University of Southern California Dissertations and Theses

The response of high-rise structures to lateral ground movements

(USC Thesis Other)

The response of high-rise structures to lateral ground movements

PDF

Download a page range

Download transcript

Copy asset link

Request this asset

Transcript (if available)

Content THE RESPONSE OF HIGH-RISE STRUCTURES TO LATERAL GROUND MOVEMENTS by Handy Irianto A Thesis Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree MASTER OF BUILDING SCIENCE August 1987 UMI Number: EP41414 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Di sser t at i on Pu b l is h ing UMI EP41414 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346 UNIVERSITY OF SOUTHERN CALIFORNIA THE GRADUATE SCHOOL 0 C UNIVERSITY PARK OU fJ' LOS ANGELES. CALIFORNIA 9 0 0 0 7 ? n 1 6 8 33 <7 $ This thesis, w ritten by HANDY IRIANTO under the direction of h..i,S..Thesis Committee, and approved by a ll its members, has been p re sented to and accepted by the Dean of The Graduate School, in p artia l fu lfillm e n t of the requirements fo r the degree of Master of Building Science D ate. Dean THESI£ COMMITTEE _ Chairman ACKNOWLEDGMENTS I wish to acknowledge with sincere thanks my thesis committee chairman. Professor G. G. Schierle, for his valuable suggestions, assistance, constant in te re st, and encouragement for the development of this study. I especially wish to thank the other members of my committee, Professor Dimitry Vergun and Professor James Ambrose, who gave many hours of th eir time to critique the preliminary draft of this thesis. Last, but by no means least, I wish to thank Mrs. O'Detta Hawkins for her editing and typing s k ills which made possible the final draft of this study. TABLE OF CONTENTS ACKNOWLEDGMENTS LIST OF FIGURES INTRODUCTION Chapter I. THE DEVELOPMENT OF HIGH-RISE BUILDINGS Periods of Skyscraper Development I I . HIGH-RISE BUILDING STRUCTURES .................... Common Structures Advantages and Disadvantages of Structural Systems Examples of High-rise Structures with Combination of Structural Elements I I I . STRUCTURAL PROBLEMS IN HIGH-RISE BUILDINGS. Wind Loads Types of Wind Pressure Mean (Steady) Velocity Seismic Force Types of Faults and Faulting Earthquake Magnitude Earthquake Effects on Buildings IV. STRUCTURAL INVESTIGATION.................... Objectives Test Method Procedures Test Equipment Materials Used Definitions Investigated Structures Experiments Chapter Page V. CONCLUSIONS AND RECOMMENDATIONS ........................... 113 REFERENCES.........................................................................................................115 APPENDIX..............................................................................................................116 i v 5 7 10 13 16 17 18 19 20 20 21 22 23 24 25 25 26 27 LIST OF FIGURES Figure 1 . 2 . 3 . 4. 5. 6 . 7 . 8 . 9 . 1 0 . 1 1 . 12 . 13 . 14. 15. 16. 17. 18. Photographs of skyscrapers erected the period 1850 to 1908........................... during Photographs of skyscrapers erected the period 19 09 to 1939........................... during Photographs of high-rise buildings during the period 1940 to 1974. erected Photographs of high-rise buildings erected during the period 1975 to the present time. ...................................................................................... Parallel bearing w a l l ................................ Core and facade bearing walls. . , Self-supporting boxes................................ Cant i lever ed s la b .......................................... FI at si ab.............................................................. Inters pati a 1. ........................................ Suspension. ............................................. Staggered tru s s ............................................... R i g i d f r a m e ..................................................... Rigid frame and core. .................... Trussed frame................................................ Belt truss frame and core. . . . Tube i n t u b e . ........................................ Bundled tube. ........................................ 33 38 44 49 58 59 59 60 60 61 72 73 Architectural drawings of the Seagram Building erected in New York City in 1958 depicting: 19-a. Typical flo or plan; 19-b. Framing plan; 19-c. Framing section................................................................................... Architectural drawings of the U.S. Steel Building erected in Pittsburgh, PA in 1970 depicting: 20-a. Floor plan upper le vel; 20-b. Framing plan; 20-c. Framing secti on................................................................................... Architectural drawings of the Citicorp Central Tower erected in New York City in 1975 depicting: 21-a. Typical floor plan; 21-b. Framing plan; 21-c. Framing se ctio n................................................................................... Architectural drawings of the Chase Manhattan Bank Central Office Building erected in New York City in 1963 de picting: 22-a. Typical flo or plan; 22-b. Framing plan; 22-c. Framing s ect i on................................................................................... The quiescent f a u l t ..................................................... Strained fa u lt prior to earthquake, . . Adjusted f a u l t a fte r earthquake....................... Combination fa u lt movements................................. Right lateral f a u l t ..................................................... Vertical fa u lt . ........................................................ Static loads used in Experiment No. 1. Illu s tra tio n s of d iffe re n t deflections of each floor but with the same overall lateral deflection for d iffe re n t types of l o a d i n g ........................................................................................... Figure Page 31. Simplified ground waves transferred to the structure (1/2 cycle shown) (super structure rigid frame). Direction of ground movement is (-.......... 78 32. Simplified responses of the structure (super structure rigid frame). Ratio between building and ground movement periods = 7/1. . 79 33. Experiment 2. The response of a super struc ture frame system to lateral ground move ments. Pictures were taken at .03 second i n t e r v a l s ........................................................................................80 34. Simplified ground waves transferred to the structure (brace-dampened rig id frame) (1/2 cycle shown). Direction of ground movement is <(-............... ...................................................................................84 35. Simplified responses of the structure (brace- dampened rigid frame). Ratio between building and ground movement periods = 4/1. . 85 36. Experiment 3. The response of a super struc ture system, with brace-dampener on the base, to lateral ground movements.........................................86 37. Simplified ground waves transferred to the structure (alterna te brace-dampened rigid frame) (1/2 cycle shown). Direction of ground movement = <............ 90 38. Simplified responses of the structure ( a l t e r nate brace-dampened rigid frame). Ratio be tween building and ground movement periods = 2 / 1 ..............................................................................................................91 39. Experiment 4. The response of a super stru c ture system, with brace dampener located a ltern ately on every other le v el, to lateral ground movements. ................................................................ 92 40. Simplified ground waves transferred to the structure (super structure rigid frame) (1/2 cycle shown). Direction of ground movement = 4 .......... 96 v i i Figure Page 41. Simplified responses of the structure (super structure rigid frame). Ratio between building and ground movement periods = 2/1. . 97 42. Experiment 5. The response of a s t i f f e r super structure frame system to lateral ground movements. ........................................................ 98 43. Simplified ground waves transferred to the structure (shear wall system) (1/2 cycle shown). Direction of ground movement = <r ..................................................................... 102 44. Simplified responses of the structure (shear wall system). Ratio between building and ground movement periods = 4 / 1 .................................103 45. Experiment 6. The response of a shear wall system to lateral ground movements. . . . . 104 46. Simplified ground waves transferred to the structure (conventional structure rigid frame) (1/2 cycle shown). Direction of ground movement = <-....................................... 108 47. Simplified responses of the structure (conventional rigid frame). Ratio between building and ground movement periods = 4/1. . 