Page 63 - Urban Construction Project Management

38 Chapter Three
components are to perform in order to determine their effectiveness. Thus, the PM must
be familiar with the drawings and specifications to understand the working capability
of all the components that constitute the project.

MOCK-UPS AND WIND MODEL TESTS

In addition to tests that are performed in the field, certain assemblies of buildings are
mocked up at full scale and fully tested. This would be true for the assembles that are
associated with curtain wall construction. These mock-ups are required because it is
extremely difficult to test in situ (on site when constructed). Also, it is more cost effec-
tive to check the assembly in the laboratory rather than finding a failure when the
assembly is installed. In addition, in the urban environment, wind loads on a building
are impacted by other structures in the area. To account for this variable, a model of the
building is created, along with models of the surrounding buildings. These models are
then tested in a wind tunnel. Sensors are placed on the building being tested and read-
ings are taken of the pounds per square foot (psf) that would be imposed on the total
outside surface of the building. The wind tunnel loads that are used for testing are based
on historical wind data of the area in question and requirements from the local code.

When a mock-up of the curtain wall is constructed (full scale) in a laboratory setting, it
usually consists of a typical two-story curtain wall section of the building. Any unusual
condition may have to be mocked-up for testing as well. The mock-up assembly is tested
to determine:
1. Amount of air and water infiltration observed
2. Drainage of the system
3. Structural capability of the mullions and glass
4. Expansion and contraction of the assemblies
5. Deflection of materials

Corrections are made to the mock-up, if required, so that all the assemblies are perform-
ing according to specified criteria. The components are then fabricated based on the
results of the test. Thus, the installation of the curtain wall should perform according to
the standards established by the organizations. This eliminates the potential for failure
that could have occurred and the consequence of replacement of the curtain wall if the
mock-up was not tested in the laboratory.

FIELD FABRICATION OF STRUCTURAL COMPONENTS
(MIXTURE AND COMPONENTS)

Structural components that are fabricated on site by trades people constitute the
greatest risk for a catastrophic failure. This is due to the fact that control of putting parts
together in the field is not done with the same diligence and controlled environment as