SEISMIC DESIGN OF A SUPER FRAME STRUCTURAL SYSTEM WITH .

2y ago
31 Views
2 Downloads
908.41 KB
8 Pages
Last View : 14d ago
Last Download : 2m ago
Upload by : Camryn Boren
Transcription

0744SEISMIC DESIGN OF A SUPER FRAME STRUCTURAL SYSTEM WITH PASSIVEENERGY DISSIPATION DEVICESYukihiro OMIKA1, Tadashi SUGANO2, Jun OHKAWA3, Toshiyuki YOSHIMATSU4, YukimasaYAMAMOTO5 And Yasukazu TSUJI6SUMMARYA super frame structural system with passive energy dissipation devices (Super-RC frame system)has been developed and applied to a high-rise residential tower. The proposed system is composedof core walls, hat beams incorporated into the top level, outer columns and viscous dampersvertically installed between the tips of the hat beams and the outer columns. During an earthquake,the hat beams and outer columns act as outriggers and reduce the overturning moment in the core,and the installed dampers also reduce the moment and the lateral deflection of the structure. Thisinnovative system can eliminate inner beams and inner columns on each floor, and thereby providebuildings with column-free floor space even in highly seismic regions. A 29-story reinforcedconcrete building incorporating this system has been designed and its structural safety has beenverified.INTRODUCTIONIn Japan, since the first high-rise RC building developed by our group in the 1970’s [Muto et al, 1973] was built,a large number of high-rise RC buildings of up to 30 stories have been constructed. Furthermore, during thisdecade, continual research and study on high-rise RC construction engineering by our group has realized theconstruction of a RC residential tower with high strength materials as high as 50 stories that has same beam andcolumn cross sections as normally designed for a 30-story high-rise concrete frame [Sugano et al, 1998].Because of their high ductility and high degree of redundancy during inelastic behavior under earthquakeexcitations, the structural system used in these high-rise RC buildings has usually comprised a moment resistingframe made of high strength materials.In recent years, because of the need for flexibility in architectural design, lateral load resisting elements havebeen concentrated around service cores, elevator shafts and stairwells to create column-free floor space. Forhigh-rise residential buildings, concrete core walls around these shafts are used for shear walls against lateralforces. However, because these structural elements are often relatively small, deformation of the upper stories isliable to be high under seismic load because of the lack of lateral stiffness.Furthermore, reduction of vibrations in structures has become an important issue, and many mechanical devicesand artificial systems have been developed for seismic and/or wind response control [kobori, 1996]. As a typicalexample, a high-damping device (hidam) has been developed and used for passive vibration control [niwa et al,1995]. An innovative structural system (super-rc frame system) has also been developed by utilizing the energydissipation properties of these devices along with the core wall to reduce vibrations. This system can compensatefor the lack of lateral stiffness of the core wall at the upper stories and thus provide a column-free floor inbuildings even in highly seismic regions.This paper first reports the concept of the developed structural system and the fundamental characteristics of thedynamic response, and then presents its practical implementation in a 29-story residential building, now underconstruction in tokyo.123456Architectural and Engineering Design Group, KAJIMA CORPORATION, Tokyo, Japan, E-mail omika@ae.kajima.co.jpArchitectural and Engineering Design Group, KAJIMA CORPORATION, Tokyo, Japan,Tel 81-3-5561-2111Architectural and Engineering Design Group, KAJIMA CORPORATION, Tokyo, Japan,Tel 81-3-5561-2111Architectural and Engineering Design Group, KAJIMA CORPORATION, Tokyo, Japan,Tel 81-3-5561-2111Architectural and Engineering Design Group, KAJIMA CORPORATION, Tokyo, Japan,Tel 81-3-5561-2111Architectural and Engineering Design Group, KAJIMA CORPORATION, Tokyo, Japan,Tel 81-3-5561-2111

2. CONCEPT OF STRUCTURAL SYSTEMThe developed structural system consists of a T-shaped super structure composed of a core wall and hat beams,outer columns, flat slabs and viscous dampers. The concept of the structural system is shown in Figure1.A reinforced concrete core wall usually located in the center of the floor and made of high-strength materials,can resist most lateral external loads. To avoid the interference with occupiable space, the hat beams are onlylocated at the top of the structure. The outer columns are arranged round the exterior and mainly support verticalloads. They sometimes compose a perimeter frame with shallow spandrel beams, but have less lateral resistancethan the core wall. The viscous dampers are installed vertically between the tips of the hat beams and some ofthe outer columns. They comprise extensively developed highperformance oil dampers (HiDAM). When lateral loads act onH at B eamthe structure, bending deformation of the core wall causesvertical deformation of the tips of the hat beams, causing themO il D a m p erto operate the dampers and thus dissipate vibration energy iD A M )(Hduring earthquake excitations. The hat beams, outer columnsand viscous dampers act as outriggers protruding from the core wall. This reduces the bending moment in the core wall and thelateral deflection of the structure, specially at the upper levels.To improve the efficiency of the dampers during earthquakes,the hat beams and outer columns may be post-tensioned usingC o re W a llhigh strength steel strands formed into tendons.The floor system adopts concrete post-tensioned flat slabs inconsideration of serviceability issues such as perceptibility ofoccupant-induced floor vibration. With this system, there are nofloor beams between the core wall and the outer columns, thusinherently allowing the free passage of the building-servicesductwork and piping. Moreover, story height can be reduced,leading to significant economies. O u te r C o lu m n F lat S la b In p u t M o tio n Figure 1 Concept of super frame structural system(Super-RC frame system)3. FUNDAMENTAL CHRACTERISTICS AGAINST EARTHQUAKESTo grasp the dynamic characteristics, an earthquake response analysis using a representative model is conductedfor comparison with other structural systems. The representative model is a 122m-tall 35-story residential towerwith a H-shaped core wall located at the center of the floor and 16 outer columns. The structural system with thisconfiguration employed for comparative analysis is shown in Table 1. This developed Super-RC frame system isdenoted as case 1. Case 2 is a core wall system, in which core wall can only resist lateral loads. Case 3 is a coreand outrigger system in which hat beams and outer columns are rigidly connected. Case 4 is a core and boundarybeam system in which boundary beams are installed at each floor between a core wall and outer columns. Case 5is a core and tubular system in which perimeter beams are rigidly connected to outer columns that can composetubular frames. In each case, the members are rationally designed as a reinforced concrete element. Dynamicresponse analysis is conducted in consideration of the nonlinear characteristics of each element under destructiveearthquake motion, which is simulated from the design spectrum proposed in a Japanese national project, calledthe “New-RC” project [AIJ, 1993].Typical maximum responses resulting from the response analyses are shown in Figure 2. The story drift angles-2-

remain at around 1/100, except for case 2. The core wall system cannot suppress the flexure of the upper storiesby itself. Case 1, the developed system, shows the least responses of all cases. Generally, story shear forcedecreases with increasing natural period due to decreasing input vibration energy, but lateral deflection and storydrift are liable to increase. In the developed system with the longest natural period shown in Table1, the installedviscous dampers consume vibration energy and suppress deformation, while maintaining the benefits of thereduction of induced vibration energy.Table 1 Comparative study on structural systemC a se 1C a se 2C a se 3C a se 4C a se 5S u p er-R C F ram eC o re W allC o re W allw ith H at B ea mC o re W all an dB o u n d ary B e amC o re W all an dT u b u lar F ra m eT 1 3 .3 1 se cT 1 3 .2 6 se cT 1 2 .9 8 se cT 1 2 .7 7 se cH iD A MT 1 3 .5 3 se cFigure 2 Maximum responses in comparative studyCase 1 (Developed System)R floorCase 2Case 3floorRCase 4R303030252525202020151515101010555100 1/1111 1/100Story drift angle1 1/50050100Shear force (MN)-3-Case 5floor015003000Core wall bending moment (MNm)

