FIGURE 1.1 Multistory rigid frame. ...2
FIGURE 1.2 Beam-to-column rigid connection: (a) beam-to-column flange; (b) beam-to-column web. ...3
FIGURE 1.3 Beam-to-column semirigid connection: (a) elevation; (b) plan. ...3
FIGURE 1.4 Beam–column subassemblage. H, floor to floor height; L, beam span. ...4
FIGURE 1.5 (a) Beam and column subassemblage restrained against sway, Δx. Slightest. deviation.of.column.from.a.straight.configuration.may.have.substantial. effect.on.column.stresses..When.column.reaches.the.critical.load,.the. bending.of.column.becomes.a.characteristic.sudden.buckling.mode. (b) Beam and column subassemblage unrestrained against sway lateral deflection (Δx ) causes additional moments in the subassemblage. (c) Portal method of lateral load analysis: Horizontal shear distribution in rigid frames of equal bays. (d) Cantilever method of lateral load analysis: Girders are assumed infinitely rigid, and axial forces in columns are assumed to be proportional to their distance from the frame centroid. ...5
FIGURE 1.6 Moment–rotation M–θ curves for PR connections. ...7
FIGURE 1.7 Classification of moment–rotation response of FR, PR, and simple connections. ..8
FIGURE 1.8 Beam-to-column field-bolted shear connection. (a) Elevation, (b) plan. ...9
FIGURE 1.9 Unstiffened seated beam connection. ...9
FIGURE 1.10 Beam line concept: Moment–rotation (M–θ) curves. ... 10
FIGURE 1.11 (a) Response of rigid frame to lateral loads. (b) Flexural deformations of beams and columns. (c) Typical early built-up and rivetted connection. (d) Rivetted, unstiffed seat angle connection. (e) Pre-Northridge moment connection (1970–1994): welded unreinforced flange-bolted web (WUF-B) moment connection. ... 12
FIGURE 1.12 Cantilever bending of rigid frame. ... 15
FIGURE 1.13 Shear racking of rigid frame. ... 15
FIGURE 1.14 Special truss moment frame. ... 16
FIGURE 1.15 Braced frame deformation: (a) flexural deformation; (b) shear deformation; (c) combined configuration. ... 18
FIGURE 1.16 Load path for horizontal shear through web numbers: (a) single diagonal bracing; (b) X-bracing; (c) chevron bracing; (d) single-diagonal alternate direction bracing; (e) knee bracing. ... 18
FIGURE 1.17 Gravity load path in braced frames: (a) single diagonal single direction bracing; (b) X-bracing; (c) single diagonal alternate direction bracing; (d) chevron bracing. ... 19
FIGURE 1.18 Bracing configurations. ...20
xxii List of Figures
FIGURE 1.19 Eccentric bracing system: (a–f) Links at one end of brace...22 FIGURE 1.20 Eccentric bracing configurations: (a and b) Links at each end of brace...23 FIGURE 1.21 Link rotation angle λp: This is related to the plastic story drift Δp, and is
strongly influenced by the link length. The limits of Vp are 0.08 and 0.02 radians for shear yielding and flexural yielding links. L = Bay width, H = Story height, Δp =.Plastic.story.drift.(conservatively,.may.be.taken.
