There are some circumstances, however, where the rigid diaphragm assumption may not be appropriate: floors with numerous openings, roof diaphragms of metal decking without concrete fill or of plywood sheathing, etc. Long, narrow diaphragms may be considered rigid in one direction but not in the other. For structures with multiple wings, such as L- or C-shaped buildings where the ends of the wings can drift independently of each other, the rigid diaphragm analysis may not be appropriate since it would lock the ends of the wings together, constraining them to move in unison Seismic analysis and design

1. 1
Dr Youssef Hammida
Diaphragm For Seismic Analysis
‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺔ‬ ‫ﺗﺻﻣﯾم‬‫ﻟﻣﻘﺎوﻣﺔ‬‫ﻗو‬‫ى‬‫اﻟزﻻزل‬
Rigid – Semi Rigid - Flixible

2. 2
The rigid diaphragm‫اﻟﺻﻠب‬ ‫اﻟدﯾﺎﻓرام‬
is a convenient analytical technique for distributing the lateral forces
to the frames and walls; forces are distributed to those elements as a
function of their relative stiffnesses and position.
Analysis using the rigid diaphragm assumption is generally adequate
when the diaphragm in-plane stiffness is high relative to that of the
frames.
There are some circumstances, however, where the rigid diaphragm
assumption may not be appropriate: floors with numerous openings,
roof diaphragms of metal decking without concrete fill or of plywood
sheathing, etc. Long, narrow diaphragms may be considered rigid in
one direction but not in the other.
For structures with multiple wings, such as L- or C-shaped buildings
where the ends of the wings can drift independently of each other,
the rigid diaphragm analysis may not be appropriate since it would
lock the ends of the wings together, constraining them to move in
unison.
In these cases it may be necessary or required to analyze the
structure modeled with semi-rigid diaphragms. It is often appropriate
to analyze some stories using the rigid diaphragm assumption and
other stories using the semi-rigid assumption.
‫اﻟ‬ ‫ﻣن‬ ‫اﻷﻓﻘﯾﺔ‬ ‫اﻟﺣﻣوﻻت‬ ‫ﯾﺣول‬ ‫اﻟذي‬ ‫ھو‬ ‫اﻟﺻﻠب‬ ‫اﻟدﯾﺎﻓرام‬‫واﻟزﻻزل‬ ‫رﯾﺎح‬
‫ﺻﻼﺑﺗﮫ‬ ‫وﻓﻖ‬ ‫ﻛل‬ ‫واﻷﻋﻣدة‬ ‫اﻟﺟدران‬ ‫ﻣن‬ ‫اﻟرأﺳﯾﺔ‬ ‫اﻟﻌﻧﺎﺻر‬ ‫اﻟﻰ‬
‫ﻛﺑﯾرة‬ ‫ﺻﻼﺑﺗﮫ‬ ‫ﺗﻛون‬ ‫ﻋﻧدﻣﺎ‬ ‫ﺻﻠب‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﻓرض‬ ‫ﯾﻣﻛن‬ ‫اﻟﺗﺻﻣﯾم‬ ‫ﻓﻲ‬
‫ﺻﻼﺑﺔ‬ ‫ﻣﻊ‬ ‫وﻣﻘﺎرﻧﺗﮭﺎ‬‫اﻟرأﺳﯾﺔ‬ ‫اﻟﻌﻧﺎﺻر‬

3. 3
‫ھﯾﺎﻛل‬ ‫ﻣﺑﺎﻧﻲ‬‫ﻣﻊ‬‫أﺟﻧﺣﺔ‬،‫ﻣﺗﻌددة‬‫ﻣﺛل‬L-‫أو‬‫اﻟﻣﺑﺎﻧﻲ‬‫ﻋﻠﻰ‬‫ﺷﻛل‬C‫ﺣﯾث‬‫ﻧﮭﺎﯾﺎت‬‫اﻷﺟﻧﺣﺔ‬‫ﯾﻣﻛن‬‫أن‬
‫ﺗﻧﺗﻘل‬‫ﺑﺷﻛل‬‫ﻣﺳﺗﻘل‬‫ﻋن‬‫ﺑﻌﺿﮭﺎ‬،‫اﻟﺑﻌض‬‫ﻗد‬‫ﻻ‬‫ﯾﻛون‬‫ﺗﺣﻠﯾل‬‫ﺻﻠب‬ ‫دﯾﺎﻓرام‬
‫اﻟﻣﻧﺎﺳب‬ ‫ھو‬‫ﻷﻧﮫ‬‫ﺳﯾﻛون‬‫ﻗﻔل‬‫ﻟﻧﮭﺎﯾﺎت‬‫اﻷﺟﻧﺣﺔ‬،‫ﻣﻌﺎ‬‫وﺗﻘﯾﯾد‬‫ﻟﮭم‬‫اﻟﺣرﻛﺔ‬ ‫ﻣن‬
‫ﺻﻠب‬ ‫ﻏﯾر‬ ‫دﯾﺎﻓرام‬ ‫ﯾﻔﺿل‬ ‫ﻟذﻟك‬
diaphragm can be considered "flexible" if it is constructed of
untopped steel decking or wood structural panels and the structural
system is steel, concrete or masonry frames or walls, or when the
maximum in-plane deflection of the diaphragm under lateral load is
more than two times the average drift of the adjacent lateral frames.
In contrast, it specifies that a diaphragm can be considered "rigid" if it
is a concrete slab or concrete-filled metal deck, with some limitations.
Otherwise, the diaphragm must be modeled and analyzed as semi-
rigid.
It may also be more practical to analyze the diaphragms as semi-rigid
and avoid the need to perform the deflection calculations necessary
to classify the diaphragms otherwise.
It is permissible in any case to model and analyze the diaphragm as
semi-rigid.

4. 4
‫اﻟﺳﻘف‬ ‫ﻣﺛل‬ ‫ﻣﺳﻠﺣﺔ‬ ‫ﺧرﺳﺎﻧﺔ‬ ‫ﺑﻼطﺔ‬ ‫ﺗﺣوي‬ ‫ﻻ‬ ‫اﻟﺗﻲ‬ ‫اﻟدﯾﺎﻓراﻣﺎت‬
‫ﺻﻠﺑﺔ‬ ‫ﻏﯾر‬ ‫اﻋﺗﺑﺎرھﺎ‬ ‫ﯾﻣﻛن‬ ‫اﻟﻔوﻻذي‬ ‫اﻟﺻﺎج‬ ‫اﻟواح‬ ‫ﻣن‬ ‫واﻟﻣﻌدﻧﻲ‬ ‫اﻟﺧﺷﺑﻲ‬
‫ﻟﻺﻧﺗﻘﺎﻻت‬ ‫اﻟﻼزم‬ ‫اﻟﺣﺳﺎب‬ ‫اﺟراء‬ ‫ﻋن‬ ‫ﻋوﺿﺎ‬ ‫ﺻﻠب‬ ‫ﺷﺑﮫ‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﻓرض‬ ‫ﯾﻣﻛن‬
‫ﺷﺑﮫ‬ ‫او‬ ‫ﻧﺻف‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﻓرض‬ ‫وﻗﺑول‬ ‫اﻟﺗﺻﻣﯾم‬ ‫ﻣﺑﺎﺷرة‬ ‫وﯾﻣﻛن‬
‫وﻟو‬ ‫ﺣﺗﻰ‬ ‫ﺻﻠب‬‫ﺻﻠﺑﺎ‬ ‫ﻛﺎن‬
‫ا‬‫ﻟدﯾﺎﻓرام‬" :"Diaphragm
‫اﻟﻌﻧﺎص‬ ‫ﻋﻠﻰ‬ ‫ﯾطﻠﻖ‬‫اﻟﻣﺳﺗوﯾﺔ‬‫اﻷﺣﻣﺎل‬ ‫ﺑﻧﻘل‬ ‫ﺗﻘوم‬ ‫اﻟﺗﻲ‬‫اﻷﻓﻘﯾﺔ‬
‫واﻟزﻻزل‬ ‫اﻟرﯾﺎح‬ ‫ﻣن‬‫اﻻﺧرى‬ ‫اﻟﻌﻧﺎﺻر‬ ‫إﻟﻰ‬ ‫ﻣﺳﺗوﯾﮭﺎ‬ ‫ﻓﻲ‬‫ارأﺳﯾﺔ‬‫ﺑﮭﺎ‬ ‫اﻟﻣرﺗﺑطﺔ‬
‫دﯾﺎﻓراﻣﺎت‬ ‫اﻟﺑﻼطﺎت‬ ‫ﺗﻌﺗﺑر‬ ‫ﺣﯾث‬‫ﺻﻠﺑﺔ‬‫اﻟﻘوى‬ ‫ﻋن‬ ‫اﻟﻧﺎﺗﺟﺔ‬ ‫اﻟﺟﺎﻧﺑﯾﺔ‬ ‫اﻷﺣﻣﺎل‬ ‫ﺑﻧﻘل‬ ‫ﺗﻘوم‬ ‫ﻋﻧدﻣﺎ‬
‫اﻟﻘص‬ ‫وﺣواﺋط‬ ‫ﻛﺎﻻﻋﻣدة‬ ‫اﻟراﺳﯾﺔ‬ ‫اﻟﻌﻧﺎﺻر‬ ‫إﻟﻰ‬ ‫اﻟرﯾﺎح‬ ‫أو‬ ‫اﻟزﻟزاﻟﯾﺔ‬.
‫ﺻﻼﺑﺗﮫ‬ ‫وﻓﻖ‬ ‫ﻛل‬ ‫اﻟﻌﻧﺎﺻر‬ ‫اﻟﻰ‬ ‫اﻟﻘوى‬ ‫وﺗوزع‬

5. 5
‫ﯾﻌﺘﻤﺪ‬ ‫ﻓﮭﻮ‬ ‫ﻣﺮن‬ ‫او‬ ‫ﺻﻠﺐ‬ ‫ﻛﺎن‬ ‫ﺳﻮاء‬ ‫اﻟﺪﯾﺎﻓﺮام‬‫وﯾﺘﺄﺛﺮ‬
‫اﻟﺮأﺳﯿﺔ‬ ‫اﻟﻌﻨﺎﺻﺮ‬ ‫ﺑﺼﻼﺑﺔ‬
-‫اﻟﻤﺴﺎﻧﺪ‬ ‫اﻟﻰ‬ ‫ﺗﻨﺘﻘﻞ‬ ‫اﻷﻓﻘﯿﺔ‬ ‫اﻟﺤﻤﻮﻻت‬ ‫اﻟﻤﺮن‬ ‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﻓﻲ‬
‫ﻣﻨﺼﻒ‬ ‫ﺑﻄﺮﯾﻘﺔ‬ ‫اﻟﺠﺪران‬‫طﺮﻓﻲ‬ ‫ﻋﻠﻰ‬ ‫اﻟﺒﻼطﺔ‬ ‫ﻣﻦ‬ ‫اﻟﻤﺴﺎﺣﺎت‬
‫اﻟﻌﺎﻣﻮد‬ ‫ﺣﻤﻮﻟﺔ‬ ‫ﺣﺴﺎب‬ ‫ﺣﺎل‬ ‫ﻓﻲ‬ ‫ﻛﻤﺎ‬ ‫اﻟﺠﺪار‬

6. 6
‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﻟﺒﻼطﺔ‬ ‫اﻷﻓﻘﻲ‬ ‫اﻻﻧﺘﻘﺎل‬ ‫ﺣﺴﺎب‬

7. 7

8. 8
‫ﺻﻼﺑﺔ‬ ‫وﻓﻖ‬ ‫اﻟﻘﺺ‬ ‫ﻣﻦ‬ ‫اﻟﺠﺪران‬ ‫ﺣﺼﺔ‬ ‫ﺣﺴﺎب‬
‫ﺻﻠﺐ‬ ‫دﯾﺎﻓﺮام‬ ‫ﻓﻲ‬ ‫اﻟﺠﺪران‬

9. 9

10. 10
‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﺑﻼطﺎت‬ ‫ﺑﯿﻦ‬ ‫اﻟﻘﺎﻋﺪي‬ ‫اﻟﻘﺺ‬ ‫ﻗﻮى‬ ‫اﻧﺘﻘﺎل‬ ‫ﻛﯿﻔﯿﺔ‬
‫اﻷﺳﻔﻞ‬ ‫اﻟﻰ‬ ‫اﻷﻋﻠﻰ‬ ‫ﻣﻦ‬

11. 11
‫اﻟﺼﻠﺐ‬ = ‫اﻟﺪﯾﺎﻓﺮام‬–‫ﺻﻠﺐ‬ ‫ﺷﺒﮫ‬-‫اﻟﻤﺮن‬

12. 12
‫اﻟﺠﺪران‬ ‫اﻟﻰ‬ ‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﺑﻼطﺔ‬ ‫ﻣﻦ‬ ‫اﻟﻘﺺ‬ ‫ﻗﻮى‬ ‫اﻧﺘﻘﺎل‬
‫ﻗﺼﯿﺔ‬ ‫وﻣﺠﻤﻌﺎت‬ ‫ﻣﺴﺎرات‬ ‫وﻓﻖ‬–‫ﻣﺪﻓﻮﻧﺔ‬ ‫ﻛﻤﺮة‬

