Chapter 9.

Urban Conditions
 Final Report

CHAPTER 9. URBAN CONDITIONS

9.1 Buildings
1) Characteristics of NSO data, Distribution of Residential Buildings

(1) General

In order to estimate building damage against earthquake occurrence, detailed information on each
building is indispensable. Therefore, the Study Team visited relevant organizations to find the
best resources for the Study. Fortunately, the “2000 Census of Population and Housing” was
implemented by National Statistics Office (hereinafter referred to as “NSO”) and results will be
published soon. Therefore, the Study Team officially requested to receive the data in a form that
could be converted to building units, since the original data is in the form of each dwelling unit.
Because damage estimation of buildings is calculated for each building, the Study Team
requested to include building serial number in the data.

The Study Team received data in early January 2003 consisting of various information, such as 1)
Number of Households, 2) Number of Habitants, 3) Type of Building, 4) Construction Materials
of the Outer Wall, and 5) Construction Year.

In general, for the damage estimation of buildings, the fundamental information is: 1) Structure,
2) Construction Year, and 3) Number of Story. However, from the Census, number of story
information cannot be gathered. The Study Team will consider how to assume this information in
the later stage, or how to make the fragility function of the buildings without the number of story
information.

Table 9.1.1 shows the general information on buildings by district. According to the Census 2000,
total number of buildings in Metropolitan Manila is counted as 1,325,896 buildings and its
building density is 22 buildings/hectare.

Figure 9.1.1 shows building distribution by Barangay and Figure 9.1.2 shows Building density
distribution by Barangay. In detail, Quezon City has the largest number of buildings in
Metropolitan Manila, counted as 302,818. However, area of Quezon City is rather large compared
to other cities in Metropolitan Manila and its building density is 18 buildings /ha, which is less
than average.

Pateros and Manila have the largest building density at 45 buildings/ha and 41 buldings/ha
respectively. On the contrary, Valenzuela City, Muntinlupa City, Makati City, and Paranaque City
have the lowest building density at 14 buildings/ha, 15 buildings/ha, 16 buildings/ha, and 16
buildings/ha respectively. However, this argument is focused on LGU level, therefore, in
Barangay level, more detailed special characteristics can be found.

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Table 9.1.1 General Information on Building by LGU

Total No. of Building Density Total No. of Total No. of Total Floor Area
LGU Name Area (ha)
Building (buildings/ha) Household Habitant (m2)
Manila 4,130 168,528 41 333,546 1,569,581 11,475,903
Mandaluyong City 1,107 32,942 30 59,681 275,106 2,149,173
Marikina City 2,265 53,422 24 80,159 389,758 4,217,033
Pasig City 3,189 72,143 23 107,834 503,674 4,856,306
Quezon City 16,539 302,818 18 480,623 2,166,314 22,194,266
San Juan 588 11,793 20 24,604 117,392 1,253,073
Kalookan City 5,314 168,480 32 249,566 1,174,669 9,116,205
Malabon 1,597 51,694 32 74,136 336,511 2,498,690
Navotas 1,095 35,124 32 49,449 229,710 1,537,689
Valenzuela City 4,454 62,778 14 106,381 481,039 3,866,230
Las Pinas City 3,228 73,919 23 97,961 471,764 5,600,672
Makati City 3,197 50,381 16 103,980 470,304 5,031,045
Muntinlupa City 3,814 55,522 15 78,015 370,329 3,398,054
Paranaque City 4,563 72,230 16 94,108 447,901 6,084,705
Pasay City 1,779 39,968 22 78,179 354,011 2,597,026
Pateros 195 8,726 45 12,028 57,389 470,536
Taguig 2,753 65,428 24 102,722 464,552 3,825,264
MM: Total 59,809 1,325,896 22 2,132,972 9,880,004 90,171,870

Source: NSO, 2002

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Figure 9.1.1 Number of Buildings per Barangay

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Figure 9.1.2 Building Density per Barangay

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(2) Building Type

In the Census 2000, type of building is indicated to identify scale of building. Type of building is
classified into 6 categories, 1) Single House, 2) Duplex, 3) Multi-Unit Residential (3 or more
units), 4) Commercial/Industrial/Agricultural, 5) Institutional living quarters, and 6) Other
housing units. The definition of each category is shown in Table 9.1.2.

Table 9.1.2 Definition of Building Type

No. Type of Building Definition
1 Single House This is an independent structure intended for one household separated
by an open space or walls from all other structures.
2 Duplex This is a structure intended for two households, with complete living
facilities for each. It is divided vertically or horizontally into two separate
housing units, which are usually identical.
3 Multi-Unit Residential This is a building intended for residential use only, consisting of 3 or more
(3 or more units) housing units.
4 Commercial/Industrial/Agricultu These buildings are not intended mainly for human habitation but used as
ral living quarters of households at the time of the pilot census.
5 Institutional living quarters hotel, lodging house, dormitory, hospital, convent, school, penal
institution, refugee camp, military camp, etc.
6 Other housing units This refers to living quarters which are not intended for human habitation
nor located in permanent buildings but which are nevertheless, used as
living quarters at the time of the pilot census.
Source: NSO, Census 2000

Since Census 2000 does not include number of story information, this building type can be used
to identify scale of building to estimate building story. For instance, Single house and Duplex can
be a one or two story buildings and Multi-Unit Residential can be considered as rather high story
buildings. However, it has been cleared that this type of building are not correctly answered at the
time of survey. Table 9.1.3 shows counts of households in each category of building type. As
indicated in the definition of building type, Single houses are occupied by one household which
should be only available in “1” in the table (74,559 households). However, sometimes there are
more than 2 households existing in this category. Likewise, duplex should have only “2
households”. However, these are sometimes occupied by only 1 household or more than 3
households. Therefore, this information cannot be used to assume building story, unfortunately.

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Table 9.1.3 Number of Household by Type of Building

LGU Type 1 2 3 4 5-10 11-20 21-50 51- 101- 200-

100 200
MANILA Single house 74,559 14,860 6,307 3,098 3,661 253 38 4 3 0
MANILA Duplex 6,263 3,910 1,000 416 461 31 9 1 0 0
MANILA Multi-unit 21,374 7,189 6,464 4,024 6,220 795 248 63 21 3
residential
MANILA Commercial/indust 1,013 190 96 52 109 28 15 2 0 0
rial/Agricultural
MANILA Others 5,132 335 104 62 96 10 9 0 0 0
Source: NSO, Census 2000

Table 9.1.4 Building Type Distribution by District

No of Buildings Percentage (%)