equal.to.the.design.story.drift),.θp =.Plastic.story.drift.angle.=.Δp /H,
Vp = Link.rotation.angle...24 FIGURE 1.22 Schematics of link-to-column connection: note that beam-to-column
connections which qualify for use in an SMF may not necessarily perform adequately when used as a link-to-column connection in an EBF. Link-to-column connections must therefore be tested in a manner that properly simulates the forces and inelastic deformations expected in an EBF. ...25 FIGURE 1.23 Example of reinforced link-to-column connection. ...25 FIGURE 1.24 EBF with W-shape bracing. ...26 FIGURE 1.25 EBF with HSS bracing. ...27 FIGURE 1.26 (a and b) Key elevations of EBF. ...27 FIGURE 1.27 Detail A. ...28 FIGURE 1.28 Detail B. ...28 FIGURE 1.29 Main components of buckling restrained brace frames: (a and b) elevations;
(c) BRBF Chevron braces; (d) bracing components. Note: K and X-braces are not viable options for BRBF. ...29 FIGURE 1.30 Details of buckling restrained brace: (a) partial elevation of BRBF; (b) HSS
encasement and steel core; (c) section AA; (d) section BB; (e) section CC. ...30 FIGURE 1.31 Components of buckling restrained brace: (1) buckling restrained brace;
(2) core; (3) sleeve; (4) section. The yielding of core plates in compression without buckling results in a stable hysteric loop with excellent
energy-dissipating characteristics. ... 31 FIGURE 1.32 Steel plate shear wall. ... 32 FIGURE 1.33 Staggered truss system: (a) architectural floor plan; (b) arrangement
of staggered truss plan; (c) schematics. ...34 FIGURE 1.34 Staggered truss bracing for a rectangular building. ... 35 FIGURE 1.35 Staggered truss system for a circular building: (a) plan; (b) section A;
(c) section B. ...36 FIGURE 1.36 Conceptual model for staggered truss system: (a) building plan; (b) lateral
load transfer through diaphragm action. ... 37 FIGURE 1.37 Load path in staggered truss system... 37 FIGURE 1.38 Conceptual two-dimensional model for staggered truss system: (a and b)
lateral deformation of adjacent bays; (c) overall behavior. Note: the absence of local bending of columns. ... 38 FIGURE 1.39 Building plan showing core braces and perimeter rigid frames. ... 41
xxiii List of Figures
FIGURE 1.40 Building plan showing braced core and exterior/interior rigid frames. ... 41 FIGURE 1.41 Building plan showing core braces and outriggers... 42 FIGURE 1.42 Building plan showing full-depth interior K braces and exterior
moment frames. ... 42 FIGURE 1.43 Schematic section showing primary K brace and secondary core brace. ... 43 FIGURE 1.44 Interaction between braced and moment frames: (a) characteristic
deformation shapes; (b) variation of shear forces resulting from interaction. ... 43 FIGURE 1.45 Core and outrigger system: (a) centrally located core; (b) offset core. ... 45 FIGURE 1.46 Outrigger system with diagonal bracing. ...46 FIGURE 1.47 Moment-connected girders acting as outrigger. ...46 FIGURE 1.48 Building with central core and cap truss: (a) roof plan; (b) lateral
deformation; (c) curvature reversal due to tie-down action of cap truss. ... 47 FIGURE 1.49 Outrigger located at top: (a) analytical model; (b) deflected shape; (c and d)
moment diagrams. ... 49 FIGURE 1.50 Outrigger located at quarter-height from top: (a) analytical model;
(b) deflected shape; (c and d) moment diagrams. ...50 FIGURE 1.51 Outrigger located at mid-height: (a) analytical model; (b) deflected shape;
(c and d) moment diagrams. ... 51 FIGURE 1.52 Outrigger located at quarter height from bottom: (a) analytical model;
(b) deflected shape; (c and d) moment diagrams. ... 52 FIGURE 1.53 (A) Idealized analytical model of a single outrigger located at distance x
from top: (a) schematics; (b) analysis assumptions. (B) Single outrigger, analysis assumptions: (a) schematic section; (b) moment without outrigger;
