Page 36 - Building Regulation and Design Guidelines - Structural (Grey Code)
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SECTION: 2 STRUCTURAL DESIGN GUIDELINES – BUILDING STRUCTURES SECTION: 2 STRUCTURAL DESIGN GUIDELINES – BUILDING STRUCTURES
2.5.2.3 GENERAL CONSIDERATIONS considered in design of vertical and horizontal members.
In plane section modifiers for slabs shall be reduced to
1. Where the structure is composed of a flexible upper account for concrete cracked section area as per the code
portion and lower stiffer basement/podium, the seismic
scale factor shall be calibrated at foundation level to governing the design.
design the basement elements and at top of basement to 10. Structural design shall accommodate shrinkage, creep and
design the tower elements. thermal strains by providing appropriate reinforcement or
specifying control or expansion joints. Expansion joints
2. The augmented section modifiers could be used to
check the maximum drift and vibration acceleration only shall satisfy seismic requirements of relevant code.
as permitted by ACI, provided that the designer has to 11. Floor slabs shall be designed to be adequately supporting
estimates the degree of cracking and comply with the the entire construction loads from the next slab without
serviceability limit state at the adopted design service compromising the ultimate or/and service limit states
loads. requirements.
3. Permanent drift due to gravity loads to be checked and 12. Transfer element design shall be confirmed by alternative
shall be eliminated or minimized with proper technical design method.
arrangement.
13. For dead loads & earth pressure/uplift load combinations,
4. All structural framing elements and their connections, not the loads shall be factored as per clause 1909.2, UBC1997.
required by design to be part of lateral–force-resisting
system, shall be designed to be adequate to maintain 14. Individual pile caps and isolated footings subjected to
support of design dead plus live loads when subjected to seismic forces shall be interconnected by ties. Such ties
the deformation caused by seismic forces. shall be designed as per clause 1807.2, UBC 1997.
5. Effects of axial long term shortening due to elastic, 15. Third party structural review is required for
shrinkage and creep effects shall be investigated and specific structures as classified in CED circular Ref.
accounted for in the design and construction. If measures CIRCULAR-52027/2009/sk dated 26-04-2009.
to compensate for the effects of differential shortening
are taken, consultant shall include such information on 2.5.2.4 SERVICEABILITY LIMITS
engineering drawings and relevant documents. 1. All buildings shall be designed to limit maximum drift
6. Manual take down of gravity loads for all key vertical under 50 years wind load to 1/500 of building height.
elements to be compared with resulting loads from 2. All buildings shall be designed to limit inter-story drift to
analyzed model. 1/500 of the story height and not more than 10mm under
7. Loading and Design shall be carried out in compliance serviceability of 10 years wind. If no wind tunnel test results
with the code that the governing load combination was are available, 10 years serviceability wind speed of 38 m/s
derived from. can be adopted in Dubai for inter-story drift calculations.
Inter-story drift due to seismic shall be assessed and shall
8. Calculation of effects of accidental eccentricities and load not exceed the limitations of clause 1630.10, UBC 1997.
reductions shall be consistent with the code used for the
structural design. 3. Adequate provisions shall be adopted to eliminate risk of
damage to non-structural elements due to inter-story drift
9. Thermal effects shall be evaluated based on realistic and long term deflection of beams and slabs.
temperature distribution. Seasonal temperature change
shall not be less than 25 deg. C or in accordance 4. Wind induced vibration due to 10 years wind shall be
with credible local climate record. This effect shall be limited to 15 milli-g for residential and hotel buildings
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