seismic evaluation
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SEISMIC EVALUATION OF
ST. AUGUSTINE CHURCH USING
NONLINEAR STATIC ANALYSIS
SEISMIC EVALUATION OF
ST. AUGUSTINE CHURCH USING
NONLINEAR STATIC ANALYSIS
Baclayon Church, Bohol
Loboc, Church
Maribojoc Church
Loon Church
The PROBLEM AND A REVIEW OF RELATED
LITERATURE AND STUDIES
Brief History of the Structure
• In 1613, construction started.
• In 1645, it was slightly damaged during the earthquake.
• In 1942 and in 1962, it was damaged by the war and strong typhoons.
• In1949-1952,it was then repaired.
• In 2007, it was reconstructed with new red block bricks.
The St. Augustine Church of Lubao is not only Pampanga’s oldest and largest Agustinian church in Central Luzon but also in the entire Northern Luzon.
• In August 2013, the church was recognized by the National Commission on Culture and the Arts (NCCA) as one of the country’s national treasure.
Brief History of the Structure
Construction Materials Used• Adobe mud blocks• Stone• Sand with Lime• Egg Albumen
Nonlinear Static Analysis
ASCE 41 (ASCE 2007)• Immediate Occupancy
• Life Safety• Collapse Prevention
Static Nonlinear versus Static Linear
Statement of the Problem
Specific Problems
•What is the current performance level of the building?•What are the weak parts of the structure?•What is the present integrity of the structure?
Significance of the Study
Range and Restriction
Conceptual Framework
• Gathering Information
• Testing of Adobe Bricks
• Structural Modeling
RESEARCH METHODOLOGY AND PROCEDURES
Testing of Adobe BricksAdobe brick in
situ
2”x2”x2” specimens
Grinding Process
Crushed adobe sample
Structural ModelingETABS (Extended Three-Dimensional Analysis of Building Systems)
(Figure 2.3.1)
(Figure 2.3.2)
(Figure
2.3.3)
Defining Material Properties of Adobe
Sample Mass (kg) Volume (cu.m) Density (kg/cu.m)
1 0.2 0.000125 1,600
2 0.167 0.000125 1,336
3 0.227 0.000125 1,816
Defining Section Properties
Column (C1)
Column (C4)
Column (C5)
Masonry WallThickness= 2.46m
Defining Static Load CasesLoad Name Load Type Details Value
DEAD
Dead Load
Self-Weight of Structural Members Calculate automatically using Self
Weight Multiplier in ETABS
--
Uniform Load on Roof
0.5 kN/m2
LIVE
Live Load Uniform Load on Roof(Table 205-3 NSCP 2010)
0.6 kN/m2
EQY
Quake Load UBC 1997
--
EQX
QuakeLoad
UBC 1997
--
Figure 2.3.1.2 Dead loads acting on each columns
Figure 2.3.1.3 Live loads acting on each columns
Figure 2.3.1.4 Base shear distribution using Portal Method, EQYFigure 2.3.1.5 Lateral force distribution, EQX
Parameter Values Remark
Zone 4 Table 208-3
Time Period (T) 0.285 Eq. (208-8)
Response Modification Factor (R)
5.5
Table 208-11
Seismic Source Type A Table 208-6
Soil Profile Type SD Table 208-2
Seismic Coefficient, Ca 0.44 Table 208-7
Seismic Coefficient, Cv 0.64 Table 208-8
Horizontal Force Factors, ap
1.0
Table 208-12
Horizontal Force Factors, Rp
3.0
Table 208-12
Table 2.3.3.1 Equivalent Static Force Parameters (NSCP 2010)
Members
Weight ( kN )
Weight considering half of the height ( kN )
C1 9902.306688 4951.153344
C4 4207.096532 2103.548266
C5 2504.389644 1252.194822
Walls 55069.22952 27534.61476
Roof 1741.344 1741.344
TOTAL 73424.36638 37582.85519
Table 2.3.3.2 Weight Calculation of The
Structure
PRESENTATION, ANALYSIS AND INTERPRETATION OF
RESULTS
Process of Non Linear Static Analysis• Modeling of Adobe Masonry Infill
λ1hcol)-0.4rinf
=
Where:• α = width of the compression strut
• hcol = column height between centerlines of beams;
• hinf = height of infill;
• Efe = expected modulus of elasticity of frame material;
• Eme = expected modulus of elasticity of infill material;
• Icol = moment of inertia of column;
• Linf = Length of infill panel;
• rinf = diagonal length of infill panel;