and (c) moment with outrigger. ...54 FIGURE 1.54 Improved model of a single outrigger located at distance x from top:
(a) building plan and (b) schematic elevation. ... 56 FIGURE 1.55 Deflection index DI, versus outrigger level,
Note: DI Deflection at top without outrigger Deflection at top wi
= tth outrigger . ... 57 FIGURE 1.56 Building schematics with two outriggers. ... 59 FIGURE 1.57 Analytical model with two outriggers and belt trusses. ... 59 FIGURE 1.58 Conceptual method of analysis for two outrigger system: (a) two outrigger
structure; (b) external moment diagram; (c) M1 moment diagram; (d) M2
moment diagram; (e) core resultant moment diagram. ...60 FIGURE 1.59 Drift index verses belt and outrigger location. ... 61 FIGURE 1.60 Optimum location of outriggers: (a) single outrigger; (b) two outriggers;
(c) three outriggers; and (d) four outriggers. ... 62 FIGURE 1.61 Vulnerability of core and outrigger system to progressive collapse: (a) plan;
(b) schematic section; (c) elevation. ... 63
xxiv List of Figures
FIGURE 1.63 First Wisconsin Center, Milwaukee. ...65 FIGURE 1.64 One Houston Center, Houston, Texas. ...65 FIGURE 1.65 Framed tube: (a) schematic plan; (b) isometric view. ...66 FIGURE 1.66 Axial stress distribution in a square hollow tube with and without shear lag. ... 67 FIGURE 1.67 Axial stress distribution in tube structures neglecting shear lag effects:
(a) rectangular tube; (b) triangular tube; (c) circular tube. ...68 FIGURE 1.68 Free-form tubular configurations. ...69 FIGURE 1.69 Shear lag effects in tube structures: (a) cantilever tube subjected to lateral
loads; (b) shear stress distribution; (c) distortion of flange element caused
by shear stress. ... 70 FIGURE 1.70 Axial stress distribution. ... 70 FIGURE 1.71 Shear lag in framed tube. ... 71 FIGURE 1.72 Offset tubes: (a) semicircular tube; (b) rectangular tube with semicircular sides. ...72 FIGURE 1.73 Tube building with closely spaced diagonal columns. ... 73 FIGURE 1.74 (a) Tube building with multilevel diagonal bracing; (b) rotating tube with
super diagonals. ... 73 FIGURE 1.75 Bundled tubes. ... 74 FIGURE 1.76 Bundled tube behavior. ... 75 FIGURE 1.77 Structural concept for ultra-high-rise building. ... 76 FIGURE 2.1 Composite beam with formed metal deck: (a) schematic view; (b) section A. ...80 FIGURE 2.2 (a) Concrete encased composite column; design considerations. Note: Bond
and adhesion must be ignored in calculating shear transfer. (b)
Concrete-filled composite pipe column. ... 82 FIGURE 2.3 Japanese composite construction details: (a) beam column intersection;
(b and c) composite column with welded ties; (d) general view. ... 83 FIGURE 2.4 Bank of China, structural schematics: (a) elevation; (b–e) plans;
(f) photograph. ... 84 FIGURE 2.5 Reinforced concrete infill in steel frame: (a) elevation; (b) plan. ...84 FIGURE 2.6 Composite steel plate shear walls: (a) plan; (b) section; (c) and (d) shear wall
with single plate; (e) steel plate on both faces of wall; (f) and (g) concrete
wall with steel boundary elements. ...85 FIGURE 2.7 Composite shear wall with steel link beams: (a) plan; (b) elevation. ...87 FIGURE 2.8 Moment transfer between steel link beam and concrete wall. ...87 FIGURE 2.9 Composite moment frame. ...88 FIGURE 2.10 Spandrel beam-to-composite column connection: (a) plan; (b) elevation. ...88 FIGURE 2.11 Seismic tie-arrangement in composite columns: (a) rectangular column;
(b) circular column. ...90 FIGURE 2.12 Encased composite column; shear design parameters. ...90
List of Figures xxv
FIGURE 2.13 Composite concentrically braced frames: (a) V-bracing; (b) inverted V-bracing; (c) X-bracing; (d) diagonal bracing; (e) two-story X-bracing;
(f) zipper column with inverted V-bracing. ... 91 FIGURE 2.14 Composite concentric braced frame: Connection schematics; (a) plan;
