Civil Engineering Reference
In-Depth Information
2.5 Fabrication and Erection
The role of the structural engineer during fabrication and erection differs in important
details from that in other forms of construction. The engineer's work generally
includes the following:
1. Response tocontractor requests for information.
2. Consulting on or review of the contractor's erection scheme. The engineer
must pay particular attention to stability of supporting members during
erection in structures where the supports rely on the fabric membrane or on
the cables that are installed together with the membrane. In some larger
structures, the engineer must check supporting members and cables for
loading conditions that occur only during erection.
3. Minimum construction observation visits by the engineer include those
dictated by the building official or by contractual agreement. Inspection of
foundations and supporting members will be similar to those performed on
more conventional structures. The engineer will generally make at least a
qualitative evaluation of cable and membrane prestress by visual inspection
and touch. The fabric surface should be walked or, where necessary,
inspected from a lift to check for pinholes or tears that occurred during
erection. Special attention is required for evidence of damage or overstress at
cable cuff terminations, membrane plates, tension rings, and other
singularities. Where fabric interfaces with rigid steel elements, the final as-
built condition should be reviewed for fabric tears where the fabric comes in
contact with the steel under load. This inspection should generally be
performed before the erection crew has demobilized, in order to facilitate any
required corrections.
2.6 Inspection and Maintenance
On some structures, the fabric roof installer may be contracted to perform one or
more inspections following the completion of construction. On structures employing
polyester or other material subject to creep strain under prestress, retensioning may
be carried out in conjunction with inspection 6 to 12 months after completion. For
large structures, a regular inspection and maintenance program should be established
with the owner, and is usually carried out by the fabric roof installer, as described in
Section 9.3.5.
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