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

THANK FOR LISTENING