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1
Soetanto, R., J. Glass, A. R. J. Dainty, and A. D. F. Price. "Structural frame selection: case studies of hybrid concrete frames." Building Research & Information 35, no. 2 (March 20, 2007): 206–19. http://dx.doi.org/10.1080/09613210600809029.
2
Coffield, Amy, and Hojjat ADELI. "IRREGULAR STEEL BUILDING STRUCTURES SUBJECTED TO BLAST LOADING." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 22, no. 1 (December 18, 2015): 17–25. http://dx.doi.org/10.3846/13923730.2015.1073172.
Анотація:
In seismic design, structural irregularity has been found to have a significant influence on structural response. The impact of structural irregularity on the global response of steel frame structures subjected to blast loading has not been examined. In the paper, six seismically designed steel framed structures are considered: moment resisting frames (MRF), concentrically braced frames (CBF) and eccentrically braced frames (EBF) each with geometric irregularity in the plan and with a geometric irregularity in the elevation. The blast loads are assumed to be unconfined, free air burst detonated 15 ft from one of the center columns. The structures are modeled and analyzed using the Applied Element Method, which allows the structure to be examined during and through structural failure. A plastic hinge analysis is performed as well as a comparative analysis observing roof deflection and acceleration to determine the effect of geometric irregularity under extreme blast loading conditions. Two different blast locations are examined. Conclusions of this research are a concentrically braced frame provides somewhat of a higher level of resistance to blast loading for irregular structures and geometric irregularity has an impact on the response of a structure subjected to blast loading.
3
Pakizeh, Mohammad Rezaeian, Abdul Kadir Marsono, and Masine M. Tap. "Structural System of Safe House against Tornado and Earthquakes." Key Engineering Materials 594-595 (December 2013): 449–54. http://dx.doi.org/10.4028/www.scientific.net/kem.594-595.449.
Анотація:
Every year earthquakes, tornadoes and other extreme windstorm cause fatalities or even kill people, devastate and millions of dollars worth of property. The likelihood that a tornado will strike building is a matter of probability. The study describes the analysis and design, the engineering process the new type of tornado safe room (Fig. 1) according to the FEMA guidance. It also evaluates the effects of in-fill frames and the linear response of reinforced concrete braced frames and comparison with frames with shear wall. The main conclusion drawn from this study is to elaborate that the masonry in-fills, are strongly influence the structural seismic response and contribute to the overall stiffness and can decrease drifts and displacements. Infill walls have significant role in the strength and ductility of RC framed structures and should be considered in both analysis and design globally. These walls make the structure significantly stiffer, and reduce the natural period of the structure. Locally, infill walls changed the load path, the distribution of forces between different elements of the structure, and the change the demand of forces on their adjacent elements of the bounding frame. Due to the high relative stiffness of the infill frames, they act as the main lateral load-resisting system and attract larger portions of the earthquake and tornado induced inertia forces.
4
Mo, Y. L., and S. F. Perng. "Behavior of Framed Shearwalls Made of Corrugated Steel under Lateral Load Reversals." Advances in Structural Engineering 3, no. 3 (July 2000): 255–62. http://dx.doi.org/10.1260/1369433001502184.
Анотація:
Reinforced concrete buildings with shearwalls are very efficient to resist earthquake disturbances. In general, reinforced concrete frames are governed by flexure and low-rise shearwalls are governed by shear. If a structure includes both frames and shearwalls, it is generally governed by shearwalls. However, the ductility of ordinary reinforced concrete framed shearwalls is very limited. The experiments on framed shearwalls made of corrugated steel was recently reported. It was found that the ductility of framed shearwalls can be greatly improved if the thickness of the corrugated steel wall is appropriate to the surrounding reinforced concrete frame. If the thickness of the corrugated steel wall is too large when compared to the surrounding frame, the ductility will be reduced. It is shown in this paper that the fiber-reinforced plastic composites can be used to strengthen the critical regions of the reinforced concrete frames, so that the seismic behavior (including ductility and energy dissipation capability) is greatly improved.
5
Park, Seon-Chee, Won-Kee Hong, Sunkuk Kim, and Xiangyu Wang. "Mathematical Model of Hybrid Precast Gravity Frames for Smart Construction and Engineering." Mathematical Problems in Engineering 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/916951.
Анотація:
The structural stability, constructability, economic feasibility, environmental-friendliness, and energy efficiency of hybrid composite frame systems have been demonstrated by practical application and research. A hybrid composite frame system combines the economy of precast concrete structures with the constructability of steel frame structures, including erection speed. Novel composite frames will ultimately maximize the efficiency of structural design and facilitate construction. This paper presents hybrid precast frames, which are precast composite frames based on a simple connection between precast concrete columns and beams. The hybrid precast frames designed to resist gravity loading consist of PC columns, PC beams, and steel inserted in the precast members. Steel sections located between the precast columns were simply connected to steel inserted at each end of the precast beams. Dynamic analysis of a 15-story building designed with the proposed composite frame was performed to determine the dynamic characteristics of a building constructed of hybrid frames, including frequencies and mode shapes.
6
Oh, Sang Hoon, and Hong Sik Ryu. "Seismic Performance of Steel Frames for Sustainable Structural System." Applied Mechanics and Materials 204-208 (October 2012): 2705–12. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2705.
Анотація:
A test on a full-scale model of a three-spans and two-story steel moment frame with dampers and releasable slab was conducted. The details of the test frames, test instruments, set-up procedures, and test procedures were presented. The column and beam were connected by dampers that could initiate the plastic deformation during cyclic loading before damage occurred in the beam and column. The precast concrete slab was designed to be releasable and for saving story height. The primary objective of this test was to verify structural performance and constructability of a full-scale sustainable steel frame. Test results confirm that the sustainable frame showed stable hysteretic behavior without any serious damage up to a drift angle of 1/12; and the sustainable frames were released systematically in spite of serious cyclic loading.
7
Kumar, Puneet, and Gaurav Srivastava. "Numerical modeling of structural frames with infills subjected to thermal exposure." Journal of Structural Fire Engineering 8, no. 3 (September 11, 2017): 218–37. http://dx.doi.org/10.1108/jsfe-05-2017-0031.
