Plastic Hinge Research Papers - Academia.edu (original) (raw)

— Most of the steel structures in India are made of conventional steel sections (such as angle, channel and beam sections). However, new hollow steel sections (such as square and rectangular hollow sections) are gaining popularity in recent steel constructions due to a number of advantages such as its higher strength to weight ratio, better fire resistance properties, higher radius of gyration, lesser surface area, etc. This type of hollow sections can save cost up to 30 to 50% over the conventional steel sections (Tata Steel brochure, 2012). But unlike the conventional steel sections these hollow sections do not have standard connection details available in design code or in published literature. To overcome this problem the objective of the present study was identified to develop a suitable and economic connection detail between two square hollow sections which should be capable of transmitting forces smoothly and easy to be fabricated. To achieve the above objective, a square hollow beam to square hollow column connection was selected and modeled in commercial finite element software ABAQUS. This model was analyzed for nonlinear static (pushover) analysis considering a number of connection details. Following four alternative scheme of connection details were selected for this study: (i) using end-plate, (ii) using angle section, (iii) using channel sections, and (iv) using collar plates. The base model (rectangular hollow beam welded to one face of the rectangular hollow column) is also studied for reference. The performance of the selected connection details are compared and the best performing connection details is recommended for rectangular hollow beam-to-rectangular hollow column joints. The result shows that the load carrying capacity of the joint and the maximum deformation capacity is highly sensitive to the type of connection used. Also, the location of formation of plastic hinges in the structure (which can be at joint or at beam) depends highly on the type of connection used.

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- Civil Engineering, Connectionism, Deformation and strain, Pushover Analysis

In this paper a theoretical and experimental research of the steel beam-column connections is presented. Eight types of specimens were being researched, composed of rigid and semi-rigid connections from which 4 connections are with IPE - profile and 4 connections with tube's section for the beam. From the numerical analysis of the researched models, and especially from the experimental research at the Laboratory for Structures in the Faculty of Mechanical Engineering - Skopje, specific conclusions were received that ought to have theoretical and practical usage for researchers in this area of interest.

- by Tem Journal
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- Structural Design, Collapse, Plastic Hinge, Rotation

Struktur gedung tidak beraturan memiliki resiko timbulnya torsi pada saat terjadi pergoyangan struktur akibat gerakan tanah saat gempa, menyebabkan pusat massa dan pusat kekakuan struktur tidak terletak pada titik yang sama atau berhimpit sehingga mempengaruhi kinerja struktur.
Pemodelan struktur yang ditinjau dalam tugas akhir ini adalah struktur beraturan (simetris) dan struktur ketidakberaturan horizontal yang memiliki karakteristik ketidakberaturan torsi tipe 1.a. kemudian dianalisis baik beban gravitasi dan beban gempa mengacu pada SNI 03-1726-2012 menggunakan program ETABS v.9.6.0. Dilanjutkan dengan melakukan pushover analysis dari struktur gedung beraturan dan struktur gedung tidakberaturan. Mengacu pada FEMA 451 b bahwa dengan dilakukan perencanaan urutan sendi plastis mampu meningkatkan redundansi lokal struktur. Dalam tugas akhir ini upaya untuk meningkatkan kinerja struktur melalui perencanaaan urutan sendi plastis dilakukan dengan menambahkan tulangan pada elemen balok dan kolom pada lokasi tertentu yang membutuhkan perhatian khusus dan dianalisa dengan metode pushover untuk mengetahui komparasi yang relevan pada struktur beraturan dan struktur ketidakberaturan torsi tipe 1.a. terhadap kondisi sendi plastis terjadi secara serentak. Sehingga struktur memiliki kinerja yang maksimal dan juga perencanaan lebih ekonomis dengan dilakukannya perencanaan urutan sendi plastis.
Dengan dilakukannya perencanaan urutan sendi plastis pada struktur beraturan dan struktur ketidakberaturan torsi bahwa struktur ketidakberaturan torsi memiliki kinerja yang efektif dibandingkan dengan struktur beraturan. Struktur beraturan dengan perencanaan sendi plastis pola 4 pushover arah X prosentase peningkatan tulangan mencapai 75% pada elemen balok dan kolom kinerja titik kinerja struktur (performance point) berdasarkan nilai displacement sebesar 57% dan base shear 53%. Dilanjutkan dengan pola 5 perencanaan urutan sendi plastis arah X prosentase peningkatan tulangan mencapai 47% diperoleh nilai displacement sebesar 25% dan base shear 38%. Perencanaan sendi plastis pada struktur ketidakberaturan torsi tipe 1.a. dengan pola 4 pushover arah X prosentase peningkatan tulangan mencapai 75% pada elemen balok dan kolom kinerja titik kinerja struktur (performance point) berdasarkan nilai displacement sebesar 65% dan base shear 51%. Dilanjutkan dengan pola 5 perencanaan urutan sendi plastis dengan X prosentase peningkatan tulangan mencapai 45% diperoleh nilai displacement sebesar 50% dan base shear 40%. Hanya saja penambahan tulangan pada pola 4 perencanaan urutan sendi plastis ini dinilai boros. Maka dengan pola 5 perencanaan urutan sendi plastis dinilai memiliki kinerja yang lebih baik dan ekonomis. Indeks redundansi dari kedua struktur yang ditinjau mengalami peningkatan yang signifikan dengan perencanaan sendi plastis pada kolom dibandingkan dengan perencanaan urutan sendi plastis pada elemen balok saja.