13. 13
‫ﺳﻤﺎﻛﺔ‬ ‫وﻓﻖ‬ ‫اﻟﻜﻮد‬ ‫ﺣﺪدھﺎ‬ ‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﻧﻮع‬ ‫اﺧﺘﯿﺎر‬
‫اﻟﻤﺎدة‬ ‫وﻧﻮﻋﯿﺔ‬ ‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﺑﻼطﺔ‬
-‫ﺑﺎﻧﻮاﻋﮭﺎ‬ ‫اﻟﻤﺴﻠﺤﺔ‬ ‫اﻟﺨﺮﺳﺎﻧﺔ‬ ‫ﺑﻼطﺎت‬ ‫ﻓﻜﻞ‬
‫ﺑﻼطﺎت‬ ‫ﺣﺘﻰ‬‫اﻟﺼﻨﻊ‬ ‫اﻟﻤﺴﯿﻖ‬ ‫ﻓﻲ‬ ‫اﻟﺘﻐﻄﯿﺔ‬
‫ﺗﻌﺘﺒﺮ‬Rigid‫ﺻﻠﺒﺔ‬
-‫ﺣﺴﺎب‬ ‫ﯾﺘﻄﻠﺐ‬ ‫اﻟﻜﻮدات‬ ‫وﺑﻌﺾ‬‫دﯾﺎﻓﺮام‬ ‫اﻧﺘﻘﺎل‬
‫ﺗﻌﺘﺒﺮ‬ ‫واﻻ‬ ‫ﻣﻌﯿﻨﺔ‬ ‫ﺣﺪود‬ ‫ﺿﻤﻦ‬ ‫اﻟﺴﻘﻒ‬ ‫ﺑﻼطﺔ‬
–semi
‫اﻟﻤﻌﺪﻧﯿﺔ‬ ‫اﻟﺴﺘﯿﻞ‬ ‫واﺳﻘﻒ‬ ‫ﺑﻼطﺎت‬ ‫ﺑﺎﻗﻰ‬ ‫اﻣﺎ‬
‫اﻟﻌﺎزل‬ ‫واﻟﺼﻨﺪوﯾﺶ‬ ‫اﻟﺼﺎج‬ ‫اﻟﻮاح‬ ‫ﻣﻦ‬
‫ﻣﺮﻧﺔ‬ ‫ﻓﺘﻌﺘﺒﺮ‬flexible

14. 14
‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﻧﻮع‬ ‫ﺗﺤﺪﯾﺪ‬ ‫ﻧﻘﺼﺪه‬ ‫ﻣﺎ‬‫ﻧﻮع‬ ‫ﻋﻠﻰ‬ ‫ﯾﻌﺘﻤﺪ‬
‫ﻧﻔﺴﺔ‬ ‫اﻟﺪﯾﺎﻓﺮام‬ ‫وﻣﺎدة‬
-‫ﻋﻠﻰ‬ ‫ﻓﯾﻌﺗﻣد‬ ‫اﻷﻓﻘﯾﺔ‬ ‫اﻟﻘص‬ ‫ﻗوة‬ ‫ﻣﻘدار‬ ‫ﺗوزﯾﻊ‬ ‫اﻣﺎ‬
‫اﻟرأﺳﯾﺔ‬ ‫اﻟﻌﻧﺎﺻر‬ ‫وﺻﻼﺑﺎت‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﻧوع‬
 in the analysis of multistory buildings subjected to lateral loads, a common
assumption is that the floor system undergoes no deformation in its own
plan [1, 2].
 Building structures are typically designed using the assumption that the
floor systems serve as a rigid diaphragm between the vertical elements of
the lateral load-resisting system.
 For the majority of buildings, floor diaphragms offer the most economical
and rational method of resisting the lateral forces, since they are ordinarily
included in the buildings to support the vertical workloads.
 It is thus, of the utmost importance, that they must be provided with
sufficient in-plane stiffness and strength, together with efficient
connections to the vertical structural elements
 investigation into the Floor Diaphragms Flexibility inReinforced Concrete
Structures and Code Provision
 All the seismic codes generally accept that in most cases the floor
diaphragms may be modeled as fully rigid without inplane deformability.

15. 15
 Even though a rigid floor diaphragm is a good assumption for seismic
analysis of the most buildings, several building configurations may exhibit
significant flexibility in floor diaphragms.
 In these configurations, some codes like (EC8, NZS4203, GSC- 2000) set
certain qualitative criteria related to the shape of the diaphragm, while
some others (2800, UBC-97, SEAOC-90, FEMA-273) set quantitative criteria
relating the in-plane deformation of the diaphragm with the average drift
of the associated storey


16. 16
‫اﻟﺘﺤﻘﻖ‬‫ﺑﺤﺴﺎب‬ ‫وذﻟﻚ‬ ‫ﺻﻠﺐ‬ ‫ﺷﺒﮫ‬ ‫ام‬ ‫ﺻﻠﺐ‬ ‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﻧﻮع‬ ‫ﻣﻦ‬
‫اﻟﺮاﺳﻲ‬ ‫اﻟﻌﻨﺼﺮ‬ ‫واﻧﺘﻘﺎل‬ ‫اﻟﺪﯾﺎﻓﺮام‬ ‫اﻧﺘﻘﺎل‬
A. Floor diaphragms shall be classified as either
“flexible”, “stiff”, or “rigid”.
B. “Flexible” when the maximum lateral deformation of the diaphragm along
its length is more than twice the average inter-storey drift of the storey
immediately below ( λ ≥ 2 ),
C. “rigid” when this
lateral deformation of the diaphragm is less than half the
average inter-storey drift of the associated storey (
λ < 5.0 ) and
D. “stiff” when the diaphragm it is neither
flexible nor rigid ( 0. λ <≤ 25 ).