4. APPLICATION TO RESIDENTIAL TOWER4.1 OUTLINE OF BUILDING AND STRUCTURAL PLANNINGO u te r C o lu m nShiba Park-Tower, a 29-story residential tower, islocated in Minato-ku, Tokyo. It is rectangular inplan, measuring 32.5 by 36.0m. It has a gross areaof about 32,300m2 and is about 90m high, asshown in Figure 3. It has 25 stories above groundused as a condominium with story heights of 3.2to 5.0m, and 3 stories below ground usedprimarily as a parking garage and machine rooms.9 ,0 0 03 ,5 0 0F la t S la bAAF L -1 09 ,0 0 05 ,5 0 03 6 ,0 0 05 ,5 0 0C o u p lin g B e a mF L -1 1 0F L -4 03 ,5 0 0300 70FL300C o re W a ll370A -A S E C T IO N7 ,5 0 09 ,0 0 03 ,5 0 03 2 ,5 0 0In this building, coupling beams and oil dampersoperate together to reduce the vibration of thestructure under earthquake excitation. The formersuppress excessive deformations in the lowerlevels and the latter suppress those in the upperlevels.Belled-bottom cast-in-place RC piles supportedby a GL-22m hard clay layer are arranged belowthe core walls and outer columns as shown inFigure 5. Footing beams 6.5m deep have theability to resist the overturning moment at thebase of the core walls and no uplift of the footingsoccurs even in destructive earthquakes.H at B eamO il D a m p e r(H iD A M )F c4 2G L 8 9 .4 mC o re W a llFigure 4 Typical floor planC o lu m n , B e a m , S la b9 ,0 0 0F c3 63 ,5 0 025FLC o re W a ll15FLO u te r C o lu m nF c5 4F c4 820FLF c4 2C o u p lin g B e a mF c3 9The design project started in 1997, and afterseveral trial designs, the Super-RC frame systemwas adopted because of its flexibility ofarchitectural planning. Figure 4 shows a typicalfloor plan, in which four L-shaped core wallsaround elevator shafts and stairwells areconnected by four coupling beams. Outer columnsand 600mm-deep shallow perimeter beamscompose perimeter frames with wide openings.Hat beams 3.5m deep span between the core wallsand outer columns, as seen in Figure 5. Oildampers are installed at the tip of each hat beam(see Figure 6), with a damping coefficient ofC 4.9kNs/mm. Flat slabs 300 to 400mm thick arepost-tensioned using bonded and unbondedtendons.P e rim e te r B e a mF la t S la bF c4 210FL1FLB 3FLFigure 5 Framing elevationFigure 3 Shiba Park-Tower-4-F c3 6F c2 7F c(M P a)F c5 4GLF c4 2F c4 8F c6 05FL

4.2 DESIGN PHILOSOPHY AND CRITERIAThe aseismic design criteria for this building are described in Table 2. Two design procedures, static anddynamic, are carried out, and the satisfaction of these criteria assures the building’s safety. Perimeter frames aredesigned using so-called strong-column-weak-beam concept. Core walls and hat beams are prevented fromyielding except for the base of each core wall, and coupling beams are required to possess sufficient ductility toprevent excessive deformation of the structure. In other words, some surplus strength is contained in the bearingforce of the core walls and so forth. For example, for the ultimate bending strength of the core walls, more than1.5 times the stress is provided at Stage 2 for the base and at Stage 3 for the rest. The performance criteria of thedampers are a maximum damping force of 1373kN and a stroke of 150mm.Table 2 Aseismic design criteriaDesign ProcedureLimit State or Load LevelDesign or CriteriaStage 1 : Serviceability Limit StateStatic DesignTemporary Allowable Stress DesignStage 2 : Design Limit StateUltimate Stress DesignStage 3 : Ultimate Limit StateDynamic DesignLevel 1 : Severe EarthquakeStory Drift Angle is less than 1/200Stress of Element is less than Allowable StressLevel 2 : Worst EarthquakeStory Drift Angle is less than 1/100Typical sections of the members derived from the above design philosophy are shown in Figure 6. The designstrengths of the concrete shown in Figure 5 are classified according to the elements. Relatively high-strengthconcrete is adopted for the core wall, to ensure high stiffness and bearing force. Longitudinal reinforcing bars1 ,0 0 0H a t B e am1 ,0 0 0O u te r C o lu m n (2 n d F lo o r) -030 90 9 H -3 0 0 3 0 0 1 0 1 5H -4 0 0 4 0 0 1 3 2 1H -4 0 0 4 0 0 1 3 2 13 ,5 0 01 ,0 0 0L o n g . R eb a r : D 4 1 (S D 3 9 0 )H oop :D 13@ 100(S B P D 1 2 7 5 )13600L o n g . R eb a r : D 4 1 (S D 4 9 0 )S tirru p :1 ,0 0 0H -4 0 0 4 0 0 1 3 2 1D 13@ 100(S D 7 8 5 )P e rim e te r B e a m (2 n d F lo o r)O il D am p e r (H iD A M )1 ,0 0 0L o n g . R eb a r : D 5 1 (S D 6 8 5 )H a t B e a m a n d O il D a m p e r (H iD A M )D 16@ 150(S D 7 8 5 )L a te ral R ein fo rce m e n t :D 16@ 150(S D 7 8 5 )D iag o n a l R e in fo rc em e n tFLL o n g . R eb a r :D 4 1 (S D 4 9 0 )7001 ,2 0 04 ,5 0 0H oop :1 ,2 0 03 ,2 5 02 ,0 0 0C o re W a ll (2 n d F lo o r)C o u p lin g B e a m (2 n d F lo o r)Figure 6 Typical sections of designed members-5-S tirru p :D 16@ 75(S D 7 8 5 )