Structural frames are often filled with infilled walls serving as partitions. Although the infills usually are not considered in the structural analysis and design, their influence on the seismic behaviour of the infilled frame structures is considerable. In the present study, a parametric study of certain infilled frames, using the strut model to capture the global effects of the infills was carried out. Three concrete planar frames of five-stories and three-bays are considered which have been designed in accordance with Turkish Codes. Pushover analysis is adopted for the evaluation of the seismic response of the frames. Each frame is subjected to four different loading cases. The results of the cases are briefly presented and compared. The effect of infill walls on seismic behavior of two sample frames with different infill arrangements was investigated. The results yield that it is essential to consider the effect of masonry infills for the seismic evaluation of moment-resisting RC frames, especially for the prediction of its ultimate state, infills having no irregularity in elevation have beneficial effect on buildings and infills appear to have a significant effect on the reduction of global lateral displacements.

- by Konuralp Girgin
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- Pushover Analysis, Plastic Hinge, Seismic response, Capacity Spectrum Method

The report presents the results of a series of experiments and analysis done on a threestory single-bay steel moment frame. The aim was dynamic characterization of the system to obtain the mode shapes, frequencies and damping ratios. Thereafter, structure was tested under some real ground acceleration to see its performance. For dynamic characterization, snap back test, linear mass shaker test and white noise tests were performed and all of them yielded fairly identical values of mode shapes and frequencies of the structure. In case of linear mass shaker, however, frequencies and mode shapes were slightly deviated due to the fact that the weight of the mass shaker was greater than the floor weight itself. For real time ground motions, a non-linear time history analysis has been done in SAP2000 to obtain the analytical acceleration-time histories and compare with the experimentally recorded values. Pushover analysis and analytical modeling of the structure in SAP2000 has also been presented to see the accuracy of analytical predictions in dynamic analysis. It has been seen that the damping depends on the type of input excitation since we obtained different damping ratios for each test whereas the mode shapes and frequencies were very close and similar from all of them. Also from the calculated modal participation factors it is seen that the contribution of the first mode to the total response is maximum as expected and the higher modes have a very small contribution. An attempt towards base isolation of the structure using locally available resources failed due to improper lubrication and unbalanced structure. Hence its performance under base isolated conditions could not be analyzed.

- by SAKET KUMAR
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- Modal Analysis, Base Isolation, Dynamic Analysis, White noise analysis

Seismic behavior of beam-to-column connections can be improved by shifting the location of inelasticity away from the column's face. Such connections can be achieved by reducing the flange area at a specific distance from the beam-column connection, called reduced beam section (RBS), or by reducing web area by introducing a perforation into the web, called reduced web section (RWS). This paper presents a parametric study that is carried out on the effect of the perforation size, perforation location, and the beam span length in the RWS connections, using finite element modeling. Next, an interaction formula is derived for design purposes, and a step by step design method is developed. Finally, a frame is analyzed to verify the reliability of the proposed design process and assess the impact of the RWS connections on the behavior of special moment frames. The study concludes that RWS connections can effectively improve seismic performance of special moment frames, causing plastic hinges to form around the perforation away from the column's face.

