San Sebastian Basilica

SAVING SAN SEBASTIAN:

From points to alignments and movements

Location

The current church was completed in
1891. But originally was built in the 17th century, made of wood and burned
down. Succeeding structures were built of brick, but also destroyed by fire and
earthquakes. In the 19th century, Manila suffer 3 earthquakes, the last one in
1880 destroyed many buildings in the city.

As this one: the cathedral of
Manila in Intramuros. For these reasons, the priests hire the Spanish Arquitect
Genaro Palacios, to create a structure that would not fall victim to these kind
of disasters

Palacios worked with the help of Belgian
contractors to create a design of an all steel neo-gothic style church that was
both, fire and earthquake resistant.

Parts were manufactured in Belgium,
the glass windows were imported from Germany and the finish paintings were made
by local artists.

The 52 tons of prefabricate steel were
transported in 8 shipments, from Belgium to Philippines. The 1st one was in
1888. So the earthquake was in 1880, in 1888 was the 1st shipment and the
basilica was completed in 1891.

Here you can see the basilica in a
construction phase and how was the life around when it was finished.

But Manila not only suffers natural
disasters. This city was one of the 4 cities that more suffered in the WWII. It
was a massive destruction!

Luckely SSB and the area around was
intact as you can see. So, what we have is a survivor church that is going to
be the 1st good intervention in heritage in the country, a good example to
follow. Why?

This is an example of another
church in Philippines. This picture shows us how it was originally and this other
one, how is now.

Or this other example. In both of
them just part of the altar and the perimetral walls were kept. They change completely
the sense of the space.

And here is SSB a century ago, and
now. Just the furniture and the tile pavement added up the wooden one changes.

The full church was painted since
the begin to look as a stone church. Even the exterior was painted to simulate
this effect.

But over the years the external
paint change for maintain the church and layers of paint was added to the
original one.

Here is how it looks now.

But the interior paintings are
still there and are all original and authentic.

However, the church was not built
to be a waterproof structure, and Philippines is a tropical country with a wet
and rainy season between June and October. And in this season is normal to have
typhoons and floods. I was there last August when they got the worst flood in 3
years and I can tell you that is really like that.

So, how is it affecting the
SS B?As you can imagine, there are leaks
and corrosion all over the church.

Another problem for the
preservation team was that they couldn't see the state of conservation of
mostly of the internal columns, because there is a second layer just for
decoration around the structural ones.

You can see here how they look in
an upper level of one of the towers.

What they did is go to the attic,
open the top of the columns and through down a camera. And guess what they
found.

There is water on the bottom of
some of the columns. So What we have until now is a lovely and original church,
built in metal with apparently a lot of deterioration.

Special buildings need special
actions! Is for this, that many volunteers are helping in this project to save
SSB. From architects and structural engineers in NYC, conservators in
Pennylvania, local photographers, writers and designers; to digiScript and I.
All of us are helping Tina Paterno and her team to conserve this amazing
building. As all of you know, heritage field is a delicate sector where not
always is easy to take founds to study properly the building. Even if the
technology is there, usually they cannot afford to pay for it. And here is
where laser scanning was involved and the technology steps in.

Digiscript Philippines donated the
service and they scan the full basilica in 4 days with a total of 85 scans that
were registered together to create a 3d point cloud data set.

Paulo Canivel & Conrad Alampay

And I am the person who works with
these data to help the team to understand what is happening in the building.

Leica C10 scanning the interior of SSB

Usually I used the scan data to
create high accuracy CAD drawings, but in this case, the team already had
architects who made a traditional survey before DigiScrip scan de basilica. So
to take advantage of their work, they have been provided with high-quality
orthoimages to superimpose over their drawings. This way the architects can see
where errors or movements are and provide any needed corrections.

Building columns and steel panels
on the walls are manifested in misalignments. The alignments of a building are
very difficult to measure with traditional methods. For this reason, the
structural engineers have been provide with enough information to measure it. I
took the resulting of a point path area from the bottom and the top of the area
to study and measure the angles with the vertical and horizontal plane. This
way it's better than just take a individual point, it's more reliable to take a
path area.