17. 17
‫اﻟﺪﯾﺎﻓﺮام‬ ‫ﺑﻼطﺎت‬ ‫ﻓﻲ‬ ‫ﺗﻌﻤﻞ‬ ‫اﻟﺘﻰ‬ ‫اﻟﻘﺎﻋﺪى‬ ‫اﻟﻘﺺ‬ ‫ﻣﺜﻠﺚ‬ ‫ﻗﻮى‬ ‫ﺣﺴﺎب‬
‫طﺎﺑﻖ‬ ‫ﻛﻞ‬ ‫ﻓﻲ‬

18. 18
‫اﻟ‬‫ﺘﺤﻘﯿﻖ‬‫ﻣﻦ‬‫ﻧﻮﻋ‬‫ﯿﺔ‬‫اﻟﻄﺎﺑﻖ‬ ‫اﻧﺘﻘﺎل‬ ‫اﻟﻰ‬ ‫اﻧﺘﻘﺎﻟﺔ‬ ‫ﻧﺴﺒﺔ‬ ‫ﻣﻘﺪار‬ ‫ﻣﻦ‬ ‫اﻟﺪﯾﺎﻓﺮام‬

19. 19
 Eccentricity – For rigid diaphragms,
 the accidental eccentricity associated with seismic loading is concentrated
and applied at the center of mass, whereas for semi-rigid diaphragms,
accidental eccentricity is applied to every node for seismic loads.
 If no diaphragm is assigned eccentricity will not be applied to any node.
 For wind cases and rigid diaphragm, load is applied at geometric centroid,
in case of semi-rigid diaphragm loads are distributed in 10 nodes, so that
the summation of these forces with respect to centroid will be equivalent
to lateral and torsional wind cases.
 Reporting forces – In-plane chord, shear, and collector forces are only
reported when using semi-rigid diaphragms.
‫ﻓﻲ‬‫اﻟﻌطﺎﻟﺔ‬ ‫ﻗوى‬ ‫اﻟﺻﻠب‬ ‫اﻟدﯾﺎﻓرام‬‫اﻟﻛﺗﻠﺔ‬ ‫ﻣرﻛز‬ ‫ﻓﻲ‬ ‫ﺗطﺑﻖ‬
‫واﻟﺟدران‬ ‫اﻷﻋﻣدة‬ ‫ﻋﻘد‬ ‫ﻓﻲ‬ ‫ﺗطﺑﻖ‬ ‫ﺻﻠب‬ ‫ﻏﯾر‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﺣﺎل‬ ‫ﻓﻲ‬ ‫ﻟﻛن‬
Forces in diaphragms under earthquakes
‘Inertia’ forces
– Inertia at a particular floor
• ‘Transfer’ forces
– Forces develop between primary lateral
force resisting structures

20. 20
– These forces are often very large.
Force distribution in a floor diaphragm =
Inertia + Transfer forces
Floor plan configuration issues
‫ﺻﻠﺑﯨﺔ‬ ‫ﺷﺑﮫ‬ ‫اﻟﺗﺻﻣﯾم‬ ‫ﻓﻲ‬ ‫ﻗرﺿﮭﺎ‬ ‫ﯾﻘﺿل‬ ‫ﻣﻧﺗظﻣﺔ‬ ‫اﻟﻐﯾر‬ ‫اﻷﺷﻛﺎل‬ ‫دﯾﺎﻓرام‬
‫اﻟ‬ ‫وﺣرﯾﺔ‬ ‫اﻷﺟﻧﺣﺔ‬ ‫ﺑﯾن‬ ‫اﻟﻔﺻل‬ ‫او‬‫ﺣرﻛﺔ‬
‫ﺻﻠب‬ ‫دﯾﺎﻓرام‬(rigid diaphragm ):
‫و‬ ‫اﻟﺑﻼطﺔ‬ ‫ﻣﺳﺗوي‬ ‫ﻓﻲ‬ ‫ﺗﺷوه‬ ‫ﯾﺣدث‬ ‫ﻻ‬ ‫وﺑﺎﻟﺗﺎﻟﻲ‬ ‫ﻛﺑﯾرة‬ ‫ﺻﻼﺑﺔ‬ ‫ذات‬ ‫اﻟﺑﻼطﺔ‬ ‫أن‬ ‫أي‬
‫ﺟﺳﺎﺋﺗﮭﺎ‬ ‫ﻟﻧﺳب‬ ‫ﺗﺑﻌﺎ‬ ‫اﻹﻧﺷﺎﺋﯾﺔ‬ ‫اﻟﻌﻧﺎﺻر‬ ‫ﻋﻠﻰ‬ ‫اﻷﺣﻣﺎل‬ ‫ﺗوزﯾﻊ‬ ‫ﯾﻛون‬
‫ﺻﻠب‬ ‫ﺷﺑﮫ‬ ‫دﯾﺎﻓرام‬Simi rigid diaphragm)
‫اﻷﺣﻣﺎل‬ ‫ﺗوزﯾﻊ‬ ‫ﯾﻛون‬ ‫ﻻ‬ ‫وﺑﺎﻟﺗﺎﻟﻲ‬ ‫اﻟﺑﻼطﺔ‬ ‫ﻣﺳﺗوي‬ ‫ﻓﻲ‬ ‫ﺗﺷوه‬ ‫ﯾﺣدث‬ ‫و‬ ‫ﻛﺎﻓﯾﺔ‬ ‫ﻏﯾر‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﺻﻼﺑﺔ‬ ‫أن‬ ‫أي‬
‫ﺟﺳﺎﺋﺗﮭﺎ‬ ‫ﻟﻧﺳب‬ ‫ﺗﺑﻌﺎ‬ ‫اﻹﻧﺷﺎﺋﯾﺔ‬ ‫اﻟﻌﻧﺎﺻر‬ ‫ﻋﻠﻰ‬

21. 21
.‫اﻟﻣراﻓﻖ‬ ‫ﻟﻠطﺎﺑﻖ‬ ‫اﻹزاﺣﺔ‬ ‫ﻣﺗوﺳط‬ ‫ﺿﻌﻔﻲ‬ ‫ﻣن‬ ‫أﻛﺑر‬ ‫ﻟﻠدﯾﺎﻓرام‬ ‫اﻷﻋظﻣﻲ‬ ‫اﻟﺟﺎﻧﺑﻲ‬ ‫اﻻﻧﺗﻘﺎل‬ ‫ﯾﻛون‬ ‫ﻋﻧدﻣﺎ‬
‫اﻹزاﺣﺔ‬ ‫ﺑﻣﻘﺎرﻧﺔ‬ ‫ذﻟك‬ ‫ﺗﺣدﯾد‬ ‫وﯾﻣﻛن‬‫ﻟﻠدﯾﺎﻓرام‬ ‫اﻟﻣﺳﺎﻓﺔ‬ ‫ﻣﻧﺗﺻف‬ ‫ﻓﻲ‬ ‫ﻟﻠﻧﻘطﺔ‬ ‫اﻷﻓﻘﻲ‬ ‫اﻟﻣﺳﺗوي‬ ‫ﻓﻲ‬ ‫اﻟﻣﺣﺳوﺑﺔ‬
‫اﻟرأﺳﯾﺔ‬ ‫ﻟﻠﻌﻧﺎﺻر‬ ‫اﻟدور‬ ‫إزاﺣﺔ‬ ‫ﻣﻊ‬ ،‫اﻟﺟﺎﻧﺑﻲ‬ ‫اﻟﺣﻣل‬ ‫ﺑﺗﺄﺛﯾر‬ ،‫ذاﺗﮫ‬
‫اﻟﺑﻼطﺔ‬ ‫ﺻﻼﺑﺔ‬ ‫ﺗﻧﺧﻔض‬ ‫وﺑﺎﻟﺗﺎﻟﻲ‬ ‫اﻟدﯾﺎﻓرام‬ ‫أﺟزاء‬ ‫ﺑﻌض‬ ‫ﻓﻲ‬ ‫اﻧﻘطﺎﻋﺎت‬ ‫وﺟود‬ ‫ﯾﻛون‬ ‫ﻋﻧدﻣﺎ‬.
‫دون‬ ‫ﺳﺗﯾل‬ ‫اﻟﻣﻌدﻧﯾﺔ‬ ‫واﻟﺑﻼطﺎت‬ ‫ﻟﻠﺳﻘوف‬ ‫ھو‬ ‫اﻟﻣرن‬ ‫اﻟدﯾﺎﻓرام‬‫ﺧﺷﺑﯾﺔ‬ ‫او‬ ‫ﺧرﺳﺎﻧﺔ‬ ‫ﺑﻼطﺔ‬
‫اﻟﺮأﺳﯿﺔ‬ ‫اﻟﻤﻘﺎوﻣﺔ‬ ‫اﻟﻌﻨﺎﺻﺮ‬ ‫إﻟﻰ‬ ‫اﻟﺠﺎﻧﺒﯿﺔ‬ ‫اﻟﻘﻮى‬ ‫ﺑﺘﻮزﻳﻊ‬ ‫ﻳﻘﻮم‬ ‫اﻟﺼﻠﺐ‬ ‫اﻟﺪﻳﺎﻓﺮام‬
‫ﻻ‬ ‫)أي‬ ‫اﻟﺠﺎﻧﺒﯿﺔ‬ ‫اﻟﻘﻮى‬ ‫ﺗﺄﺛﯿﺮ‬ ‫ﺗﺤﺖ‬ ‫ﻳﻨﺤﻨﻲ‬ ‫ﻻ‬ ‫وھﻮ‬ ‫اﻟﻌﻨﺎﺻﺮ‬ ‫ھﺬه‬ ‫ﺻﻼﺑﺔ‬ ‫ﺑﺤﺴﺐ‬
.‫اﻟﺮأﺳﯿﺔ‬ ‫اﻟﻤﻘﺎوﻣﺔ‬ ‫اﻟﻌﻨﺎﺻﺮ‬ ‫إﻟﻰ‬ ‫اﻟﻔﺘﻞ‬ ‫ﻧﻘﻞ‬ ‫ﻋﻠﻰ‬ ‫ﻗﺎدر‬ ‫ھﻮ‬ ‫ﻟﺬﻟﻚ‬ (‫ﻳﺘﺸﻮه‬
‫ﻋﻨﺼﺮ‬ ‫ﻓﮫﻮ‬ ‫اﻟﻠﯿﻦ‬ ‫اﻟﺪﻳﺎﻓﺮام‬ ‫أﻣﺎ‬،‫اﻟﺠﺎﻧﺒﯿﺔ‬ ‫اﻟﻘﻮى‬ ‫ﺗﺄﺛﯿﺮ‬ ‫ﺗﺤﺖ‬ ‫ﻳﻨﺤﻨﻲ‬ ،‫ﻧﺤﯿﻒ‬ ‫إﻧﺸﺎﺋﻲ‬
‫ﻋﻠﻰ‬ ‫وﻳﻌﺘﻤﺪ‬ ،‫اﻟﺮأﺳﯿﺔ‬ ‫اﻟﻤﻘﺎوﻣﺔ‬ ‫اﻟﻌﻨﺎﺻﺮ‬ ‫إﻟﻰ‬ ‫اﻟﻔﺘﻞ‬ ‫ﻧﻘﻞ‬ ‫ﻋﻠﻰ‬ ‫ﻗﺎدر‬ ‫ﻏﯿﺮ‬ ‫ھﻮ‬ ‫ﻟﺬﻟﻚ‬
‫اﻟﻌﻨﺎﺻﺮ‬ ‫إﻟﻰ‬ ‫اﻟﺠﺎﻧﺒﯿﺔ‬ ‫اﻟﻘﻮى‬ ‫ﻳﻮزع‬ ‫وﻻ‬ ،‫ﺗﺸﻮھﺎﺗﻪ‬ ‫ﻣﻦ‬ ‫ﻟﻠﺤﺪ‬ ‫اﻟﻌﻨﺎﺻﺮ‬ ‫ھﺬه‬ ‫ﺻﻼﺑﺔ‬
‫ﺗﺤﻤﻠﮫﺎ‬ ‫اﻟﺘﻲ‬ ‫اﻟﻤﺴﺎﺣﺔ‬ ‫ﻧﺴﺒﺔ‬ ‫ﺑﺤﺴﺐ‬ ‫وإﻧﻤﺎ‬ ،‫ﺻﻼﺑﺘﮫﺎ‬ ‫ﺑﺤﺴﺐ‬ ‫اﻟﺮأﺳﯿﺔ‬ ‫اﻟﻤﻘﺎوﻣﺔ‬
‫اﻟﻌﻨﺎﺻﺮ‬ ‫ھﺬه‬.
‫ﻓﺘﻌﺘﺒﺮان‬ ‫واﻟﺨﺸﺒﯿﺔ‬ ‫اﻟﺨﻔﯿﻔﺔ‬ ‫اﻟﻔﻮﻻذﻳﺔ‬ ‫أﻣﺎ‬ ‫ﺻﻠﺐ‬ ‫دﻳﺎﻓﺮام‬ ‫اﻟﺨﺮﺳﺎﻧﯿﺔ‬ ‫اﻟﺒﻼطﺔ‬ ‫ﺗﻌﺘﺒﺮ‬
.‫ﻟﯿﻦ‬ ‫دﻳﺎﻓﺮام‬
‫ﺗﻌﺮﺿﻪ‬ ‫ﻋﻨﺪ‬ ‫ﻳﺘﺸﻮه‬ ‫ﻻ‬ ‫أﻧﻪ‬ ‫ﻳﻌﻨﻲ‬ ‫ﻓﮫﺬا‬ ‫اﻟﺼﻠﺐ‬ ‫اﻟﺴﻘﻒ‬ ‫دﻳﺎﻓﺮام‬ ‫ھﻮ‬ ‫اﻟﻤﻄﻠﻮب‬ ‫أن‬ ‫وﺑﻤﺎ‬
‫اﻟﻤﻘﺎوﻣﺔ‬ ‫اﻟﻌﻨﺎﺻﺮ‬ ‫إﻟﻰ‬ ً‫أﻳﻀﺎ‬ ‫اﻟﻔﺘﻞ‬ ‫ﺑﻨﻘﻞ‬ ‫ﻳﻘﻮم‬ ‫ﻓﺈﻧﻪ‬ ‫ﻳﺘﺸﻮه‬ ‫ﻻ‬ ‫أﻧﻪ‬ ‫وﺑﻤﺎ‬ ،‫ﺟﺎﻧﺒﯿﺔ‬ ‫ﻟﻘﻮة‬

22. 22
‫ﻓﺗل‬ ‫ﺗواﺟد‬ ‫ﻓﻲ‬ ‫اﻟﺻﻠب‬ ‫اﻟدﯾﺎﻓرام‬ ‫ودوران‬ ‫اﻧﺗﻘﺎل‬–‫ﺗورﺷن‬
‫اﻟﻘﺻﯾﺔ‬ ‫ﻟﻠﺟدران‬ ‫واﻟﺻﻼﺑﺔ‬ ‫اﻟﻛﺗﻠﺔ‬ ‫ﻣرﻛز‬ ‫ﺑﯾن‬ ‫ﻻﻣرﻛزﯾﺔ‬

23. 23
‫ا‬
‫واﻟﻣﺻﺎﻋد‬ ‫واﻟﺳﻼم‬ ‫اﻟﻔﺗﺣﺎت‬ ‫وﺗواﺟد‬ ‫ﻣﻔﺿﻠﺔ‬ ‫ﻏﯾر‬ ‫اﺷﻛﺎل‬
‫ﺗﺟﻧﺑﮭﺎ‬ ‫وﯾﻔﺿل‬ ‫اﻟدﯾﺎﻓراﻣﺎت‬ ‫ﻓﻲ‬

24. 24
‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺎت‬ ‫واﻧواع‬ ‫اﺷﻛﺎل‬

25. 25
Structural Behaviour of Diaphragms
‫ﻛﯾﻔﯾﺔ‬‫واﻟﺟدرا‬ ‫اﻟﻛور‬ ‫اﻟﻰ‬ ‫اﻷﻓﻘﯾﺔ‬ ‫اﻟﻘوى‬ ‫وﻧﻘل‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﻋﻣل‬‫ن‬
Beam Analogy ‫اﻟﻌﻣﯾﻘﺔ‬ ‫واﻟﻛﻣرة‬ ‫اﻟﺟﺎﺋزي‬ ‫اﻟﻌﻣل‬- deep beaam
‫اﻟرأﺳﯾﺔ‬ ‫اﻟﻌﻧﺎﺻر‬ ‫ﻋﻠﻰ‬ ‫ﻣﺳﻧود‬ ‫ﻋﻣﯾﻖ‬ ‫ﻛﺟﺎﺋز‬ ‫اﻟﺑﻼطﺔ‬ ‫ﺗﻌﻣل‬
‫ﻗص‬ ‫وﻗوى‬ ‫اﻧﺣﻧﺎء‬ ‫ﻋزوم‬ ‫ﻓﯾﮭﺎ‬ ‫وﺗﺗوﻟد‬ ‫واﻷﻋﻣدة‬ ‫واﻟﺟدران‬ ‫اﻟﻛور‬ ‫ﻣن‬
‫ﺿﺎﻏطﺔ‬ ‫ﺷﺎدة‬ ‫ﻣﺣورﯾﺔ‬ ‫وﻗوى‬‫ﺣﺎﻟﮫ‬ ‫ﻟﻛل‬ ‫اﻟﻼزم‬ ‫اﻟﺗﺳﻠﯾﺢ‬ ‫اﯾﺟﺎد‬ ‫وﯾﺟب‬
‫اﻟﺷﺎﻗوﻟﯾﺔ‬ ‫اﻟﺣﻣوﻻت‬ ‫ﺗﺳﻠﯾﺢ‬ ‫اﻟﻰ‬ ‫واﺿﺎﻓﺗﮫ‬

26. 26

27. 27

28. 28

29. 29
The code is allowing the designer to consider Rigid Diaphragm for
reinforced concrete monolithic slab-beam floors or those consisting of
prefabricated/ precast elements with topping reinforced screed.
The following condition has been proposed to evaluate the flexibility of a
diaphragm.
‫ﻟﻧﻘل‬ ‫ﻣﺟﻣﻌﺎت‬ ‫ﻛﻠﯾﻛﺗور‬ ‫ﻣدﻓوﻧﺔ‬ ‫ﻛﻣرات‬ ‫ﺗﺻﻣﯾم‬‫اﻟﺟدار‬ ‫ﺣﺻﺔ‬
‫اﻟﺟدار‬ ‫اﻟﻰ‬ ‫اﻟﺑﻼطﺔ‬ ‫ﻣن‬ ‫اﻟﻘص‬ ‫ﻣن‬

30. 30
‫اﻟﻘص‬ ‫ﻗوى‬ ‫ﺗوزﯾﻊ‬ ‫وﻗﯾﻣﺔ‬ ‫ﻧوﻋﮫ‬ ‫وﻓﻖ‬ ‫اﻟدﯾﺎﻓرام‬ ‫اﻧﺗﻘﺎل‬
‫اﻟدﯾﺎﻓرام‬ ‫ﺻﻼﺑﺔ‬ ‫وﻓﻖ‬ ‫اﻟﺟدران‬ ‫ﻋﻠﻰ‬

31. 31
‫ﺑ‬‫اﻻﺣﻣﺎل‬ ‫ﺗﺣت‬ ‫اﻟﺑﻼطﮫ‬ ‫ﻟﺗﺻﻣﯾم‬ ‫ﺎﻻﺿﺎﻓﮫ‬‫واﻟﻣﯾﺗﺔ‬ ‫اﻟﺣﯾﺔ‬ ‫اﻟﺷﺎﻗوﻟﯾﺔ‬
‫ﻣن‬ ‫اﻟﺗﺣﻘﻖ‬ ‫ﻣن‬ ‫ﻻﺑد‬‫اﻟﺿﻐط‬ ‫و‬ ‫اﻟﺷد‬ ‫ﻗوه‬ ‫ﻣﻘدار‬‫اﻟﻘص‬ ‫وﻗوى‬
‫ﻓﻲ‬ ‫اﻟﻣﺗوﻟده‬diaphragm‫ﻣﻘدار‬ ‫ﺣﺳﺎب‬ ‫و‬‫اﻟﻼزم‬ ‫اﻟﺗﺳﻠﯾﺢ‬
‫اﻟﻘو‬ ‫ھذه‬ ‫ﯾﻘﺎوم‬ ‫اﻟذي‬‫ى‬

