64 STORY STEEL OFFICE TOWER
1. Building Description and Loading 
The lateral force resisting elements of this 64 story structure
consist of moment- resisting steel frames on the perimeter
and concrete shear walls in the centre. Composite beams
with 1.5" deck and 2.5" slab make up the floor systems.
The building elevations are shown in Fig. A and the typical
floor plan is shown in Fig. B.
Superimposed floor dead load is 25 psf and floor live 70
psf, except in the elevator core area where it is 120 psf.
The curtain wall load is 350 plf. Wind pressure is as per
ANSI standard for 90 mph velocity. The structure was designed
in accordance with the American Institute of Steel Construction
"LRFD Specification for Structural Steel Buildings". Table
of properties of large built-up shapes were input to supplement
the standard shapes. By taking advantage of the AMECO-17
symmetry commands, only one half of the structure was designed.
The input commands for AMECO-17 to design the structure
are shown in Fig. C. Once the framing scheme was selected,
it took 4 hours to prepare this input. No member sizes had
to be inputted, no loads had to be manually calculated,
no loading cases or combinations had to be specified. Basically,
only
loading parameters and member connectivities and member
spans had to be specified. AMECO-17 generates a rigid floor
diaphragm at each level, unless otherwise specified.
If you wish to familiarize yourself with the basics
of the AMECO-17 input language, it would be helpful to read
the next section. Otherwise, proceed to section 3.
2. Input Command Description (see Fig. C.1 and C.2)
After the 7 Job Title Statements, general data for the
entire structure is entered.
AMECO STEEL and USE CODE AISC-93 LRFD commands load the
AMECO STEEL system and the American Institute of Steel Construction
"Load and Resistance Factor Design Specifications" and the
table of steel shapes made in USA.
USE STEEL 50000, LLR UBC specifies steel yield strength
of 50,000 psi and Live Load Reduction procedure according
to the Uniform Building Code.
USE CONSTRUCTION SIMULATION EVERY 2 LEVELS erects the structure
2 levels at a time.
The next two SUPPRESS commands are entered for tall structures
to avoid premature global buckling collapse during the first
design cycle. Then the ANSI wind load is specified. The
bay width was manually adjusted, since only half of the
structure is analysed. COMPUTE COSTS, CONCRETE 500 overrides
AMECO current concrete cost of $160.00/cyd.
RESTRICT DRIFT TO MAX H/150 overrides AMECO default value
of 250. USE FRAME ACCURACY 0.5 forces the iterative analysis
process to continue until at all joints the unbalanced moments
and forces are less than 0.5 k-ft.
CYCLE MAX 3 limit global analysis/design
cycles to maximum 3.
After the three LIST commands, requesting certain result
files, TRACE FRAME STATICS checks statics at each floor
level; compares applied lateral loads to developed shears
and shows the difference in percent. The difference normally
is the second order analysis effect.
All data input into AMECO-17 is entered by floor levels,
starting from the top level.
LEVEL 64 TO1. The input data for the 64 levels is the same.
After the structure is stored, it can be modified on any
level see Fig. C.2.
DESIGN BEAMS - select beam sizes. USE SLAB 2.5 etc. specifies
2.5" slab over 1.5" steel deck and floor projection of 16"
around the perimeter of the building.
USE FLL 70 FDL 25, SPANS 28 specifies floor live load of
70 psf and dead load of 25 psf. 28' span is to be used,
until another value is entered, USE SHAPES W BI, where W
means WF shape and BI means built-up shape of "I" shape
and BB built-up box shape. Table of large built-up shapes
(BI and BB) were input to supplement the standard American
shapes see Fig. D. RESTRICT DEPTH TO MIN 10 sets 10"
as minimum depth for beams. Beams are entered on the next
8 input lines. Beam marks are prefixed with the letter B.
For beams
202 and 204, 14' span is entered to override the 24' value
given in the command. Floor live load, FLL 120, is entered
for 202 and 203.
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PROJECT- CHICAGO LAKESIDE CORPORATION
FILE - CHICAGO64.DAT
CLIENT- OLIMPIA AND YORK DEVELOPMENTS LTD.