with a nominal yielding strength up to 685MPa and shear reinforcing bars up to 1275Mpa are used to improvestructural ductility. Flat slabs are designed as partially post-tensioned cast-in-place concrete, and around the corewalls and outer columns, slab stirrups are arranged to prevent punching shear failure.Figure 7 shows a typical tendon arrangement of thepost-tensioned slabs. It can be seen that 21.8mmdiameter tendons are arranged in some rows to allowvertical large penetrations, such as piping,mechanical ductwork, and so on. The change ofpenetrations is also easy during future renovations.Bonded tendons are arranged around the core wallsto ensure the strength of the slabs under inducedrotational displacement by the core walls duringearthquakes.B ondedThe fixed anchorages of the tendons are placed onthe outside of the perimeter beams and the stressinganchorages are placed in pockets on the top of theslab. Thus stressing procedure of the tendons can beusually performed on the cast-in-place concrete slab.B ondedF ix e d A n ch o rag eS tress in g A n ch o rag eB ondedB ondedFigure 7 Typical tendon arrangement4.3 NONLINEAR EARTHQUAKE RESPONSE OF DESIGNED SUPER FRAME STRUCTUREIn the dynamic design of the structure, nonlinear earthquake response analysis was conducted using anequivalent vibration model considering soil-structure interaction. As the entire mass of each story is concentratedat each floor level, a 26-lumped-mass model is adopted for the above ground part. The basement is assumed tobe a unitary rigid body. All core walls, hat beams, outer columns, coupling beams, flat slabs and perimeterframes are modeled by equivalent bending shear elements, and horizontal and rotational interaction springs areinserted. Their nonlinear characteristics are evaluated on the basis of experimental data and their analytical study,such as a nonlinear static analysis with a fiber flexibility model for the core walls, a nonlinear FEM analysis forthe flat slabs, a nonlinear static incremental loading analysis for the perimeter frames, and so on. Three recordedseismic motions, El Centro (1940 NS), Taft (1952 EW) and Tokyo101 (1956 NS), are used for the designearthquakes, with the maximum input velocity normalized at 25 cm/s (Level 1) and 50 cm/s (Level 2). Anartificial earthquake is also adopted, considering seismic activities and ground conditions at the site. Thedamping matrix is assumed to take a Rayleigh type damping form, and the modal damping factor is estimated tobe 3% for the first and second natural modes.Figure 8 shows the resulting maximum responses in the longitudinal direction under Level 2 design earthquakes.The fundamental period for longitudinal vibration is 1.92 sec. From Figure 8, the maximum story drift angle fallswithin the criterion 1/100 mentioned above, and the maximum story shear is about 75MN. Without the dampers,the story drift angle might reach or exceed the criterion in the levels above the 20th floor. The ultimate bendingand shearing strength of the core wall is 2 to 3 times more than the maximum response, so sufficient safety isensured against failure.The maximum responses of the oil dampers are summarized in Table 3, and it can be seen that all the responsesfall within the described criteria.-6-

El CentroTaftTokyo101floorArtificial EarthquakeR floor25R2520202015151510101055510 01/1R25111 1/1001 1/50050Shear force (MN)Story drift angleEl CentroR25floorTaftfloor020004000Overturning moment (MNm)100Tokyo101R25Artificial EarthquakefloorUltimate Bending StrengthUltimate Shearing Strength20201515101055110200400Core wall bending moment (MNm)02040Core wall shear force (MN)Figure 8 Typical response quantities in design analysisTable 3 Maximum damper responsesDamper PerformanceResponses(Input wave)Maximum Stroke43.5 mm(El Centro NS)Maximum Damping Force1022 kN(Tokyo101 NS)-7-