LGU Name 1 2 3 4 5 6 9 LGU: Total 1 2 3 4 5 6 9
Manila 102,783 12,091 46,401 1,505 153 1,547 4,048 168,528 61.0 7.2 27.5 0.9 0.1 0.9 2.4
Mandaluyong City 21,215 2,493 8,487 157 18 40 532 32,942 64.4 7.6 25.8 0.5 0.1 0.1 1.6
Marikina City 41,370 4,204 6,456 206 21 180 985 53,422 77.4 7.9 12.1 0.4 0.0 0.3 1.8
Pasig City 53,956 6,398 10,115 245 15 38 1,376 72,143 74.8 8.9 14.0 0.3 0.0 0.1 1.9
Quezon City 207,345 24,364 60,574 1,535 201 1,709 7,090 302,818 68.5 8.0 20.0 0.5 0.1 0.6 2.3
San Juan 6,322 718 4,189 122 8 65 369 11,793 53.6 6.1 35.5 1.0 0.1 0.6 3.1
Kalookan City 122,133 14,662 26,441 1,023 66 269 3,886 168,480 72.5 8.7 15.7 0.6 0.0 0.2 2.3
Malabon 38,183 5,072 6,945 295 26 76 1,097 51,694 73.9 9.8 13.4 0.6 0.1 0.1 2.1
Navotas 28,084 2,564 3,483 179 10 102 702 35,124 80.0 7.3 9.9 0.5 0.0 0.3 2.0
Valenzuela City 41,040 6,971 13,044 485 32 81 1,125 62,778 65.4 11.1 20.8 0.8 0.1 0.1 1.8
Las Pinas City 60,904 4,097 6,784 265 26 127 1,716 73,919 82.4 5.5 9.2 0.4 0.0 0.2 2.3
Makati City 29,652 4,838 14,251 271 37 247 1,085 50,381 58.9 9.6 28.3 0.5 0.1 0.5 2.2
Muntinlupa City 41,781 5,190 7,385 97 17 40 1,012 55,522 75.3 9.3 13.3 0.2 0.0 0.1 1.8
Paranaque City 58,310 4,950 7,097 275 26 139 1,433 72,230 80.7 6.9 9.8 0.4 0.0 0.2 2.0
Pasay City 25,607 3,097 10,035 275 39 231 684 39,968 64.1 7.7 25.1 0.7 0.1 0.6 1.7
Pateros 6,624 859 1,016 30 14 183 8,726 75.9 9.8 11.6 0.3 0.0 0.2 2.1
Taguig 48,312 7,012 8,975 148 19 28 934 65,428 73.8 10.7 13.7 0.2 0.0 0.0 1.4
MM: Total 933,621 109,580 241,678 7,113 714 4,933 28,257 1,325,896 70.4 8.3 18.2 0.5 0.1 0.4 2.1

Source: NSO, Census 2000

Note: 1. Single house, 2.Duplex, 3.Multi-unit residential (three units or more), 4.Commercial/industrial/agricultural (office, factory,

rice mill, etc.), 5.institutional living quarters (hotel, hospital, etc.), 6.Other housing unit (boat, cave, etc.), 9.Not Reported

(3) Outer Wall Material

In Census 2000, Building Outer Wall Material is classified into 10 types, 1) Concrete/brick/stone,
2)Wood, 3) Half concrete/brick/stone/ and half wood, 4) Galvanized iron/aluminum, 5)
Bamboo/sawali/cogon/nipa, 6) Asbestos, 7) Glass, 8) Makeshift/salvaged/improvised materials,
9) Others, and 10) No walls. This information is used to identify type of structure of each
building.

Table 9.1.5 shows building outer wall material distribution in each LGU. As a whole for
Metropolitan Manila, 44.4 % of buildings are constructed with Concrete/brick/stone, 30.1% Half

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concrete/brick/stone/ and half wood, and 18.6% Wood. Those three types of structure occupies
93.1% of buildings existing in Metropolitan Manila.

Focusing on each LGU, buildings in Marikina City, Kalookan City, Valenzuela City, Las Pinas
City, Taguig are mostly constructed with Concrete/brick/stone, which comprises 56.2%, 53.5%,
54.6%, 53.5%, and 54.3 respectively. For the buildings constructed with Wood, these are
remarkably distributed in Malabon and Navotas, which occupies 32.4%, and 36.2 respectively.
However, most of LGU have more than 15% of buildings constructed with Wood. In addition,
buildings in Manila, Mandaluyong City, and Pasay City are constructed with Half
concrete/brick/stone/ and half wood, which comprises 41.7%, 45.4%, and 39.1% respectively.

In Barangay level, characteristics of building distribution by structure is different. Therefore, data

were prepared in Barangay level as well and these data are attached in the end of this report. To
understand the distribution visually, several GIS maps are prepared. Figure 9.1.3 illustrates
Concrete/brick/stone Structure Distribution by Barangay, Figure 9.1.4 illustrates Wood Structure
Distribution by Barangay, and Figure 9.1.5 illustrates Half concrete/brick/stone/ and half wood
Structure Distribution by Barangay.

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Table 9.1.5 Building Outer Wall Material Distribution by LGU

No of Buildings
LGU 1 2 3 4 5 6 7 8 9 10 99 LGU: Total
Manila 45,489 42,013 70,319 1,193 84 55 59 3,828 89 245 5,154 168,528
Mandaluyong City 9,796 6,449 14,947 282 24 19 16 599 4 17 789 32,942
Marikina City 30,015 6,795 13,276 683 64 23 42 876 18 62 1,568 53,422
Pasig City 32,391 16,422 19,387 381 112 37 40 1,139 14 128 2,092 72,143
Quezon City 141,864 42,181 94,089 3,676 594 162 204 9,024 122 497 10,405 302,818
San Juan 4,340 2,670 4,002 79 4 3 3 88 6 15 583 11,793
Kalookan City 90,085 20,961 45,754 1,721 670 99 60 3,406 183 240 5,301 168,480
Malabon 16,324 16,729 15,889 411 64 17 31 595 5 78 1,551 51,694
Navotas 9,295 12,718 10,979 210 55 13 13 769 34 56 982 35,124
Valenzuela City 34,307 9,672 15,567 448 109 30 40 1,067 24 102 1,412 62,778
Las Pinas City 39,558 14,425 13,151 374 356 13 49 3,397 18 81 2,497 73,919
Makati City 23,825 7,497 15,370 276 34 10 34 1,746 32 142 1,415 50,381
Muntinlupa City 25,552 10,765 14,783 649 398 18 49 1,593 22 66 1,627 55,522
Paranaque City 33,669 15,763 17,740 597 140 27 76 1,730 9 87 2,392 72,230
Pasay City 13,324 8,516 15,645 302 15 8 26 1,098 37 64 933 39,968
Pateros 3,670 1,866 2,676 52 5 1 2 152 0 6 296 8,726
Taguig 35,552 10,886 14,893 751 237 21 31 1,443 12 80 1,522 65,428
MM: Total 589,056 246,328 398,467 12,085 2,965 556 775 32,550 629 1,966 40,519 1,325,896
Percentage (%)
LGU 1 2 3 4 5 6 7 8 9 10 99 LGU: Total
Manila 27.0 24.9 41.7 0.7 0.0 0.0 0.0 2.3 0.1 0.1 3.1 100
Mandaluyong City 29.7 19.6 45.4 0.9 0.1 0.1 0.0 1.8 0.0 0.1 2.4 100
Marikina City 56.2 12.7 24.9 1.3 0.1 0.0 0.1 1.6 0.0 0.1 2.9 100
Pasig City 44.9 22.8 26.9 0.5 0.2 0.1 0.1 1.6 0.0 0.2 2.9 100
Quezon City 46.8 13.9 31.1 1.2 0.2 0.1 0.1 3.0 0.0 0.2 3.4 100
San Juan 36.8 22.6 33.9 0.7 0.0 0.0 0.0 0.7 0.1 0.1 4.9 100
Kalookan City 53.5 12.4 27.2 1.0 0.4 0.1 0.0 2.0 0.1 0.1 3.1 100
Malabon 31.6 32.4 30.7 0.8 0.1 0.0 0.1 1.2 0.0 0.2 3.0 100
Navotas 26.5 36.2 31.3 0.6 0.2 0.0 0.0 2.2 0.1 0.2 2.8 100
Valenzuela City 54.6 15.4 24.8 0.7 0.2 0.0 0.1 1.7 0.0 0.2 2.2 100
Las Pinas City 53.5 19.5 17.8 0.5 0.5 0.0 0.1 4.6 0.0 0.1 3.4 100
Makati City 47.3 14.9 30.5 0.5 0.1 0.0 0.1 3.5 0.1 0.3 2.8 100
Muntinlupa City 46.0 19.4 26.6 1.2 0.7 0.0 0.1 2.9 0.0 0.1 2.9 100
Paranaque City 46.6 21.8 24.6 0.8 0.2 0.0 0.1 2.4 0.0 0.1 3.3 100
Pasay City 33.3 21.3 39.1 0.8 0.0 0.0 0.1 2.7 0.1 0.2 2.3 100
Pateros 42.1 21.4 30.7 0.6 0.1 0.0 0.0 1.7 0.0 0.1 3.4 100
Taguig 54.3 16.6 22.8 1.1 0.4 0.0 0.0 2.2 0.0 0.1 2.3 100
MM: Total 44.4 18.6 30.1 0.9 0.2 0.0 0.1 2.5 0.0 0.1 3.1 100

