A third bridge to Mactan?

People have been continuously arguing about the proposed third bridge between the island of Mactan and mainland Cebu.  On one hand, there are diverse opinions on where it should be located, with the majority convinced it should be at the southern part of the metropolis this time, connecting Cordova and downtown Cebu City, connecting directly with Osmeña Boulevard.  Wouldn't that be “cool?”  Then we start to imagine other future “developments” branching out from that concept.  Then we start imagining many other future things that might happen.

The main drawback of trying to look at things this way is that it's a two-dimensional image.  In engineering and architecture, we call this the “plan” view, which is, looking at things from above.  Other may call this an aerial view or a map or satellite view.  Works well most of the time, but may have implementation challenges later on.  The only way to address the challenge is to consider the “elevation” view, or how it would look from the ground.  Then we can see some realistic restrictions which have otherwise escaped our analysis when viewed from above.

If a bridge connecting Cebu and Mactan would best be placed as described above, the first question that we should ask is, “Why is the second bridge, the Marcelo Fernan Bridge, not built there in the first place?”  The second bridge was planned in 1991 after that notorious ship, Sanko Elegance, bumped the (first) Mandaue-Mactan Bridge, breaking off one span of lower chords, disabling the bridge for two months and crippling Cebu's economy in the process.  The Osmeña Blvd.-Shell Island-Cordova alignment was considered then and in fact, was highly favored.  Yet the decision made at that time was the present location, beside the first bridge.

A bridge is defined as a structure carrying a road (or railroad) across a river, cliff, another road, railroad, or other obstacles.  In short, bridges connect points which cannot be connected by the usual normal means.  These are also made in order to bypass or circumvent points of areas where other activities occur and in order not to interfere with them.  A tunnel, built underground would serve exactly the same function.  In fact, in engineering, we don't differentiate between a bridge or a tunnel - the first is simply above-grade; the latter below grade.  At-grade is synonymous with natural ground level.

So a third bridge to Mactan, if built at the southern part of the metropolis, would either be a long bridge or a tunnel.  The next obstacle would be its length.  Bridges are not stairs that you can build straight up - they have minimum allowable slopes, for safety purposes.  And since a bridge in the south should have minimum height clearances to allow big ships to pass underneath, this would have to be unnecessarily long.  Note that ships that ply from Manila to Cebu do not pass under the existing two bridges - they can't, because of the height restriction and they sail all the way around Mactan and Cordova and enter the Port of Cebu from the south.  We can't have the third bridge in the south with the same height clearance as the two existing bridge, otherwise, we have to close the Port of Cebu.

So we have to design it very high, so high in fact that it might end up with approaches so far inland.  It might be a good icon, though, imagine that very high bridge structure so far up in the sky with the city underneath.  The cost would be monumental.  The other option would be to dig below the earth and bore a tunnel.  The limiting depth would be the existing depth of Mactan Strait, which is not much, so the approaches would be shorter and won't reach up to the Capitol.  But it would still be costly, too, and this needs to be evaluated further.

A third option and not a popular one because most people like the more grandiose idea of a bridge or a tunnel better is simply to put up a short roll-on-roll-on (RoRo) service between Shell Island and the city and build a road direct to Lapu-Lapu City or Cordova, wherever we like.  It doesn't sound grand, but's it's more workable and flexible, not to mention, less expensive.  Many will have issues on capacity but this is a matter of design.  In the end, as we have established in the past, what matters most is the financial and economic viability of the options.  At any rate, it is best we consider all options at the moment and do a scientific feasibility study and a complete due diligence work before coming up with a decision.

Including one which would not require building a third bridge!  (To be continued…)