109 48. Experiment 7. The response of a conven tional structure rigid frame system to lateral ground movements................................................110 v i i i INTRODUCTION The primary aim of this thesis is to present results of investigations in the behavior of high-rise building structure systems in response to lateral forces. Systems considered include: super structure of rigid frame, shear w a ll, brace-damper rigid frame, and conven tional rigid frame. Since the behavior of high-rise structures is very complex, the investigation of this study was done using simpler idealized systems, model simulations of the structures, and a shaking table to generate lateral forces. For the background of the study, a brief history of high-rise structures is introduced in the f i r s t chapter of this thesis, including t a l l buildings from the early eighteenth century up to the present time. The d iffe re n t concepts of high-rise structures are described in Chapter I I . Chapter I I I contains a discus sion of the structural problems of high-rise buildings, especially lateral loads such as wind load and seismic load. Chapter IV presents the primary subject of this study. I t consists of the method of investigation, the data and pictures, and includes evaluations of the investigation. 1 The conclusions of the investigation and recom mendations are presented in Chapter V. I t is hoped that the recommendations w ill contribute to t a l l building design. 2 CHAPTER I THE DEVELOPMENT OF HIGH-RISE BUILDINGS In the study of the development of high-rise buildings, i t is interesting to note that the term "skyscraper" was used to denote or describe a very ta ll building or the t a l l e s t building in a city ( P e l l i , 1982). Vertical circulation was a major architectural element in the erection of t a ll buildings. The necessity for a mechanical means of reaching upper floors became apparent and in 1852, Elisha G. Otis, an American obligingly invented the f i r s t passenger elevator. This was considered to be a starting point in the further development of high-rise buildings. Periods of Skyscraper Development Pelli (1982) classified the development of sky scrapers into four main periods: (1) 1850-1908; (2) 1909-1939; (3) 1940-1974; (4) 1975-present. Period from 1950-1908 The invention of the elevator in 1852 really began the f i r s t period of building skyscrapers and lasted until 1908. During this period both architects and engineers 3 endeavored to adapt existing building types and materials especially the palazzo, up to the heights allowed by the elevators. The form was tra d itio n a l palazzo and was adapted for the most part to the functions of an office building. Examples of typical skyscrapers of the period are shown in Figure 1. Period from 1909-1939 The Singer and Metropolitan Life buildings b u ilt in 1909 ty p ified the skyscraper structures of this period They were characterized by the abundant exploration of various p o s s i b ilit ie s . This period lasted during the t h i r t i e s and was disrupted by the Great Depression. During this period buildings were selected for their images and symbolic q u a litie s . Structures shifted to building types that had no functional relationship to o ffice buildings. They were b u ilt to celebrate the achievement of erecting very t a ll vertical objects which became the dominant element on the skyline. During this period many symbolic architectural elements were introduced, such as clock towers, watch towers, campaniles, obelisks, and spires. In addition, a complete and successful urban form, lik e downtown Manhattan, came into being, evolving into a most powerful and u p liftin g silhouette. Examples of skyscrapers b u ilt during this second period are shown in Figure 2. Figure 1 Photographs of skyscrapers erected during the period 1850 to 1908. (1 (2 (3 (4 (5 (6 (7 (8 Tribune Building, New York Home Insurance Building, Chicago Tacoma Building, Chicago Wainwright Building, St. Louis Monadnock Building, Chicago Reliance Building, Chicago Guaranty Building, Buffalo Singer Building, Chicago 5 iffimFfr? L FiiiitRfii: w f t i m f M M i i : ( 5 ) ( 6 ) ( 7 ) ( 8 ) Figure 1, Figure 2. Photographs of skyscrapers erected during the period 1909 to 1939. (1) Metropolitan Life Insurance Building, New York (2) Woolworth Building, New York (3) Chicago Tribune Building, Chicago (4) Chrysler Building, New York (5) New York Daily Building, New York (6) McGraw-Hill Building, New York (7) Empire State Building, New York (8) RCA Building, New York ( 1 ) Period from 1940-1974 This period began afte r World War I I and lasted until the late seventies. During this time span many European architects emigrated to the United States. I t was during this period also that the term "skyscraper" became obsolete and the term "high-rise building" came into usage. Buildings were designed to express regular spatial grid, especially in steel structures. Most buildings cle a rly looked lik e containers of in d is tin c t functions. The structure was important not only because i t referred to how the buildings were b u i l t , but the structure i t s e l f became the repository of ideal order. Since the buildings were designed as containers of equal floors and equal space, there was no need for change from the f i r s t floor to the top flo o r (excluding the ground f l o o r ) . The c l a r i t y of orthogonal grid was pre eminent. Also, the enclosure was very l i g h t , some with all glass and minimal mullions to accent re fle c tio n s , and some with curtain walls. Figure 3 depicts high-rise buildings erected during this period of time. Period from 1975 to the Present Time This fourth period probably began with the con struction of the Citicorp Building, b u i l t in 1975, and continuing up to the current period of time. During this 9 Figure 3 Photographs of h ig h - r is e b u ild in g s erected during the period 1940 to 1974. (1 (2 (3 (4 (5 (6 (7 (8 United Nations Building, New York Chase Manhattan Bank, New York World Trade Center, New York John Hancock Tower, Chicago Sears Tower, Chicago United Nations Plaza, New York Citicorp Building, New York John Hancock Building, Boston ( 1 ) ( 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 ) Figure 3 ( 7 ) ( 8 ) period people were not interested in the ideal prism but in balancing internals with externals and public needs. The most important factor was to have the a b i l i t y to shape or give form that eventually would become a public architectural element which would have civic responsi b i l i t i e s . Figure 4 ty p ifie d high-rise structures of this period (Rush, 1980). 12 Figure 4. Photographs of h ig h - r is e b u ild in g s erected during the period 1975 to the present time. (1) F irst City Tower, Houston (2) AT&T Building, New York (3) Trump Tower, New York (4) One Tampa City Center, Tampa (5) The Dravo Building, Pittsburgh (6) Georgia Pacific Building, Atlanta 13 ( 5 ) _ ( 6 ) Figure 4. CHAPTER II HIGH-RISE BUILDING STRUCTURES According to Schueller (1986) a building consists of three basic structural elements: 1. Linear element Columns and beams capable of resisting axial and r o ta tional forces; 2. Surface element Walls (so lid , trussed) capable of carrying axial and rotational forces; 3. Spatial element Facade envelope or core capable of tying the building together to act as a unit. However, the bone structure of the building also can be a combination of these three basis elements. Thus, an i n f i n i t e number of possible combinations of the struc tural solutions are available for selection. Typical common building types are discussed under the caption "Common Structures" along with figures of each type. 15 Common Structures In order to sim plify and c l a r i f y the discussions of the various types of common building structures, each type w ill include a figure i l l u s t r a t i n g such type. Parallel Bearing Walls Because i t is comprised of planar ve rtical elements that are prestressed by sheer weight, this system absorbs la te ra l forces e f f i c i e n t l y . This system is used mostly for apartment buildings and hotels where only small spaces are needed. Walls are used to provide sound insulation as well as structural supports. Figure 5 below il l u s t r a t e s cons tru cti on. Figure 5. Parallel bearing w all. 16 Core and Facade Bearing Walls Planar ve rtical elements form walls around a core structure. Thus, depending upon the spanning capacities of the flo o r structure, open i n te r io r spaces can be created. The core houses mechanical and ve rtical trans portation systems and adds to the building's stiffness (Figure 6) . 'r Z * »• • • • / r - : t i V f v * - 1 4 K *•? J ! L *:■ < • '."X-Z, p ; ; . * V i JS * ■ ■ vv .• " T r ~ D —I I — Figure 6. Core and facade bearing walls. Self-supporting Boxes In this system the boxes are prefabricated three- dimensional units which resemble the bearing wall building 17 when they are joined together and in place. In Figure 7 the boxes are stacked lik e bricks in the "English pattern bond," creating the crossed wall beam system. — w — 1 ■ ■ ■ ■ 1 " " ■ ■ ■ ■ 1 —- " 1 1 Figure 7. Self-supporting boxes. Cantilevered Slab A central core works as an element that supports the flo o r system and allows for a column-free space with the strength of the slab lim itin g the building size. Very large quantities of steel are required, p a rt ic u la rly with long slab projections. However, by taking advantage of the prestressing technique, the slab's stiffn ess can be increased (Figure 8). 18 Figure 8. Cantilevered slab. Flat Slab In this system the horizontal planar system con sists mostly of uniformly thick concrete flo o r slabs sup ported by the columns. Where there are no drop panels and/ or capitals on top of the columns, the system is referred to as a f l a t plate system. With any form, this system has no deep beams allowing for only a minimum story height as shown in Figure 9. 