Анотація:
PurposeReinforced concrete structural frames with masonry infills (infill-frames) are commonly used for construction worldwide. While the behavior of such frames has been studied extensively in the context of earthquake loading, studies related to their fire performance are limited. Therefore, this study aims to characterize the behavior of infill-frames under fire exposure by presenting a state-of-the-art literature review of the same.Design/methodology/approachBoth experimental and computational studies have been included with a special emphasis on numerical modeling (simplified as well as advanced). The cold behavior of the infill-frame and its design requirements in case of fire exposure are first reviewed to set the context. Subsequently, the applicability of numerical modeling strategies developed for modeling cold infill-frames to simulate their behavior under fire is critically examined.FindingsThe major hurdles in developing generic numerical models for analyzing thermo-mechanical behavior of infill-frames are identified as: lack of temperature-dependent material properties, scarcity of experimental studies for validation and idealizations in coupling between thermal and structural analysis.Originality valueThis study presents one of the most popular research problems connected with practical and reliable utilization of numerical models, as a good alternative to expensive traditional furnace testing, in assessing fire resistance of infill-frames. It highlights major challenges in thermo-mechanical modeling of infill-frames and critically reviews the available approaches for modeling infill-frames subjected to fire.
8
Dawe, J. L., A. B. Schriver, and C. Sofocleous. "Masonry infilled steel frames subjected to dynamic load." Canadian Journal of Civil Engineering 16, no. 6 (December 1, 1989): 877–85. http://dx.doi.org/10.1139/l89-130.
Анотація:
Experimentally determined dynamic responses of ten scale models of masonry infilled steel frames were compared with the results of three simple analytical models. Effects investigated included stiffening and strengthening contribution of the masonry infill, degradation of the system, motion intensity, frame stiffness, and rotational joint rigidity at slab-to-column intersections. Tests on one-third scale models, subjected to sinusoidal motions, revealed that masonry infill markedly increases the dynamic strength and stiffness of the system. At weak-to-moderate motions (below 0.5 g), models exhibited a nonlinear response before the final failure, while strong motions accelerated the system degradation rate. Stiffer frames and rotationally rigid joints resulted in significantly increased system dynamic strength. A braced frame model wherein cross-bracing replaces the panel action adequately predicted linear and lower-region nonlinear responses of infilled frames with flexible column-to-slab rotational conditions. Satisfactory predictions of the linear response of framed walls with rigid column-to-slab rotational conditions were made with a single degree of freedom model. The third analytical model based on an equivalent strut technique was found to be unsatisfactory for predicting dynamic response of masonry infilled frames. Key words: masonry panel, steel frame, shear, dynamic, analytical, experimental.
9
Soleimani, Reza, Horr Khosravi, and Hamed Hamidi. "Substitute Frame and adapted Fish-Bone model: Two simplified frames representative of RC moment resisting frames." Engineering Structures 185 (April 2019): 68–89. http://dx.doi.org/10.1016/j.engstruct.2019.01.127.
10
Kim, Yeon Su, Sung Hyuk Park, Rag Gyo Jeong, and Tae Kon Lim. "Structural Safety Evaluations of Bogie Frames for Rubber-Tired AGT Vehichles." Key Engineering Materials 321-323 (October 2006): 1491–94. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1491.
Анотація:
This study was aimed at evaluating the structural safety of the new bogie frames for Korean-standardized rubber-tired AGT vehicles. The guidance frame and the rotation frame were designed according to Korean-standardized specifications for rubber-tired AGT vehicles, and their stresses were analyzed by using the finite element method. Based on the results of the analysis, dynamic stresses were measured while the train was running under various conditions in the test track. Analytical and experimental results verified the structural safety of the new bogie frames.
11
Mayencourt, Paul, John Ochsendorf, and Caitlin Mueller. "Shaping Indeterminate Frames." Journal of the International Association for Shell and Spatial Structures 62, no. 3 (September 1, 2021): 172–84. http://dx.doi.org/10.20898/j.iass.2021.011.
Анотація:
The large impact of building structures on the environment must be reduced to meet the global targets fixed by the Intergovernmental Panel on Climate Change. Standard building structures with constant prismatic cross-section have material inefficiencies of around 66% (and up to 75% in some cases) that need to be addressed. Structural shaping, a subfield of shape optimization, offers a pathway to reduce the impact of building materials on the environment. Shaping statically determinate structures such as simply supported beams is relatively straightforward, but offers few design options compared to statically indeterminate structures. However, no methods provide an efficient way for designers to shape these systems according to their design intent or efficiency goals. Based on plasticity theory, this paper presents a shaping methodology to explore the design space of shaped indeterminate frame structures. The methodology is implemented in three case studies.<br/> In all the case studies, the methodology allows for the exploration of material-efficient yet diverse designs of shaped indeterminate frame structures. The implementation of this methodology can promote the use of structural shaping by offering more agency to structural designers to create diverse and efficient structural systems.
12
Tasligedik, A. S., S. Pampanin, and A. Palermo. "Damage states and cyclic behaviour of drywalls infilled within RC frames." Bulletin of the New Zealand Society for Earthquake Engineering 45, no. 2 (June 30, 2012): 84–94. http://dx.doi.org/10.5459/bnzsee.45.2.84-94.
Анотація:
Drywalls are the typical infill or partitions used in new structures. They are usually located within structural frames and/or between upper and lower floor slabs in buildings. Due to the materials used in their construction, unlike masonry blocks, they can be considered as light non-structural infill/partition walls. These types of walls are especially popular in New Zealand and the USA. In spite of their popularity, little is known about their in-plane cyclic behaviour when infilled within a structural frame. The cause of this lack of knowledge can be attributed to the typical assumption that they are weak non-structural elements and are not expected to interact with the surrounding structural system significantly. However, recent earthquakes have repeatedly shown that drywalls interact with the structure and suffer severe damage at very low drift levels. In this paper, experimental test results of two typical drywall types (steel and timber framed) are reported in order to gather further information on; i) their reverse cyclic behaviour, ii) inter-storey drift levels at which they suffer different levels of damage, iii) the level of interaction with the surrounding structural frame system. The drywall specimens were tested using quasi-static reverse cyclic testing protocols within a full scale precast RC frame at the Structures Laboratory of the University of Canterbury.
13
Yoon, Sung Cheol, Jeong Guk Kim, Kwang Sun Baik, Byeong Choon Goo, and Kang Youn Choe. "A Study on the Fracture Test in Railroad Truck." Key Engineering Materials 488-489 (September 2011): 210–13. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.210.
