• Fire Science and Engineering
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• v.26 no.3
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• pp.100-105
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• 2012

In this study, seismic design in pipeline of pressurized water supply system of water extinguishing system has been carried out. This study described a generation of artificial earthquake wave compatible with seismic design spectrum, and also determined equivalent static loads to analyzed the response spectra acceleration by the simulated earthquake motion. This study constructed powerful engineering base for seismic design, and presented equivalent static analysis method for seismic design of water and gas extinguishing piping system. Also, this study readied basis that can apply seismic design and performance estimation of fire fighting system as well as pipeline of water extinguishing system from result of this research. Hereafter, if additional research by earthquake magnitude and ground kind is approached, reliance elevation, safety raising and performance based design of fire fighting system see to achieve.

• Earthquakes and Structures
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• v.15 no.6
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• pp.583-593
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• 2018

Seismic performance is particularly important for life-line structures, especially for long-span transmission tower line system subjected to multi-component ground motions. However, the influence of multi-component seismic loads and the coupling effect between supporting towers and transmission lines are not taken into consideration in the current seismic design specifications. In this research, shake table tests are conducted to investigate the performance of long-span transmission tower-line system under multi-component seismic excitations. For reproducing the genuine structural responses, the reduced-scale experimental model of the prototype is designed and constructed based on the Buckingham's theorem. And three commonly used seismic records are selected as the input ground motions according to the site soil condition of supporting towers. In order to compare the experimental results, the dynamic responses of transmission tower-line system subjected to single-component and two-component ground motions are also studied using shake table tests. Furthermore, an empirical model is proposed to evaluate the acceleration and member stress responses of transmission tower-line system subjected to multi-component ground motions. The results demonstrate that the ground motions with multi-components can amplify the dynamic response of transmission tower-line system, and transmission lines have a significant influence on the structural response and should not be neglected in seismic analysis. The experimental results can provide a reference for the seismic design and analysis of long-span transmission tower-line system subjected to multi-component ground motions.

• Steel and Composite Structures
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• v.39 no.1
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• pp.65-80
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• 2021

Irregularities of a building in plan and elevation, which results in the change in stiffness on different floors highly affect the seismic performance and resistance of a structure. This study motivated to investigate the seismic responses of high-rise steel-frame buildings of twelve stories with various stiffness irregularities. The building has five spans of 3200 mm distance in both X- and Z-directions in the plan. The design package SAP2000 was adopted for the design of beams and columns and resulted in the profile IPE500 for the beams of all floors and box sections for columns. The column cross-section dimensions vary concerning the number of the story; one to three: 0.50×0.50×0.05m, four to seven: 0.45×0.45×0.05 m, and eight to twelve: 0.40×0.40×0.05 m. Real recorded ground accelerations obtained from the Vrancea earthquake in Romania together with dead and live loads corresponding to each story were considered for the applied load. The model was validated by comparing the results of the current method and literature considering a three-bay steel moment-resisting frame of eight-story height subject to seismic load. To investigate the seismic performance of the buildings, the time-history analysis was performed using ABAQUS. Deformed shapes corresponding to negative and positive peaks were provided followed by the story drifts and fragility curves which were used to examine the probability of collapse of the building. From the results, it was concluded that regular buildings provided a seismic performance much better than irregular buildings. Furthermore, it was observed that building with torsional irregularity was more vulnerable to seismic failure.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.733-736
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• 1999

R/C columns, one of the main structural members of reinforced concrete structures, usually sustain the axial forces of combined dead loads and live loads. When subjected to lateral loads, however, they are repeatedly subjected to bending moment, shearing forces and brittle failure such as shear failure can occur. This failure mode is not desirable and extra reinforcement is usually needed to induce a ductile failure. The design equation which is used to evaluate the maximum shear strength of a R/C column is still unsatisfactory. The objective of this study was, therefore, to evaluate the hysteretic strengthening effect and the maximum shear strength of R/C columns strengthened using carbon fibers on the seismic performance of the R/C columns under anti-symmetrical by acting moment. According to this study, it may be suggested that the shear of the strengthened R/C column were adequate to induce ductile failures.

• Earthquakes and Structures
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• v.15 no.2
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• pp.155-164
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• 2018

Design of structures subjected to blast loads are usually carried out through nonlinear inelastic dynamic analysis followed by imposing acceptance criteria specified in design codes. In addition to comprehensive aspects of inelastic dynamic analyses, particularly in analysis and design of structures subjected to transient loads, they inherently suffer from convergence and computational cost problems. In this research, a strategy is proposed for design of steel moment resisting frames under far range blast loads. This strategy is inspired from performance based seismic design concepts, which is here developed to blast design. For this purpose, an algorithm is presented to calculate the capacity modification factors of frame members in order to simplify design of these structures subjected to blast loading. The present method provides a simplified design procedure in which the linear dynamic analysis is preformed, instead of the time-consuming nonlinear dynamic analysis. Nonlinear and linear analyses are accomplished in order to establish this design procedure, and consequently the final design procedure is proposed as a strategy requiring only linear structural analysis, while acceptance criteria of nonlinear analysis is implicitly satisfied.

