Page 48 - Building Regulation and Design Guidelines - Structural (Grey Code)

SECTION: 3 GUIDELINES FOR PRE STRESSED CONCRETE WORKS (SLABS) SECTION: 3 GUIDELINES FOR PRE STRESSED CONCRETE WORKS (SLABS)

5. CVs for designers and site engineers 3.6.2.5 STORAGE, TRANSPORTATION, HANDLING AND ERECTION
6. Quality assurance and quality control procedures. Pre cast units shall be designed to resist all kinds of stresses
induced by storage, handling, transport and erection, without
7. Test certificates, design mix… and full scale test.
permanent deformation and shall be braced for handling and
8. List of projects already completed successfully with the transportation when necessary, Figs (3.14 a - f).
same product/s.

3.6.2 PRE CAST DESIGN GUIDELINES
3.6.2.1 DESIGN CODES:
The following codes and reports are permitted to be used in pre-
cast design:

1. BS 8110-1997
2. ACI 318 – 2008
3. PCI Design handbook fifth edition. Supplemental line with “ Come-Along”
4. CPCI design manual 4.
Fig. (3.14a) Supplemental Lifting Points
5. UBC 1997 and ASCE 7-7 (Seismic loads).
6. ASCE 7 – 2005 (Wind loads).
Crane Line Load = W
7. IBC-2006 (International Building Code) WF
T = Sling Load = 2
3.6.2.2 Durability: Material strength of factory produced pre cast
reinforced and pre-tensioned concrete components shall comply Sling Angle =
with design performance of the structure during its life span.
Concrete cover, fire resistance, crack and deflection control and
resistant to chloride ion attack should be maintained within the
relevant codes limitations.
Total Load = w
3.6.2.3 Concrete strength: The 28-day design strength of concrete used
in pre-cast and pre stressed products shall be 40 MPa minimum.
The transfer strength (when the pre stress force is transferred to
the concrete) can be 25 MPa or as required by the design. Multiplication Factor “F” for the Total Load
on Sling With a Sling Angle of
3.6.2.4 Span to depth ratio: as a guidance for span to depth ratios of 90 75 60 45 30 a
flexural elements, the following figures could be adopted: F 1.00 1.04 1.16 1.41 2.00

1. Hollow core floor slabs: 30 to 40 NOTE: is usually not less than 60
check bl-directional sling angle.
2. Double tee floor slabs: 25 to 35 a A 30 sling angle is not recommended.
3. Beams: 10 to 20 Fig. (3.14b) Force in Lift Lines

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