Анотація:
The truck that is used as running equipment for freight car support is a core structural part that supports the load of the car body and that greatly influences the safety of freights and vehicles, as well as their running performance. The running equipment is composed of truck frames, wheels and wheel axles, independent suspensions, and brakes. Among these components, the truck frame supporting the load of the vehicles and freights may be the most important one. This study was carried out to analyze the structure of truck frames and to determine whether they are safe when the maximum vertical load, breaking load, and front and rear loads are applied to them. This was done by subjecting the truck frames to stress tests and then measuring the stress on each of their parts. Before the load test, a structural-analysis program was used for the stress distribution analysis of the truck frame. To measure the stresses based on the results of the structural analysis, strain gages were attached to the surfaces of truck frames. The results of the stress tests showed that truck frames have a safe vehicle load design.
14
Yoon, Sung Cheol. "A Study on the Fatigue Test of Truck Materials for Railway Vehicles." Key Engineering Materials 627 (September 2014): 405–8. http://dx.doi.org/10.4028/www.scientific.net/kem.627.405.
Анотація:
The truck that is used as running equipment for freight car support is a core structural part that supports the load of the car body and that greatly influences the safety of freights and vehicles, as well as their running performance. The running equipment is composed of truck frames, wheels and wheel axles, independent suspensions, and brakes. Among these components, the truck frame supporting the load of the vehicles and freights may be the most important one. This study was carried out to analyze the structure of truck frames and to determine whether they are safe when the maximum vertical load, breaking load, and front and rear loads are applied to them. This was done by subjecting the truck frames to stress tests and then measuring the stress on each of their parts. Before the load test, a structural-analysis program was used for the stress distribution analysis of the truck frame. To measure the stresses based on the results of the structural analysis, strain gages were attached to the surfaces of truck frames [1].
15
Kanagasundaram, Subramaniam, and Bhushan L. Karihaloo. "Maximum Strength Design of Structural Frames." Journal of Structural Engineering 111, no. 6 (June 1985): 1267–87. http://dx.doi.org/10.1061/(asce)0733-9445(1985)111:6(1267).
16
Nafday, Avinash M., Ross B. Corotis, and Jared L. Cohort. "Failure Mode Identification for Structural Frames." Journal of Structural Engineering 113, no. 7 (July 1987): 1415–32. http://dx.doi.org/10.1061/(asce)0733-9445(1987)113:7(1415).
17
Chan, Alice Z. Y., Martin S. Copenhaver, Sivaram K. Narayan, Logan Stokols, and Allison Theobold. "On structural decompositions of finite frames." Advances in Computational Mathematics 42, no. 3 (October 30, 2015): 721–56. http://dx.doi.org/10.1007/s10444-015-9440-1.
18
Karihaloo, B. L., and S. Kanagasundaram. "Minimum-weight design of structural frames." Computers & Structures 31, no. 5 (January 1989): 647–55. http://dx.doi.org/10.1016/0045-7949(89)90198-3.
19
Dawe, J. L., C. K. Seah, and Y. Liu. "A computer model for predicting infilled frame behaviour." Canadian Journal of Civil Engineering 28, no. 1 (February 1, 2001): 133–48. http://dx.doi.org/10.1139/l00-083.
Анотація:
A computer model is developed for the structural analysis of masonry infilled frames. Structural interaction of the panel and its peripheral frame is considered. Various failure criteria are incorporated into the model and special elements are developed to account for masonry failure by cracking and crushing as well as to account for the complex interaction of frame and panel. Comparison of analytical findings with the results of 31 laboratory tests on steel and reinforced concrete infilled frames showed favourable correlation and verification of the computer model.Key words: masonry, infill, frame, steel, concrete, computer, model, testing, correlation, failure.
20
Fukumoto, Y., T. Takaku, T. Aoki, and K. A. S. Susantha. "Innovative Use of Profiled Steel Plates for Seismic Structural Performance." Advances in Structural Engineering 8, no. 3 (July 2005): 247–57. http://dx.doi.org/10.1260/1369433054349051.
Анотація:
This paper presents the innovative use of hot-rolled thickness-tapered mill products, longitudinally profiled (LP) plates, for the seismic performance of bridge bents of single and portal framed piers. The study involves the inelastic cyclic testing and numerical analysis of tested beam-columns and portal frames in order to evaluate the effects of tapering ratios of LP plates, penetration of yielding, and number of locally buckled panels on their structural ductility. A structural design method is proposed for the portal frames having LP panels under cyclic loadings.
21
Lakusic, Stjepan. "Structural behavior of single bay two-story basalt fiber reinforced concrete frame." Journal of the Croatian Association of Civil Engineers 74, no. 12 (January 2023): 1085–92. http://dx.doi.org/10.14256/jce.3550.2022.
Анотація:
This study focuses on structural design, which is a primary aspect of civil engineering. Investigating the behavior of reinforced concrete (RC) frame systems subjected to lateral loading and estimating the damage state of a structure still remain challenging tasks in civil engineering. Reinforced concrete is currently used in a majority of constructions and Conventional buildings remain vulnerable to seismic earthquakes. The aim of this research is to identify how well RC frames with basalt and steel fibers perform under cyclic loading. Steel and basalt fibers are chopped to a size of 2.5 cm. The reinforcements details are made according to IS 13920-2016. The concrete specimen used for this work is in the form of a single-bay, two-story frame, which is composed of reinforced concrete along with chopped steel and basalt fibers of two different proportions. Three frames are cast. One is a RC concrete frame with no fiber materials (conventional concrete) and the other two frames are cast with different proportions of fiber content. The basalt fiber is added to the specimens in proportions of 0.25 % and 0.50 %. The experimental outcome attained from the specimens of 0.25 % of basalt fiber has superior load-carrying capacity as well as minimum story drift than the other two frames. The ductile behavior of BFRC is increased compared to that in conventional ones. It is observed that the crack width of the BFRC is less when compared to that in the conventional concrete.
22
Barclay, Abigail, Nicolai Tidemand Johansen, Frederik Grønbæk Tidemand, Lise Arleth, and Martin Cramer Pedersen. "Global fitting of multiple data frames from SEC–SAXS to investigate the structure of next-generation nanodiscs." Acta Crystallographica Section D Structural Biology 78, no. 4 (March 11, 2022): 483–93. http://dx.doi.org/10.1107/s2059798322001838.
Анотація:
The combination of online size-exclusion chromatography and small-angle X-ray scattering (SEC–SAXS) is rapidly becoming a key technique for structural investigations of elaborate biophysical samples in solution. Here, a novel model-refinement strategy centred around the technique is outlined and its utility is demonstrated by analysing data series from several SEC–SAXS experiments on phospholipid bilayer nanodiscs. Using this method, a single model was globally refined against many frames from the same data series, thereby capturing the frame-to-frame tendencies of the irradiated sample. These are compared with models refined in the traditional manner, in which refinement is based on the average profile of a set of consecutive frames from the same data series without an in-depth comparison of individual frames. This is considered to be an attractive model-refinement scheme as it considerably lowers the total number of parameters refined from the data series, produces tendencies that are automatically consistent between frames, and utilizes a considerably larger portion of the recorded data than is often performed in such experiments. Additionally, a method is outlined for correcting a measured UV absorption signal by accounting for potential peak broadening by the experimental setup.