• Computational Structural Engineering
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• v.2 no.2
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• pp.73-83
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• 1989

A computer program, MSSLL, was developed for the analysis of the "Multiple Shell Subjected to Lateral Loads" by utilizing 2-dimensional finite elements in a 3-dimensional global assemblage with 6 DOF at each nodal point. In this program, substructuring procedure with frontal solver was introduced in the solution procedure to save both human and computer resource when the whole structure consists of repeated identical substructures. Some of the results obtained by MSSLL were compared with the existing solutions by other methods. The effect of rise to span-length ratio was investigated for the behavior of the multiple conical shell with 8 substructures subjected to seismic loads by performing a parametric study.

• Structural Engineering and Mechanics
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• v.32 no.3
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• pp.399-406
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• 2009

A three-dimensional panel system, which was offered as a new method for construction in Jordan using relatively high strength modular panels for walls and ceilings, is investigated in this paper. The panel consists of two steel meshes on both sides of an expanded polystyrene core and connected together with a truss wire to provide a 3D system. The top face of the ceiling panel was pored with regular concrete mix, while the bottom face and both faces of the wall panels were cast by shotcreting (dry process). To investigate the structural performance of this system, an extensive experimental testing program for ceiling and wall panels subjected to static and dynamic loadings was conducted. The load-deflection curves were obtained for beam and shear wall elements and wall elements under transverse and axial loads, respectively. Static and dynamic analyses were conducted, and the performance of the proposed structural system was evaluated and compared with a typical three dimensional reinforced concrete frame system for buildings of the same floor areas and number of floors. Compressive strength capacity of a ceiling panel is determined for gravity loads, while flexural capacity is determined under the effect of wind and seismic loading. It was found that, the strength and serviceability requirements could be easily satisfied for buildings constructed using the three-dimensional panel system. The 3D panel system is superior to that of conventional frame system in its dynamic performance, due to its high stiffness to mass ratio.

• Structural Engineering and Mechanics
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• v.65 no.6
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• pp.721-730
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• 2018

This paper aims to inspect the effectiveness of the Simple Adaptive Control Method (SACM) to control the response of asymmetric buildings with rotationally non-linear behavior under seismic loads. SACM is a direct control method and was previously used to improve the performance of linear and non-linear structures. In most of these studies, the modeled structures were two-dimensional shear buildings. In reality, the building plans might be asymmetric, which cause the buildings to experience torsional motions under earthquake excitation. In this study, SACM is used to improve the performance of asymmetric buildings, and unlike conventional linear models, the non-linear inertial coupling terms are considered in the equations of motion. SACM performance is compared with the Linear Quadratic Regulator (LQR) algorithm. Moreover, the LQR algorithm is modified, so that it is appropriate for rotationally non-linear buildings. Active tuned mass dampers are used to improve the performance of the modeled buildings. The results show that SACM is successful in reducing the response of asymmetric buildings with rotationally non-linear behavior under earthquake excitation. Furthermore, the results of the SACM were very close to those of the LQR algorithm.

• Steel and Composite Structures
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• v.22 no.2
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• pp.235-255
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• 2016

This paper experimentally investigated the behavior of steel frame structures of traditional-style buildings subjected to combined constant axial load and reversed lateral cyclic loading conditions. The low cyclic reversed loading test was carried out on a 1/2 model of a traditional-style steel frame. The failure process and failure mode of the structure were observed. The mechanical behaviors of the steel frame, including hysteretic behaviors, order of plastic hinges, load-displacement curve, characteristic loads and corresponding displacements, ductility, energy dissipation capacity, and stiffness degradation were analyzed. Test results showed that the Dou-Gong component (a special construct in traditional-style buildings) in steel frame structures acted as the first seismic line under the action of horizontal loads, the plastic hinges at the beam end developed sufficiently and satisfied the Chinese Seismic Design Principle of "strong columns-weak beams, strong joints-weak members". The pinching phenomenon of hysteretic loops occurred and it changed into Z-shape, indicating shear-slip property. The stiffness degradation of the structure was significant at the early stage of the loading. When failure, the ultimate elastic-plastic interlayer displacement angle was 1/20, which indicated high collapse resistance capacity of the steel frame. Furthermore, the finite element analysis was conducted to simulate the behavior of traditional-style frame structure. Test results agreed well with the results of the finite element analysis.

• Structural Engineering and Mechanics
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• v.49 no.3
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• pp.395-410
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• 2014

Fiber Reinforced Elastomeric Bearings (FREBs) are a relatively new type of laminated bearings that can be used as seismic/vibration isolators or bridge bearings. In an unbonded (U)-FREB, the bearing is placed between the top and bottom supports with no bonding or fastening provided at its contact surfaces. Under shear loads the top and bottom faces of a U-FREB roll off the contact supports and the bearing exhibits rollover deformation. As a result of rollover deformation, the horizontal response characteristics of U-FREBs are significantly different than conventional elastomeric bearings that are employed in bonded application. Current literature lacks an efficient analytical horizontal stiffness solution for this type of bearings. This paper presents two simplified analytical models for horizontal stiffness evaluation of U-FREBs. Both models assume that the resistance to shear loads is only provided by an effective region of the bearing that sustains significant shear strains. The presented models are different in the way they relate this effective region to the horizontal bearing displacements. In comparison with experimental results and finite element analyses, the analytical models that are presented in this paper are found to be sufficiently accurate to be used in the preliminary design of U-FREBs.