Source: NSO, Census 2000

Note: 1. Concrete/brick/stone, 2.Wood, 3.Half concrete/brick/stone/and half wood, 4.Galvanized iron/aluminum,

5.Bamboo/sawali/cogon/nipa, 6.Asbestos, 7.Glass, 8.Makeshift/salvaged/improvised materials, 9.Others, 10.No walls, 99.Not

Reported

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Figure 9.1.3 Concrete-Walled Buildings per Barangay (2000)

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Figure 9.1.4 Wood-Walled Buildings per Barangay (2000)

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Figure 9.1.5 Half Concrete-Walled Buildings per Barangay (2000)

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(4) Construction Year

In Census 2000, Construction Year is divided into 10 categories, 1) 2000, 2) 1999, 3) 1998, 4)
1997, 5) 1996, 6) 1991-1995, 7) 1981-1990, 8) 1971-1980, 9) 1961-1970, and 10) 1960 and
earlier. From the original data, to understand urban development pattern clearly, data have been
re-categorized into 5 categories, 1) 1960 and earlier, 2) 1961-1970, 3) 1971-1980, 4) 1981-1990,
and 5) 1991-2000. Table 9.1.6 is a summarized table of construction year distribution by LGU.

Table 9.1.6 Building Construction Year Distribution by LGU

No of Buildings Percentage (%)
LGU Name 1 2 3 4 5 6 LGU: Total 1 2 3 4 5 6
Manila 32,651 20,061 25,156 33,269 32,507 24,884 168,528 19.4 11.9 14.9 19.7 19.3 14.8
Mandaluyong City 2,959 3,471 5,175 7,627 9,809 3,901 32,942 9.0 10.5 15.7 23.2 29.8 11.8
Marikina City 2,632 4,249 8,562 15,065 18,314 4,600 53,422 4.9 8.0 16.0 28.2 34.3 8.6
Pasig City 3,147 4,700 10,290 18,756 27,283 7,967 72,143 4.4 6.5 14.3 26.0 37.8 11.0
Quezon City 15,709 18,636 41,915 82,085 109,616 34,857 302,818 5.2 6.2 13.8 27.1 36.2 11.5
San Juan 2,672 1,652 1,642 1,659 1,931 2,237 11,793 22.7 14.0 13.9 14.1 16.4 19.0
Kalookan City 7,702 8,356 14,865 51,013 71,864 14,680 168,480 4.6 5.0 8.8 30.3 42.7 8.7
Malabon 4,162 4,713 8,260 13,960 15,119 5,480 51,694 8.1 9.1 16.0 27.0 29.2 10.6
Navotas 2,726 2,317 6,326 9,995 11,293 2,467 35,124 7.8 6.6 18.0 28.5 32.2 7.0
Valenzuela City 2,290 3,703 8,920 16,880 23,176 7,809 62,778 3.6 5.9 14.2 26.9 36.9 12.4
Las Pinas City 1,072 2,852 11,451 23,351 29,925 5,268 73,919 1.5 3.9 15.5 31.6 40.5 7.1
Makati City 5,764 6,070 7,235 11,813 12,406 7,093 50,381 11.4 12.0 14.4 23.4 24.6 14.1
Muntinlupa City 1,506 2,485 8,290 18,522 19,979 4,740 55,522 2.7 4.5 14.9 33.4 36.0 8.5
Paranaque City 2,935 3,522 9,242 21,432 28,051 7,048 72,230 4.1 4.9 12.8 29.7 38.8 9.8
Pasay City 4,693 4,567 7,114 9,894 8,089 5,611 39,968 11.7 11.4 17.8 24.8 20.2 14.0
Pateros 912 1,124 1,756 2,071 2,242 621 8,726 10.5 12.9 20.1 23.7 25.7 7.1
Taguig 1,485 2,193 7,855 19,439 29,508 4,948 65,428 2.3 3.4 12.0 29.7 45.1 7.6
MM: Total 95,017 94,671 184,054 356,831 451,112 144,211 1,325,896 7.2 7.1 13.9 26.9 34.0 10.9

Source: NSO, Census 2000

Note: 1. 1960 or earlier, 2.1961-1970, 3.1971-1980, 4.1981-1990, 5.1991-2000, 6. Unknown

According to the original data, up to Year 1960, number of buildings in Metropolitan Manila was
only 95,017 (7.2% of total number of buildings in year 2000). Development in Metropolitan
Manila rapidly increased from 1980’s. Old town like City of Manila is almost equally developed
and even from 1981-1990, new construction increased only to 19.3%. Other LGU constructed
more than 30% of the buildings in this decade, except for San Juan, Makati City, Pasay, and
Pateros. However, Makati City mostly constructed high-rise buildings. Therefore, from the
statistical table, this trend cannot be observed clearly.

In this study, construction year data is used to visualize the urban development pattern in
Metropolitan Manila (Figure 9.1.6 to Figure 9.1.10). These figures clearly show the urban
development trend in Metropolitan Manila in each Barangay. Data table for each Barangay is
attached in the last part of this report.

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Figure 9.1.6 Buildings Built in Year 1960 or Earlier per Barangay (2000)

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Figure 9.1.7 Building Built in Year 1961-1970 per Barangay (2000)

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Figure 9.1.8 Building Built in Year 1971 – 1980 per Barangay (2000)

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Figure 9.1.9 Building Built in Year 1981 – 1990 per Barangay (2000)

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Figure 9.1.10 Building Built in Year 1991 – 2000 per Barangay (2000)

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2) Distribution of Mid-rise and High-rise Buildings

The Study Team identified locations and heights of each building, with height over 12m, using the
aerophoto taken in 2003. These include commercial and residential buildings. Table 9.1.7 shows
the summary of mid-rise and high-rise buildings in Metropolitan Manila.

Table 9.1.7 Mid-rise and High-rise Buildings in Metropolitan Manila

Number of Stories Building Count
10-30 Stories 981
Over 30 Stories 119

3) Distribution of Major Public Facility Buildings

Public and governmental facility buildings examined in the Study are described here and shown
in Table 9.1.8. Data source are shown in the table. Number of facilities in each LGU is
summarized in Table 9.1.8 to Table 9.1.12. Location maps are shown in Figure 9.1.11 to Figure
9.1.15.

Table 9.1.8 Contents of Public and Governmental Facility Buildings

Type Data Data Source (year)

Police Station Location of Police Regional,District HQ & Stations ROD, NCRPO
Police Districts in Metropolitan Manila (2003)
Fire Fighting Station Location of Fire District HQ, Stations & Substations BFP
Fire Districts in Metropolitan Manila (2003)
Location of Fire Hydrants in Metropolitan Manila
Hospitals Location of Hospitals DOH
Hospital Districts (2003)
Public schools Location of Public Elementary and High Schools DepED(2003)
Private Schools Location of Private Elementary and High Schools CHED(2003)
Department of Education Divisions
Location of Higher Educational Institutions
17 LGU City and Municipality Hall Building Location The Study Team
MMDCC organizing Department and (2003)
Agencies

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Table 9.1.9 Police Stations in Metropolitan Manila

No. of Police Stations
LGU Code LGU
Stations District HQ Regional HQ Total
390 Manila 11 1 0 12
741 Mandaluyong 1 0 0 1
742 Marikina 1 0 0 1
743 Pasig 1 1 0 2
744 Quezon 11 1 0 12
745 San Juan 1 0 0 1
751 Valenzuela 1 0 0 1
752 Kalookan 1 1 0 2
753 Malabon 1 0 0 1
754 Navotas 1 0 0 1
761 Las Pinas 1 0 0 1
762 Makati 1 1 0 2
763 Muntinlupa 1 0 0 1
764 Paranaque 1 0 0 1
765 Pasay 1 0 0 1
766 Pateros 1 0 0 1
767 Taguig 1 0 1 2
Total 37 5 1 43