With these angles, generic heights
from the original design and basic trigonometric functions they will be able to
calculate the exact displacements of the external columns and cornices. (I
couldn't map the internal columns because of the second layer).

Next output is a well-know method
to create photoplans for preservation projects. But I have to say that this is
not photogrammetry, so the surveyors in the room can avoid this part of my
presentation. Well, to create them it is necessary to superimpose the
orthoimages from the point cloud data with the CAD drawings also created from the
data and the individual pictures like a puzzle. But in this case, because I did
not make the CAD drawings, I use just the orthoimages to rectify the individual
pictures. This one, for example, can easily containe around 50 individual
pictures.

Each picture was rectified with one
of many computer software programmes currently on the market, as photoshop,
having the orthoimage on the background, manipulating them to move the pixels
to the right position. This position is shown with the overlay between different
parts of the process.

All the pictures have been taken
with a reflex camera and it is recommend to have a professional photographer on
the team. In this project Estan Cabigas was the photographer who took the high
quality pictures. Each shot provides an adequate overlap area with the continues
one and were taken maintaining the focus the more perpendicular as possible to
the surface in order to minimize distortions of perspective. Lastly, the
pictures of this puzzle have been treated so they are not visible on the final
file saved in .tiff format. This final file is inserted in the CAD drawings
files inside the respective sections. In this way, the photos become metrically
correct (according to the nominal scale declared). This is a powerful tool in
preservation studies because it will provide a record of colour, materials,
texture, degradation and the current state of conservation.

Estan Cabigas taking pictures fot the photoplans

The main part of my work consists
in the surface mappings, topographic maps of linear surfaces. These forensic
studies clearly illustrate deviation from horizontal and vertical planes. With
this information we can quickly identify problem areas and the surface movement
that the wind might caused to the surfaces of the church. It is particularly
important to this project because there are a lot of movements in the building.
This method can reveal causal mechanism for this condition and help the
structural engineers to confirm if their suspicious about the warping of the
wall panels are due to seismic tremors.

This last method consists of
slicing the external and internal walls, floors, ceilings and external columns.
I couldn't apply this to the main ceiling of the church because it cannot be
applied to non linear surfaces, such as curved, spherical or parabolic. The topographic
maps are coloured and each colour is a slice of 3mm of thickness. The number of
colours chosen has varied depending on the size of the area to study.

In the columns I found the presence
of oil canning. A structural engineer in NY recommends us to check for this
concept. It's a waviness that can appear in flat metal panels that usually
originates from the steel mill. It is an aesthetic problem and normally
structure integrity is not affected. However, structural integrity must be
reviewed if the distortion results from an extreme external influence. Waviness
has been located in the 2nd level of the front faces of 10 columns and also in
the lateral faces of 2 columns.

Until now, I only know this latter
method to extract relevant information from the point cloud data to use in
preservation studies. However, as an architect, I believe that it's possible to
gain more practical information from the point cloud data. It's been more than
10 years that this technology is on the market. I think it's time to obtain
more than just great surveys and visualizations, because at the end, that's
just a base to start to study a historic building.

2nd Scanning phase (August 2012):

TrueView image

Charles Cunanan

Lourdes G. Cerezuela

Lecia C10 scanning inside one of the towers

Roz Li, from Li-Saltzman Architects in NYC, showed me this project last February and I'm going to collaborate directly with them this month of August. I'm in permanent contact with the Conservator Tina Paterno, foundation Executive Director of San Sebastian Basilica Conservation and Development Foundation Inc., who is getting incredible support and contributions to this project.

The non-profit organization, BAKAS PILIPINAS, is trying to raise funds for it. If you hear of any grant foundations who you think may be interested in this project, please let us know. We would also welcome volunteers/interns to work with us in Manila.

They are currently doing the Investigation Phase - doing probes of the columns for corrosion. They finished the measured drawings recently. They received a grant from the US Ambassador to the Philippines for the Investigation Phase. Meanwhile, they are also interested in doing a socio-economic-cultural historical survey of the surrounding neighborhood, which is a poor neighborhood. They are very interested in using the preservation of the Basilica as a job-creating and economic development tool for the neighborhood.

SSB Point Cloud Video: