VIBRATION ANALYSIS OF NONLINEAR CONICAL SPRING BRACING SYSTEM SUBJECTED TO SEISMIC LOAD Amir ateh1, arzad Hejazi1, , Mohd Saleh aafar1, Azlan Bin Adnan Department of Civil Engineering, aculty of Engineering, University Putra Malaysia, Serdang, Selangor, Darul Ehsan, Malaysia. Email: farzad fhejazi.com aculty of Civil Engineering, University Technology Malaysia, 1 1 , UTM Skudai, ohor, Malaysia. 1 ABSTRACT n this study, an attempt has been made to assess the impact of proposed nonlinear conical spring bracing ( CSB) system on seismic response subjected to earth uake. The developed system includes of two telescopic conical spring springs that operate in axial compression. Due to shape of spring, the proposed system can performed as a nonlinear stiffness element that provide more lateral stability to structural frame. The action of CSB does not control the low and moderate vibration due to earth uake but i t acts for severe vibration whereas the frame displacement pass the allowable boundary. This inconstant performance avoids excessive effects of conventional bracing system if they attached as retrofitting components to moment resistant steel frame. by other words, due to the aforementioned characteristics of CSB system, the inherent ductility of steel frame is not scarified and earth uake energy can be dissipate due to frame ductility, but, CSB system provided more stability of structures and prevent large story drift. n this study, pushover and time history analyses has been conducted to evaluate the seismic performance of introduced device. The results from pushover disclose a considerable enhancement of structural capacity and ductility. Besides, the application on CSB device changed the location of plastic hinge formation in structural elements. urthermore, time history results proved the efficiency of CSB device on reducing the maximum displacement. KEYWORDS Dynamic analysis, earth uake records, pushover analysis, nonlinear conical spring bracing, plastic hinge formation, ductility. INTRODUCTION ibration impacts due to dynamic loads such as earth uake, wind and etc., can induce an unnecessary structure oscillations which may cause to catastrophic collapse. mprovement of structural performance subjected to dynamic loads is the most important concern in structural engineers, experts and researchers. The aforementioned enhancement shall consider the structural stability (safety) and economical design feasibility. t means that, the appropriate design techni ue especially choice of vibration control device is the most imperative issue to prevent the structure from any vibration induced failure. The prior earth uake design approach was based on inherent ductility of structures to dissipate the imposed earth uake energy. This practise was considered as the most feasible and safe design. But it may lead to unrealistic design and structural damage. A lot of research has been focused on supplementary energy dissipation devices which are installed in structures. hereas these devices don t belong to main structural system can be offered as external energy dissipation system which can be easily substituted after severe excitation (Tsu T Soong and Dargush 1 ). ibration control techni ues n can be categorized into three main types: active control ( ao 1 ), passive control and semi active control. Passive control methods were introduced at the earliest stage, and were used commonly in seismic design procedure due to the minimum maintenance cost. Table 1, briefly presents the seismic control system which has been introduced in a few studies. Active variable stiffness (A S), a system for structural control has absorbed numerous attentions and interests. The desire effects and improvement of the structural performance in earth uake excitation of A S systems were proven by previous studies(Takuji Kobori et al. 1 )( ang, u, and i 1 ) Such a s ystem has been investigated experimentally with implementation in full-scale building in apan(T Kobori and Kamagata 1 ). Most of available variable stiffness system are operated using external electrical controller which might cause delay in system performance. These systems are highly depended on energy recourse and also need repetitive maintenance. ariable stiffness bracing system is developed as retrofitting system for steel structures which included of four leaf springs in series with wire rope cable which its totally fabricate without dependency to ) focused on the nonlinear electrical supply ( ateh et al. 1 )(Hejazi, aafar, and ateh 1 ).