(b) elevation. ...92 FIGURE 2.15 Examples of composite eccentrically braced frames. ...93 FIGURE 2.16 Schematic details of link beam: (a) link at center of beam; (b) link adjacent
to column. ...94 FIGURE 2.17 General construction sequence in composite structures...95 FIGURE 2.18 Typical floor plan, building with central core and steel surround. ...97 FIGURE 2.19 Core supported composite building: (a) concrete core; (b) core
with steel surround. ...97 FIGURE 2.20 Beam-to-shear wall connection: (A) embedded plate detail; (a) elevation;
(b) plan; (B) pocket detail. ...98 FIGURE 2.21 Typical floor plan showing interacting shear walls and moment frames. ...99 FIGURE 2.22 Composite tube building with concrete spandrels: (a) floor plan; (b) section
at spandrel; (c) photograph of composite column and concrete spandrel. ... 100 FIGURE 2.23 Composite tube building with steel spandrels: (a) floor plan; (b) section
at spandrel; (c) photograph of composite column and steel spandrel. ... 101 FIGURE 2.24 Vertically mixed system: Schematic perimeter framing. ... 101 FIGURE 2.25 Vertically mixed system: Schematic bracing. ... 102 FIGURE 2.26 Structural concept for a super tall building: (a) plan; (b) schematic
elevation; (c) interior schematics of mega module; (d) exterior schematics
of mega module. ... 103 FIGURE 3.1 Buckling of columns: (a) cantilever column; (b) bending of cantilever
column; (c) column with hinged ends; (d) column with built-in (or fixed) ends. ... 114 FIGURE 3.2 Buckling of cantilever column; energy method. ... 116 FIGURE 3.3 Euler stress Pcr/Ag versus KL/r. ... 118 FIGURE 3.4 Local buckling of steel sections. Notes: Steel section subjected to
compression from direct forces or flexure may be classified as compact, noncompact, or slender–element sections. For a section (such as an I or a box section) to qualify as compact, the flanges must be continuously connected to the web or webs and the width-thickness ratios of compression elements must not exceed a certain limiting width–thickness ratio, γp. If the width–thickness ratio of any compression element exceeds γp, but does not exceed the limit γr, the section is termed noncompact. Further, if the width-thickness ratio of any elements exceed γr, the section is referred to as slender–element compression section. Values of λp and λr for numerous cases are given in Table B4.1 and AISC specifications 2005. ... 120 FIGURE 3.5 Stress reduction factor Q versus slenderness. ... 121
xxvi List of Figures
FIGURE 3.7 Examples of built-up columns. ... 123 FIGURE 3.8 (a) Axial compression strength of selected W14 columns. (b) Axial
compression strength of selected W12 columns.. ... 125 FIGURE 3.9 Axial compression strength of selected HSS 7 × 7 and HSS 6 × 6 columns. ...127 FIGURE 3.10 Lateral torsional buckling of beams: (a) continuous beam with a uniformly
distributed load; (b) bending moment diagram showing positive bending
regions; (c) point of contraflexure. ... 128 FIGURE 3.11 Lateral buckling of beams: (a) continuous beam, uniformly distributed
load; (b) bending moment diagram; (c) portion of positive bending region;
(d) lateral-torsional buckling of I beam. ... 129 FIGURE 3.12 Concept of Lb, Length between points that are either braced against
lateral displacement of compression flange or braced against twist of the cross section: (a) lateral restraints limit effective length of compression flange; (b) effective lateral restraint must prevent translation of
compression flange. ... 130 FIGURE 3.13 Buckling of narrow deep beams: (a) simply supported beam subject
to moments M in the vertical plane; (b) plan showing lateral displacement of beam; (c) section showing lateral and torsional displacements. ... 131 FIGURE 3.14 Nominal flexural strength as a function of flange width–thickness ratio