- by Seyedbabak Momenzadeh
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- Plastic Hinge, Steel Beam to Column Connections

Structural vulnerability evaluation is essential for assessing building behaviour in case of an earthquake. Among the basic design concepts is weak beam-strong column, but nevertheless the earthquakes effects lead to different failure mechanisms. This paper investigates constructive solutions to direct plastic hinges from columns to beams, in order to prevent the collapse of the structure. The virtual-experimental simulation of reinforced concrete elements subjected to horizontal loads is discussed. In this study a 3-D ground floor frame structure was considered in order to determine: development of cracks in the concrete, the influence of stresses in the reinforcement, the plastic hinge formation. Different comparisons were performed, changing the geometry of the slab and the reinforcement. The analysis was conducted in ATENA, a computer program using stress analysis with finite elements. Recommended…, 2000). Usually, in most of the current seismic codes is desirable in case of an earthquake structures can dissipate seismic energy, with displacement control initially, without brittle failure of the elements. Frame structure are recommended in seismic areas because can dissipate energy through vibration in the elastic range. As the earthquake induces higher inertial forces on the structure, a ductile plastic mechanism is formed designed to avoid brittle collapse.

- by Olteanu Ioana
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- Numerical Simulations, Pushover Analysis, Plastic Hinge

During strong earthquakes, reinforced concrete (RC) structures experience cyclic lateral loads that result to degradation in load-carrying capacity, and failure of columns in shear and/or flexure. This study presents a simple hysteretic hinge model that may be used in displacement-based analysis of RC columns, classified as flexure critical, shear critical, and shear-flexure critical, subjected to cyclic loads. The proposed hinge model made up of zero-length nonlinear springs can simulate the hysteretic behavior of reinforced concrete material in axial, shear, and flexure. The nonlinear parameters of the springs were derived from geometric and material properties of the column and estimated using Response-2000 software. Pushover analysis and response to cyclic loading were performed using the Open System for Earthquake Engineering Simulation (OpenSees) program and validated by comparing the force-displacement response of select forty-three RC columns available in the PEER Structural Performance Database. Results show that for the six rectangular columns, the numerical experiments using the proposed hinge model and the actual force-displacement curves gave R-squared values greater than 0.80 signifying good agreement of results. Therefore, it was concluded that the model can reasonably replicate nonlinear behavior of shear-, shear-flexure, and flexure-critical columns subjected to cyclic loading and, therefore, may be used to assess performance of actual RC columns.

- by Patrick Aylsworth Garcia and +1
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- Pushover Analysis, Reinforced concrete, Plastic Hinge, Displacement based pushover

The aim of this study is to investigate the plastic hinge length and peak displacement relationship for rectangular cross-sectional high ductile concrete shear walls in seismic zones. For plastic hinge lengths related to seismic design; the conditions given in the current regulations are used in the literature. An analytical study was conducted to evaluate the peak displacement relationship of reinforced concrete shear walls in seismic loads under plastic hinge regions. The length of the plastic deformation zone called the plastic hinge length has been investigated in this study by considering the regulations proposed by different regulations and researchers. Plastic hinge lengths of the designed reinforced concrete shear walls were calculated by plastic hinge models proposed by different researchers and regulations. Then, according to the plastic hinge lengths obtained from different relations, the yield displacement and plastic displacement values of the reinforced concrete shear walls were calculated and the total peak displacement values of the shear walls were obtained. The results of this study indicated that increase in plastic hinge length has a significant effect on the displacement and displacement ductility values of reinforced concrete shear walls. The most important parameter affecting the plastic hinge length is the dimensions of the reinforced concrete shear walls.

The objective of the present work is to evaluate the influence of two different methods of improving the ductility of Reinforced Concrete Frames and their influence on the full range behavior of the frames with M40 grade of concrete. For this purpose one fourth scale reinforced concrete square frames are experimentally tested subjected to static cyclic loading for three cases and monotonic loading for one case. The parameters are varied as method introducing ductility to the frame viz. (i) by using conventional concrete (ii) adding 1% of steel fibres by volume of concrete at hinging zones (iii) using self-compacting concrete with fibres at hinging zones. The behavior of frames tested under cyclic loading have revealed that there is a positive trend in improvement of ductility of frames when fibreous concrete is used along with self-compacting concrete.