23
Lee, Ho-Haeng, Ki-Ho Kim, Seunghyun Son, Kwangheon Park, and Sunkuk Kim. "TIME REDUCTION EFFECTS OF STEEL CONNECTED PRECAST CONCRETE COMPONENTS FOR HEAVILY LOADED LONG-SPAN BUILDINGS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 26, no. 2 (February 7, 2020): 160–74. http://dx.doi.org/10.3846/jcem.2020.11673.
Анотація:
The characteristics of large logistics buildings are their long spans and the ability to take heavy loads. Usually, PC components are used for their frames to ensure quick construction. However, the erection of most pin jointed PC structures increases the time and the cost incurred for ensuring structural stability and construction safety. To solve this problem, “smart” frames have been developed, which have tapered steel joints at both ends of the PC components. A smart frame with the moment frame concept not only assures structural stability and construction safety, but it also simplifies and quickens the erection because of its tapered joint detail. The purpose of this study is to compare the erection time and cost effects of the steel connected PC components for heavily loaded long-span logistics buildings with the existing PC frames. For this study, we selected a logistics building constructed with PC components and redesigned it as the smart frame, and the erection simulations were performed. We analyzed the time reduction effects of the smart frame. Our results confirmed that the use of the smart frame reduced the erection time and cost practically. Our investigations will help develop the erection simulation algorithms for smart frames.
24
Kianmehr, Alireza. "Effect of the Bracing System on the Probability of Collapse of Steel Structures under Maximum Credible Earthquake." Shock and Vibration 2021 (October 18, 2021): 1–16. http://dx.doi.org/10.1155/2021/2323758.
Анотація:
Simple bracing frames can be divided into two types in terms of concentric or eccentric. Concentric bracing frames are frames that intersect with other structural members at one point in the structure along the bracing members. Otherwise, the braced frame will be eccentric. It is said empirically that due to this type of shaping, eccentric bracing frames exhibit more ductile behavior and concentric bracing frames exhibit more stiff behavior. This behavioral difference caused this study to be numerically computing for five frames, including unique concentric and eccentric bracing frames of 5 and 10 stories and an ordinary 5-story concentric bracing frame. Their tensions and drift ratios should be acceptable for the use of residential buildings. Using the primary two steps of the new PEER probabilistic framework, namely, probabilistic seismic hazard analysis and structural analysis, which leads to the drawing of fragility curves, the probability of collapse is obtained to compare the safety capability of these frames according to their different characteristics against earthquakes. The results show that increasing the ductility or increasing the number of floors or the height of these systems can reduce collapse. Also, according to the results of the probability of collapse obtained in frames with 5-story concentric bracing frames, it can be said that some of the current regulations, which work based on previous approaches of analysis, can lead to unsafe structures with a high probability of collapse.
25
Jain, A. K., R. G. Redwood, and Feng Lu. "Seismic response of concentrically braced dual steel frames." Canadian Journal of Civil Engineering 20, no. 4 (August 1, 1993): 672–87. http://dx.doi.org/10.1139/l93-084.
Анотація:
Concentrically braced steel frames are one of the most commonly used structural systems because of their structural efficiency, simplicity to analyze and design, and ease of construction and repair. Canadian design codes provide specifications for their design under seismic loading based on the large amount of knowledge related to their seismic response accumulated over the past two decades. This paper examines the impact of a dual system with a moment resisting frame acting in parallel with the concentrically braced frame. Four different frames were designed in accordance with the National Building Code of Canada and CSA-S16.1-M89, and their inelastic responses are studied under the action of both monotonically increasing load and seismic load. The relative strengths and stiffnesses of the frames comprising the dual systems were varied. The ductility demands on members, and overall building deflections and storey drifts, were examined under the action of ten earthquake records. It is concluded that improved performance such as reduced ductility demand and improved uniformity of the distribution of yield throughout the structure can be achieved. However, the stiffness and strength in the moment resisting frame necessary to provide marked improvement must be a significant proportion of those of the braced frame. Key words: structural engineering, earthquakes, inelastic analysis, concentric bracing, dual system, steel, buckling.
26
YILMAZ, Mehmet Fatih. "The Effect of Different Braced Configurations on the Nonlinear Seismic Behavior of Steel Structure." Civil Engineering Beyond Limits 1, no. 1 (December 30, 2019): 22–28. http://dx.doi.org/10.36937/cebel.2020.001.005.
Анотація:
Improvements in construction technologies have allowed steel structural elements to become more frequently used today in order to enable different architectural designs and to meet structural performance more effectively and efficiently. Structural steel has been used for more than a hundred years and has been tested under real earthquakes, which provide the basis of many earthquake-resistant steel construction standards. The major advantage of steel construction material is that it allows for large plastic deformations. Structural deformations vary depending on the deformation capacity of the structural components in addition to the configuration of the structural components. In this study, moment resisting frames (MRF), X braced frame (XBF), Inverse V braced frame (IVBF), K braced frame (KBF), and eccentric inverse V braced frames (EIVBF) were used to examine the effect of different steel braced systems on the plastic deformation capacity of steel structure with the help of nonlinear static pushover analysis. Bilinear material model was utilized to represent nonlinear steel material behavior and inelastic displacement-based frame element were used to represent column and beam element. The analyses' results demonstrated that the braced frame configuration had a significant effect on the lateral response of steel frame structures.
27
Song, Baoxi, Dongsheng Du, Weiwei Li, Shuguang Wang, Yue Wang, and Decheng Feng. "Analytical Investigation of the Differences between Cast-In-Situ and Precast Beam-Column Connections under Seismic Actions." Applied Sciences 10, no. 22 (November 22, 2020): 8280. http://dx.doi.org/10.3390/app10228280.
Анотація:
At present, the engineering designers generally design and analyze the precast structural models according to the equivalent cast-in-situ principle, and have a vague understanding of non-identical problems. However, these issues cannot be ignored, especially for high-intensity areas. This paper considers the differences of the hysteretic relationship between two typical precast joints and cast-in-situ (RC) joints, and researches the influence of these differences on the seismic response of frame structures. For the monolithic precast joint, the force mechanism was analyzed based on its assembly form, and the differences with the RC joint in the testing phenomena were explained accordingly. The dimensionless hysteresis models of two types of joints were proposed, and the rationality of the monolithic precast joint model was verified according to the existing experimental results. Different performances of joints were realized by assigning the constitutive models calculated from sectional reinforcement to the spring elements of analysis models. Considering two possible performance deficiencies of each type of precast joint separately, a total of seven structural analysis models were formed. Nonlinear static analysis and dynamic time-history analysis methods were adopted to reveal the differences between precast frames and the RC frame in terms of structural capacity curve, displacement response, ductility demands of components and structural residual deformation. The results showed that under strong seismic excitation, the response differences between precast frames and the RC frame were significant, so it is worthwhile to establish nonlinear models suitable for precast frames in seismic analysis. This study is valuable for understanding and distinguishing the nonlinear response of precast frames and traditional RC frames.
28
Hamburger, Ronald O., and John D. Meyer. "The Performance of Steel-Frame Buildings with Infill Masonry Walls in the 1906 San Francisco Earthquake." Earthquake Spectra 22, no. 2_suppl (April 2006): 43–67. http://dx.doi.org/10.1193/1.2185656.
Анотація:
Following the great 1906 San Francisco earthquake and fire, engineers recognized the superior performance of buildings with complete vertical load–carrying steel frames and infill masonry walls. These buildings were noteworthy in their ability to survive both the ground shaking and fire, many remaining in service today. Observation of this superior performance led many California structural engineers to believe that steel frames were the best structural system for resisting earthquake damage, in turn, leading to a proliferation of steel-frame construction in California cities. Not until the 1994 Northridge earthquake did many California engineers recognize that steel-frame structures can and do experience severe earthquake damage. The performance capability of early steel-frame buildings with infill masonry walls, however, remains unclear, despite improved understanding of their structural response characteristics.
29
Kodur, V. K. R., M. A. Erki, and J. H. P. Quenneville. "Seismic design and analysis of masonry-infilled frames." Canadian Journal of Civil Engineering 22, no. 3 (June 1, 1995): 576–87. http://dx.doi.org/10.1139/l95-066.
Анотація:
A simple analytical procedure, which can be used by practicing engineers, for the seismic design of masonry-infilled frames is presented. The analysis procedure, based on the experimental and analytical studies reported in the literature, accounts for the effect of infills in all three stages, namely, in computing seismic loading, in predicting response of the infilled frame, and in determining the strength of the infilled frame. Seismic loading is computed using the dynamic properties of the structure rather than arbitrary empirical relationships as recommended in design codes. Recommendations regarding the choice of infilled frame idealization, structural damping ratio, earthquake design spectrum, structural irregularity, and computational aids are made. Practical guidelines, which can be implemented during the construction phase and which have beneficial effects on the behaviour of infilled frames, are provided. Application of the proposed analytical procedure in a design situation is demonstrated through a numerical example, and it is shown that infills can be accounted for in the seismic design of frames during the normal course of design. Key words: masonry, infilled panels, frame behaviour, seismic design.
30
Tunc, Gokhan, Mohammed Moatasem Othman, and Halit Cenan Mertol. "Finite Element Analysis of Frames with Reinforced Concrete Encased Steel Composite Columns." Buildings 12, no. 3 (March 18, 2022): 375. http://dx.doi.org/10.3390/buildings12030375.
Анотація:
Structural frame systems that consists of concrete-encased-steel-embedded composite columns and reinforced concrete beams are typically used in mid-rise to tall buildings. In order to understand their overall structural behavior, a total of 12 frame models with high and low ductility features were constructed and analyzed using LS-DYNA software. Two of these models were validated using the results of previously tested frames. The remaining 10 models were studied to predict the behavior of frames with varying concrete strengths, reinforcement configurations, and structural steel sections under vertical and lateral loads. The results were investigated in terms of cracks and failure patterns, load-deflection relationships, energy dissipation, and stiffness degradation. The analytical results indicated that the high ductile frame models showed slightly better lateral load carrying performances compared to low ductility frame models. Moreover, the analytical studies demonstrated that the existence of structural steel in a column, regardless of its cross-sectional shape, was the most important parameter in improving the lateral load carrying capacity of a frame.
31
Shendkar, Mangeshkumar R., Denise-Penelope N. Kontoni, Ercan Işık, Sasankasekhar Mandal, Pabitra Ranjan Maiti, and Ehsan Harirchian. "Influence of Masonry Infill on Seismic Design Factors of Reinforced-Concrete Buildings." Shock and Vibration 2022 (February 27, 2022): 1–15. http://dx.doi.org/10.1155/2022/5521162.
Анотація:
Infill walls are the most common separator panels in typical reinforced-concrete (RC) frame structures. It is crucial to investigate the influence of the infill walls on the earthquake behavior of RC frames. The load resistance of infill materials was often not taken into account in the designing phase, whereas the infill walls have significant contributions to the structural behavior under lateral and vertical loadings. A three-dimensional 4-story RC building is designed, and in order to make a realistic model, different infill walls configurations were taken into account with the openings in the infill. Four different models were created for structural analysis for infill wall effects, namely, full RC infilled frame (Model I), corner infill at ground story RC infilled frame (Model II), open ground story RC infilled frame (Model III), and bare RC frame (Model IV). Static adaptive pushover analysis has been performed for all structural models by using the SeismoStruct software. The double strut nonlinear cyclic model was used for modeling the infill walls. In this study, three different compressive strengths of infill walls are taken into consideration, and the effects on seismic design factors (namely, the response reduction factor, the ductility, the overstrength factor, and the deflection factor) are calculated. The obtained values of the response reduction factor (R) are compared with the given values in the BIS code. The results show that the R factors of all RC infilled frames are decreased when the compressive strength of the masonry infill reduces. However, the R values of bare frames are less than the corresponding values recommended in the BIS code. It is worth noting that the National Earthquake Hazards Reduction Program (NEHRP) provisions underestimate the deflection factors of the reinforced-concrete (RC) frames according to the evaluated deflection factors of the herein studied RC frames.
32
Strelkova, Mariia D., Ksenia I. Strelets, Victor Z. Velichkin, and Marina V. Petrochenko. "The application efficiency of precast monolithic frame systems in civil engineering." Vestnik MGSU, no. 11 (November 2021): 1493–507. http://dx.doi.org/10.22227/1997-0935.2021.11.1493-1507.