Table 9.1.10 Fire Stations in Metropolitan Manila

No. of Fire Station
LGU Code LGU
Head Quarter Station Sub - station Total
390 Manila 1 1 13 15
741 Mandaluyong 0 1 2 3
742 Marikina 0 1 6 7
743 Pasig 1 1 9 11
744 Quezon 1 0 17 18
745 San Juan 0 1 1 2
751 Valenzuela 0 1 6 7
752 Kalookan 0 1 10 11
753 Malabon 0 1 3 4
754 Navotas 0 1 6 7
761 Las Pinas 0 1 8 9
762 Makati 1 0 10 11
763 Muntinlupa 0 1 3 4
764 Paranaque 0 1 6 7
765 Pasay 0 1 2 3
766 Pateros 0 1 0 1
767 Taguig 0 1 3 4
Total 4 15 105 124

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Table 9.1.11 Hospitals in Metropolitan Manila

No. of Hospitals
LGU Code LGU
Primary Secondary Tertiary Total
390 Manila 1 11 20 32
741 Mandaluyong 0 2 3 5
742 Marikina 0 5 1 6
743 Pasig 4 6 4 14
744 Quezon 12 12 25 49
745 San Juan 0 1 2 3
751 Valenzuela 4 3 1 8
752 Kalookan 6 7 2 15
753 Malabon 3 1 0 4
754 Navotas 1 0 0 1
761 Las Pinas 2 5 3 10
762 Makati 1 1 4 6
763 Muntinlupa 2 3 3 8
764 Paranaque 0 4 1 5
765 Pasay 3 1 4 8
766 Pateros 0 0 0 0
767 Taguig 1 2 0 3
Total 40 64 73 177

Table 9.1.12 Schools in Metropolitan Manila

No. of Public Schools No. of Private Schools
LGU
LGU Elementary High All
Code CHED Total CHED Total
School School Category
390 Manila 71 31 7 109 81 67 148
741 Mandaluyong 15 5 1 21 10 4 14
742 Marikina 18 8 1 27 19 6 25
743 Pasig 27 10 1 38 39 7 46
744 Quezon 98 42 3 143 82 61 143
745 San Juan 9 1 0 10 13 7 20
751 Valenzuela 36 11 0 47 27 7 34
752 Kalookan 50 23 1 74 23 19 42
753 Malabon 28 6 1 35 20 1 21
754 Navotas 15 6 1 22 6 1 7
761 Las Pinas 20 6 1 27 32 8 40
762 Makati 30 7 2 39 21 16 37
763 Muntinlupa 17 4 1 22 27 7 34
764 Paranaque 20 6 0 26 38 5 43
765 Pasay 19 8 3 30 17 11 28
766 Pateros 6 2 0 8 3 0 3
767 Taguig 22 6 2 30 15 2 17
Total 501 182 25 708 473 229 702

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Figure 9.1.11 Location Map of Police Station

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Figure 9.1.12 Location Map of Fire Fighting Station

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Figure 9.1.13 Location Map of Hospitals

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Figure 9.1.14 Location Map of Public Schools and Private Schools

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Figure 9.1.15 Location Map of 17 LGU City and Municipality Hall, MMDCC Departments and
Agencies

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4) Structural Features of Residential Buildings

(1) Classification of Residential Buildings

In Metropolitan Manila, qualities of the residential buildings have wide variety. Few buildings are
well designed, well constructed and well maintained while almost all buildings are of moderate
and/or low quality. Although NSO (National Statistics Office) gives building and population
census, data regarding the buildings’ structural classification and its quality are limited to several
items. They are;

1. Floor area of housing unit

2. Construction materials of the outer walls

3. Year of construction

4. Construction materials of the roof

From the site observation, it is found that the residential buildings have the façade that uses the
same material as that of the structure. Therefore it is reasonable to classify the residential
buildings by using the classification of construction materials of the outer walls. Construction
materials of the outer walls are categorized into four groups by Census data. They are as shown in
the photographs;

1. Concrete/brick/stone

2. Half concrete/brick/stone and half wood

3. Wood

4. Others (Galvanized iron, Bamboo, Makeshift etc)

Through the observation in the study area, many residential buildings are of concrete frames with
reinforcing bars that are very often filled with C.H.B (Concrete Hollow Brick). Exceptionally,
very few and new tall condominium buildings are made of reinforced concrete shear wall
structures.

Concrete Half concrete and half wood Wood

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(2) Construction Material

Concrete structure

Individual house: Regarding the concrete residential buildings in Metropolitan Manila, it is usual
that the house owner himself constructs his house with low-engineered construction method. For
example, concrete is mixed by human laborers without proper mixing criteria. Sometimes, mere
sand is used as aggregate material and the non-skilled laborers often ignore to mix coarse
aggregate, which means that the constructor is never concerned with the proper mix proportioning
of concrete. Very often, the in-filled CHB wall is first constructed, and then a portion of the CHB
wall is used as form to make concrete column. The column depth is, in general, equal to that of the
CHB. Although the reinforcing bars of column are placed with ties, the spacing is not strictly
defined. It was not found that design and construction code is enforced during the construction of
this type of structure.

Large condominium: On the other hand, few large-scale residential buildings such as
condominium buildings apply proper construction methods. A mixer mixes concrete with
appropriate mix proportioning practice. Sometimes most updated techniques such as Jumping
forms for structural wall and Flying shores for floor systems are used. Even the concrete strength
of 8000 psi for core concrete and 6000 psi for floor slab is sometimes allocated in the structural
design. In order to pour the concrete, concrete bucket by crane for vertical members is used while
pumping is used for horizontal members such as beams and slabs. Concrete test specimen are
taken and cured for the strength verification. In general, quality assurances in the large-scale
building construction are rather in a good condition.

Individual house Large condominium (Good Quality)

Wood Structure

Wood structure is composed of lumber, wooden structural panel, particleboard, end-jointed

lumber, fiberboard sheathing and hardboard siding (if latter two materials are used structurally). It
is observed in Metropolitan Manila that structural quality of this type is widely scattered due to

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their conditions for design, construction and maintenance. For example, low-cost house lacks
structural component to resist earthquake forces while, in a subdivision area, the large wooden
structure looks much stronger than the badly constructed concrete structure.

(3) Legal Procedure of Building Construction

Construction approval

All the private buildings are to be constructed after getting the construction approval
(Construction Permit) from the Building Officials in LGU. Building officials in LGU have to
check the legality on the light of the use of the land and other items.

Role of Building officials

However, the building officials do not review the design of the applied buildings, which means
that, although structural code exists for implementation, only law-abiding designer and/or owner
of the building can assure the safeness of the building structure. Building officials have to check
the legality at the time of completion of the building

(4) Supply of Construction Material

Study Team visited factories for Rebar, Ready mixed concrete and Concrete Hollow Brick (CHB)
for understanding of the present condition of building industry in view of structural and
earthquake engineering. Names of the factory are STEEL ASIA Company, DAROMAR Ready
Mix Industries Inc., and ALLIED Concrete Products, Inc. respectively. Through the visit and
interview with local engineers and/or with those who are involved in the building industry, study
team could, to some extent, clarify the overall conditions regarding the building construction. It is
to be pointed out that, in all the factories, the product machines are under good operational
conditions with proper quality assurance process. The produced building materials are kept under
appropriate quality control even after the delivery to the construction sites. Therefore, it was
found so far that the quality of the building material products in the factory is as good as in Japan.

Rebar Factory Concrete Hollow Brick Factory

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On the other hand, many of concrete hollow bricks, those are actually supplied at construction
sites, have very low strength. These are hand-made brick, often prepared at construction site.
Some construction site manager said that there are serious strength problem even with
factory-made bricks.