(Dct behavior of the spring that could be achieved by varying the mean spring diameter in axial direction. n Conical 1270 springs we have some advantages compared to cylindrical springs. n non-telescoping springs, the coils stack one above the other during compression. Another advantage of the conical springs can have a higher sideways stability, so they will better resist buckling. (Dct ). Table 1 Seismic control systems ibration Control System Metallic yield damper(Tyler 1 )(Scholl 1 )(T T Soong and Spencer r ) riction damper(Pall et al. 1 ) isco- elastic dampers(Crosby, Kelly, and Singh 1 )(Moliner, Museros, and Mart nez-Rodrigo 1 ) Passive energy isco-fluid damper (Arima et al. 1 )(Rama Raju, Ansu, and yer 1 ) dissipation Tuned mass damper( ujino and Ab 1 )(Soto and Adeli 1 ) system Tuned li uid damper(Tamura et al. 1 )( eorgakis 11) Rubber bearing Base isolation system( aeim 1 ) riction Pendulum Bearings( ang, Chung, and iao 1 )(Mos ueda, hittaker, and enves ) Active Mass Damper Systems( amamoto et al. 1) Active Tendon Systems(Bossens and Preumont 1) Active Active Brace Systems(Cheng, iang, and ou 1 ) Control Active coupled building systems(Christenson et al. ) System Pulse eneration Systems(Cheng, iang, and ou 1 ) Distributed actuators( isco and Adeli 11) Hybrid Mass Dampers(Saito, Shiba, and Tamura 1) HybridControl Hybrid Base- solation System( ang, Danielians, and iu 1 1) System Hybrid Damper-Actuator Bracing Control(Cheng and iang 1 ) Semi-active Tuned Mass Dampers(Hrovat, Barak, and Rabins 1 ) Semi-active Tuned i uid Dampers(Banerji et al. ) Semi-active riction Dampers(Chen and Chen ) Semi-active ibration Absorbers(T T Soong and Spencer r ) Semi-active Semi-active Stiffness Control Devices(Patten et al. 1 ) Control System Electrorheological Dampers(Makris et al. 1 ) Magnetorheological(MR) dampers(He, Huang, and iu 1 )(Dyke et al. 1 ) Semi-active iscous luid Damper(Symans and Constantinou 1 ) Piezoelectric dampers(Preumont et al. ) The new bracing system with onlinear Conical Spring system was developed as adaptive structural control system to protect the building against severe vibration and ground movement. CSB system includes nonlinear leaf springs which induce nonlinear and onlinear Conical Spring capacity at different frame displacement. The onlinear Conical Spring system ( CSB) system does not scarify the energy dissipation characteristics and ductility capability of moment resistance frame. or large vibration amplitudes, the bracing member and nonlinear spring acting and restrain unacceptably large storey drift. So, the braced frames can display ductile performance which is dissipating seismic energy. DEVELOPMENT OF NCSB DEVICE CSB device installation in frame is shown in igure 1. nce the frame subjected to dynamic force such as earth uake excitations, it sways to left and right and CSB device intents to move to the right and left. Due to dual action of CSB and compression resisting of conical spring, the induced force form vibration transfer to the device by cables. Since the cable is buckling free element, the force can be easily transfer to the main device in unlimited cycle. The action of CSB can be divided to two main phases include solid telescopic conical spring and cable actions. or more explanation, whenever the device reaches to maximum deflection of conical spring, the cable stiffness adds to system stiffness since it works as braces which fixed at both ends.The D schematic model is presented in igure . The details of CSB elements layout is describe in igure . The CSB device comprises of a nonlinear solid conical