public disturbance was not realized. A number of projects were completed long after the deadlines. The high cost of using steel bridges was then not negated.
Generally, the DPWH selects the type of superstructure most suited for certain bridge lengths using certain factors. Under the DPWH Bridge Master Plan, the two factors to be adopted in deciding the type of bridge technology are as follows:
The assessment of financial and economic aspect of certain type of bridge in relation to its technical merits is also applied in the technical studies for foreign assisted projects. Thus, in various foreign assisted projects, cost comparisons between modular steel bridge and concrete bridge were undertaken as in these cases:
• In the DILG Austrian-assisted project, the modular steel bridges were selected for bridge spans of more than 20 meters as this type was evaluated to be more economically advantageous compared to reinforced concrete deck girder (RCDG).
• In the case of UK-Assisted Special Bridge Project, the use of steel bridging materials, was recommended for bridge spans which are 12 meters or above as it is claimed that it is more economical to replace short span bridges using local concrete bridging technology.
• In the financial cost comparison between Austrian-assisted modular steel bridges and OECF-funded RCDG/PCDG prepared by ICC-NEDA in aid of its review of Austrian-assisted President’s Bridge
Cost of the bridge
Suitability to site conditions
the technology to be used should be in accordance with specific geo-technical aspect of the location of the bridge
the bridge with the least cost requirement should be selected
OBSERVATIONS
Program II (DILG Component), it was disclosed that the RCDG bridge is cheaper than the Austrian modular steel bridge. At 15% discount rate, the present value of costs of the Austrian steel bridge is higher than RCDG by 18% to 23%.
• The cost comparison conducted by the DPWH between Waagner-Biro Modular Bridge System of Austria and RCDG/PSC Girder Bridge Local Technology also shows that the cost of modular bridge is higher by 23% to 49% when compared with RCDG/PSCG as tabulated
• In the Joint Study conducted by the DPWH and Japan International Cooperation Agency (JICA) published in the document titled Roads in the Philippines, 2003 Edition, bridges made of concrete are more cost effective when compared with steel bridge by 20% to 46% as illustrated below:
• As cited in the Local Bridges Master Plan, the DPWH recommended the following span lengths for concrete and steel superstructures:
Type of Superstructure
Recommended for (bridge length) Concrete Bridge:
1. Reinforced Concrete Precast slab
or Reinforced Flat Slab 6.00 m 2. Reinforced Concrete Deck Girder
(RCDG) 8.00 to 21.00 m
3. Reinforced Concrete Box Girder 22.00 to 30.00 m 4. Prestressed Concrete Bridge
• Channel Beams
The audit, however, disclosed that despite results of such studies demonstrating the cost effectiveness of concrete bridges over steel bridges, especially for short span bridges, the government still opted for the construction of bridges of various lengths under different bridge projects using modular steel. These projects included the construction of a number of short span bridges.
Project Length
No. of
It was claimed that, while steel bridges may be considered costly, the cost may be compensated by its speedy installations. It was perceived that as steel materials are pre-fabricated, construction time on site will be minimized; road closure time will be reduced; disturbance to the public using the road network will be minimized and benefits to be derived therefrom will immediately be enjoyed.
As further indicated in the Approved Project Proposal, the modular steel bridge was reported to have been selected for the President’s Bridge Project as the need is urgent and it is more appropriate. It is claimed to be very quick to assemble and is unlikely to suffer from poor quality workmanship as all components are pre-fabricated to high standards.
The audit, however, disclosed that while the government apparently sacrificed cost effectiveness for speedy installation, this advantage of being able to address the need on time did not materialize. Steel bridges, which should have been completed within 65 to 210 calendar days, were actually completed within 196 to 339 days as tabulated in the next page.
Project Region Name of Bridge
completed Difference San Antonio 135 267 132
This condition contributed to delay in project implementation that necessitated project extension. As discussed in Chapter I, the validity of loan agreements had to be extended for as many as three times covering as long as three years as the construction works could not be completed on time. As it is, the government is paying loans for bridges that costs more as the compensating benefits were not realized.
Comparison of the actual costs incurred by the DPWH in constructing steel and concrete bridges revealed significant variances. The comparison was made on bridges of the same or approximate lengths constructed almost at the same time. Results of comparison revealed that the cost of superstructure using steel was higher by 94% to 203%
than the cost of superstructure using concrete as illustrated below:
Concrete Steel Difference
Bridge (lowest cost of steel bridge less cost of concrete
bridge) % 30 P 4,256,073* P 8,241,220 P 8,247,220 P 3,985,147 94 42 3,859,939 11,461,310 P 11,363,310 7,503,371 194
55 4,820,065 14,616,734 9,796,669 203
Note: * Prestressed I Girder Type IV-B
2. Out of the total 36,871.67 lm bridging materials delivered under the