5. CONCLUSIONThis paper has presented the concept and practical implementation of a newly developed structural system, asuper frame structural system with passive energy dissipation devices (Super-RC frame system), which canprovide column-free floor space and lead to increased flexibility in architectural design even in highly seismicregions. The results of this study and development can be summarized as follows:1. Super frame structural system is mainly composed of core walls, hat beams, outer columns, viscous dampersand flat slabs. The high-performance oil dampers (HiDAM) play an important role in reducing vibrationsunder earthquake excitation.2. The fundamental characteristics of the developed system are clarified by earthquake response analysis andcompared with other structural systems.3. The developed system is applied to a 29-story residential tower, and sufficient surplus safety is confirmedthrough a static and dynamic design procedure.ACKNOWLEDGEMENTSThis study was performed by Kajima research project “The Development of Super-RC Frame structural system”.The authors would like to express their gratitude to the project members for their cooperation and helpful advice.REFERRENCESAIJ (1993), Earthquake Motion and Ground Condition, The Architectural Institute of Japan(AIJ)Kobori, T. (1996), “Structural Control for Large Earthquakes”, Proceedings of the XIXth International Congressof Theoretical and Applied Mechanics, Kyoto, Japan, 25-31 August, pp.2-28.Muto, K. et al. (1973), “Earthquake Design of a 20 Story Reinforced Concrete Building”, Proceedings of 5thWCEE, June, Vol.2, pp.1960-1969.Niwa, N. et al. (1995), “Passive Seismic Response Controlled High-rise Building with High Damping Device”,Earthquake Engineering and Structural Dynamics, Vol.24, pp.655-671.Sugano, T. et al. (1998), “Design of 45-Story Reinforced Concrete Building with High-strength Materials”,Structural Engineers World Congress, July, T205-2.-8-

SEISMIC DESIGN OF A SUPER FRAME STRUCTURAL SYSTEM WITH PASSIVE ENERGY DISSIPATION DEVICES Yukihiro OMIKA1, . forces. However, because these structural elements are often relatively small, deformation of the upper stories is . An innovative structural system (super-rc frame system) has also been developed by utilizing the energy .

Related Documents:

AEQB Super QuickBooks-Export (i.e. Accounting-Export QuickBooks) BRW Super Browse DIA Super Dialer FF Super Field-Filler IE Super Import-Export INV Super Invoice LIM Super Limiter PCD Super Passcode QBE Super QBE SEC Super Security TAG Super Tagging MHSTF Super Stuff (a.k.a

Both SAS SUPER 100 and SAS SUPER 180 are identified by the “SAS SUPER” logo on the right side of the instrument. The SAS SUPER 180 air sampler is recognizable by the SAS SUPER 180 logo that appears on the display when the operator turns on the unit. Rev. 9 Pg. 7File Size: 1MBPage Count: 40Explore furtherOperating Instructions for the SAS Super 180www.usmslab.comOPERATING INSTRUCTIONS AND MAINTENANCE MANUALassetcloud.roccommerce.netAir samplers, SAS Super DUO 360 VWRuk.vwr.comMAS-100 NT Manual PDF Calibration Microsoft Windowswww.scribd.com“SAS SUPER 100/180”, “DUO SAS SUPER 360”, “SAS .archive-resources.coleparmer Recommended to you b

Super Mario 64 Super Mario 64 Randomizer Super Mario Bros. 2 Super Mario Bros. 3 Super Mario Kart Super Mario RPG Super Mario World Super Mario World 2: Yoshi’s Island Super Metroid Terraria The Binding of Isaac: Afterbirth ToeJam & Earl

Super Mario 64 Super Mario 64 Randomizer Super Mario Bros. 2 Super Mario Bros. 3 Super Mario Kart Super Mario RPG Super Mario World Super Mario World 2: Yoshi’s Island Super Metroid Terraria The Binding of Isaac: Afterbirth ToeJam & Earl ToeJam & Earl: Back i

EXAMPLE 9 SEISMIC ZONE 1 DESIGN 1 2018 Design Example 9 Example 9: Seismic Zone 1 Design Example Problem Statement Most bridges in Colorado fall into the Seismic Zone 1 category. Per AASHTO, no seismic analysis is required for structures in Zone 1. However, seismic criteria must be addressed in this case.

the seismic design of dams. KEYWORDS: Dam Foundation, Probabilistic Seismic Hazard Maps, Seismic Design 1. INTRODUCTION To perform seismic design or seismic diagnosis, it is very important to evaluate the earthquake hazard predicted for a dam site in order to predict earthquake damage and propose disaster prevention measures. There are two .

Both SAS SUPER 100 and SAS SUPER 180 are identified by the “SAS SUPER 100” logo on the right side of the instrument. International pbi S.p.AIn « Sas Super 100/180, Duo Sas 360, Sas Isolator » September 2006 Rev. 5 8 The SAS SUPER 180 air sampler is recognisable by the SAS SUPER 180 logo that appears on the display when the .File Size: 1019KB

The Seismic Tables defined in Pages 5 & 6 are for a seismic factor of 1.0g and can be used to determine brace location, sizes, and anchorage of pipe/duct/conduit and trapeze supports. The development of a new seismic table is required for seismic factors other than 1.0g and must be reviewed by OSHPD prior to seismic bracing. For OSHPD,