- by kasilingam Senthil and +1
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- Plastic Hinge, Self Compacting Concrete Using Steel Fibre
- by Pal Bergan
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- Engineering, Numerical Simulations, Pushover Analysis, Plastic Hinge

Usage of steel braces has become a solution not only for retrofitting of RC structures but as a method in designing of concrete frames in recent years. Although X-braced RC frames have been number of successful studies, but eccentric braced RC frames have not been studied seriously. Maybe it's because of the non ductile behaviour of concrete beams. In this article, a numerical study was conducted to evaluate performance of concrete frames, braced with eccentric steel brace with a vertical steel shear link. Vertical steel shear link eliminated shortcomings of non ductile concrete beam. Therefore 4, 8 and 12 storey concrete frames were designed and subjected to a push over analysis. Life safety level was chose to evaluate the frames and hinges performance. Results were compared with the same frames designed with X braces and moment resisting frame. Results indicated that steel braces shift the place of plastic hinges to be formed on the bracing members instead of columns and beams. Furthermore steel braces delayed the process of formation of first plastic hinge and column failure mechanism

- by Maysam Namazi and +1
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- Plastic Hinge

SUMMARY: Seismic behavior of beam to column connections can be improved by shifting the location of inelasticity away from the column's face. Such connections can be achieved by reducing flange area at a specific distance from the beam-column connection, called Reduced Beam Section (RBS) or by reducing web area by introducing a perforation into the web, called Reduced Web Section (RWS). Research on RWS connections shows that, if properly designed, they can satisfy the " strong column-weak beam " and " strong connection-weak component " criteria. Shear and moment interaction in RWS connections is in high importance for designing of these connections. A parametric study has been done on the effect of perforation size, perforation location and span length of these connections. In addition, an interaction formula for moment and shear is derived for design purposes. Furthermore, a step by step method for designing of these connections is prescribed.

- by Seyedbabak Momenzadeh and +1
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- Plastic Hinge, Beam - Column Connections

Irregularity structure has the risk of torsion due to structure’s motion is caused by ground movement during an earthquake, where the centre of mass and the centre of stiffness structure is not located at the same point or coincide and... more

On 18 September 2011, all the Indian states and countries surrounding Sikkim witnessed a devastating moderate earthquake of magnitude 6.9 (Mw). Originating in Sikkim–Nepal border with an intensity of VI+ in MSK scale, this earthquake caused collapse of both unreinforced masonry buildings, heritage structures and framed structures followed by landslides and mud slides at various places of Sikkim. Significant damages have been observed in relatively new framed structures mainly in Government buildings, thick masonry structures, while, the older wooden frame (ekra) non-engineered structures performed well during the earthquake. Further, it is noteworthy that government buildings suffered more than private ones and damages were observed more in newer framed structures than older ones. Analysis of the damages identify lateral spreading of slope, pounding of buildings, out-of-plane rotation, generation of structural cracks, plastic hinge formation at column capitals and damage of infill wall material as predominant damage features. A few remedial measures are also attempted to be mentioned with future need of research and application. It has been felt to create awareness regarding these issues and is the need of the hour.

- by Rajib Saha and +2
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- Seismic Pounding, Damage analysis, Plastic Hinge, Soil deterioration
- by Sunil Gowda
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- Structural Engineering, Plastic Hinge, Hinge

ABSTRACT On 18 September 2011, all the Indian states and countries surrounding Sikkim witnessed a devastating moderate earthquake of magnitude 6.9 (Mw). Originating in Sikkim–Nepal border with an intensity of VI+ in MSK scale, this earthquake caused collapse of both unreinforced masonry buildings, heritage structures and framed structures followed by landslides and mud slides at various places of Sikkim. Significant damages have been observed in relatively new framed structures mainly in Government buildings, thick masonry structures, while, the older wooden frame (ekra) non-engineered structures performed well during the earthquake. Further, it is noteworthy that government buildings suffered more than private ones and damages were observed more in newer framed structures than older ones. Analysis of the damages identify lateral spreading of slope, pounding of buildings, out-of-plane rotation, generation of structural cracks, plastic hinge formation at column capitals and damage of infill wall material as predominant damage features. A few remedial measures are also attempted to be mentioned with future need of research and application. It has been felt to create awareness regarding these issues and is the need of the hour.

- by Parthasarathi Mukhopadhyay and +1
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- Civil Engineering, Geophysics, Seismic Pounding, Damage analysis