Анотація:
Introduction. The partial replacement of cast-in-situ concrete with precast concrete in the residential construction sector allows to reduce construction time and cost, increase labour productivity and cut CO2 emissions. Combinations of prefabricated and monolithic elements in precast monolithic frames are presented; they encompass 6 different structural options of precast monolithic frames and 2 types of monolithic frames. The co-authors compare production costs and integrated labor intensity for all frame design options, construction periods per 1,000 m3 of a residential building for various structural options of the frame, and assess potential reduction in carbon dioxide emissions due to a change in the amount of precast reinforced concrete in the building frame structure.
Materials and methods. The co-authors have developed a method that employs weighted average to identify the optimal type of a precast monolithic frame. The method takes account of such factors as production costs, integrated labour intensity, construction time and reduction in carbon dioxide gas emissions (in per centum) per 1,000 m3 of the frame structure.
Results. The optimal structure of a precast monolithic frame was selected and calculated using weighted average. Weighted average was used to identify the most effective structural frame. The calculation results have shown that ARKOS precast monolithic frame with precast columns is the leader in terms of weighted average; it best suits the construction of a residential building. If we consider each of the selected indicators separately, RECON frame with precast floors is to be selected; however, RECON is inferior to ARKOS in terms of weighted average due to different values of the weight coefficients attached to each of the assessment criteria.
Conclusions. The co-authors have proven the efficiency of precast monolithic frame systems in comparison with monolithic frames if applied to construct a residential building. The proposed method was employed to select the optimal type of frame.
33
Shi, Yunyu, Haisheng Yang, Ming Gong, Xiang Liu, and Yongxiang Xia. "A Fast and Robust Key Frame Extraction Method for Video Copyright Protection." Journal of Electrical and Computer Engineering 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/1231794.
Анотація:
The paper proposes a key frame extraction method for video copyright protection. The fast and robust method is based on frame difference with low level features, including color feature and structure feature. A two-stage method is used to extract accurate key frames to cover the content for the whole video sequence. Firstly, an alternative sequence is got based on color characteristic difference between adjacent frames from original sequence. Secondly, by analyzing structural characteristic difference between adjacent frames from the alternative sequence, the final key frame sequence is obtained. And then, an optimization step is added based on the number of final key frames in order to ensure the effectiveness of key frame extraction. Compared with the previous methods, the proposed method has advantage in computation complexity and robustness on several video formats, video resolution, and so on.
34
Nwosu, D. I., and VKR Kodur. "Behaviour of steel frames under fire conditions." Canadian Journal of Civil Engineering 26, no. 2 (April 1, 1999): 156–67. http://dx.doi.org/10.1139/l98-056.
Анотація:
A state-of-the-art review of the behaviour of steel frame structures in fire is presented. Results from different studies indicate that the behaviour of a complete structure is different from that of a single structural member under fire conditions from the point of view of fire resistance. Earlier studies also show that analysis and design of steel structures against fire based on their overall behaviour could lead to a reduction or the elimination of applied fire protection to certain structural members. The effects of continuity, restraint conditions, and load ratio on the fire resistance of frame structures are discussed. The beneficial aspects derived from considering overall structural rather than single-member behaviour in fire are illustrated through the analysis on two one-bay, one-storey, unprotected steel portal frames, a column, and a beam. Also comparison is made between the performance of a beam with different end restraints in fire. Results from the analyses indicate that the fire resistance of a member is increased when it is considered as part of a structure compared with when it is considered as a single member.Key words: steel, frames, fire resistance, buckling, loads, overall structural behaviour.
35
Lyu, Naesung, and Kazuhiro Saitou. "Decomposition-Based Assembly Synthesis of Space Frame Structures Using Joint Library." Journal of Mechanical Design 128, no. 1 (November 25, 2004): 57–65. http://dx.doi.org/10.1115/1.1909203.
Анотація:
This paper presents a method for identifying the optimal designs of components and joints in the space frame body structures of passenger vehicles considering structural characteristics, manufacturability, and assembleability. Dissimilar to our previous work based on graph decomposition, the problem is posed as a simultaneous determination of the locations and types of joints in a structure and the cross sections of the joined structural frames, selected from a predefined joint library. The joint library is a set of joint designs containing the geometry of the feasible joints at each potential joint location and the cross sections of the joined frames, associated with their structural characteristics as equivalent torsional springs obtained from the finite element analyses of the detailed joint geometry. Structural characteristics of the entire structure are evaluated by finite element analyses of a beam-spring model constructed from the selected joints and joined frames. Manufacturability and assembleability are evaluated as the manufacturing and assembly costs estimated from the geometry of the components and joints, respectively. The optimization problem is solved by a multiobjective genetic algorithm using a direct crossover. A case study on an aluminum space frame of a midsize passenger vehicle is discussed.
36
Bao, Yanhong, Bowen Chen, and Lei Xu. "Analysis of Concrete-Filled Steel Tube Reinforced Concrete Column-Steel Reinforced Concrete Beam Plane Frame Structure Subjected to Fire." Advances in Civil Engineering 2021 (April 7, 2021): 1–12. http://dx.doi.org/10.1155/2021/6620030.
Анотація:
The ABAQUS finite-element analysis platform was used to understand the mechanical behavior of concrete-filled steel tube reinforced concrete (CFSTRC) columns and steel reinforced concrete (SRC) beam plane frames under fire conditions. Thermal parameters and mechanical constitutive model of steel and concrete materials were reasonably selected, the correct boundary conditions were chosen, and a numerical model for the thermal mechanical coupling of CFSTRC columns and SRC beam plane frame structure was established. The finite-element model was verified from related experimental test results. The failure modes, deformation, and internal force distribution of the CFSTRC column and SRC beam plane frames were analyzed under ISO-834 standard fire conditions and with an external load. The influence of beam and column fire-load ratio on the fire resistance of the frame structure was established, and the fire-resistance differences between the plane frame structures and columns were compared. The CFSTRC column-steel reinforced concrete beam plane frame may undergo beam failure or the column and beam may fail simultaneously. The frame structure fire-resistance decreased with an increase of column and beam fire-load ratio. The column and beam fire-load ratio influence the fire resistance of the frames significantly. In this numerical example, the fire resistance of the frames is less than the single columns. It is suggested that the fire resistance of the frame structure should be considered when a fire-resistant structural engineering design is carried out.
37
Işık, Yahya, and Mücahit Göle. "Optimum structural design of seat frames for commercial vehicles." Materials Testing 63, no. 2 (February 1, 2021): 138–42. http://dx.doi.org/10.1515/mt-2020-0028.