5) Structural Features of Major Public Facilities

(1) Design and Construction of Public Building Facilities

All the public buildings such as school, hospital and other governmental facilities are designed
and constructed by DPWH. The organizational chart is shown in the Figure 9.1.16.

For instance, engineers in BOD (Bureau of Design) are in charge of review and check of designed
structures. The engineers in DPWH are strictly referring to the national building code. On the
other hand, buildings, which belong to the LGU, such as city hall and barangay hall, are designed
and constructed through the building officials in LGU.

(2) Seismic Performance of Public Buildings in View of Seismic Diagnosis

A. Procedure of Building Diagnosis

a) For Reinforced Concrete Buildings with Medium Heights

According to the Japanese practice in order to briefly estimate seismic performance of existing
medium heights’ reinforced concrete (RC) buildings, basic structural index Is is used as diagnosis
index by using following equation(s).

Is= β (C2+0.7C3) ･ 1.0 ---- (1)

Is= β (C1+0.7C2+0.5C3) ･ 0.8 ---- (2)

Larger Is value are adopted
Where β=(n+1)/(n+i)
n=total number of stories
i= story level under consideration
Cj = Σ Qj / Σ wk (j=1 Extremely short column, j=2 Column, j=3 Wall)
Σ Qj=sum of story shear of Group-j at ultimate stage
Σ wk=building weight above the story
Qj =τ ･A
τ=Shear Stress
A= cross sectional area

During calculation of the equation above, the building weight should be assumed as, for instance,
1 ton per square meter. Is value is obtained for each story level, but the ground floor level’s Is is

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Earthquake Impact Reduction Study for Metropolitan Manila in the Republic of the Philippines

the most important. Threshold value of Is is more or less 0.6 if the building would be located in
Japan.

BRS - Bureau of Research and Standards CAR - Cordillera Administrative Region

MIS - Monitoring and Information NCR - National Capital Region

LLO - Legislative Liaison Office DEOs - District Engineering Office

PEAC - Pre-Qualification, Evaluation and Awards RESs - Regional Equipment Services

Committee for Consultancy CFMS - Comptrollership & Financial Management

BOD - Bureau of Design Service

BOC - Bureau of Construction AMMS - Administrative & Manpower Management

BOM - Bureau of Maintenance Service

BOE - Bureau of Equipment MWSS - Metropolitan Waterworks & Sewerage System

BAC TWG - Bids and Awards Committee Technical LWUA - Local Water Utilities Administration

Working Group PNCC - Phil. National Construction Corp.

RB - Road Board

Figure 9.1.16 Organization Chart of DPWH

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b) Tall RC Buildings and Steel Buildings and Others

Except medium height RC buildings described above, taller RC buildings and Steel (S) buildings
and others are not possibly estimated by numerical procedure. Therefore, Study Team uses a rapid
visual screening (RVS) method developed by FEMA as a brief diagnosis for the existing
buildings.

RVS was designed to be a procedure in which no structural analysis calculations are performed.
The judgment whether the building is safe or not is based on the scoring system. In this RVS, the
inspection, data collection and decision making process typically will occur at the building site.
Threshold score value of this scoring system is 2.0, which means that the buildings with score
higher than 2 is considered potentially safe at the time of earthquake.

c) Combination of two diagnosis methods

As described above, Japanese and FEMA methods’ threshold value is 0.6 and 2.0 respectively.
Therefore, by using factor 0.3, FEMA results are adjusted to be compatible to Japanese method.

B. Buildings to be Inspected

Study Team conducted the diagnostic survey of existing public buildings located in Metropolitan
Manila composed of 17 LGUs. The number of the building inspected by diagnosis is total 80.
Selection of 68 buildings was done by MMDA based on the requests from 17 each LGU. The rest
of 12 buildings were selected by MMDA and PHIVOLCS.

C. Results of Diagnostic Inspection and discussion

Result of diagnostic inspection is summarized in Table 9.1.13, Figure 9.1.17.

Table 9.1.13 Results of Building Diagnosis for Public Buildings

Evaluation
Type Total Low Moderate High
Government Building 11 3 2 6
City Hall 16 2 7 7
School Building 27 4 6 17
Hospital Building 19 4 7 8
Barangay Hall 7 0 1 6
Total 80 13 23 44

In this figure, low seismic performance buildings have Is values less than 0.6, moderate ones have
Is values between 0.6 and 0.8 and high performance buildings have Is values larger than 0.8.

The correlation between Is and the degrees of structural damage was examined by Umemura
(1980) and others applying it to the case of 1968 Tokachi-oki earthquake and 1978 Miyagiken
earthquake both in Japan, and it is suggested that the value of Is of 0.6 is the border between

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damaged and undamaged buildings experienced 25-30 %.g level ground motion. It is noteworthy
that 55% of the inspected buildings have high performance.

Low performance buildings have, in general, small number of columns in comparison of the
occupant area. There are very few concrete shear walls. Although the construction year was not
identified, it was observed that these buildings were possibly constructed before and during the
1960s before the establishment of structural code.

High performance buildings have, on the contrary, large sized concrete columns and sometimes
sufficient shear walls. They are relatively new buildings and maintenance condition is good.
According to the Japanese experience, these buildings are supposed to resist to the earthquake
strong motion with 0.3g maximum acceleration without any damage. It is difficult to predict
ultimate strength of these buildings. However, considering the Japanese experiences, it is also
supposed that these buildings would survive the severer earthquake strong motion with 0.6g
maximum acceleration.

It is also difficult to how to judge the seismic performance of Moderate performance buildings. It
is desired to inspect by using more accurate method, and, if any, some strengthening therapy may
be necessary to avoid fatal damages.

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Government Building
100%
80%
55%
60%
40% 27%
18%
20%
0%
Low Moderate High

City Hall
100%
80%
60% 44% 44%
40%
20% 12%
0%
Low Moderate High

School Building
100%
80%
63%
60%
40%
22%
15%
20%
0%
Low Moderate High

Hospital Building
100%
80%
60%
37% 42%
40%
21%
20%
0%
Low Moderate High

Barangay Hall
100%
86%
80%
60%
40%
14%
20%
0%
0%
Low Moderate High

TOTAL
100%
80%
55%
60%
40% 29%
16%
20%
0%
Low Moderate High

Figure 9.1.17 Results of Building Diagnosis for Public Building

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Earthquake Impact Reduction Study for Metropolitan Manila in the Republic of the Philippines

6) Structural Code

(1) Chronology of Changes in the Seismic base Shear Formula

Since 1977, the National Building Code of the Philippines (NBCP) promulgated as Presidential
Decree (PD) 1096, has been adopting by referral the National Structure Code for Buildings
(NSCB) (previously developed by the Association of Structural Engineers of the Philippines
(ASEP) and Philippines Association of Civil Engineers (PICE) in 1972) or its successors codes.

The referral code NSCB has since metamorphosed into the National Structure Code of the
Philippines (NSCP) Volume 1 – Buildings, Towers and Other Vertical Structures.

The various editions of the NSCP, now in its 5th edition are reviewed to provide historical insights
into the seismic design practices and experiences in the Philippines. A comparison of pertinent
seismic provisions of the codes from the NSCB 1972 to NSCP 2001 is presented in Table 9.1.14.
Table 9.1.14 is a comparison of the general procedure in computing for the base shear coefficient
by the static lateral force procedure.

The static lateral force procedure, and most features of Philippine seismic codes for buildings, has
been patterned after the Uniform Building Code (UBC) and/or the Bluebook of the Structural
Engineers Association of California (SEAOC). In terms of seismic zone, Metropolitan Manila has
always been categorized as one zone – the highest zone. In 2001, near-source factors have been
introduced that add to the design requirement for buildings within 15 km of such known sources
as the West Valley Fault.