19 Figure 9. Flat slab. Interspa tial On every other flo o r cantilevered story-high framed structures are employed to create usable space within and above the frame. Thus, the t o t a l l y free space above the frame can adapt to any type of a c t i v i t y with the space within the framed flo or used for fixed operations. Figure 10 i l l u s t r a t e s construction of this design. l E T Z 71 11 I || 11 I II 11 I II 11 I II 11 I 11 11 I II Figure 10. In te r s p a tia l. 20 Suspens ion Hangers are employed instead of columns to carry the flo o r loads. Thus, this system offers very e f f i c i e n t usage of m aterial. The strength of a compression member must be reduced to avoid buckling but is not the case for a tensile element which is capable of u t i l i z i n g the m aterial's fu ll capacity. The gravity loads are carried by the cables to trusses c a n ti1 evering from a central core (Figure 11). A A A A A A 1 r • > J___ L Figure 11. Suspension. 21 Staggered Truss In this system the story-high trusses are arranged in such a way that the building flo o r rests a lt e r n a t e ly on the top chord of one truss orthe bottom of the next one. In addition to carrying the vertical loads, this truss arrangement minimizes wind-bracing requirements by trans ferring wind loads to the base through web members and the flo o r slab as shown in Figure 12. z w v s zssss SSZSS szszszs A/VV\ 7\AAA SZ2S5 7 v w \ Figure 12. Staggered truss. Rigid Frame Between an assemblage of lin ea r elements to form v e rtical and horizontal plans, rig id joints are used. The v e rtica l planes consist of columns and girders, mostly 22 on a rectangular grid. A sim ilar organizational grid is used for the horizontal planes consisting of beam and girders. The in te g r it y of the spatial skeleton depends on the strength and r i g i d i t y of the individual columns and beams. Story height and column spacing are major design considerations. This type of construction is shown in Figure 13. Figure 13. Rigid frame. Rigid Frame and Core Since the rigid frame responds to la te ral loads primarily through flexure of the beams and columns, the latera l d r i f t for a building of a certain height sometimes is considered too large. Therefore, introducing a core 23 structure w ill reduce s ig n if ic a n t ly the la te ra l d r i f t of the building as a result of the frame and core interaction . Core systems can be used to house the mechanical and vertical transportation systems. (See Figure 14 below.) i Figure 14. Rigid frame and core. Trussed Frame By combining a rig id (or hinged) frame with v e rtical shear trusses, this system can provide an increase in strength and stiffness of the structure. The design of the structure may be based upon u t i l i z i n g the frame for the resistance of gravity loads and the v e rtical truss for wind and seismic loads sim ila r to the rig id frame and core case. Figure 15 i l l u s t r a t e s the construction used in this systern. 24 i zf Figure 15. Trussed frame. Belt Truss Frame and Core Belt trusses are tied to the facade columns and to the core, thus avoiding the individual action of frame and core. Such bracing is called cap trussing when i t is on top of the building with b e lt trussing in the midsections (Figure 16). w s n u » OB ra Figure 16. Belt truss frame and core. 25 Tube in Tube In this system the facade has the appearance of a wall with perforated window openings because the ex terior columns and beams are spaced so closely. The building acts e n tire ly as a hollow tube c a n ti1evering out of the ground (Figure 17). The i n t e r i o r tube (core) adds to the s t i f f ness of the building by sharing the loads with the facade tube. !!< !■ '!* !■ !! ■■•■■■■■mi iiiiiiiiiiii Figure 17. Tube in tube. Bundled Tube The bundled tube system consists of individual tubes that are arranged in a multiple cell tube. The addition in the stiffness is contributed by the reduction 26 of shearlag. The span of the beam is less when the inner tube is present. Thus, the system allows for the greatest height and the most flo o r area as shown in Figure 18. • • • • • • • • • * • • • • • #«• ••• * • • • • • • ♦ % • • • • • • • Figure 18. Bundled tube. Advantages and Disadvantages of Structural Systems The structural systems most commonly used in high- rise construction are categorized in four groups: rig id frames, shear w alls, cores, and tubes. Both the advantages and disadvantages for each group are discussed here. 27 Rigid Frames Advantages: A. B . C . D. Disadvantages: A. B . C. Shear Walls Advantages: A. The framework can play a dual role by carrying both vertical and horizontal loads. Rigid frames allow the bays between the columns to remain open . Frames can carry loads as soon as they are erected. Frames permit more f l e x i b i l i t y in absorbing horizontal forces. This system is more expensive than other systems. Columns, for the most part, cover larger sections than the usual simply connected columns. Accordingly, an important advantage of the structural work is lo st. Rigid frames are less s t i f f than in other systems; h o ri zontal connections are larger. Shear walls serve the double function of carrying load and of space enclosure. 28 c . D. Di sadvantages : A. B . C. By using concrete or brick w alls, they serve as compart ment ( f i r e ) walls. Pre-assembled shear walls can be used in a load-bearing capacity immediately a fte r erection. Stiffened steel plates and concrete panels have s i g n i f i cant s tre n g th . Temporary support is needed for a building with in situ concrete or brick walls until they have attained th e ir s tre n g th „ The shutteringand concreting of in situ concrete walls after the steel work has been erected is complicated. Walls are fix e d , giving less f l e x i b i l i t y for architectural purposes . Brick shear walls have limited s tr e n g th . 29 Cores Advantages : Disadvantages : Tube Construction Advantages : A. Cores serve a dual function of v e rtical c ircu lation and bracing. B. Cores attain high r i g i d i t y . C. Cores need less area. A. Tolerance difference or pre cise positioning of the con nection components is d i f f i c u l t and especially so with climbing and sliding shuttering. B. The procedure is time con suming i f the core construction and steel erection follow one another. C. Windows and doors as well as service openings weaken the core walls. D. Very thick walls usually are required for very t a l l buildings. A. Outer skin bracing is less ex pensive than internal s ti ffeni ng . 30 B. Buildings are r ig id . C. Vertical circ u lation shafts need no s t iffe n in g and can be used exclusively for space enclosure and f i r e protection. Disadvantages: A. The tube generally requires a prismatic shape. B. This method of construction needs a compact and usually square plan. C. The l a t t i c e work u t i l i z e d has a profound e ffe c t on the ap pearance of the building. Examples of High-rise Structures with Combination of Structural Elements Several structural systems that u t i l i z e d a combina tion of structural elements were discussed by Guise (1985) He selected the Seagram Building, the U.S. Steel Building, the Citicorp Building, and the Chase Manhattan Building as being typical of combination structural elements. Seagram Building Architect: Mies van der Rohe with Philip Johnson, Kahn & Jakobs Location: New York City (1958) 31 Structure: A. Framing system: Steel structure with poured-in- place, one-way concrete flo o r slabs spanning 6'-11" B. Typical framing bay: 27 '-9" x 27 '-9" C. Typical beam depth/span ra tio : 1/ 20.8 Design consideration. To provide meaningful con tiguous o f fic e spaces on each f l o o r , the overall propor tions of the building required that cores be set off from the center. As a r e s u lt, lim ited places for wind bracing occurred. The bracing had to be placed along a pair of e x terior walls. The wind bracing was not expressed as a d i f f e r e n t special function but, rather, i t was embedded in 1 2 -inch thick concrete shear walls. Concrete walls were covered with exactly the same window frames as the rest of the building. The window spaces then were glazed with green marble which gave the e ffe c t of thin glass windows. The flo o r plan, framing plan, and framing section of the Seagram Building are depicted in Figures 19-a, 19-b, and 19-c . U.S. Steel Building Architects: Harrison, Abramovitz & Abbe 32 Figure 19. Architectural drawings of the Seagram Building erected in New York City in 1958 depicting: 19-a. Typical flo o r plan; 19-b. Framing plan; 19-c. Framing section. 33 r - - SEAGRAM BUILDING Typical Floor Plan Figure 19-a. Floor plan of Seagram B u ild in g . 34 n M ■ i SEAGRAM BUILDING Framing Plan Figure 19-b. Framing section of Seagram Building. 35 i i I * * s 5 * F F 1 1 1 3 - i r • fF - - -F t 4 H P 1 P ^ i p A b H h V F - - -F n — i w i - v N —4 - - - -H t J M | L . . ~ J / y x i f * n . P " P I H / y x / y x b - d f r - 4 / u h h H J 3 / . y x y x / y x y x y y > y x * 1 y y x y x » " • n y y x y x W ^ F “ “ * y y x V y x y r'N * , A . ’ K y x ■ * irx ) J - y y x y x / y S ^.s i s /X / < c ^ w J y P ‘ AP - - - - F ' y 'y y x / i i - ^ » - - 1 / y x p - -^ / ; x • " * “ 1 F - ■ 1 - - — H / /X ^ / / y x y x r*- - - - - - - -^ L 4 / C • A * . l . - J i y y T £ i/s, PA ^ : 1 , % 1 1 i i / 2 3 * 5- & 7 e o SEAGRAM BUILDING Fram ing Section a* ft. 7 he MAe/ b rae /n f / * > etn iod /oe/ i*t f uef vc -//k J t fA / cA a r/t& rc e s 6 e *r m a I f * u f C o C h e 2 *t VA£e e / r i 4 /fo r 7 * f t . {d o rh a v A /i fo ) i x / i a e e A a fo fA A n** 5 4 f / * > Che eanCo~a/ / 4t e core And befoe& t e r/v /n rt A nef *> 4 6 < n M e rfiCer a{ C h e . care. 7her e i t an sdb' sf/ona/ off$*6 fo C Z > / o m r 7 Art e 7 o n T h e . f o r t h fto o r Figure 19-c. Framing section of Seagram Building. 