the ceiling substrates are appropriately defined. Because cross-sectional shapes, physical properties, and other variables of the ceiling substrates can be easily changed in the models, it is expected that suspended ceiling manufactures will be able to design and confirm the seismic performance of suspended ceilings with different cross-sectional shapes or materials via computers, instead of spending large amounts of time and money on shake table tests.

Key Words
integrated ceiling; seismic ceiling; ceiling modules; FEM analysis

Address
Zhilun Lyu and Yasuyuki Nagano: Graduate School of Simulation Studies, University of Hyogo, 7-1-28 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo, Japan
Masakazu Sakaguchi: Asahibuilt Industry Corporation Limited, 4-32, Ota-ku, Tokyo, Japan 3JSOL Corporation, 2-2-4 Tosabori, Nishi-ku, Osaka, Japan
Tomoharu Saruwatari: JSOL Corporation, 2-2-4 Tosabori, Nishi-ku, Osaka, Japan

Abstract
In this paper, static nonlinear analysis of gable frame is performed using OpenSees software. Both geometric and material nonlinearities are considered in analyses. To consider large displacements, co-rotational coordinate transformation is used in software. The effects of symmetric and asymmetric support conditions including clamped and simple supports are studied. On the other hand, the material nonlinearity is reflected on analyses using Giuffre-Menegotto-Pinto steel material. Note that strain hardening characteristics are also considered in this model. Moreover, I-shaped cross-section is assumed for all members. The results are provided for different geometry properties of gable frame including shallow and deep inclined roof. It should be added that buckling and post-buckling behaviors of gable frame are investigated using related equilibrium paths. A comparison study is also implemented on the responses of buckling loads obtained for different support and geometry conditions. To trace snap-through paths completely, a displacement control method entitled arc-length is utilized. Findings show the capability of proposed model in nonlinear analysis of gable frames.

Key Words
nonlinear analysis; co-rotational; strain hardening; buckling and post-buckling; steel gable frame; OpenSees software

Address
Department of Civil Engineering, Ferdowsi University of Mashhad, Iran


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