Historically, the effect of changes in the several factors that contribute to seismic base shear is
such as to generally increase the base shear according to NSCB 1981, and to reduce (back to
almost NBCP 1977 level) according to NSCP 1992. By NSCP 2001, design base shear increases
again when within 15 km of known major earthquake source. It is noteworthy that design base
shear is not necessarily bigger in NSCP 1992 than previously, even after the 1990 Luzon
Earthquake. The increase by NSCP 2001 (associated mainly with near source factors) is mainly
motivated by observations in the 1994 Northridge Earthquake and 1995 Kobe Earthquake. What
the NSCP 1992 edition has strengthened are the additional requirements for reinforced concrete
members that are part of the earthquake lateral-force resisting systems.

The more important change between NSCP 1992 and NSCB 1972 are summarized below:
The minimum concrete compressive strength f’c is changed to 20 MPa (NSCP 1992) from 21
MPa (NSCB 1972).
Minimum width to depth ratio the flexural members is changed to 0.3 (NSCP 1992) from 0.4
(NSCB 1972).
Additional maximum longitudinal steel ratio (r = 0.025) in beams is added in NSCP 1992.

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Additional requirement to assure a strong column, weak beam behavior in NSCP 1992 is given by
the condition.
Maximum spacing of hoops in beams is replaced by 8*smallest longitudinal bar (NSCP 1992)
from 16*smallest longitudinal bar (NSCB 1972).
Maximum longitudinal steel ratio for columns is replaced by 0.06 (NSCP 1992) from 0.08 (NSCB
1972).
Additional requirement in transverse reinforcement spacing in columns in NSCP 1992 states that
tie spacing should be spaced no more than ¼ minimum member dimension or 100 mm.
New equations for development length is defined in NSCP 1992.

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Table 9.1.14 Chronologies of Coefficients and Factors in Seismic Design

(1) (2) (3) (4) (5)
NSCB 1972, NBCP NSCB 1981 NSCP Vol.1 1986 NSCP Vol.1 1992 NSCP Vol.1 2001
1977
Item (1st Edition) (2nd Edition) (3rd Edition) (4th Edition) (5th Edition)
(a) Formula for design base V = ZKC W V = ZIKCS W V = ZIKCS W V = (ZIC/Rw) W V = (CvI/RT) W
shear by static lateral V = (0.8 ZNvI/R) W
force procedure V = 0.11 CaI W
V = (2.5CaI/R) W max.
(b) Zone designation Zone 4 Zone 4 Zone 4
(c) Zone seismicity Z = 1.0 rock Z = 1.0 rock Z = 1.0 Z = 0.4 Z = 0.4
coefficient Z = 1.2 intermediate Z = 1.2 intermediate
Z = 1.4 alluv. or poor Z = 1.4 alluv. or poor
(d) Near-source factors Nv = 1.0 beyond 15 km
Nv = 1.2 about 10 km
Nv = 1.6 within 5 km
Na = 1.0 about 10 km
Na = 1.2 within 5 km
(e) Site and structure S = 1.0 ~ 1.5 S = 1.0 ~ 1.5 S = 1.0 ~ 2.0
resonance coeff.
(f) C coefficient Cv = 0.32 Nv for soil SA
Cv = 0.40 Nv for soil SB
Cv = 0.56 Nv for soil SC
Cv = 0.64 Nv for soil SD
Cv = 0.96 Nv for soil SE
C = (1.0) / (15 (T)1/2) C = (1.0) / (15 (T)1/2) C = (1.25 S) /
C = (0.05) / (T)1/3 Cv = site-specific for SF
C = 0.12 max. C = 0.12 max. (T)2/3
C = 0.10 max. Ca = 0.32 Na for soil SA
CS = 0.14 max. CS = 0.14 max. C = 2.75 max.
Ca = 0.40 Na for soil SB
Ca = 0.40 Na for soil SC
Ca = 0.44 Na for soil SD
Ca = 0.36 Na for soil SE
Ca = site-specific for SF
(g) Fundamental (elastic)
period of vibration of the
building (in seconds) T = (0.0906 hn) / (D)1/2 T = (0.0906 hn) / (D)1/2 T = (0.09 hn) / (D)1/2 T = 0.050 (hn) 3/4 T = 0.0488 (hn) 3/4
based on height and
base width (in meters)
(h) Fundamental (elastic) T = 0.075 (hn)3/4
T = 0.0731 (hn)3/4 Conc.
period of vibration of the Conc.
moment-resisting space T = 0.085 (hn)3/4 T = 0.0853 (hn)3/4 Steel
frame building (in T = 0.10 N T = 0.10 N T = 0.10 N Steel
seconds) based on
number of stories or
height (in meters)
(I) Structural system K or K = 0.67 ~ 1.33 K = 0.67 ~ 1.33 K = 0.67 ~ 1.33 Rw = 12 ~ 4 R = 8.5 ~ 2.8
Rw or R
(j) Importance factor I = 1.0 ~ 1.5 I = 1.0 ~ 1.5 I = 1.0 ~ 1.25 I = 1.0 ~ 1.25

(2) National Structural code of Philippines and its comparison with Japanese Code

Present national structural code of Philippines, Volume 1 covering Buildings, Towers, and Other
Vertical Structures, is the fifth edition following to, in turn, the first (1972), second (1981), third
(1986) and fourth (1992) edition. The code itself is composed of 7(seven) chapters; 1.General
Requirements, 2.Minimum Design Loads and Lateral Forces, 3.Foundations and Excavations,
4.Structural Concrete, 5 Structural Steel, 6 Wood, and 7. Masonry. Volume II of National
Structural Code of the Philippines covers Bridges and issued in 1997 as 2nd Edition. Seismic

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items such as Seismic Criteria, Earthquake loadings and Computational procedures are described
in the Section 208 of Chapter 2 as Earthquake Design. Besides, special seismic provisions for
each structure are described in several sections. For example, Section 421 of Chapter 4. Structural
Concrete describes the Special Provisions For Seismic Design. By comparison of the main factors
that constitute the seismic code provisions of Building Standard Low in Japan and National
Structural Code of Philippines, it is pointed out that while the two codes differ in detail, they have
essential common features and are comparable. Both codes include the effect of seismic risk,
spectral content, structural behavior and soil/foundation effect for seismic load. The force levels
to be applied to the building structure are almost compatible in the 5th edition.

However, in the actual design practice, design earthquake force by NSCP become to small in
comparison with Japanese Code. This is because large ductility factor (R) is applied to the
structure in case of NSCP. For instance, in case of concrete structure, although the detail of
column and beam connection does not allow high ductility factor (R), the code of the Philippines
specifies the R value up to 8.5. The ductility of this grade is not assured even in Japanese.

Reference to Section 9.1

Applied Technology Council, Rapid Visual Screening of Buildings for Potential Seismic Hazards: A
Handbook, FEMA-154, ATC-21, 1988.
Applied Technology Council, Rapid Visual Screening of Buildings for Potential Seismic Hazards:
Supporting Documentation, FEMA-155, ATC-21-1, 1988.
Association of structural engineers of the Philippines (ASEP); National Structural Code of the Philippines
2001,Volume 1, Buildings, Towers, and Other Vertical Structures.
Umemura; Hajime, A guideline to evaluate seismic performance of existing medium-and low-rise
reinforced concrete buildings and its application; Proceedings of the 7th World conference on
Earthquake Engineering, 1980.

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9.2 Infrastructures
9.2.1 Roads
Road network in Metropolitan Manila is the most important infrastructure for transportation that
maintains urban lives. The road network also has a function as lifelines and communication since
lifelines and communication facilities are buried under it. Therefore, there are two aspects on
earthquake disaster of the road network as follows:,
1) Damages on each individual structure
2) Dysfunction of the whole network system due to damage of individual structure.