32. 32

33. 33

34. 34
‫ﻋﻣﯾﻖ‬ ‫ﻛﺟﺎﺋز‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺔ‬ ‫ﺗﺻﻣﯾم‬
‫اﻟﻘﺎطﻊ‬ ‫واﻟﺟﮭد‬ ‫اﻟﻌزم‬ ‫ﻣﺧطط‬ ‫اﯾﺟﺎد‬
‫اﻻﻧﻌطﺎف‬ ‫ﺗﺳﻠﯾﺢ‬ ‫اﯾﺟﺎد‬‫اﻟﻌرﺿﻲ‬ ‫اﻟﻘص‬ ‫وﺗﺳﻠﯾﺢ‬ ‫اﻷطراف‬ ‫ﻋﻧد‬
‫ﻓﻲ‬ ‫اﻟﻌﻣل‬ ‫ﻛﻣﺎ‬‫اﻟﻛﻣرات‬
‫اﻷﻓﻘﻲ‬ ‫اﻟﻔﻌل‬ ‫رد‬ ‫ﻟﻘﯾﻣﺔ‬ ‫اﻟﻣﺳﺎوﯾﺔ‬ ‫اﻟﺷﺎدة‬ ‫اﻟﻘوى‬ ‫ﻣن‬ ‫ﻛﻠﯾﻛﺗور‬ ‫ﺗﺳﻠﯾﺢ‬ ‫ﺛم‬
‫اﻟﺟدار‬ ‫ﻣﺳﺎﻧد‬ ‫ﻋﻧد‬

35. 35
TYPES OF DIAPHRAGM
Rigid Diaphragms
A diaphragm may be considered rigid when its midpoint displacement, under
lateral load, is less than twice the average displacements at its ends.
Rigid diaphragm distributes the horizontal forces to the vertical resisting
elements in direct proportion to the relative rigidities.
It is based on the assumption that the diaphragm does not deform itself and
will cause each vertical element to deflect the same amount.
Rigid diaphragms capable of transferring torsional and shear deflections and
forces are also based on the assumption that the diaphragm and shear walls
undergo rigid body rotation and this produces additional shear forces in the
shear wall.
Rigid diaphragms consist of reinforced concrete diaphragms, precast
concrete diaphragms, and composite steel deck.

36. 36
FLEXIBLE DIAPHRAM.
Flexible diaphragms — Roofs or floors including, but not necessarily limited
to, those sheathed with plywood, wood decking, or metal decks without
structural concrete topping slabs.
Metal decks with lightweight fill may or may not be flexible. Diaphragms are
considered flexible when the maximum lateral deformation of the
diaphragm is more than two times the average story drift of the associated
story.
This may be determined by comparing the computed midpoint in-plane
deflection of the diaphragm itself under lateral load with the drift to
adjoining vertical elements under tributary lateral load.
A diaphragm is considered flexible, when the midpoint displacement, under
lateral load, exceeds twice the average displacement of the end supports.
It is assumed here that the relative stiffness of these non-yielding end
supports is very great compared to that of the diaphragm.
Therefore, diaphragms are often designed as simple beams between end
supports, and distribution of the lateral forces to the vertical resisting
elements on a tributary width, rather than relative stiffness.
Flexible diaphragm is not considered to be capable of distributing torsional
and rotational forces.
Flexible diaphragms consist of diagonally sheated wood diaphragms,
sheathed diaphragms etc.
The rigidity of the diaphragms is classified into two groups on relative
flexibility: rigid and flexible diaphragm.

37. 37

38. 38

39. 39

40. 40

41. 41

42. 42
The components at the diaphragm boundary acting in
tension and compression are known as the tension chord and
the compression chord, respectively.

43. 43
If the diaphragm moment is resisted by tension and compression
chords at the boundaries of the diaphragm as shown in Figure
3-1a, then equilibrium requires that the diaphragm shear be
distributed uniformly along the depth of the diaphragm as
shown in Figure 3-1c.
Tension and compression elements
called collectors are required to “collect” this shear and transmit
it to the walls
A collector can transmit all its forces into the
ends of the walls as shown on the right side of Figure 3-2a,
or if the forces and resulting congestion are beyond practical

44. 44
limits, the collector can be spread into the adjacent slab as
shown on the left side of Figure 3-2a.
Figure 3-3. As used in this Guide, a collector is an element that takes distributed
load from the diaphragm and delivers it to a vertical element, whereas a
distributor takes force from a vertical element and distributes it into the diaphragm.
‫دﯾﺎﻓرام‬ ‫ﺗﺄﻣﯾن‬‫ﺻﻠب‬‫اﻷﻗﺑﯾﺔ‬ ‫طﺎﺑﻖ‬ ‫ﺳﻘف‬ ‫ﻓﻲ‬ ‫ﻣدﻓوﻧﺔ‬ ‫وﻛﻣرات‬
‫اﻟﺑدرو‬‫اﻟﺑدروم‬ ‫ﺟدران‬ ‫اﻟﻰ‬ ‫اﻟﻘص‬ ‫ﻗوى‬ ‫ﻟﺗﺣوﯾل‬ ‫م‬-‫اﻷﻗﺑﯾﺔ‬

45. 45
In addition, the inclined ramps can act as unintended diagonal braces
that interrupt intended framing action of the vertical elements and result
in considerable axial load in the diaphragm. Expansion joints can relieve
this action
if provided at every level.

