Page 324 - Forensic Structural Engineering Handbook

TEMPORARY STRUCTURES IN CONSTRUCTION 10.13

the process of updating and revision at the time of this writing, and the second edition is
expected to be published in 2010. The standard provides design criteria and design loads
for temporary works during construction which are used for temporary support and access
during construction, as well as for partially completed structures during their construction
phases. The standard is intended for use by engineers familiar with the design and perfor-
mance of structures. The standard does not specify who the responsible party is for the
design of temporary works or who the responsible party is for on-site supervision of the
construction of temporary works. The standard is intended to complement SEI/ASCE 7-05,
Minimum Design Loads for Buildings and Other Structures. The standard addresses loads
imposed by construction equipment, materials, and personnel; as well as environmental
loads and earth pressures during construction. The wind and seismic loads are probabilis-
tically based, and account for the short lifetime of temporary works during construction,
resulting in environmental loads on the temporary works that are generally lower than the
respective loads in SEI/ASCE 7-05 for permanent structures.
For bridges, the FHWA document: Guide Design Specifications for Bridge Temporary
6
Works is a valuable guide.Some state and municipal design manuals, such as those by CAL-
TRANS and the New York City Transit Authority, are good sources for local conditions.
Some of the foreign design codes and standards that have criteria specific to temporary struc-
tures are the various Canadian Standards, the Construction Safety Codes of the various
Canadian provinces, the British Code of Practice for Falsework and the one for Scaffolds,
the Australian standard for formwork, the “Design for Construction and Temporary
Structures” section of the Australian State Road Authorities’ Bridge Design Specifications,
the New Zealand Code of Practice for Falsework, the Japanese Bridge Standards, the Israeli
Standard on Formwork, the Russian State Standard Specifications for scaffolding, erection,
platforms, etc., the Eurocodes, and others.

Building Codes
Prior to 2006 most local building codes in the United States, were patterned after the so-
called model building codes, which included the National Building Code (NBC) by the
Building Officials and Code Administrators (BOCA), the Uniform Building Code (UBC)
by the International Conference of Building Code Congress (ICBC), and the Southern
Standard Building Code by the Southern Building Code Congress (SBCC). With the pub-
lication of the 2006 International Building Code (IBC) these model codes were replaced by
the IBC, but forensic investigators should still be aware of the earlier codes, and have
access to them when dealing with construction claims and disputes that have to do with
problems of construction under those past requirements.
Provisions related to construction safety and temporary works in the US model codes
were generally minimal or nonexistent—they did not intend to place controls on construction.
For example, the provision in section 1612.5, Construction Loads and Erection Stresses, of
the BOCA National Building Code 1996:

Provisions shall be made for temporary construction loads which occur during the erection of
the building; and all structural members and connections shall be designed and erected so as to
prevent overstressing during construction

was typical of the superficial treatment of temporary structures in building codes. What
provisions were to be made and for what magnitudes of temporary erection loads? What
was considered overstressing?
The International Building Code, as its predecessor model codes, does adopt many of
the national design standards developed by organizations such as the American Concrete