spring bracing attached to a cable to counter the dynamism of the force resulted from the vibration on the structure of a building The nonlinear conical spring bracing device further comprising, of a rectangular 1271 frame having an exterior clamper (label 1) at each vertical side of the rectangular frame. A telescopic conical spring (label ) attached at each end of the rectangular frame at the exterior clamper (lable1). urthermore a steel rail (label ) fixed at middle of the rectangular frame. An interior clamper ( abel ) attached to each telescopic conical spring (label ), the cylindrical core (label ) is slidable along the steel rail (label ) and a steel rod (label ) passes through each end of the rectangular frame and the interior clamper ( ) and ended at the middle of the cylindrical core (label ). igure 1 CSB nstallation and action in frame igure -D schematic view of CSB 1 3 4 5 2 igure 1 CSB elements layout 1272 DYNAMIC EVALUATION OF NCSB IN DEVELOPED ARCS3D The mathematical model of CSB has been implemented in developed web based software called as ARCS D which is abbreviated of Analysis of Reinforced Concrete Structure- D. The push over and time history analysis of reinforced concrete (RC) structures furnished by CSB device performed for -story building. More over the results compared with bare frame and efficiency of CSB application has been discussed. The compressive concrete strength grade for both pushover and time history analyses are considered as MPa. The columns and beams are modeled with same geometry sizes of X mm as shown in igure . The diameter of reinforcement bars and concrete cover to steel bars are assumed mm and mm respectively in all the cases. n addition to, the story height and bay width for all models are and m correspondingly. mm mm igure beams and columns sections RESULTS AND DISCUSSIONS Pushover Analysis Pushover analysis is conducted for frame e uipped with and without CSB device as presented in igure . The CSB spring wire s diameter and spring s length are e ualed to and 1 mm respectively. The biggest and smallest diameters of conical spring considered as and 1 mm. urthermore, the diameter of wire rope cable e uals to 1 mm with high strength steel material. Results from pushover analysis for both models are reported in igure . As can be observed, the implementation of CSB device caused to increase the pushover capacity by and reached to K and also the ductility characteristic of frame furnished by CSB enhanced. n addition to, the locations of plastic hinge formation in structures are monitored and presented in igure . n the bare frame the plastic hinge initially formed at base nodes at columns then extended to upper columns. But, once the CSB applied, the locations of plastic hinges altered and moved into the device around 1 .it means CSB implementation in frame not only increase the structure capacity and ductility but also reduce the plastic hinge formation in structural components and shift them in CSB device. igure Pushover models in ARCS D 1273 500000 bare frame Force(N) 400000 300000 200000 100000 0 0 igure (a) igure 50 Displacement(mm) 100 150 200 250 Push over curve for frame with and without CSB system (b) ocation of plastic hinge formation at (a) bare and (b) CSB frames Time History Analysis Ground Acceleration(g) Time history analysis for bare and CSB subjected to El-Centro orth-South (1 ) as shown in igure , is conducted with developed finite element program. The -story models are analyzed with and without CSB system. All beams are subjected to the e ual Kn m distributed loads. Moreover, 1 K point loads are applied at all columns as illustrated in igure . The results reported in terms of time history of top node displacement. igure 1 shows the displacement change verse time of considered top nodes in both models. As can be observed, application of CSB device in frame caused to reduce the maximum absolute displacement about . 0.4 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 0 10 20 30 Time(Sec) igure El-Centro Earth uake (1 40 50 ) acceleration orth South record 1274 60 igure Pushover models in ARCS D Displacement (mm) 25 15 Bare frame 5 -5 -15 -25 Displacement(mm) 0 10 20 30 Time(sec) (a)Bare frame 20 15 10 5 0 -5 -10 -15 -20 40 50 60 NCSB frame 0 10 20 30 40 50 Time(sec) (b) CSB frame igure 1 displacement response histories under El-Centro earth uakes 60 CONCLUSION This study introduced a rapid retrofitting techni ue for frame structures. onlinear conical bracing system comprised of two telescopic solid conical springs which are attached to wire rope cables. CSB device can be applied as a new rapid retrofitting practice due to simplicity of CSB fabrication and installation process in high ductility frame. Moreover it can be used as supplementary lateral resisting element in ne w framed building. Push over and time history analyses of story RC frame with and without CSB device has been performed. The results from push over analysis reveal the efficiency of CSB device in structure. ot only the capacity and ductility characteristics of frame enhanced but also, the location of plastic hinge formations altered from main structural elements and shifted in CSB device as supplementary energy dissipation system. urthermore, time history analysis reports a considerable reduction of maximum displacement value. 1275 or future study, finite element simulation is extremely essential to assess the CSB ductility performance under monotonic displacement. Besides, the experimental dynamic test must be conducted to evaluate the seismic response of aforesaid method in reality by use of pseudo dynamic actuator or shaking table. ACKNOWLEDGEMENT This work received financial support from the Ministry of Science, Technology, and nnovation of Malaysia under Research Project o. . This support is gratefully acknowledged. The CSB system is under filling patent grant at Malaysia intellectual property organizations (My P ). CONFLICT OF INTERESTS The authors declare that there is no conflict of interests regarding the publication of this paper. REFERENCES Arima, ., Miyazaki, M., Tanaka, H., amazaki, . (1 ). A study on buildings with large damping using viscous damping walls . n Proceedings of the 9th World Conference on Earthquake Engineering ( ol. 1). Banerji, P., Murudi, M., Shah, A. H., Popplewell, . ( ). Tuned li uid dampers for controlling earth uake response of structures . Earthquake Engineering & Structural Dynamics, 29( ), . Bossens, ., Preumont, A. ( 1). Active tendon control of cable stayed bridges: a large scale demonstration . Earthquake Engineering & Structural Dynamics, 30( ), 1 . Chen, C., Chen, . ( ). Shake table tests of a uarter scale three storey building model with piezoelectric friction dampers . Structural Control and Health Monitoring, 11( ), . Cheng, . ., iang, H. (1 ). Hybrid control of seismic structures with optimal placement of control devices . Journal of Aerospace Engineering, 11( ), . Cheng, . ., iang, H., ou, K. ( 1 ). Smart structures: innovative systems for seismic response control. CRC Press. Christenson, R. E., Spencer r, B. ., Hori, ., Seto, K. ( ). Coupled building control using acceleration feedback . Computer-Aided Civil and Infrastructure Engineering, 18(1), 1 . Crosby, P., Kelly, ., Singh, . P. (1 ). Utilizing visco-elastic dampers in the seismic retrofit of a thirteen story steel framed building . n Structures Congress XII (pp. 1 1 1). ASCE. Dct, B. ( ). onlinear dynamic behavior of a conical spring with top mass . Dyke, S. ., Spencer r, B. ., Sain, M. K., Carlson, . D. (1 ). Modeling and control of magnetorheological dampers for seismic response reduction . Smart Materials and Structures, 5( ), . ateh, A., Hejazi, ., aafar, M. S., bin Adnan, A. ( 1 ). Dynamic Analysis of ariable Stiffness Bracing System in Structure . n Applied Mechanics and Materials ( ol. , pp. ). Trans Tech Publ. isco, . R., Adeli, H. ( 11). Smart structures: part active and semi-active control . Scientia Iranica, 18( ), . ujino, ., Ab , M. (1 ). Design formulas for tuned mass dampers based on a perturbation techni ue . Earthquake Engineering & Structural Dynamics, 22(1 ), . eorgakis, C. T. ( 11, uly ). Tuned li uid damper . oogle Patents. He, . M., Huang, ., iu, C. ( 1 ). ield and rheological behaviors of magnetorheological fluids . Advanced Materials Research, 97, . Hejazi, ., aafar, M. S., ateh, A. ( 1 ). A variable stiffness bracing device . Hrovat, D., Barak, P., Rabins, M. (1 ). Semi-active versus passive or active tuned mass dampers for structural control . Journal of Engineering Mechanics, 109( ), 1 . Kobori, T., Kamagata, S. (1 ). Dynamic intelligent buildings: Active seismic response control . Intelligent Structures, 2, . Kobori, T., Takahashi, M., asu, T., iwa, ., gasawara, K. (1 ). Seismic response controlled structure with active variable stiffness system . Earthquake Engineering & Structural Dynamics, 22(11), 1. Makris, ., Hill, D., Burton, S., ordan, M. (1 ). Electrorheological fluid damper for seismic protection of structures . n Smart Structures & Materials’ 95 (pp. 1 1 ). nternational Society for ptics and Photonics. Moliner, E., Museros, P., Mart nez-Rodrigo, M. D. ( 1 ). Retrofit of existing railway bridges of short to medium spans for high-speed traffic using viscoelastic dampers . Engineering Structures, 40, 1 . Mos ueda, ., hittaker, A. S., enves, . . ( ). Characterization and modeling of friction pendulum bearings subjected to multiple components of excitation . Journal of Structural Engineering, 130( ), . 1276 aeim, . (1 ). Design of seismic isolated structures: from theory to practice”. ohn iley Sons. Pall, A., ezina, S., Proulx, P., Pall, R. (1 ). riction-dampers for seismic control of Canadian space agency head uarters . Earthquake Spectra, 9( ), . Patten, . ., Mo, C., Kuehn, ., ee, . (1 ). A primer on design of semiactive vibration absorbers (SA A) . Journal of Engineering Mechanics, 124(1), 1 . Preumont, A., De Marneffe, B., Deraemaeker, A., Bossens, . ( ). The damping of a truss structure with a piezoelectric transducer . Computers & Structures, 86( ), . Rama Raju, K., Ansu, M., yer, . R. ( 1 ). A methodology of design for seismic performance enhancement of buildings using viscous fluid dampers . Structural Control and Health Monitoring, 21( ), . Saito, T., Shiba, K., Tamura, K. ( 1). ibration control characteristics of a hybrid mass damper system installed in tall buildings . Earthquake Engineering & Structural Dynamics, 30(11), 1 1 . Scholl, R. E. (1 , March ). Added damping and stiffness elements . oogle Patents. Soong, T. T., Dargush, . . (1 ). Passive energy dissipation systems in structural engineering . Soong, T. T., Spencer r, B. . ( ). Supplemental energy dissipation: state-of-the-art and state-of-thepractice . Engineering Structures, 24( ), . Soto, M. ., Adeli, H. ( 1 ). Tuned Mass Dampers . Archives of Computational Methods in Engineering, 20( ), 1 1. Symans, M. D., Constantinou, M. C. (1 ). Development and experimental study of semi-active fluid damping devices for seismic protection of structures . Tamura, ., ujii, K., htsuki, T., akahara, T., Kohsaka, R. (1 ). Effectiveness of tuned li uid dampers under wind excitation . Engineering Structures, 17( ), 1. Tyler, R. . (1 ). urther notes on a steel energy-absorbing element for braced frameworks . Bulletin of the New Zealand National Society for Earthquake Engineering, 18( ), . ang, ., Chung, ., iao, . (1 ). Seismic response analysis of bridges isolated with friction pendulum bearings . Earthquake Engineering & Structural Dynamics, 27(1 ), 1 1 . amamoto, M., Aizawa, S., Higashino, M., Toyama, K. ( 1). Practical applications of active mass dampers with hydraulic actuator . Earthquake Engineering & Structural Dynamics, 30(11), 1 1 1 . ang, . ., u, . ., i, . (1 ). Control of seismic-excited buildings using active variable stiffness systems . Engineering Structures, 18( ), . doi:1 .1 1 1 1( ) 1 -1 ang, . ., Danielians, A., iu, S. C. (1 1). Aseismic hybrid control systems for building structures . Journal of Engineering Mechanics, 117( ), . ao, . T. P. (1 ). Concept of structural control . Journal of the Structural Division, 98( ), 1 1 . 1277
© Copyright 2025 Paperzz