CEE598_Gummaraj_Bharath_Final_Project

12/6/2016
CIVIL, ENVIRONMENTAL AND SUSTAINABLE ENGINEERING
SCHOOL OF SUSTAINABLE ENGINEERING AND THE BUILT ENVIRONMENT
CEE598 – STRUCTURAL DAMAGE
EVALUATION AND STRENGTHENING
FALL 2016
FINAL PROJECT ON “STRUCTURAL
STRENGTHENING”
BHARATH GUMMARAJ
ASU ID - 1209909997

CEE598 – FALL 2016 Final Project
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CONTENTS
LIST OF FIGURES ........................................................................................................................ 2
1. PROBLEM STATEMENT..................................................................................................... 3
2. BUILDING CODES............................................................................................................... 6
3. SOFTWARE HELP................................................................................................................ 6
4. APPLIED LOADS.................................................................................................................. 6
5. INITIAL DESIGN .................................................................................................................. 8
A. CANOPY ......................................................................................................................... 8
B. BUILDING....................................................................................................................... 9
6. STRENGTHENING DESIGN................................................................................................ 9
A. CANOPY ......................................................................................................................... 9
I. BEAM B1......................................................................................................................... 9
II. BEAM B2................................................................................................................... 11
B. BUILDING..................................................................................................................... 14
I. TRUSSES....................................................................................................................... 14
II. STEEL I BEAM ......................................................................................................... 15
7. NDT METHODS.................................................................................................................. 19
A. COVER METER............................................................................................................ 19
B. GROUND PROBING .................................................................................................... 19
8. CONCLUSIONS................................................................................................................... 20
9. REFERENCES ..................................................................................................................... 21

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LIST OF FIGURES
SL NO DESCRIPTION
1 View from South-West Direction
2 View from North-East Direction
3 View from West Direction
4 Framing Key plan
5 Wind Loads for Partially Enclosed Structure
6 Wind Loads for Enclosed Structures
7 Beam B1 Design
8 Beam B2 BMD
9 Beam B2 Design
10 Beam B2 Equivalent Section
11 Nail Capacity table from ESR1639, Page 5
12 Truss Load Table from Vulcraft
13 Live Load Reduction
14 Steel I Beam BMD
15 Steel I Beam Design
16 Steel I Beam Equivalent Section
17 Ground Probing Method

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1. PROBLEM STATEMENT
A one storied masonry structure with a built up roof deck, SSMA Studs as joists, Open web K-
Series trusses, steel beams and column with a Canopy made of Wood joists and beams with steel
column, located in the city of Mesa, Arizona. The structure is built without structural design and
without permit from city council.
To obtain permit from city, the structure need to meet loading conditions governed by design
codes. Owner need help of structural engineer to reanalyze all the structural components to make
sure it meets codal requirements and to provide strengthening if required.
Figure 1. View from South-East direction

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Figure 2. View from North-East direction
Figure 3. View from West direction

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Figure 4. Framing Key Plan

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2. BUILDING CODES
Governing codes for city of Mesa, IBC 2006, NDS 2005, AISC 360-05, CBC 2007 for gravity
loads and ASCE 7-05 for Wind Loads. Seismic load is not applicable.
3. SOFTWARE HELP
ENERCALC is used for initial Analysis, strengthening design and to find wind loads acting on
enclosed building.
ENGINEERING INTERNATIONAL is used to find wind loads on partially enclosed building.
4. APPLIED LOADS
 Gravity Loads –
 7psf Dead Load(DL) & 20psf Roof Live Load(LR) for Canopy.
 9psf Dead Load(DL) & 20psf Roof Live Load(LR) for Building.
 Wind Loads – Risk category II, Exposure C, Basic wind speed 90mph.
 14.88psf uplift pressure for Canopy. (See Figure 5)
 15.49psf for Building. (See Figure 6)

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Figure 5. Wind Loads for Partially Enclosed Structure

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Figure 6. Wind Loads for Enclosed Structure
5. INITIAL DESIGN
Top Down, Bottom Up process is used, i.e., structure is designed from top to bottom and
construction is carried out from bottom to top.
For the current project, design is divided into two parts. One for the Canopy and another for the
building.
A. CANOPY
Site Notes –
 Roof – 22Ga ‘B’ Deck
 Joists – 2x3 DF#2 @ 2’9” O.C.
 Beams –
 B1 – 2x6 DF#2 @ 2’8” O.C.
 B2 – 4x6 DF#2 Carrying B1’s and bearing on column.
 B3 – 2x6 DF#2 Ledger beam
 Column – HSS 2.375x0.125 Circular Column.