Анотація:
Abstract Seat frames in commercial vehicles generally consist of components such as foot brackets, seats, back, head restraints and fasteners. In addition to mechanical properties, comfort is another important parameter. This study aims to reduce the cost of a commercial vehicle by means of alternative materials and design changes in the passenger seat frame. For this purpose, three different methods were used to optimize seat back pipes: reducing the cross-section, using thinner sections in the seat frame via alternative material and making design changes in the foot brackets. In the methods applied, mitigation and cost reductions were achieved. The suitability of the design changes in the seat through geometric changes was confirmed by international ECE R14 test results and finite element method analyses.
38
Carr, A. J., and P. J. Moss. "Impact between buildings during earthquakes." Bulletin of the New Zealand Society for Earthquake Engineering 27, no. 2 (June 30, 1994): 107–13. http://dx.doi.org/10.5459/bnzsee.27.2.107-113.
Анотація:
A numerical study of the parameters affecting the impact between adjacent buildings subjected to seismic excitation has been carried out in an endeavour to quantify the relative importance of the structural parameters.
A two-dimensional inelastic dynamic analysis program was used to model various combinations of adjacent framed structures subjected to ground accelerograms and where the frames are assumed to be separated by distances sufficiently small as to permit contact. Collisions were modelled using special contact elements which will transmit forces when the specified gap has been closed.
It will be shown that where there are adjoining frames are of different heights, large increases in response are observed in the upper part of the taller frame. Pounding can also amplify the effects of localised changes in stiffness and strength up the frame-, producing member demands greatly in excess of the normal design values.
39
Nurchasanah, Yenny, Muhammad Ujianto, and Abdul Rochman. "Diagonal reinforcement as strengthening to increase the stiffness and strength of concrete frame." MATEC Web of Conferences 195 (2018): 02033. http://dx.doi.org/10.1051/matecconf/201819502033.
Анотація:
Two test objects of concrete frame behavior against lateral loading were performed by applying structural analysis with the wall as diagonal reinforcement in modeling. The results of the structural analysis indicated that concrete frames with walls have better performance than concrete frames without walls. Twelve objects consisting of the frame without the wall, frame with the wall, and frames with a group of steel and bamboo as diagonal reinforcement at brick walls and concrete panel walls were tested at the laboratory with monotonic lateral forces that work parallel to the wall as the illustration of earthquake loads. The diagonal reinforcement elements can spread the force received by the wall and increase the strength of the wall as well as enhance the stiffness of the structural system at once. Bracing contributes to increasing the strength, especially in resisting the compressive forces due to the earthquake loads. Deformation occurs in the opposite direction between compression path and tension path at the diagonal area. The failure in the concrete frame can be caused by the in-plane force parallel to the wall. Bamboo is quite effective to be used as a substitute for steel reinforcement as bracing material despite its shortage of steel quality.
40
Xue, Weichen, Kun Li, Renguang Zheng, and Liang Li. "Cyclic performance of frames with prestressed steel–concrete composite beams." Canadian Journal of Civil Engineering 35, no. 10 (October 2008): 1064–75. http://dx.doi.org/10.1139/l08-040.
Анотація:
This paper presents a study of the cyclic performance of moment-resisting frames with prestressed steel–concrete composite beams subjected to cyclic displacement reversals. The failure patterns, failure mechanism, hysteretic model, ductility, energy dissipation capacity, stiffness degradation, and deformation-restoring capacity of two composite frames are discussed. Larger slip could be observed along the beam span of the frame with the common composite beam in comparison with the prestressed composite beam. A four-linear hysteretic model with descending branches and two pinching pivot points is proposed for the two composite frames. Tests show that both the test frames failed in a beam side-sway mechanism within the plane of the frame, and the frame with the prestressed composite beam develops relatively high deformation restoring capacity. The applied prestressing in the composite beam has a small contribution to cyclic behavior of the composite frame. Studies also show that more energy is dissipated by the frame with the prestressed composite beam than that with the common composite beam.
41
Sun, Tao, Yugui Tang, and Zhen Zhang. "Structural Information Reconstruction of Distorted Underwater Images Using Image Registration." Applied Sciences 10, no. 16 (August 15, 2020): 5670. http://dx.doi.org/10.3390/app10165670.
Анотація:
Imaging through wavy air-water surface suffers from uneven geometric distortions and motion blur due to surface fluctuations. Structural information of distorted underwater images is needed to correct this in some cases, such as submarine cable inspecting. This paper presents a new structural information restoration method for underwater image sequences using an image registration algorithm. At first, to give higher priority to structural edge information, a reference frame is reconstructed from the sequence frames by a combination of lucky patches chosen and the guided filter. Then an iterative robust registration algorithm is applied to remove the severe distortions by registering frames against the reference frame, and the registration is guided towards the sharper boundary to ensure the integrity of edges. The experiment results show that the method exhibits improvement in sharpness and contrast, especially in some structural information such as text. Furthermore, the proposed edge-first registration strategy has faster iteration velocity and convergence speed compared with other registration strategies.
42
Susanti, Lilya, and Ming Wijaya. "Eccentricity effect on the cyclic response of braced frame type-V." Civil and Environmental Science 005, no. 01 (April 1, 2022): 089–95. http://dx.doi.org/10.21776/ub.civense.2022.00501.9.
Анотація:
Eccentricity on the braced frames can sometimes not be avoided to facilitate some structural considerations, such as openings. V-type braced frames are among the most widely used bracing types because of their satisfying performance. The present study investigated the effect of eccentricity as 15 cm, and 25 cm on the reinforced concrete braced frames of 80 cm x 100 cm in dimension compared to V-type of Concentric Braced Frame (CBF). Results indicated that a frame with 15 cm of eccentricity has almost similar stress but higher strain compared to the CBF while the frame with 25 cm of eccentricity resulted in lowest stress but highest strain. As the eccentricity rises, a frame is likely to behave as a moment-resisting frame. Link beams are the most critical part of the Eccentric Braced Frame
43
Hong, Sung Gul, Namhee K. Hong, and Sun Young Lee. "Hysteretic Behavior of Korean Traditional Wooden Frames." Advanced Materials Research 133-134 (October 2010): 703–8. http://dx.doi.org/10.4028/www.scientific.net/amr.133-134.703.
Анотація:
The objective of this paper is to provide basic information on structural behavior of Korea traditional wooden frames under earthquake loading. One of prototype wooden frames for this study was chosen from a designated national treasure in Korea. A series of experimental work were prepared to investigate the behavior and hysteresis characteristics of traditional wooden frames under cyclic lateral loading. Three test specimens of a full scale were performed for cyclic hysteretic behaviors based on one static test specimen as a pilot test. The experimental observation showed stiffness degradations and slips after experiencing initial yield point and the first cycle at a new larger displacement due to inherent gaps in connections between columns and connection parts of beams and a gradual indentation of interfaces under pull and push. Addition of structural components such as an upper beam and clay-filled wall to the basic beam and columns increased the initial stiffness, strength and energy dissipation than those of basic frames. The behaviors of the wooden frames were simulated by DRAIN-2DX program for the dynamic analysis of an entire wooden frame system. Comparison between analysis models and the experimental behaviors showed that the behavior of wooden frames under consideration could be represented by a combination of link and truss elements. The maximum response of a wooden frame system under three earthquakes showed a safe behavior for a potential earthquake.
44
Kruger, T. S., B. W. J. van Rensburg, and G. M. du Plessis. "Non-linear analysis of structural steel frames." Journal of Constructional Steel Research 34, no. 2-3 (January 1995): 285–306. http://dx.doi.org/10.1016/0143-974x(94)00029-h.
45
Jaspart, Jean-Pierre. "Design of structural joints in building frames." Progress in Structural Engineering and Materials 4, no. 1 (January 2002): 18–34. http://dx.doi.org/10.1002/pse.105.
46
Corliss, George, Christopher Foley, and R. Baker Kearfott. "Formulation for Reliable Analysis of Structural Frames." Reliable Computing 13, no. 2 (December 20, 2006): 125–47. http://dx.doi.org/10.1007/s11155-006-9027-0.
47
Hu, Bo, Xinyu Wei, Henglin Lv, Tribikram Kundu, and Ning Li. "Experimental and Analytical Study on Seismic Behavior of Strengthened Existing Single Frame Structures with Exterior Cantilevers." Advances in Materials Science and Engineering 2019 (February 3, 2019): 1–13. http://dx.doi.org/10.1155/2019/3597480.
Анотація:
Three single reinforcement concrete (RC) frames, including 1 reference specimen and 2 specimens strengthened with shear walls, were fabricated and subjected to low cyclic loadings, in order to evaluate seismic performances of strengthened single frame structures with exterior cantilevers. Through comparison and analysis of failure mode, hysteretic behavior, skeleton curve, energy dissipation, strength, and stiffness degradation of the tested frames, the validity of the shear wall-based reinforcement method for single frames was verified. Test results indicate that the stiffness and load-bearing capacities of strengthened frames increased considerably in comparison with the reference frame. A “strong column-weak beam” failure pattern was observed on the cantilever side, and the failure of the shear wall was always prior to the column, which can increase the structural redundancy and improve the failure mechanism and seismic performance of an existing single frame.
48
Mohebkhah, Amin, and Marzieh Akefi. "Seismic Behavior of Concentrically Braced Steel Frames with Out-of-Plane Offset Irregularity." Open Civil Engineering Journal 11, no. 1 (June 30, 2017): 485–95. http://dx.doi.org/10.2174/1874149501711010485.
Анотація:
Braced steel frames are sometimes designed with out-of-plane shifted bracing members on the first story due to architectural or functional considerations. Such frames are classified and designated as frames having the Type-4 horizontal structural irregularity entitled “frames with out-of-plane offset irregularity” as per theMinimum Design Loads for Building and Other Structures(ASCE 7-10). The purpose of this study is to investigate the nonlinear seismic behavior of ordinary steel concentrically braced frames with out-of-plane offset irregularity and evaluate their seismic design parameters. To this end, two 3-story and 6-story three-dimensional ordinary concentrically braced frames (OCBFs) with and without out-of-plane offset of one of the vertical elements on the first story were considered (i.e. irregular and regular configurations). The seismic design parameters considered in this study includes: frame overall overstrength factor, column overstrength factor and the inelastic dynamic inter-story drift demands. Nonlinear time-history dynamic analysis of the frames showed that overall overstrength factor of the low- and mid-rise irregular frames studied in this research is lower than that of the regular ones. Moreover, it was found that theSeismic Provisionsprescribed overstrength factor (i.e. Ωo=2.0) to amplify columns axial seismic forces in OCBFs is not conservative for the studied regular frames’ columns as well as the columns in the vicinity of the shifted bracing members on the first story of the irregular frames. Also, it was shown that the studied low- and mid-rise regular and irregular concentrically braced frames experience greater inter-story drift demands than predicted by the amplified elastic analysis proposed in the codes.
49
Diaz, Orlando, Enrique Mendoza, and Luis Esteva. "Seismic Ductility Demands Predicted by Alternate Models of Building Frames." Earthquake Spectra 10, no. 3 (August 1994): 465–87. http://dx.doi.org/10.1193/1.1585785.
Анотація:
Peak values of story ductility demands produced by earthquakes on several models of multistory rigid frames are evaluated by means of step-by-step nonlinear dynamic analysis of structural response to simulated ground motion time histories. The models studied include the basic rigid frame model with nonlinear behavior concentrated at plastic hinges eventually forming at the ends of beams and columns, as well as two approximations, the conventional shear-beam system and a shear-frame system constituted by ordinary reinforced concrete columns and infinitely stiff and strong beams. Two families of models were studied, including seven-story and fourteen-story systems, respectively. The contributions of soil-structure interaction, stiffness-degradation and P-delta effects were analyzed. The equivalent shear-beam model produced results clearly different from those of its rigid frame counterpart: while peak values of story ductility demands vary gradually along the height of rigid frames, they concentrate at the bottom story of shear-beam systems, where they are significantly greater than for the corresponding rigid frame. The responses of both, shear-beam and shear-frame systems, displayed a more pronounced sensitivity to variations in the lateral strengths of structural members than that observed in rigid frames.
50
Popov, Egor P. "On California Structural Steel Seismic Design." Earthquake Spectra 2, no. 4 (October 1986): 703–27. http://dx.doi.org/10.1193/1.1585407.
Анотація:
A number of new code developments, largely initiated in California, are taking place in the USA for the seismic design of steel structures. The principal ones are reviewed and commented upon in the paper. Key experimental support for some of the changes is indicated. Major attention is directed to the three main types of steel construction: moment-resisting frames, concentrically braced steel frames, and, the relatively new method for seismic design, eccentric bracing. Some of the proposed and possible practical improvements in moment-resisting connections are given; the reasons for some concern over the use of concentrically braced frames for severe seismic applications are discussed; and a brief overview on the application of eccentrically braced steel frames is presented. The paper concludes with a few remarks on future trends and needs in structural steel seismic design.