of rolled I-shapes. ... 133 FIGURE 3.15 Nominal flexural strength as a function of unbraced length
and moment gradient. ... 134 FIGURE 3.16 Beam section showing area for the calculation of rt, the radius of gyration
used in determining Lp and Lr. ... 134 FIGURE 3.17 Design example: Transfer girder, unbraced top flange. ... 137 FIGURE 3.18 Moment Mu versus unbraced length. ... 138 FIGURE 3.19 Design example: plates in tension, bolted splice. ... 141 FIGURE 3.20 Design example: tension member—welded connection... 142 FIGURE 3.21 Design example: tension splice of truss bottom chord. (a) Elevation;
(b) cross section; (c) plan. ... 145 FIGURE 3.22 (a) Pin-connected tension member; (b) dimensional requirements
for pin-connected members. ... 146 FIGURE 3.23 (a) Eye bar tension members; (b) dimensional limitation for eye bars. ... 148 FIGURE 3.24 Shear buckling coefficient Cv for Fy = 50 ksi and kv = 5.0. ... 150 FIGURE 3.25 Moments in beam–columns: (a) column subjected to simultaneous axial
load and bending moments; (b) combined moment diagram; (c) moment
diagram due to equal end moments M0; (d) moment due to PΔ effect. ... 155 FIGURE 3.26 Behavior of building column: (a) building frame showing deflected
shape of column; (b) column subjected to simultaneous action of axial loads and moments; (c) moment diagram due to end moment
and PΔ effect. ...155
xxvii List of Figures
FIGURE 3.27 PΔ effects in laterally unbraced frames: (a) deflected shapes due to horizontal load H and vertical load P; (b) moment at column ends due to horizontal load H; (c) moment at column ends due to axial load P;
(d) maximum moment due to H and P occurs at the ends of columns
resulting in Cm = 1.0. ... 156 FIGURE 3.28 PΔ and Pδ effects in beam columns. ... 159 FIGURE 3.29 (A) Concept of notional load: (a) column with initial curvature;
(b) equivalent lateral load He. (B) Equivalent loading using notional loads to represent the effect of geometric imperfections of a column. (C) Residual Stresses: (a) hot-rolled shapes; (b) welded box sections; (c) I-shape
fabricated from flame-cut plates. Note: + indicates tension; − indicates
compression. ... 160 FIGURE 3.30 Frame model to illustrate effects of leaning column. ... 162 FIGURE 4.1 Components of composite floor system: (a) schematics showing metal deck
perpendicular to beam; (b) section. ... 168 FIGURE 4.2 Typical composite metal deck profiles. ... 168 FIGURE 4.3 Three types of composite beams addressed in the AISC manual: (A) fully
encased steel beam; (B) concrete filled HSS; (C) steel beams with mechanical anchorage to slab. (a) Metal deck parallel to beam; (b) metal
deck perpendicular to beam; (c) cast-in-place slab without metal deck. ... 171 FIGURE 4.4 Relative shear strength of shear connectors: (a) narrow rib deck;
(b) wide rib deck; (c) equivalent portal frame. ... 172 FIGURE 4.5 Composite beam with deck ribs perpendicular to beam: (a) schematic view;
(b) section showing equivalent thickness of slab... 174 FIGURE 4.6 Composite beam with deck ribs parallel to beam: (a) schematic view;
(b) section. ... 175 FIGURE 4.7 Possible stud positions: (a) weak position; (b) strong position. Note that
AISC sets the default value for shear strength equal to that for the stud
weak position. ... 177 FIGURE 4.8 Shear connector arrangements: (a and b) plans; (c) section. ... 177 FIGURE 4.9 Composite beam, AISC requirements: (a) deck perpendicular to beam;
(b) deck parallel to beam. Note: Dimension and clearance restrictions