STRUCTRE- 64 STOREY SKYSCRAPER
JOB 800421
INPUT HB/FB
REVISION B
$
AMECO STEEL
USE CODE AISC-93 LRFD,
USE STEEL 50000, LLR UBC
USE CONSTRUCTION SIMULATION EVERY 2 LEVELS
SUPPR SIZE DECREM CYCLE 1
SUPPRESS NONLINEAR ANALYSIS CYCLE 1
COMPUTE WL XFORCES PER ANSI, VELOCITY 90, BAY 14.0
COMPUTE WL YFORCES PER ANSI, VELOCITY 90, BAY 24.5
COMPUTE COSTS,CONCRETE 500
RESTRICT DRIFT TO MAX H/150
USE FRAME ACCURACY .5
CYCLE MAX 3
$
LIST ALL
SUPPR LIST BEAM DESIGN
LIST FRAME FORCES WL LEVELS 1 6 20 21 22 40 64
TRACE FRAME STATICS
$
LEVELS 64 TO 1
DESIGN BEAMS
USE SLAB 2.5 DECK 1.5 FL PROJECTION 16
USE FLL 70 FDL 25,SPANS 28
USE SHAPES W BI
USE COMPOSITE IF RG LE .4 PARTIAL, UNSHORED
SELECT SIZE VARIABLE
B101 TO 104 B201 B202 14 FLL120 B203 FLL120 B204 14 B205
LIST BEAM DESIGN
B1201 TO 1204
B301 3(7 203) B303 3(7 204) B302 DUMMY B401 TO 404
B501 WALL502 14 301 14 802R 14 303 56 THICK 36 B503
B601 WALL602 14 302 28 304 56 THICK 36 B603
B701 3(7 102) B702 7 102 7 1202 7 102 B703 3(7 202)
B1301 3(7 104) B1302 7 104 7 1204 7 104 B1303 3(7 205)
B801 3(7 103) B802 3 103 3 1203 3 103
USE SPAN 14, RG 1
RESTRICT DEPTH TO MIN 21
SELECT SIZE CONSTANT;
USE DL W 0.35
B901 TO 904 7 101 B905 TO 906 7 201
B1001 TO 1004 7 104R B1005 TO 1006 7 205R
B1101 RGL 0 FL FS 3-6 B1102 TO 1107 FL FS 3-6
B1108 RGR 0 FL FS 3-6
$
DESIGN COLUMNS,L 12-0
USE COL SHAPES W BI BB; RESTRICT XDIM TO MIN 16
EQUATE COLUMNS 1 TO 7, 43 TO 49
EQUATE COLS 14 16 23 25 39 32 41
SPLICE COLUMNS EVERY 4 LEVELS
C1 TO 7 901 1101 101 401 1201 501 201 601
C16 TO 19 701 1103 402 C14 0 1102 C23 0 1104
C25 TO 26 801 1104R 402R
C32 TO 35 1301 1107 404 503 603 $
C39 0 1106 C41 0 1108
C43 TO 49 1001 1108R 104R 404R 1204R 503R 205R 603R $
C14 TO 16 EV 2 BETA 90
C23 TO 25 EV 2 BETA 90
C39 TO 41 EV 2 BETA 90
C32 BETA 90
$
USE YSYM 7 19 28 35 49
SUPP X Y DISPL TO LEVEL 5
FRAME X 1 16 32 43
FRAME Y 1 3 5 7
$
EXECUTE
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B701 3(7 104) connects at 3 spaces of 7' left end of beam
102 to beam 701. It also connects right end of beam 101
to 701. This illustrates how secondary beams are connected
to primary beams.
All beams are assumed to be in horizontal plane and parallel
either to the global X and Y- axis, unless otherwise specified.
Similarly, columns and walls are assumed to be vertical.
USE SPAN 14, RG 1 sets spans from now on to 14' and beam
end connection fully rigid (RG 1). By default, steel beam
end connections are pinned (RG 0).
SELECT SIZE CONSTANT - use the same size in all spans of
a beam line, e.g. select same size profile for line 9, i.e.
for beams 901 to 906, also for lines 10 and 11. USE DL W
0.35 applies 0.35 k/ft curtain wall load on beam lines 9,
10 and 11.
B1108 RGR 0 makes right end of beam pinned. FL FS 3-6 sets
floor width on far side to 3'-6".
DESIGN COLUMNS, L 12-0 select column sizes and set all
columns 12' long, i.e. set the story height to 12'.
USE SHAPES W BI BB; RESTRICT XDIM TO MIN 18 - use any of
the 3 shapes, but not less than 18" in depth.
EQUATE COLUMNS 1 TO 7, 43 TO 49 select the same size for
this group of 14 columns.
SPLICE COLUMNS EVERY 4 LEVELS equates the columns in the
vertical direction.
C1 TO 7 901 1101 etc. connects to columns 1 to 7 beams starting
with 901 in X-direction and beams 1101 101 401 1201 501
201 601 in the Y- direction.
C32 BETA 90 turns the web of column 32 parallel to Y- axis.
USE YSIM 7 19 35 49 sets Y axes of symmetry through the
four columns.
SUPPR X Y DISPL TO LEVEL 5 anchors the structure laterally
up to level 5.
FRAME X and Y commands assemble the structure for 3D analysis.
3. Analyses and Design Process
Based on the input commands of Fig. C, AMECO-17 generates
the geometry in 3D, initializes member sizes, models joints,
calculates floor dead and live loads on each member, calculates
wind forces, sets up loading cases and combinations and
through a cyclic analysis/design process designs the whole
structure. For this structure the AMECO-17 design execution
time was 96 seconds on a 1.2 GHz PC. It took 14 man-hours
to prepare the input, execute AMECO-17 and review the Design
Results.
Fig. E
AMECO-17 Cyclical Process
4.
Analysis and Design Results
In this section, representative pages are displayed
out of the total of 1,224 Design Result pages.
The sign conventions and units used to display design results
are the same as used in manual design practice. For example,
a negative moment in a beam produces tension in the top
fibers; a compression force is positive; a downward displacement
is positive; member forces and moments are in ft.kip units;
stresses in kips/sq.in.; floor and wall areas in sq.ft.;
member cross-section dimensions and displacements are in
inches. Similar compliance to manual practice is followed
for designs executed in SI units.
Steel shapes made in USA, supplemented by the shapes shown
in Fig. D, were used to design the structure.
To facilitate the reviewing of lateral load analysis,
the frame analysis results (item 2) are presented vertically
plane by plane. Moments are given at the center of joints,
which in member design tables are modified to the face of
finite joints. Member design tables (items 3 to 6) are listed
by floor levels.
The Design Results are listed in nine separate files as
named below: For the files 2. to 6., only typical pages
are shown:
1. Principal Design Parameters
2. Frame Analysis Results
3. Beam Schedules
4. Beam Design Results
5. Column Design Tables
6. Shear Wall Design Tables
7. Bill of Materials
8. Cost of Construction
9. Dayfile Execution Times
Download
this page in PDF format. The PDF includes selected parts
of the Design Result Files.