36 Pittsburgh, PA (1970) A. Framing system: Steel skeleton with two secondsry floors supported on each primary flo o r and with 1iq u id - f i 11ed e x terior box columns B. Typical framing bay: 13 1 - 0 1 1 x 50 1 -4 1 1 C. Typical beam depth/span ra tio : 1/21.7 Design consideration. The wind resisting system, in addition to the standard diagonal bracing in the core, was a deep truss located at the top of the building. This cap truss, as i t is ca lled , connected the e x terio r columns located on one side of the building with the columns on the opposite side, causing each pair of columns to act in unity; thus, the structure's sway was lim ited. A second truss across the middle of the building was added as an additional s t iffe n in g cro s s-tie . This middle truss or belt truss was located at the same level as an intermediate mechanical equipment room so that the diagonal members of the truss would not cause interference. Figures 20-a, 20-b , and 20-c show the flo o r plan upper le v e l, the framing plan, and the framing section of the U.S. Steel Building. 37 Location: S tru c tu re : Figure 20. Architectural drawings of the U.S. Building erected in Pittsburgh, PA depicting: 20-a. Floor plan upper level; 20-b. Framing plan; 20-c. Framing section. Steel in 1970 38 x r U.S. STEEL Floor Plan Upper Level Figure 20-a. Floor plan upper level of U.S. Steel Building. 39 U. S. STEEL Framing Plan Figure 20-b. Framing plan of U.S. Steel B u ild in g 40 Op* * — & * * * ■ /"? *----- £se*nJsrtf — - - C m / t m u t f l *m) I U.S. STEEL Framing Section Framing section of U.S. Steel Building 20- c 41 Hugh Stubbins with Emory Roth & Sons New York City (197 5) A. Framing system: Steel skeleton with diagonal chevrons framed into mast at center of each facade B. Typical framing bay: 38 1 -0" x 3 8 1 -0" C. Typical beam depth/span ra tio : 1/24.0 Design consideration. One part of the wind bracing system was unique. A hugh 400-ton concrete mass was set on a bed of oil that permitted i t to slide in opposition to the building's sway. I t was placed on top of the building and equipped with various electronic controls. The most s ig n ific a n t aspect of this system was the fact that less steel was required to support all this weight at the building's top than would have been needed to s t if f e n the building with t r a d i t i o n a l , structural wind bracing members. Another s ig n if ic a n t feature of the building's structure was its massive f e e t , one in the middle of each of the building's four faces, each supporting a tower. A huge structural diagonal in the plane of the facade c o l lected the v e rtic a l loads and brought them into a center 42 Citicorp Central Tower Architect: Location: Stru ctu r e : column, then down to each of the four giant legs (columns). A typical flo o r plan, framing plan, and framing section are shown in Figures 21-a, 21-b, and 21-c. Chase Manhattan Bank Central Skidmore, Owings & M e rri11 New York City (19 63) A. Framing system: Steel skeleton with e x te rio r columns and steel flo o r deck with concrete topping B. Typical framing bay: 29 '-0" x 42 '-11" C. Typical beam depth/span ra tio : 1/18.5 Design consideration. A structural problem for this building occurred when the columns on the e x terior of the structure o r ig in a ll y were placed beyond the plan of the facade. Accordingly, the spandrel beams located within the plane of the facade could not intersect the column. Thus, the column could only be braced d ire c tly by the wind-girder which spanned across the building through the core. To solve this problem the girder had to be greatly stiffened in the area where i t was intersected by the spandrel beam. The solution was accomplished by using a pair of three-foot deep girders and uniting them with a 43 Office Building Architect: Location: Struetu r e : Figure 21. Architectural drawings of the Citicorp Central Tower erected in New York City in 1975 depicting: 21-a. Typical flo o r plan; 21-b. Framing plan; 21-c. Framing section. 44 i7-l' 1 J l S ) [SI !ZUg] IS EIL I J J L L r iei e m is t II L i S M S S I S /a a fs r ? / /rro s rfte r: /tcic/ASj !/**•/*« CITICORP Typical Floor Plan Figure 21-a. Typical flo o r plan of Citicorp Central Tower. > g - o" (. s e > '-o ' ■ x i- CITICORP Framing Plan Figure 21-b. Framing plan of C i t i c o r p Central Tower. 46 CITICORP Framing Section Figure 21-c. Framing section of Citicorp Central Tower. 47 heavy steel top plate where they connected to the column. The addition of the plate s tiffe ned the girder in its horizontal plane; th is , in turn, provided i t wht the capacity to s t a b il iz e the column. Thus, the wind forces from the spandrel beam could be transferred into the e x terior columns. Figures 22-a, 22-b, and 22-c show a typical flo o r plan, framing plan, and framing section. 48 Figure 22. Architectural drawings of the Chase Manhattan Bank Central Office Building erected in New York City in 1963 depicting: 22-a. Typical flo o r plan; 22-b. Framing plan; 22-c. Framing section. 49 ♦»'- 9“ -■ h - SB CHASE MANHATTAN Typical Floor Plan Typical flo o r plan of Chase Manhattan Figure 22-a Bank Central O ffic e B u ild in g . 50 r a B B 4 '- H ■X^rwV - £ in a k r : frir T t t r c * — ft CHASE MANHATTAN Framing Plan Figure 2 2 - b . Framing plan of Chase Manhattan Bank Central O ffic e B u ild in g . 51 CHASE MANHATTAN Framing Section TFT U t — i_ _ _ 'J SSi SL. S : H i i £ 5 p p 4 S ZS P P s p : § P P z s S z§ s § zs z s zs § § zs zs z§ 3 3 s 3 3 3 E t t Figure 2 2 - c . Framing se c tio n of Chase Manhattan Bank Central O f f ic e B u ild in g . 52 CHAPTER I I I STRUCTURAL PROBLEMS IN HIGH-RISE BUILDINGS The main problem associated with high-rise s tru c tures was deformation due to la te ra l loads such as wind and earthquake. Other problems that contributed to the deformations included g ra v ity , temperature change, and shrinkage and "creep" of concrete. For high-ris e buildings, the la t e r a l loads (pro duced by wind or seismic force) were considered to be the most c r i t i c a l in designing the structural systems of high- rise buildings. This section mainly discusses the s tru c tural problems caused by la t e r a l loads. Wind Loads During the period when the f i r s t skyscrapers were erected, wind action was not a major problem because the enormous weight of the masonry bearing walls was such that wind action could not overcome the gravity forces. Even when the rig id frame was introduced in the late 1800s, gravity remained the prime determining fa c to r. To over come the wind action, much weight s t i l l was generated by the construction of heavy stone facades with small 53 openings, closely spaced columns, massive b u ilt-u p frame members, and heavy p a rt itio n walls. During the 1950s when steel frames combined with glass curtain walls were introduced weight no longer was a facto r lim itin g the potential height of buildings. However, the e ffe c t of la te r a l forces then became a dominant fa cto r. These innovations lessened some of the overall r i g i d i t y of the structure; th erefo re, the la te ra l s tiffn ess ( l a t e r a l sway) of a building became a more important consideration than its strength, and wind and seismic forces became major problems in the construction of high-rise buildings. Types of Wind Pressure Wind action is created as a resu lt of the wind pressure originating from two components (Schueler, 1986): mean (steady) velocity and gust (dynamic) ve loc ity. S tatic v e lo c ities are averaged over longer periods of time. The total s t a t ic wind pressures also are average pressures which exert a steady deflection on a building. Gust ve lo c ities have a dynamic c h a ra c te ris tic of producing correspondingly dynamic wind pressures which increase displacement approximately equal to the s ta tic de fle c tio n , becoming a dominant factor in erecting slender buildings. Such dynamic movement was called Gust buffeting. The gust action created random forces which 54 induced building o s c illa t io n generally p a ra lle l to the wind direc tio n. Mean (Steady) Velocity Wind Vibration Wind produces a dynamic e ffe c t s ig n if ic a n t to the safety of a building or its parts and on the wellbeing of its occupants. I t applies especially to t a l l buildings, making the investigation of vibration behavior necessary. I t was important to learn that the acceleration resulting from wind vibration lay below 0.5 m/sec so that human beings were not disturbed by i t (Hart, Henn & Sontag, 1985), Also, the natural frequency of the building should be less than 0 . 1 . N in which N is the number of stories in the building above the ground le v e l. Wind Deflection I t was found that the total deflection of a b u ild ing at its top consisted of the combined deflections due to the s t a t ic wind pressure plus the dynamic d e flec tio n . Wind Behavior Understanding the wind and predicting its be havior in precise s c i e n t i f i c terms may be impossible since wind behavior involves very complex environmental factors. 55 For example, the wind loads and the building depended upon : The roughness of the outer skin of the building; the aerodynamic shape of the building; the height of the building; the velocity of the wind. For these complex factors the Building Code s im p li fied the method for calculating the wind pressure by using the s t a tic approach. However, a study conducted by Michael O'Hare at M .I.T . in 1967 demonstrated several types of wind action and revealed special insight into topographical elements affe c tin g a i r movement. The study revealed that wind pressure did not necessarily increase with height as was assumed by the Uniform Building Code (U .B .C .). Thus, i t would appear that designers should develop a better conceptual understanding of the wind action affe c tin g high-rise buildings. Seismic Force The second type of force that can increase major la te ra l loads is seismic force. Until recently the cause of earthquakes was not f u l l y understood but s u f f i c i e n t geologic evidence was available for scientists to conclude that the shakes were the e ffe c t of a re-balancing of forces arising from the c o llis io n of continuously moving plates of layered rock 56 that floated upon the earth's molten i n t e r i o r . This was thetheory of continental d r i f t and plate tectonics, which held that the land surface of the crust of the earth once was concentrated in a single continental mass, super conti ne nt. As a result from the c o l l i s i o n , stresses were b u i l t up along the plate edges until sudden slippage occurred due to the fracture or e la s tic rebound of the rock. Then a sudden release of strain energy caused the upper crust of the earth to frac ture along a certain direction and from a f a u l t . Types of Faults and Faulting The Quiescent Fault The d r i f t i n g tectonic plates along the plane moved r e l a t i v e l y fre e ly and very slowly. This movement was termed f a u l t creep which was damaging to structures above the f a u l t only over a long period of time. The Calaveras Fault and a portion of the San Andreas Fault near H o l l i s t e r , C a lifo rn ia have moved in this way in the past several years. Other faults became locked with the f r i c t i o n of the c o llid in g plates and moved only when the rocky layers of the plates became strained beyond endurance and slipped apart with the violence of an earthquake. Figure 23 t y p i f i e s the Quiescent F a u lt. 57 fault u n s f a u l t u t ie ♦ ♦ Figure 23. The quiescent f a u l t . The Strained Fault Prior to an Earthquake The gradual movement of the tectonic plates created a strain in the rocky layers of the f a u l t where the two plates were c o llid in g . The f r i c t i o n a l forces of the c o llis io n locked the two sides of the f a u l t and pre vented any movement. The lim ited e l a s t i c i t y of the rocky layers allowed the strains of this locked f a u l t to ac cumulate for years and even decades. F i n a lly , the rocks gave way, allowing the two sides of the f a u l t to realign and causing the upheaval of an earthquake and surface displacements. Figure 24 i l l u s t r a t e s the strained f a u l t prior to an earthquake. 58 MEW PlftECTlO rt 0** movement Figure 24. Strained f a u l t prior to earthquake The Adjusted Fault A fter an Earthquake The f a u l t now has moved into a new unstrained position, causing surface displacements that have destroyed the continuity of the highway and fence portrayed in Figure 25 and producing intense shock waves during the quake demolishing buildings in the f a u l t zone. ♦ ♦ T - R ofp Figure 25. Adjusted f a u l t a f t e r earthquake. 59 The Direction of Faulting Faults t y p ic a lly moved e ith e r l a t e r a l l y , v e r t ic a l ly , or in a combination of ve rtic a l and la te ra l s h if ts . The San Fernando and White Wolf fa ults in C a lifo rn ia f i t this combination of movements and is quite common among fa ults (Figure 26). Figure 26. Combination f a u lt movements. The San Andreas f a u l t system in C alifo rn ia moves l a t e r a l l y to the r ig h t as i l l u s t r a t e d in Figure 27. Figure 27. Right l a t e r a l f a u l t . 60 The Garlock f a u l t in Southern C a lifo rn ia as well as others moves l e f t l a t e r a l l y . As shown in Figure 28, the Wasatch Fault in Utah and the Kern River and P lieto fa u lts in Southern C alifornia are v e rtic a l or thrust fa u lts . Figure 28. Vertica l f a u l t Earthquake Magnitude The magnitude of the earthquake was calculated from the seismogram which was the response of the seismo graph to the motion of the ground recording a zigzag line re fle c tin g the varying amplitude of the vibrations. The energy released at the focus was measured by the Richter Scale which ranges from three to nine as based on the logarithmic scale, where each unit increment refle c te d an increase of approximately 32 times more energy. Earth quakes between four and fiv e were considered moderate; those above six were severe; and a magnitude of eight was c la s s ifie d as a great earthquake. 61 Earthquake Effects on Buildings When earthquake shock waves generated opposing and irre g u la r horizontal and v e rtic a l vib ra tio nal forces in the ground, the earth's sudden movements, pushing and pulling a bu ilding's foundation, caused the structural elements of the building to expand and compress and to bend and sway from side to side. Building structures resisted these abrupt move ments rising from the foundation; as a result of the resistance, a natural in e r t ia was created which sharply snapped the building back and forth and up and down. The experience of la t e r a l inertia in a building was s im ila r to the physical response of a person in a suddenly braked c a r . The most damaging effects on structures generally were the horizontal movements in a direction p a ra lle l to ground surface (Ambrose and Vergun, 1980). The horizontal earthquake movements could easily exceed the la t e r a l strength and f l e x i b i l i t y of a building's structure and i t usually was the la t e r a l vibrations that resulted in the collapse of a ll or part of a building. Thus, for design purposes, the major e ffe c t of an earthquake usually was considered as horizontal force, s im ila r to the e ffe c t of wind. 62 In order to enable a building to absorb and d is tr ib u te the la te ra l forces without collapse or severe damage, i t was determined that la te ra l bracing and durable connection of the structural components were necessary. In addition, other factors such as the foundation, the building m ateria ls, and the a rch itectural and structural design and d e t a il in g , as well as the workmanship, also were deemed important to the earthquake resistance of a building. 63 CHAPTER IV STRUCTURAL INVESTIGATION Objectives The primary objective of the investigation was to study responses of four d i ff e r e n t types of high-rise structures to la t e r a l ground movements. A secondary objec tive was to contribute to the need for v is u a liz a tio n of high-rise structural behavior. The presentation of this study would be helpful only i f the continuation of sim ila r studies were done by others since this type of study would be necessary to provide the background for the study of dynamic structures of high-rise buildings. Test Method This study was based on the u t i l i z a t i o n of s tru c tural models that were assumed to represent structural systems of m u lti-s to ry buildings. A shaking table was used to generate la t e ra l forces which represented ground movements . Based on the s t a tic simulation models described by Professor G. G. Schierle (1968), the structural models 64 were constructed simulating the f u l l - s i z e structure based on the c r i t e r i a described as follows; Force Scale Im Em Sf = , ( i ) Ip Ep where: Sf = Force scale r e la tin g model forces to forces of prototype. Im = Moment of in e r t ia of the model. Em = E lastic modulus of the model. Ip = Moment of i n e r t i a of the prototype. Ep = Elastic modulus of the prototype. Geometric Model Dm Sg = (2) Dp where: Sg = Geometric scale. Dm = Dimension of the model. Dp = Dimension of the prototype Strain Scale Pm Lm / Im Ss = ------------ (3) Pp Lp / Ip 65 where: Ss = Strain scale. Pm = Forces or loads in model. Im = Moment of i n e r t ia of model members. Lm = Length of column of model members. Pp, Ip, and Lp are the equivalents in the prototype structure. Procedures F irs t Experiment The f i r s t experiment using s t a t ic loads was con ducted using the following procedure: 1. On every f lo o r of the structural model a paper plate was attached. 2. Reference lines were established in the middle of the floors and were independent from the movement of the floors as they deflected. 3. One ounce of s ta tic load was applied c e n tra lly on the f i f t h flo o r by using fishing weights, 4. Lateral d r i f t for each flo o r was marked, 5. Additional loads of one ounce were added in cre mentally and steps 4 and 5 were repeated until a fin al load equal to 6 ounces was reached. 6. Steps 1 through 5 were repeated except that the loading of step 3 was applied at the corner. 66 Second through Seventh Experiments For the second through the seventh experiment the following procedures were implemented; 1. The building's period was measured by using a lig h t bulb and mercury switch which was placed on top of the model. A la te ra l load was applied on the model and timed. By counting the number of flashes on the l i g h t bulb at a given time, the frequency of a building was established. This procedure was implemented several times in order to get an average value of the frequency. The building's period was calculated by the fo rmu1 a : T = 1 / f (4) where: T = Period of the building or period of the ground unit was in seconds (step 2) . f = Frequency of the building or frequency of the ground unit was in Herz/seconds (step 2) . 2. Ground movements were established by using the same method used in step 1. 67 3, The structural model was placed on top of a shaking table which generated harmonic la t e ra l fo rc es . 4. A camera with automatic motor drive was set up in fro n t of the model and shaking table. The shaking of the table was created by turning on the remote control; at the same instant the pictures were taken continuously until the la s t frame was shot. Test Equipment The te st equipment u t i l i z e d in the experiments are described as follows: 1. Shaking t a b l e . The table was constructed of wood and was powered by a small motor placed beneath i t . The motor was controlled by a remote control unit which could be carried at a distance from the table so the experiment could be carried out more eas i 1y . 2. Camera. The camera had an automatic motor drive which could take pictures continuously in sequence. The speed of the motor drive was approximately 0.3 second per fr a m e /p ic tu re . 3. Films. The films were black and white T r i- x with ASA 400 and containing 36 exposures for the most p a r t . 68 4. Mercury sw itch. A 1.5 V-9V mercury switch was connected to a 1.5 bulb which worked as a f l a s h l i g h t , providing li g h t bunch to calculate the model's period. 5. Timer. A 120V e l e c t r i c timer was used to time the frequency of building's periods and ground move ments . Materials Used Three materials were used for the structural models : 1. Steel piano wires to simulate columns. 2. Plywood to simulate s t i f f flo ors. 3. Plas tic construction models (I & C shapes) to simulate brace-dampers. Definitions The following terms were for the purpose of con venient references: Super s t r u c t u r e . A r ig id frame system with four primary columns at the corners that carried all of the major loads. Shear wall s t r u c t u r e . A structure using s t i f f walls to re s is t la t e r a l loads. The term "shear wall mass" sometimes is referred to as this shear wall system. Brace-dampened rigid frame. A rig id frame with brace dampeners. 69 Conventional rig id frame. A r ig id frame structure with multi-columns commonly used to re s is t la te ra l loads. Investigated Structures Structure 1. Floor area Column height Column diameter Building height Relationship: Sf = 1 = 1 Ss = 1 Pro to type 120' x 120' 15' / f l o o r 24 ' 600 ' 160000 240 32 Mo de 1 6" x 6" 6"/8 floors 0 . 1 " 30" Structure 2 . Floor area Column height Column diameter Building height Prototype 120' x 120 1 5 ' / f 1oo r 24" 375 ' Mo del 6" x 6" 3 . 7 5"/5 floors 0 . 1 " 18.75" 70 S tru c tu re 3. Floor area Column height Column d i ameter Building height Structure 4 . Floor area Column height Column diameter Building height Pro to type Mo del 120' x 120' 6" x 6" 1 5 ' / f l o o r 3.75"/5 floors n/a (shear walls) n/a 375* 18.75" Pro totype 120' x 120' 15' / f l o o r 14" 375 ' Exper imen ts Model 6" x 6" 3 . 7 5 "/ 5 floors 0 .06" 18.75" Experiment No. 1 (Structure : Structure 1) O b jec tiv e s. To study the rig id frame of structure No. 1 in response to two d i f f e r e n t types of s t a t i c loads: (1) loads applied at the center of the mass of the f i f t h flo o r and (2) loads applied at the corner flo o r of the same flo o r (Figure 29). E valuation. (1) The model responded to the central loading and corner loading in s im ila r manner except that in response to corner loadings, a rotation al e ffe c t oc curred much more than in response to the central loadings; (2) la t e r a l deflections for both types of loadings were the same (Figures 30-a, 30-b , 30-c). ^ CENTRAL LOADING CORNER LOADING Figure 29. Static loads used in Experiment No. 1. ISO Figure 30. I l l u s t r a t i o n s of d i f f e r e n t deflections of each flo or but with the same overall la te ra l deflection for d i f f e r e n t types of loading. 30-a. Central loading pattern 30-b. Corner loading pattern 30-c. Height vs horizontal deflection 73 tt rrr TTTTTTTT f ~ + + + ■f + + f + + 1st Floor * iJ L I 1 « i i 2nd Floor ■ L U iU il 3rd Floor Ti l I ' TTTTTI I + ■f + + + + 1,11,111 4th Floor -1 t . l I L I ■ I 5th Floor •vl ■ £ > Figure 30-a. Central loading pattern showing deflection lines on each floor. Loading direction is -------- . 3rd Floor 2nd Floor 1st Floor 5th Floor 4th Floor Figure 30-b. Corner loading pattern showing deflection lines on each floor. Loading direction is -------- . III/// Central ^ A Corner c r> Figure 30-c. Height vs horizontal deflection = Lateral deflection H = Height or number of floors 1 = 1 ounce 6 = 6 ounces Experiment No. 2 (Structure : Structure 1) O b jec tiv e s. To study the response of a super structure frame system to la te r a l ground movements and also to study the relation ship between the period of the model and the period of the ground movements. E valuation. (1) The model responded to la t e ra l ground movements with rotations and higher modes; (2) severely deformed columns appeared not only on the lowest level but also on the upper lev els ; and (3) the r a tio between bu ilding's period and ground periods equalled 7/1. Figure 31 i l l u s t r a t e s sim plified ground waves transferred to the structure and Figure 32 i l l u s t r a t e s the sim p lified responses of the structure to the ground waves. Figure 33-a and Figure 33-b portray that there was some evidence that the rig id frame system generated higher modes, that ro tation al effec ts occurred freq u e n tly , and that the lowest columns were severely deformed. The pictures in Figure 33-a and Figure 33-b were taken at 0.3 second in te r v a ls . Additional pictures taken during Experiment No. 2 are found in the Appendix. 7 7 Figure 31. Simplified ground waves transferred to the structure (1/2 cycle shown) (super structure rigid frame). Direction of ground movement is (---------. First Mode Second Mode Third Mode Figure 32. Simplified responses of the structure (super structure rigid frame). Ratio between building and ground movement periods = 7/1. Figure 33. Experiment 2. The response of a super structure frame system to la t e r a l ground movements. Pictures were taken at .03 second in te r v a ls . 80 /- 3L $mCX)t*0+ Figure 33-a. Experiment No. 3 (Structure 1 + Dampers Located on the Base) O b je c tiv e s . To study a super structure system, with brace/damper on the base, in response to the la t e r a l ground movements, and also to study the relation ship be tween the b u ilding 's period and ground movement's period. Eva!uati on. (1) The structural model responded to la t e r a l ground movements only in the f i r s t and second modes; (2) the rotational effects s t i l l occurred; and (3) the r a tio between the b u ilding's period and ground move ment's period was 2/1. Figure 34 i l l u s t r a t e s sim plified ground waves transferred to the structure and Figure 35 indicates the s im plifie d responses of the structure to the ground waves. Figures 36-a and 36-b reveal some evidence that the rotational effects s t i l l occurred and that the responses were in the f i r s t and second modes. The pictures in Figure 36-a and Figure 36-b were taken at 0.3 second intervals . Additional pictures taken during Experiment No. 3 are found in the Appendix. 83 1 2 3 4 5 Figure 34. Simplified ground waves transferred to the structure (brace- dampened rigid frame) (1/2 cycle shown). Direction of ground movement is <•--------. C O -1 ^ < First Mode Second Mode Figure 35. Simplified responses of the structure (brace-dampened rigid frame). Ratio between building and ground movement periods 4/1. C O cn Figure 36. Experiment 3. The response of a super structure system, with brace-dampener on the base, to la t e r a l ground movements. 86 O*-} 5&C0HP Q . c, 6 B 6 0 t4 P Figure 36-a. 87 * ■ * * I | H f l ■ ■ ■ v r 1 1 . % VE. c. z>*4V *f | . d 2 . 1 t> f 4 E c o H D ^ Figure 36-b. 88 Experiment No. 4 (Structure ; Structure 1 +_____ Dampers Located A lte rn a te ly on every other l e v e l ) O b jectives; To study a rigid frame system, with brace/damper placed on a lte rn a te flo o r le v e ls , in response to la te r a l ground movements, and also to study the r e l a tionship between the building's period and ground move ment ' s period. Evaluation. (1) Structural model responded to la t e ra l ground movements mostly in the f i r s t mode and s li g h t ly in the second mode; (2) rotational effects s t i l l occurred but they were largely reduced; (3) bracing or dampering on the top level did not help much in responding to the la t e ra l ground movements; and (4) the ratio between bu ilding's period and ground movement's period was 4/1. The sim plified ground waves transferred to the structure are shown in Figure 37. The sim plified r e sponses of the structure to the ground waves are t y p ifie d in Figure 38. Figures 39-a and 39-b reveal evidence that the responses were mostly in the f i r s t mode and only s li g h t ly in the second mode. The rotational effects s t i l l occurred but were largely reduced. I t was determined that dampening on the top level did not help to any degree. The pictures in Figures 39-a and 39-b were taken at 0.3 second in te rv a ls . Additional pictures taken during Experi ment 4 are found in the Appendix. 