Furthermore, road plays important roles for evacuation, fire fighting operation and medical
service as well as transportation of relief goods and rehabilitation activity.

In this point of view, it is essential to seize current status and function of the road network in order
to carry out planning of earthquake disaster prevention and reconstruction. It is also important for
this purpose to foresee damages of the road network by earthquake.

Table 9.2.1 shows distribution of road network in each category of road in Metropolitan Manila.
Road width less than 6.5 meters are considered as narrow roads which will have serious difficulty
to enter the area surrounded by narrow streets at the time of seismic disaster to do rescue activities
and emergency goods delivery and so on. Therefore, pointing out such area will help to prepare
for widening roads to keep safer area against seismic disaster.

Table 9.2.1 Distribution of Road Network in Metropolitan Manila

All Roads Outside Subdivisions Roads

Road (6.5m or over) Narrow Road (3 - 6.5m) Road (6.5m or over) Narrow Road (3 - 6.5m)
LGU
Length Density Length Density Ratio Length Density Length Density Ratio
(m) (m/Ha) (m) (m/Ha) (%) (m) (m/Ha) (m) (m/Ha) (%)
KALOOKAN CITY 650,012.69 122.38 39,078.81 7.36 6.01 398,158.19 74.96 28,789.96 5.42 7.23
LAS PINAS CITY 461,672.68 143.09 97.85 0.03 0.02 185,781.92 57.58 97.85 0.03 0.05
MAKATI CITY 512,744.28 160.43 921.63 0.29 0.18 394,737.07 123.51 340.34 0.11 0.09
MALABON 170,300.65 106.69 10,571.40 6.62 6.21 146,300.43 91.65 9,475.83 5.94 6.48
MANDALUYONG CITY 144,509.22 130.56 2,006.69 1.81 1.39 125,608.89 113.48 2,006.69 1.81 1.60
MANILA 746,599.79 180.85 36,037.06 8.73 4.83 696,995.10 168.83 35,713.41 8.65 5.12
MARIKINA CITY 350,735.66 154.88 3,155.52 1.39 0.90 179,758.28 79.38 2,754.59 1.22 1.53
MUNTINLUPA CITY 396,029.18 103.87 7,988.58 2.10 2.02 203,699.96 53.42 6,049.11 1.59 2.97
NAVOTAS 91,968.52 84.00 14,049.11 12.83 15.28 84,425.11 77.11 13,908.33 12.70 16.47
PARANAQUE CITY 593,826.98 130.21 813.73 0.18 0.14 327,514.52 71.81 710.09 0.16 0.22
PASAY CITY 195,883.72 110.18 789.63 0.44 0.40 194,352.43 109.32 789.63 0.44 0.41
PASIG CITY 399,651.73 125.35 2,282.78 0.72 0.57 303,010.54 95.04 1,612.68 0.51 0.53
PATEROS 19,232.89 98.60 982.49 5.04 5.11 18,439.02 94.53 982.49 5.04 5.33
QUEZON CITY 1,902,123.52 115.05 56,420.52 3.41 2.97 1,141,286.13 69.03 45,760.75 2.77 4.01
SAN JUAN 102,500.83 174.33 - - - 82,266.63 139.92 - - -
TAGUIG 259,954.90 94.46 1,041.51 0.38 0.40 221,326.98 80.42 1,041.51 0.38 0.47
VALENZUELA CITY 332,740.37 74.74 27,511.67 6.18 8.27 262,868.09 59.05 25,908.35 5.82 9.86
Total 7,330,487.61 122.61 203,748.98 3.41 8.27 4,966,529.29 109.19 175,941.61 3.87 3.54

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Figure 9.2.1 Road Network

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9.2.2 Bridges and Flyovers

1) Introduction

A bridge, in general, is a structure carrying a pathway or roadway over a depression or obstacles

such as rivers or creeks and roads in the case of a flyover bridge. These structures are basically
vulnerable to earthquakes. Collapse or damage to these structures would make it non-functional
and would prohibit the movement of emergency vehicles such as ambulance, fire trucks, police,
etc. In this study, data for bridges around the National Capital Region (NCR) were collected to
analyze vulnerability of these structures.

For this study, it was necessary to get vital information on the bridges in the NCR especially the
year of construction, number of lanes, length, girder type, bearing type, height of abutment,
retrofitting or strengthening works, etc to prepare database. The Study Team prepared a data table
from the original data received from the Department of Public Works and Highways (DPWH)
Bridge Inspection of 1995, to characterize these bridges. Of all the bridges in the NCR, 189
bridges and 38 flyovers were inspected and described as per the engineering data requirements.

It must be noted that in parallel to this study, another JICA Study called “The Study on the
Improvement of Existing Bridges along Pasig River and Marikina River in the Republic of the
Philippines” is in progress. This study is only focused on the bridges along Pasig and Marikina
River, however, very much detailed information is collected for each bridge. Therefore, results of
mentioned study must be considered to be in higher priority.

2) Relevant Organizations/Divisions pertaining to Bridges

DPWH is the governing body that designs, constructs, manages and maintains the bridges in the
NCR. Municipalities are responsible for monitoring the status of these structures.

3) Data Set up

The data received from DPWH were very limited for purposes of this study as the list of bridges is
not complete, and some needed data were missing. The Study Team conducted its own inventory
of the existing bridges in the National Capital Region (NCR). The Team, however, used the data
received from DPWH as a guide for naming, locating and dating the year of construction of the
bridges.

Table 9.2.2 is the summary of bridge inventory implemented in the Study. Figure 9.2.2 shows
location of 189 bridges and 38 flyovers. The field investigation undertaken by the study team
covers most of major bridges and flyovers, however, due to time limitation, not all of the bridges
and flyovers that exist in Metropolitan Manila can be investigated, therefore, bridge data must be
updated in the future. It is to be noted that most of bridges were investigated but flyover data is
limited.

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Table 9.2.2 Summary of Bridges and Flyovers Inventory in NCR

Type of Max. Height of Material of Number Foundation Minimum

Girder Type
Bearing Abut./Pier Abut./Pier of Spans type Seat Width

No of Bridges / Flyovers

Bearing (with clear design concept)

Municipality

Plain Concrete / Others

Reinforced Concrete
With Specific Device
Arch or Rigid Frame

Continuous Girder

2 or more spans
More than 10m
Simple Girder

less than 5 m

5 to 10 m
Movable

Narrow
Others
1 span

Wide
Pile
10 11 38 11 43 5 52 7 0 56 3 35 24 7 52 18 41
Manila 59
59 59 59 59 59 59 59
0 1 1 2 0 0 0 2 0 2 0 0 2 1 1 1 1
Mandaluyong 2
2 2 2 2 2 2 2
0 3 2 2 2 1 1 3 1 5 0 1 4 0 5 3 2
Marikina 5
5 5 5 5 5 5 5
0 1 8 2 7 0 3 6 0 9 0 1 8 3 6 7 2
Pasig 9
9 9 9 9 9 9 9
2 19 35 16 40 0 28 24 4 56 0 31 25 1 55 8 48
Quezon City 56
56 56 56 56 56 56 56
0 2 1 2 1 0 1 2 0 3 0 0 3 1 2 2 1
San Juan 3
3 3 3 3 3 3 3
1 1 6 3 5 0 5 3 0 8 0 4 4 0 8 3 5
Kaloocan 8
8 8 8 8 8 8 8
1 4 5 3 6 1 8 2 0 10 0 2 8 0 10 3 7
Malabon 10
10 10 10 10 10 10 10
0 3 4 1 3 3 6 1 0 7 0 0 7 0 3 3 4
Navotas 7
7 7 7 7 7 3 7
7 3 13 3 20 0 21 2 0 23 0 18 5 0 23 6 17
Valenzuela 23
23 23 23 23 23 23 23
2 0 4 3 3 0 6 0 0 6 0 3 3 1 5 0 6
Las Piñas 6
6 6 6 6 6 6 6
1 12 5 7 8 3 7 10 1 16 2 2 16 0 18 13 5
Makati 18
18 18 18 18 18 18 18
0 6 2 0 7 1 7 1 0 8 0 1 7 0 8 5 3
Muntinlupa 8
8 8 8 8 8 8 8
0 1 4 0 2 3 4 1 0 5 0 0 5 0 5 1 4
Parañaque 5
5 5 5 5 5 5 5
0 0 4 1 1 2 3 1 0 4 0 1 3 0 4 1 3
Pasay 4
4 4 4 4 4 4 4
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Pateros 0
0 0 0 0 0 0 0
0 1 3 1 3 0 4 0 0 4 0 1 3 1 3 2 2
Taguig 4
4 4 4 4 4 4 4
Total 227

Source: JICA Study Team, 2003

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Earthquake Impact Reduction Study for Metropolitan Manila in the Republic of the Philippines

Figure 9.2.2 Bridge Distribution in Metropolitan Manila

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4) General Features of the Bridge in the National Capital Region (NCR)

(1) Superstructure

The superstructure of most of the bridges in the National Capital Region which were inspected are
pre-stressed concrete girders which is expected due to construction limitations at the bridge site
and the volume of traffic in the area. The use of pre-cast AASHTO girders has been a trend in the
National Capital Region since installation of these girders are easier and reduces construction
time as compared to reinforced concrete deck girder and other types of superstructure. However,
there are still some bridges with RCDG superstructures. It is also noticeable that there are only
few bridges with steel superstructures. These few old bridges have steel beams, which are already
severely corroded. In contrast to this, recently constructed bridges/flyovers with longer spans
have resorted to the use of steel superstructure specially if horizontal curves cannot be avoided.

From the bridge survey, old bridges have simply supported girders even if they are multi-span
while recently built bridges were made continuous through diaphragms at the piers or through
continuous slabs over the piers.

Because of the July 1990 earthquake, restrainers were attached to the superstructures of some
major bridges/flyovers, which were constructed before the release of the latest AASHTO Code
and DPWH requirements. In addition, bridge seats were extended and shear keys were installed
between girders as part of seismic retrofitting.

(2) Substructure

The hammerhead type T pier was observed in most of the bridges in the National Capital Region
since it poses the least obstruction to traffic (as in the case of flyovers) and is cheaper than the
solid wall type. However the number of solid wall piers does not lag behind that of the
hammerhead as observed during the survey. For massive superstructures and very tall piers, the
double hammerhead or multi-column piers were adopted. It is only in few old bridges that one can
find pier pile bents.

Seismic retrofitting or strengthening works on the piers have already started with the major
bridges and flyovers.

The type of abutment generally adopted in the bridges cannot be ascertained because of the
presence of slope protection or shanties totally covering a portion of the coping down to the
foundation.

(3) Foundation

The type of foundation for most of the bridges inspected could not be determined because they are
not exposed except for one bridge, which has a pile bent pier. In general, for the new bridges /

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flyovers constructed in the late 1980’s, bored pile were used because they eliminate huge
excavation and construction of massive footings which obstruct traffic flow.

Spread footing was adopted in the municipalities located on stable and hard soil foundation such
as Quezon City.

It can be assumed that pile foundation is predominant since most of the municipalities are located
in alluvial deposits and in low lying areas where the presence of water table is a problem.

A detailed breakdown of the types and features of the bridges per municipality is discussed in the
next section.
9.2.3 Ports and Harbors
As Metropolitan Manila faces the Manila Bay, several important Ports and Harbors facilities
exists along the Manila Bay. Role of Ports and Harbors facilities are also important at the time of
earthquake events. Therefore, to understand existing condition of those facilities are necessary
for future preparedness against earthquake. Mainly, at the time of earthquake, ports and harbors
will function as major transport and stock facility from outside Metropolitan Manila and
neighboring country. Therefore, maintain the function will be important to keep smooth
transportation from outside.

In Metropolitan Manila, there are three main harbors, as follows;

- Manila North Harbor,
- Manila International Container Terminal, and
- Manila South Harbor

Those Ports and Harbors are operated by 2 private enterprises under control of the Philippine
Ports Authority (hereinafter referred to as “PPA”) and another one is directly operated by PPA.
PPA is the main government agency concerned with the planning and development of the
country's seaports, a vital link in both domestic and international trade. Established in 1974, the
PPA’s charter was amended by Executive Order 857 which expanded its functions to cover the
integration and coordination of port development nationwide while promoting the creation of
autonomous port development bodies in trading centers in the region.

In the Philippines, Ports and Harbors are basically classified by the Port Authority namely
Government and Private Ports, and importance is recognized but no official declaration of the
classification according to importance.

According to the interview and meeting with PPA, ICTSI, ATI, regarding countermeasures
against possible earthquakes, there are no specific preparations, unfortunately.

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Figure 9.2.3 Port Facilities of Metropolitan Manila

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Earthquake Impact Reduction Study for Metropolitan Manila in the Republic of the Philippines

1) Manila North Harbor

Manila North Harbor is function as Domestic Vessels Passenger Terminal, Domestic Container
Terminal, Domestic Non-container Terminal directly operated by PPA. This Harbor has eleven
(11) facilities as shown in Table 9.2.3.

Table 9.2.3 Facilities of Manila North Harbor

Source: PPA, 2002

LEGEND :
EXISTING STRUCTURE
SQUATTERS AREA
ER
AT TERRITORIAL
KW JURISDICTION
EA
BR
H
RT
NO

EXISTING BULKHEAD ABOUT

100 L.M. TO BE DEMOLISHED

MINAL 17
PIER-16 / TER
PIER-12 PIER-14
PIER-8 PIER-10 SLIPWAY
26 PIER-6 MARINE
PIER-4
Pier 2

27 Slip13
Slip 15 17
Slip 5 Slip11
Slip 3 Slip 7 Slip 9
MARCOS ROAD

4 5 6
3
1 2
EXISTING
SCALE
PLAN OF NORTH HARBOR, PORT OF MANILA
1: 10000

Figure 9.2.4 Existing Plan of North Harbor, Port of Manila

Source: PPA, 2002

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2) Manila International Container Terminal

Manila International Container Terminal (MICT) has function of International Container and
Non-container Terminal operated by private enterprise named International Container Terminal
Services, Inc (ICTSI). The MICT is located in Manila, which lies between the North Harbor and
the South Harbor, protruding westward into the Manila Bay with total port area of 606,740 m2. It
is situated just north of the mouth of Pasig River off Pier 2 of the PMO-North Harbor. The MICT
has a 1,300 meter wharf divided into five berths as shown detail in Table 9.2.4.

Table 9.2.4 List of Berths in MICT

Berth Length (m.) Controlling Depth (m)

1 250 10.0
2 250 10.0
3 250 10.0
4 250 10.0
5 300 10.0 – 11.0
Source: ICTSI, 2002

10

8 11
7

6
12
5
4
3

LIMIT
MIC T

13 0
2 14
15 B.M.

16
17

Figure 9.2.5 Existing Plan of MICT, Port of Manila

Source: ICTSI, 2002

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3) Manila South Harbor

Manila South Harbor has function of International Cargo and Container Terminal operated by a
private enterprise named Asia Terminal Incorporated (ATI), located South of International
Container Terminal. Manila South Harbor has 3 functions as follows;
Container Terminal (900m Berth-Pier 3, 5)
General Stevedoring (9 Berths, Pier 5, 9, and 15)
Domestic Cargo Terminal (5 Berths, Pier 15)

According to ATI personal, regarding strengthening of Piers, Pier 3, 5, 9 and 15 are old piers
constructed 30 to 40 years ago with the old design code. The Pier 5 extension was design and
constructed with seismic standard code of 1995.

Figure 9.2.6 Existing Plan of International Container Terminal, Port of Manila

Source: ATI, 2002

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