shown in either (a) or (b), apply to both unless noted. ... 178 FIGURE 4.10 Effective width concept as defined in the AISC 360-05/10 specifications... 179 FIGURE 4.11 Composite beam: (a) partial framing plan; (b) section. ... 184 FIGURE 4.12 Composite truss: (a) floor framing plan; (b) section A; (c) Vierendeel panels. ...187 FIGURE 4.13 Examples of composite floor trusses: (a–e) elevations. ... 188 FIGURE 4.14 Composite truss schematic sections: (a through c) top and bottom chords
with gusset plates; (d through f) top and bottom chords without gusset plates. .. 188 FIGURE 4.15 Composite beam with flat soffit reinforced concrete slab... 189
xxviii List of Figures
FIGURE 4.17 Semi-rigid composite beam-to-column connection. ... 190 FIGURE 4.18 (A) Plastic stress distribution for negative moment: (a) composite beam
section; (b) plastic neutral axis, PNA, in steel beam web; (c) PNA in beam flange. (B) Plastic stress distribution for positive moment: (a) plastic neutral axis, PNA, in concrete slab; (b) PNA in steel beam flange; (c) PNA in steel beam web. ... 191 FIGURE 4.19 Schematic floor plan showing haunch girders. ... 192 FIGURE 4.20 Composite girder with tapered haunch. ... 193 FIGURE 4.21 Composite girder with square haunch. ... 193 FIGURE 4.22 Stub girder framing: (a) framing plan; (b) elevation of stub girder SG-1;
(c) section A through stub girder; (d and e) photographs. ... 194 FIGURE 4.23 (a) Elevation of Vierendeel truss analytical model; (b) partial detail of model. ... 196 FIGURE 4.24 Cross section of equivalent compression chord. ... 199 FIGURE 4.25 Encased composite column. ...202 FIGURE 4.26 Filled composite column. ...205 FIGURE 4.27 Composite column interaction diagram: (a) column detail; (b) interaction
diagram...209 FIGURE 4.28 Interaction diagram for beam-column design. ... 210 FIGURE 5.1 Wind velocity profiles: (a) ASCE 7-05 wind velocity profiles; (b) variation
of mean and gust speed versus height; (c) variation of mean and gust speed over time t. Note: Vz = mean wind (also denoted as v), Vzl = gust speed. ... 214 FIGURE 5.2 Simplified 2D wind flow consisting of along-wind and across-wind. ... 216 FIGURE 5.3 Vortex shedding: Periodic shedding of vertices generates building
vibrations transverse to the direction of wind. ... 216 FIGURE 5.4 Wind speed map for the United States and Alaska. Map of (a) the United
States. (b) Western Gulf of Mexico hurricane coastline (enlarged).
(c) Eastern Gulf of Mexico and Southern United States hurricane coastline (enlarged), (d) Mid- and North-Atlantic hurricane coastline (enlarged). ...220 FIGURE 5.5 Topography factor kzt. ...224 FIGURE 5.6 External pressure coefficient Cp with respect to plan aspect ratio L/B:
(a) 0 ≤ L/B ≤ 1; (b) L/B = 2; (c) L/B > 4. Note: Linear interpolation
permitted. ...226 FIGURE 5.7 Schematic building elevations showing variation of Cp. ...226 FIGURE 5.8 Leeward suction Cp versus plan aspect ratio L/B. ... 227 FIGURE 5.9 Schematics of wind tunnels. ... 235 FIGURE 5.10 Rigid pressure model. ...236 FIGURE 5.11 Model in wind tunnel. ...236 FIGURE 5.12 High-frequency force balance model. ... 237
List of Figures xxix
FIGURE 5.13 Aeroelastic model. ... 237 FIGURE 6.1 Time-load functions. (a) Unit impulse force, (b) step force, (c–d) ramp or
linearly increasing force, (e) triangular pulse force, and (f) half-cycle sine pulse force. ...248 FIGURE 6.2 Dynamic response of a cantilever. Note: DLF = 2 for suddenly applied
point load. ...248 FIGURE 6.3 Vibrations of one-degree-of-freedom system: (a) undamped; (b) damped. ...249 FIGURE 6.4 Maximum response of one-degree elastic systems (undamped) rectangular
and triangular pulses having zero rise time. Note: T = period of
one-degree-of-freedom system and td = pulse duration. ...250 FIGURE 6.5 Cantilever column with weight at top. ... 251 FIGURE 6.6 Acceleration response spectrum. ... 251 FIGURE 6.7 Dynamic response showing deflection load factor, DLF, for undamped
SDF system to step-force with finite time: (a) T Tg/ B= 0 2. ; (b) T Tg/ B= 2 5. .
Note: DLF is 2 for 1 s gust and 1.0 for 12.5 s gust. ...254 FIGURE 6.8 Portal frame subject to static loads. Note: F = Ky, K = 24EIc/h3. ... 255 FIGURE 6.9 Portal frame subject to earthquake ground motions. ... 255 FIGURE 6.10 Example of portal frame subject to ground motions. (a) Portal frame,
(b) acceleration spectrum, and (c) tripartite (DVA) spectrum. ... 257 FIGURE 6.11 Idealized single-degree-of-freedom system. ... 258 FIGURE 6.12 D’Alembert’s principle of dynamic equilibrium: (a) Portal frame subject
to dynamic force Ft; (b) equivalent dynamic model; (c) free-body diagram. ... 259 FIGURE 6.13 Concept of free vibrations. ... 259 FIGURE 6.14 Displacement plot of free vibrations with damping. ...260 FIGURE 6.15 Portal frame subject to ground motions. ... 262 FIGURE 6.16 Equivalent load-time function due to base motions. ... 262 FIGURE 6.17 Numerical integration results. ...264 FIGURE 6.18 (a) Dynamic response of portal frame showing plot of displacement versus
time. (b) Numerical integration, lumped-impulse procedure. ...265 FIGURE 6.19 Graphical description of response spectrum. ...268 FIGURE 6.20 (a and c) Concept of response spectrum; (b and d) pendulums of varying
heights representing progressively taller buildings. ...269 FIGURE 6.21 Acceleration response spectrum: El Centro earthquake. ...269 FIGURE 6.22 Examples of SDOF systems: (a) elevated water tank and (b) restaurant
atop tall concrete core. Note from Figure 6.21, the acceleration = 26.25 ft/s2 for T = 0.5 s and β = 0.05 (water tank) and the acceleration = 11.25 ft/s2
for T = 1.00 s and β = 0.10 (restaurant). ...270
xxx List of Figures
FIGURE 6.24 (a) Ground acceleration; (b) deformation response of three SDOF systems with β = 2% and Tn = 0.5, 1, and 2 s, and (c) deformation response spectrum for β = 2%. ... 274 FIGURE 6.25 Response spectra (β = 2%) for El Centro ground motion: (a) deformation
response spectrum, (b) pseudo-velocity response spectrum,
and (c) pseudo-acceleration. ... 274 FIGURE 6.26 Pseudo-acceleration response of SDOF systems to El Centro ground motion. ....276 FIGURE 6.27 Combined DVA response for El Centro ground motion; β = 2%. ...277 FIGURE 6.28 Tripartite response spectrum... 278 FIGURE 6.29 Velocity, displacement, and acceleration read out from response spectra. ... 279 FIGURE 6.30 Idealized response spectrum for El Centro ground motion. ...280 FIGURE 6.31 Schematic response of rigid and flexible systems: (a) Rigid system,
acceleration at top is nearly equal to the ground acceleration; (b) flexible
system, structural response is most directly related to ground displacement. ... 281 FIGURE 6.32 (a) Comparison of design and actual response spectra. (b) Concept
of effective modal masses and effective modal heights. ... 282 FIGURE 6.33 Idealized steel portal frame subject to load P at top. ...284 FIGURE 6.34 Displacement plot of load P versus displacement x. ...284 FIGURE 6.35 Plot of idealized displacement x versus load P: observe the curved portion of
Figure 6.34 is replaced by straight lines depicting bilinear inelastic behavior. ... 284 FIGURE 6.36 Elastoplastic hysteresis loop. ...285 FIGURE 6.37 Rigid-plastic hysteresis loop. ...285 FIGURE 6.38 (a and b) Building behavior during earthquakes. ...287 FIGURE 6.39 Schematic magnitude of seismic force. Note: The magnitude of
seismic force depends on the building mass M, ground acceleration a,
and the dynamic response of the building itself. ... 289 FIGURE 6.40 Reentrant corners in L-, T-, and H-shaped buildings. (As a solution, add
collector elements and/or stiffen end walls A, B, C, D, E, F, G, H, and J.)...292 FIGURE 6.41 Plan irregularities: (a) geometric irregularities, (b) irregularity due to
mass-resistance eccentricity, and (c) irregularity due to discontinuity in
diaphragm stiffness. Note: CR, center of resistance, CM, center of mass. ... 293 FIGURE 6.42 Elevation irregularities: (a) abrupt change in geometry, (b) large difference
in floor masses, and (c) large difference in story stiffnesses. ...294 FIGURE 6.43 Hysteric behavior: (a) curve representing large energy dissipation
and (b) curve representing limited energy dissipation. ... 295 FIGURE 6.44 Examples of nonuniform ductility in structural systems due to vertical
discontinuities. ...296 FIGURE 6.45 Concept of 100% g. A building subjected to 1g acceleration conceptually
behaves as if it cantilevers horizontally from a vertical surface. Note: This is not a misprint! ...297
List of Figures xxxi
FIGURE 6.46 Linear viscous damper; damping is defined as a force that resists dynamic motion. A simple and yet realistic damping model for analysis purposes is to assume that the damping force, fD, is proportional to viscous friction of a fluid in a dash pot, and therefore it is called viscous damping. ... 298 FIGURE 6.47 Force displacement hysteresis loop: the area inside of the loop is a
measure of energy dissipation due to nonelastic behavior. Note: Ke = initial elastic stiffness, Kp = stiffness in the plastic range, Fy = stress at yield,
Dy = deformation at yield. ... 298 FIGURE 6.48 Relative effects of diaphragm stiffness. ...300 FIGURE 6.49 (a) Diaphragm action of floor or roof system. Note: VLLR,
vertical–lateral-load-resisting system. (b) Schematic drag and chord
for north-south seismic loads. ... 301 FIGURE 6.50 Diaphragm web failure due to large opening. ... 301 FIGURE 6.51 MCE ground motion for 0.2 s period. Spectral response acceleration, Ss,
as a percent of gravity, Site Class B, 5% critical damping. ...304 FIGURE 6.52 MCE ground motion for 1.0 s period. Spectral response acceleration, S1,
as a percent of gravity, Site Class B, 5% critical damping. ...305 FIGURE 6.53 Tributory weights for seismic dead load calculations. ...307 FIGURE 6.54 Generic design response spectrum. ...309 FIGURE 6.55 Response spectrum for a specific site in Los Angeles, CA, latitude 34°3′N,
longitude 118°14′W, Site Class D. ...309 FIGURE 6.56 Response spectrum for a specific site in Boston, MA, latitude 42°22′N,
longitude 71°2′W, Site Class D. ... 310 FIGURE 6.57 (A) Response spectrum for a specific site in Seattle, WA, latitude 47°39′N,
longitude 122°18′W, Site Class D. (B) (a) Different systems along two orthogonal axes; use corresponding R value for each system. (b) Different systems over the building’s height. Response modification coefficient, R, for any story above, shall not exceed the lowest value, in the direction
under consideration. ... 311 FIGURE 6.58 (A) (a) Highly redundant building and (b) not-so-redundant building.
(B) Column deformation for use in compatibility considerations.
(B) Column deformation for use in compatibility considerations.