89 1 2 3 4 5 Figure 37. Simplified ground waves transferred to the structure (alternate brace-dampened rigid frame) (1/2 cycle shown). Direction of ground movement = <r . First Mode Second Mode Figure 38 Simplified responses of the structure (alternate brace- dampened rigid frame). Ratio between building and ground movement periods = 2/1. Figure 39. Experiment 4. The response of a super structure system, with brace dampener located a lt e r n a t e ly on every other l e v e l, to la t e r a l ground movements. 92 p . ? f g c o r J D 6 < E c o H P Figure 39-a. I tr ).S Experiment No. 5 (Structure : Structure 2) O b je ctiv es . To repeat Experiment No. 2 but using s t i f f e r model which had shorter columns than structure 1. E valuation. (1) The model's responses were mostly in the f i r s t and second modes; (2) rota tion a l effe c t occurred; (3) the lowest columns deformed the most; (4) the r a tio between the building's period and the ground movement's period was 2/1. Figure 40 i l l u s t r a t e s the s im p lified ground waves transferred to the structure in Experiment No. 5. In Figure 41 the sim p lifie d responses of the structure to the ground movements are shown. Figure 42-a and Figure 42-b show the response of a s t i f f e r super structure frame system to la te ra l ground movements. The pictures show some evidence that the responses were mostly in the f i r s t and second modes and that rota tion al effects s t i l l occurred. The pictures in Figure 42-a and Figure 42-b were taken at 0.3 second intervals . Additional pictures taken during Experiment 5 are found in the Appendix. 95 1 2 3 4 5 Figure 40. Simplified ground waves transferred to the structure (super structure rigid frame) (1/2 cycle shown). Direction of ground movement = <---------. First Mode Second Mode Figure 41. Simplified responses of the structure (super structure rigid frame). Ratio between building and ground movement periods 2/ 1. Figure 42. Experiment 5. The response of a s t i f f e r super structure frame system to la te ra l ground movements. 98 ^ $e.coNP F ig u re 42-b. 100 Experiment No, 6 ( S tru c tu r e : S tru c tu re 3) O b jectives. To study the shear wall system in response to la te ra l ground movements and to study the relationship between the building and ground movement periods. Eva!uati on. (1) The structural model responded to harmonic la t e r a l ground movements mostly in the f i r s t mode; (2) the ro tation al e ffe c t barely occurred; and (3) the ra tio between the building's period and the ground movement's period was 4/1. Figure 43 shows the sim plified ground waves trans ferred to the structure in Experiment No. 6. Figure 44 shows the s im plified responses of the structure to the ground movements. Figure 45-a and Figure 4 5 - b show the response of a shear wall system to la te ra l ground movements. The pictures show some evidence that the responses were mostly in the f i r s t mode and that rotational effects barely occurred. The pictures in Figure 45-a and Figure 45-b were taken at 0.3 second in te rv a ls . Additional pictures taken during Experiment No. 6 are found in the Appendix. 101 1 2 3 ' 4 Figure 43. Simplified ground waves transferred to the structure (shear wall system) (1/2 cycle shown) Direction of ground movement = ^ --------. 103 Figure First Mode Second Mode 44. Simplified responses of the structure (shear wall system) Ratio between building and ground movement periods = 4/1. Figure 45. Experiment 6. The response of a shear wall system to la te ra l ground movements. 104 0*9 1-2 Figure 45-a. 105 a .j i ^ L o r\O b > Figure 45-b. 106 Experiment No. 7 ( S tr u c tu r e : S tr u c t u r e 4 ) O bjectives, To study the conventional rig id frame in response to la t e r a l ground movements and to study the relationship between the building and ground movement periods. I t should be noted here that the individual column size of structure 4 was determined by considering the moment i n t e r t i a of the individual column of structure 2 used in Experiment No. 5. Each column of the structure 2 was represented by four columns of structure 4. So moment i n e r t ia of the individual column of structure 4 was equal to 1/4 the moment i n e r t ia of the individual column of structure 2. Eva!uation. (1) The model responded in the f i r s t and second modes; (2) rota tion al effects occurred; and (3) the r a tio between the building period and the ground period equalled 2/1. Figure 46 shows sim p lifie d ground waves trans ferred to the structure; Figure 47 i l l u s t r a t e s the s im plified responses of the structure to the ground move ments . Figures 48-a and 48-b i l l u s t r a t e the response of a conventional structure rig id frame system to la te ra l ground movements. ( taken at 0.3 sec. in te r v a l s ) . See the appendix for additional pictures for Experiment No. 7. 107 108 2 1 5 4 3 Figure 46. Simplified ground waves transferred to the structure (conventional structure rigid frame) (1/2 cycle shown). Direction of ground movement = <c . 109 Second Mode First Mode Figure 47. Simplified responses of the structure (conventional rigid frame). Ratio between building and ground movement periods = 4/1. Figure 48. Experiment 7. The response of a conventional structure rig id frame system to la te ra l ground movemen t s . 110 Figure 48-a. 0 <\ Se£.oi>tD 111 CHAPTER V CONCLUSIONS AND RECOMMENDATIONS Having evaluated the data covering the experiments performed, the following conclusions are made: 1. The super structure of a rig id frame system generates higher modes, especially for higher ra tio between ground period and building periods. The higher that r a t i o , the higher is the response mode of the structure. 2. The rotational effects are most l i k e l y to occur in conventional rig id frame systems. The f l e x i b i l i t y of the system contributes a s ig n if ic a n t factor to the rotation or tw ist. 3. The shear wall system for the most part stays in the f i r s t mode in response to the ground movement. 4. The dampening location is best placed on the lowest le v e l. By locating the dampers on the lowest level where the highest shear force occurs, a high percentage of the energy caused by the ground movement is dissipated by the dampers. 5. By locating columns near the outer edges of the building, more s tiffn e s s in rotation w ill be obtained. The s tiffn es s of the building is related to the overall moment in e rtia in resisting bending or ro ta tio n , The higher the moment i n e r t i a , the s t i f f e r is the building in ro ta tio n . Thus, by separating columns away from the center of grav ity, a higher value of resisting moment of in e rt ia in terms of rotational resistance is obtained. The following are recommendations which summarize the findings of this study of high-rise structures: 1. I t would be reasonable to u t i l i z e a super structure frame. I t has greater stiffn e ss and could be considered as an a lt e r n a tiv e to the conventional system. 2. Diagonal dampening could be used e f f e c t i v e l y to reduce rotational and la te ra l d r i f t . The most e f fe c tiv e location of such dampeners would be at the f i r s t level rather than at other higher levels. 3. Higher mode response of rig id frame systems should be considered. 4. Pictures presented in this study would be useful as educational tools to v is ualize structural re sponse of high-rise buildings to la te ra l e arth quake forces . 114 REFERENCES Ambrose, J . , & Vergun, D. Simplified building design for wind and earthquake forces. New York, New York: Wiley, 1980. Guise, D. Design and technology in A rc h it e c t u r e . Toronto, Canada: Wiley & Son, 1985. Hart, F., Henn, W., & Sontag, H. M u lti-s to ry building in stee l. New York, New York: Nichols Publishing, In c ., 1985. O'Hare, M. Wind whistles through M .I .T . Tower, Progressive A rc h it e c t u r e , March 1967, pp. 169-171. P e l l i , C. Skyscraper, Perspecta, Sept. 1982, 18-19, 134-147. Rush, R. Structure and circumstance, Progres s i ve Archi t e c t u r e , December 1980, pp. 50-57. S chierle, G. Lightweight tension s t ru c tu re s . B e r k e1ey , C a lifo rn ia : U.C. Berkeley, 1968. Schueler, W. High rise building s t r u c t u r e . Malabar C ity , Florida, 1986. Yanev, P. Peace of mind in earthquake country. San Francisco, C a lif o r n ia : Chronicle, 1974. 115 APPENDIX Additional pictures of sim p lifie d responses of high-rise building structures to la t e r a l ground movements for Experiments 2 through 7. 116 3 *5 > <e^ l c t 4 U t £ 117 I 3^5. 5 & C O N P S 3 . C . & ^ 6 t 4 P ,& ■ ^ ^ p "' * ■ l ^ p , . . Q 4 - y f E h T ' ' - » l ' l : , , - - . v i- ... - I'? !' P^ - j ^ " H H I H H > y ■ , ^ I B H H R S H H E 3 ° ) I < 4 . 2 . & E . C & N P . & Experiment 3. 118 jfe 5 ? £ 3-t> £ A ^ S E ^»H P S , Experim ent 4. 119 120 J2. Jy 3^) ^E-CoMO^ Experiment 6. 121 Experiment s ' V , ft no no

Linked assets

University of Southern California Dissertations and Theses

Conceptually similar

PDF

Vibration reduction using prestress in wood floor framing

PDF

Return to the moon: MALEO, Module Assemby in Low Earth Orbit: A strategy for lunar base build-up

PDF

Investigation of sloshing water damper for earthquake mitigation

PDF

Passive cooling methods for mid to high-rise buildings in the hot-humid climate of Douala, Cameroon, West Africa

PDF

A proposal for the Indian National Lighting Code

PDF

Investigation of seismic isolators as a mass damper for mixed-used buildings

PDF

Computer aided design and analysis of anticlastic membranes and cable nets

PDF

From nescience to science and beyond: A critical investigation of 'building' in cyclone prone areas

PDF

Statistical analysis of the damage to residential buildings in the Northridge earthquake

PDF

Energy performance and daylighting illumination levels of tensile structures in an extreme climate

PDF

Terrace housing: A conscious solution

PDF

The Indian Himalayan building energy code as a step towards energy conservation

PDF

A computer teaching tool for passive cooling

PDF

A proposed wood frame system for the Philippines

PDF

Emergency shelter study and prototype design

PDF

Computer aided form-finding for cable net structures

PDF

Computer aided design and manufacture of membrane structures Fab-CAD

PDF

Computer modelling of cumulative daylight availability within an urban site

PDF

Computer aided value conscious design

PDF

DS(n)F: The design studio of the (near) future

Asset Metadata

Creator Irianto, Handy (author)

Core Title The response of high-rise structures to lateral ground movements

Degree Master of Science

Degree Program Building Science

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag engineering, architectural,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Schierle, Gotthilf Goetz (committee chair), Ambrose, James (committee member), Vergun, Dimitry K. (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c20-298825

Unique identifier UC11259059

Identifier EP41414.pdf (filename),usctheses-c20-298825 (legacy record id)

Legacy Identifier EP41414.pdf

Dmrecord 298825

Document Type Thesis

Rights Irianto, Handy

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA