Civil Engineering Reference
In-Depth Information
them out? Professor Chern dismisses this as bordering on superstition. “Basically Taiwan has
a lot of 12-story buildings, especially central Taiwan. You hardly see any 20-story high-rises
in those areas hit by the quake. The reason for this is that buildings under 50 meters in height
don't have to go to a special engineering committee to be approved, so 12 stories is just right.”
Approval of a structure by qualified structural engineers, and correct enforcement of the build-
ing codes, is the crux of the problem, Chern believes.
Another example is the Kobe earthquake in Japan on January 17, 1995. It was
observed that a large number of 20-year-old and older high-rise buildings collapsed
at the fifth floor. The cause of these building collapses was apparently an older ver-
sion of the building code that allowed a weaker superstructure beginning at the fifth
floor.
Even with a technically sound building code without loopholes, there could be many
other factors that are needed to produce earthquake-resistant structures:
1.
Qualified engineers:
There must be qualified structural and geotechnical engineers
who can prepare seismic designs and building plans. However, the availability of a profes-
sional engineering group will not ensure adequate designs. For example, concerning the
collapse of structures caused by the Chi-chi earthquake in Taiwan on September 21, 1999,
Hands (1999) states:
Professor Chern is particularly damning of some of his fellow engineers, and the
professional associations to which they belong. “In 1997 we had 6,300 registered civil
engineers. Three hundred of them are working in their own consultancies, and 2,800 are
employed by building contractors. That means that the other 3,300, or more than half, are
possibly renting their licenses.” Asked to explain further, Chern said that it was common
practice for an engineer to rent his engineer's license to a building contractor, so that the
contractor could then claim the architectural drawings had been approved by a qualified
engineer, without the engineer even having seen the blueprints. Chern sees the problem as
stemming from the way the engineers' professional associations are run. “When they elect
a president of the association, the candidate who favors license-renting will get all the
votes from those people and win the election, and then he won't be willing to do anything
about the problem.”
2.
Permit process:
After the engineers have prepared the structural plans and specifi-
cations, the plans must be reviewed and approved by the governing agency. The local juris-
diction should have qualified engineers who review the designs to ensure that proper
actions are taken to mitigate the impact of seismic hazards, to evaluate structural and non-
structural seismic design and construction practices so that they minimize earthquake dam-
age in critical facilities, and to prevent the total collapse of any structure designed for
human occupancy. An important aspect of the permit process is that the governing agency
has the power to deny construction of the project if it is deemed to be below the standard
of practice.
3.
Inspection during construction:
Similar to the permit process, there must be ade-
quate inspection during the construction of the project to ensure that the approved building
plans and specifications are being followed. Any proposed changes to the approved build-
ing plans and specifications would have to be reviewed by the governing agency. The pro-
ject engineers should issue final reports to certify that the structure was built in
conformance with the approved building plans.
4.
Construction industry:
An experienced workforce that will follow the approved
plans and specifications is needed during construction. In addition, there must be available