• tinf = thickness of infill panel and equivalent strut;• Ɵ = angle whose tangent is the infill height to length aspect ratio;
and• = coefficient used to determine equivalent width of the infill strut
Masonry Infils Calculated width (m)
1A-1B 2.37
1A-2A, 1B-2B 1.84
2A-3A, 2B-3B 1.52
3A-4A, 3B-4B 1.27
4A-5A, 4B-5B 1.33
5A-6A, 5B-6B 1.30
6A-7A, 6B-7B 1.30
7A-8A, 7B-8B 1.87
8A-9A, 8B-9B 1.33
Defining Static Nonlinear Case Data
•Defining Static Nonlinear Case Data
Where:
1 = target displacement
Te = effective fundamental period (in seconds)
Ki = elastic lateral stiffness of the building in the direction under consideration Ke = effective lateral stiffness of the building in the direction under
C0 = modification factor to relate spectral displacement and likely building roof displacement
C1 = modification factor to relate expected maximum inelastic displacements to displacements calculated for linear elastic response
C2 = modification factor to represent the effect of hysteresis shape on the maximum displacement response
C3 = modification factor to represent increased displacements due to second-order effects.
Sa = response spectrum acceleration Figure 3.2.1 Bilinear Representation of Capacity Curve for
Displacement Coefficient Method
Number of Stories Modification Factor 1
1 1.0
2 1.2
3 1.3
5 1.4
10+ 1.5
Table 3.2.1 Values for Modification Factor, C0
Ke = effective lateral stiffness of the building in the direction under consideration.
C0 = modification factor to relate spectral displacement and likely building roof displacement
T = 0.1 second T > To second
Structural Performance Level Framing Type 1
Framing Type 2
Framing Type 1 Framing Type 2
Immediate Occupancy 1.0 1.0 1.0 1.0
Life Safety 1.3 1.0 1.1 1.0
Collapse Prevention 1.5 1.0 1.2 1.0
Table 3.2.2 Values for Modification Factor, C2
C2 = modification factor to represent the effect of hysteresis shape on the maximum displacement response.
Sa = response spectrum acceleration as determined from Section 4.4.3.3 of ATC 40, at the effective fundamental period of the building.
Defining Frame Nonlinear Hinge Properties
Running the Analysis
1. Lateral Forces at Global Axis Y
2. Lateral Forces at Global Axis X
SUMMARY OF FINDINGS, CONCLUSIONS AND RECOMMENDATIONS
Summary of Findings
Performance Level Magnitude Intensity
Immediate Occupancy 1.0 – 5.9 I - VI
Life Safety 6.0 – 6.9 VII - VIII
Collapse Prevention 7.0 - higher IX - higher
Table 4.2. Corresponding Magnitude and Intensity
Conclusions
Recommendations
Seismic Retrofitting
Purposes of Retrofitting
• Public safety.
• Structure survivability.
• Structure functionality.
• Structure unaffected.
Shotcrete Method
Advantages and Disadvantages of Shotcrete Method
Advantages Disadvantages
More convenient and less costly than the other retrofitting methods.
High mass
Strong Require surface treatment
Durable Affect Architecture
Resistant to disasters, fires, molds, insects and vermin
Require finishing
Low permeability High disturbance
Good thermal mass
Wet-Mix Shotcrete Method
Process of Wet-Mix Shotcrete
1. Cleaned surface, watered and grinded
2. Placing reinforcement
Installation of Wire Mesh
3. Wall surface sprayed under 7 Mpa pressure on wall surface.
4. Wall Finishing
Plastering Finished Surface
Costs
1. Computation of External Area of Walls
a. Considering the whole structure• Total Area = 16,372.168 sq.ft ( 2,213.5 pesos per sq.ft )• Total Costs of Retrofitting is 36,239,793.868 pesos approximately
36.3Million pesos.
b. Considering the weak portions (Facade and Columns at the altar)
• Total Area = 3,620.998 sq.ft. (2,213.5 pesos per sq. ft)• Total Cost of Retrofitting is 8, 015, 079.073 pesos approximately 8.1 Million pesos
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