46. 46
‫ورﻣب‬ ‫اﻟﺳﻼﻟم‬ ‫ﺑﻼطﺎت‬ ‫ﺗواﺟد‬ ‫ﺣﺎل‬ ‫ﻓﻲ‬‫اﻟﺳﯾﺎرات‬
‫اﻟﺿﻐط‬ ‫ﻗوى‬ ‫ﻋﻠﻰ‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺔ‬ ‫ﺗﺻﻣﯾم‬ ‫ﯾﺟب‬
‫اﻷﻓﻘﻲ‬ ‫اﻟﺳﻘف‬ ‫ﻣﻊ‬ ‫اﻟﻣﺎﺋﻠﺔ‬ ‫اﻟﺑﻼطﺔ‬ ‫اﺗﺻﺎل‬ ‫ﻋﻧد‬

47. 47
‫ﻓﻲ‬‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺔ‬ ‫ﻓﻲ‬ ‫ﻛﺑﯾرة‬ ‫ﻓﺗﺣﺎت‬ ‫ﺗواﺟد‬ ‫ﺣﺎل‬
‫اﻟﺷﺎدة‬ ‫اﻟﻘوى‬ ‫ﻋﻠﻰ‬ ‫اﻟﻔﺗﺣﺎت‬ ‫ﺟواﻧب‬ ‫ﺗﺻﻣﯾم‬ ‫ﻓﯾﺟب‬
‫اﻟﺿﺎﻏطﺔ‬

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‫ﻛﺳرات‬ ‫وﯾﺣوي‬ ‫ﻣﻧﺗظم‬ ‫ﻏﯾر‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺔ‬ ‫ﺷﻛل‬ ‫ﺣﺎل‬ ‫ﻓﻲ‬ ‫ﻛذﻟك‬
‫رﺟوﻋﺎت‬ ‫او‬‫اﻟﻣﺟﻣﻊ‬ ‫وﺗﺳﻠﯾﺢ‬ ‫ﻣدﻓوﻧﺔ‬ ‫ﻛﻣرات‬ ‫وﺿﻊ‬ ‫ﯾﺟب‬-‫ﻛﻠﯾﻛﺗور‬

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‫داﺋﻣﺎ‬ ‫ھﻲ‬ ‫اﻟزﻻزل‬ ‫او‬ ‫اﻟرﯾﺎح‬ ‫ﻣن‬ ‫اﻷﻓﻘﯾﺔ‬ ‫اﻟﻘوى‬
‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺔ‬ ‫ﻓﻲ‬ ‫ﺑﺎﻧﺗظﺎم‬ ‫وﻣوزﻋﺔ‬ ‫ﻣوﺟودة‬

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‫واﻧﺗﻘﺎﻟﮭﺎ‬ ‫اﻟزﻻزل‬ ‫او‬ ‫اﻟرﯾﺎح‬ ‫ﻗوى‬ ‫ﺗوزع‬
‫اﻟﺳﻔﻠﻲ‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺎت‬ ‫اﻟﻰ‬

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‫ﺟﺎﺋز‬ ‫ﻣﺛل‬ ‫اﻟدﯾﺎﻓرام‬ ‫ﺑﻼطﺔ‬ ‫ﺗﺻﯾم‬-‫ﻋﻣﯾﻘﺔ‬ ‫ﻛﻣرة‬
‫واﯾﺟﺎد‬‫واﻟﻘص‬ ‫اﻟﻌزم‬ ‫ﻣن‬ ‫اﻟﻼزم‬ ‫اﻟﺗﺳﻠﯾﺢ‬
‫اﻟﺷﺎﻗوﻟﻲ‬ ‫اﻟﺗﺳﻠﯾﺢ‬ ‫ﻣﻘطﻊ‬ ‫اﻟﻰ‬ ‫واﺿﺎﻓﺗﮫ‬

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‫ﻣﺳﺗﻣرة‬ ‫ﻣرﻧﺔ‬ ‫ﻣﺳﺎﻧد‬ ‫ﻋﻠﻰ‬ ‫ﻋﻣﯾﻘﺔ‬ ‫ﻛﻣرة‬ ‫ﯾﻘﺎﯾﻠﮫ‬ ‫اﻟﻣرن‬ ‫اﻟﻣﺳﺗﻣر‬ ‫اﻟدﯾﺎﻓرام‬

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Horizontal Diaphragms of Complex shape

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– ‫اﻣرﯾﻛﻲ‬ ‫ﻛود‬ diaphragm ACI 318 -14

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What is the center of rigidity for a semi-rigid diaphragm?
 Answer: Center of rigidity is only applicable to rigid diaphragms because in-plane slab
deformation is variable across laterally loaded semi-rigid diaphragms.
 During computation, an arbitrary coordinate is selected and loaded, then center of rigidity
is derived, as a function of stiffness, according to the displacement at this specific poin
‫ﻟﻠﻛود‬ ‫اﻟﻣواﻓﻖ‬ ‫اﻟﺳوري‬ ‫اﻟﻛود‬‫اﻷﻣرﯾﻛﻲ‬-ASCE 2009

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‫دﯾﺎﻓرام‬ - diaphragm

64. 64

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68. 68
Diaphragm Reinforcement

69. 69
 Large diameter diaphragm and collector reinforcing bars are
commonly spliced using mechanical couplers.
 Because lap splices of No. 14 bars or larger are prohibited by ACI
318,mechanical couplers are required.
 Location of Construction Joints
Construction joints create weakened planes within a diaphragm.
They can also impact development and splices of reinforcement.
Shear-friction reinforcement can be provided across construction
joints if necessary to maintain continuity of the diaphragm in
shear.
 The impacts to the continuity and development of chord
and collector reinforcement at construction joints should also
be understood

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seismic Design of Composite Steel Deck and Concrete-
filled Diaphragms
Flexibility of the diaphragm material.
Among the usual building materials, wood or steel decking
without concrete are the most flexible.
Aspect ratio (length/width) of the diaphragm. The greater
the length/width ratio of the diaphragm, the greater the
lateral distortions may be. In general, diaphragms with
aspect ratios greater than 5 may be considered flexible.
Stiffness of the vertical structure. The flexibility of the
diaphragm should also be judged in accordance with the
distribution of rigid vertical elements in the plan. In the
extreme case of a diaphragm in which llelements are of equal
stiffness, better performance is expected than when there
are major differences in this respect.

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Openings in the diaphragm. Large openings in the diaphragm
for purposes of illumination, ventilation, and visual
connections between stories cause flexible areas that impede
the rigid assembly of the vertical structures.

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78. 78
Shear Transfer
The strength of the diaphragm deck determined for the field of
the diaphragm must be adequately transferred to the perimeter
framing members if that strength is to be utilized.
A variety of fasteners can be utilized to accomplish this load transfer.
These include arc-spot (or puddle) welds, self-tapping/self
drilling screws, powder-actuated fasteners, and steel headedstud anchors.
Additionally, the side seam fastening can be accomplished using welds,
screws, or crimping, either traditional “button-punching” or proprietary
seaming.
As has already been mentioned, the side seam fastening has little
influence on composite deck diaphragm strength.
DESING EXAMPLE

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Diaphragm forces- ‫اﯾﺗﺎب‬ ‫ﺑرﻧﺎﻣﺞ‬

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