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 Base Plate – 10”x10”x3/8” with (4) 5/8” φ A.B.
 Foundation – Need to be verified.
After initial analysis, it is found that Deck, Joists, Beam B3, Column and Base plate works under
given loads.
Beams B2 & B3 needs strengthening.
B. BUILDING
Site Notes –
 Roof – Built up roof system with 22Ga ‘B’ Deck as roof diaphragm.
 Joists – 400S200-68 SSMA studs @ 5’ O.C.
 Beams –
 B1 – 14” deep Open Web K-Series trusses
 B2 – W6x12 Steel Beam Carrying B1’s and bearing on Column.
 Column – W6x12 Steel Column.
 Base Plate – 12”x12”x1/4” with (4) 5/8” φ A.B.
 Walls – 8” thick CMU. Grouting need to be verified.
 Foundation – Need to be verified.
After initial analysis, it is found that Deck, Joists, Column, Base plate and wall works under given
loads.
Trusses, Beam B2 need strengthening.
6. STRENGTHENING DESIGN
A. CANOPY
I. BEAM B1
Span = 13’9”, Trib Width = 2’8”, Deflection Limit – L/180 for live load and L/120 for Total load.
W = (7psf DL + 20psf LR) x 2’8”
= (18.69plf DL + 53.4plf LR) + Self Weight

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Beam is 42.8% overstressed in bending and deflections are out of bounds. Hence the beam need
to be strengthened in flexure.
There are two ways to strengthen the beam. One approach is to attach another member to existing
member and another one is to double the number of beams since beam is overstressed by < 100%.
Connecting another member to existing member need another design of connections which is
difficult to provide and also uneconomical Compared to doubling the number of beams.
Hence, the latter option is chosen as the strengthening method. i.e., Provide 2x6 DF#2 @ 1’4”
O.C. Instead of 2’8” O.C. i.e., reduce the Trib width by half.
Figure 7. Beam B1 Design

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II. BEAM B2
W = (7psf DL + 20psf LR) x 6’10”
= (48.125plf DL + 137.5plf LR) + Self Weight
Beam is 114.2% overstressed in bending and deflections are out of bounds. Hence the beam need
The reason why, this beam has not cracked, even if it is more than 100% overstressed, is because
it has never seen its design live load and wind loads.
There are again two ways through which beam can be strengthened. One is to attach a new member
at the bottom of the beam or another is to attach a new member through side lap arrangement.
The former process is an expensive one since connectors need to be provided for tying wood beams
together. In the latter method beams can be nailed together. Which is an economical process
compared to the other, hence Side lap arrangement is chosen as the strengthening method,
Applied Moment - 8 K-ft, Allowable Moment – 5.22 K-ft.
Figure 8. Beam B2 BMD
From BMD, it can be seen that Applied moment exceeds allowable moment from a distance of 3’
up to a distance of 12’ from left support. Hence, beam need to be strengthened to a span of 12’, 3’
away from each support.

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Figure 9. Beam B2 Design
Beam that satisfies the applied loads is found to be 4x10 DF#2.
Approach is to find an equivalent section with existing 4x6 DF#2 whose section properties are
comparable with 4x10 DF#2.
Section Properties of 4x10 DF#2 – Ixx = 230.84 in4
and Sx = 49.91 in3
.
By trial and error, the equivalent section is found to be (2)2x10 DF#2 with existing 4x6 DF#2.
Whose section properties are, Ixx = 286.347 in4
and Sx = 53.096 in3
(See figure 10). Which is more
than that of 4x10 DF#2. Hence the Bending capacity of equivalent section is more than that of
4x10 DF#2. Therefore, (2)2x10 DF#2 are attached to existing beam 3’ away from each support.

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Figure 10. Beam B2 Equivalent Section
Connections – The beams have to be connected to resist a maximum shear of (W*L)/2 = 1400 lb.
Shear capacity of each 10d nail is 118 lb (See figure 11).

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Figure 11. Nail Capacity Table from ESR 1539, Page 5
Therefore # of nails required = 1400/118 = 12 Nails.
Spacing of nails = 15’/12 = 1.25’.
To be conservative, provide 10d nails @ 1’ O.C. Staggered on both sides.
B. BUILDING
I. TRUSSES
Span = 38’0”, Trib Width = 8’0”
W = (9psf DL + 20psf LR) x 8’0”
= (72plf DL + 160plf LR) + Self Weight
From Load Tables provided by truss manufacturer Vulcraft, minimum depth of trusses spanning
38’ id 20”. Existing load 232plf < 279plf. Hence, use 20K9 open web joist Truss. (See figure 12)

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Figure 12. Truss load tables from Vulcraft
II. STEEL I BEAM
Tributary area is 19x19 = 361 ft2
> 200 ft2
LR reduction can be used.
Reduced LR is found to be 16.78psf (See figure 13).

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Figure 13. Live Load Reduction
W = 9psf DL + 16.78psf LR) x 19’0”
= (171plf DL + 318082plf LR) + Self Weight
Beam is found to be 22.4% overstressed and deflections are out of bounds. Hence, the beam has
Applied Moment – 32.928 K-ft, Allowable Moment – 26.896 K-ft.
Figure 14. Steel I beam BMD
From BMD, it can be seen that Applied moment exceeds allowable moment from a distance of 5’
up to a distance of 14’ from left support. Hence, beam need to be strengthened to a span of 9’, 5’
away from each support.
It is found that Beam W6x20 works under given load.

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Figure 15. Steel I beam Design
Solution can be approached in two different ways. One is to find Equivalent section having section
properties close to section properties of W6x20. Another is to find equivalent section satisfying
the moment carrying capacity required.
Section Properties of W6x20 – Ixx = 41.4 in4
and Sx = 13.4 in3
.
Moment carrying capacity of steel beam = (Section Modulus) x (Yield Strength of Steel)
32.928K-ft = (Section Modulus) x (0.9 * 50ksi)
Section Modulus of the required equivalent section is 8.78 in3
.
The new member which can be added to a ‘W’ section is either a steel plate or a ‘WT’ section.

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Steel plate is bulky and difficult to install compared to WT section. Hence, WT section is used.
By trial and error, WT 3x4.25 with existing W6x12 is chosen. Whose section properties are
Ixx = 49.107 in4
and Sx = 10.8 in3
> 8.78 in3
. (See figure 16)
Hence, use WT 3x4.25 with W6x12 to a distance of 9’, 5’ away from either supports.
Figure 16. Steel I beam Equivalent Section
Connections – Tensile force acting at the connection T = M/d = 32.928/13.33 = 2.47 Kips.
From AISI steel manual, weld strength is related to Weld length by following formula,
Rn * φ = 0.928 * D * L

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Where, ‘Rn’ is Weld Strength, ‘φ’ is LRFD Factor, ‘D’ is diameter of weld in 1/16th
of an inch,
‘L’ is the weld length.
2.47 * 0.75 = 0.928 * 2 * L
Which gives L = 1’/foot.
Therefore, provide fillet weld of diameter 1/8th
” For a length of 6” staggered, both sides.
Throughout the length of connection.
7. NDT METHODS
Preliminary analysis indicated that existing CMU wall of thickness 8” is sufficient to resist applied
gravity and wind loads, with #4 bars grouted @48” O.C.
Thickness of wall is measured at the site, and was found to be 8”. But, grouting could not be
verified. Hence, NDT methods are adopted to verify Presence of reinforcement.
A. COVER METER
Works based on principle of Electromagnetic Induction. “Alternating magnetic field intersecting
an electric circuit induces an electric potential in that circuit”.
Maximum signal is obtained along the axis of the bar. Hence, cover meters should be placed
vertically along height of the walls.
Cover meter is placed with its axis parallel to height of the wall. The presence of Rebar is indicated
by change in current in the cover meter. Cover meter is moved perpendicular to wall height till
another rebar is detected. The distance between rebar’s can be measured with tape measure.
Process is repeated till all the rebar’s are detected.
B. GROUND PROBING
To detect size of footing buried underground, Stress wave methods such as, Impact echo or pulse
echo or Radiographic methods such as Ground Penetration Radar (GPR) can be used.
But for small scale projects like these, which has shallow footings, the most economical way to
determine size of footing is to use “Ground Probing” method.

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It is a “T” shaped device, stem of which is typically a steel rod measuring 3/8” diameter and 4’ to
5’ tall. Lower end of the rod consists of a cone shaped tip, which helps to break the skin friction.
By probing the rod into the ground, the concrete surface can be detected. Then, the rod is probed
into the ground on a slight batter about a foot away from the footing. Which helps in locating top
and bottom tip of the concrete footing. Using trigonometric relations, size and depth of the footing
can be determined.
Figure 17. Ground Probing Method
8. CONCLUSIONS
 In Canopy –
 Joists, Ledger beam, Column and base plate were adequate under applied loads.
 Beam B1 is strengthened by Doubling the number of beams and Beam B2 is
strengthened with an equivalent c/s of (2)2x10 DF#2 with existing 4x6 DF#2
nailed together with 10d nails @ 1’ O.C staggered.
 In Building –
 Joists, column and base plate were adequate under applied loads.
 14” deep trusses are replaced with 20” deep trusses
 Steel I Beam is strengthened with an equivalent section of WT3x4.25 with existing
W6x12.
 Cover meter is used to detect presence of rebar in CMU walls.

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 Ground Probing method is used to determine size of concrete foundation.
9. REFERENCES
 Lecture notes, CEE598 – Structural Damage Evaluation and Strengthening, Fall 2016. By
Prof. Narayanan Neithalath.
 Test methods for evaluating existing foundations by “The Structural Committee of the
Foundation Performance Association” Houston, Texas.

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