Microsoft PowerPoint - Guide RC project ngyt 2013 04 09

REINFORCED CONCRETE‐ DESIGN GUIDE‐

1ST PART

Prepared by

NAGY‐GYÖRGY TamásPhd, Lecturer

[email protected]

FLORUȚ CodruțPhd, Assistant Lecturer

[email protected]

‐ 2013 ‐

‐V2‐

REFERENCES

SR EN 1992 1 1 2004 P i t t t il d b t P t 1 1 R li l t lădi iSR EN 1992-1-1: 2004, Proiectarea structurilor de beton, Partea 1-1: Reguli generale pentru clădiri(+AC:2008)

SR EN 1992-1-1/NB: 2008, Proiectarea structurilor de beton, Partea 1-1: Reguli generale pentru clădiri.Anexa Naționalăț

EN 1992-1-1: 2004, Design of concrete structures - Part 1-1: General rules and rules for buildings

SR EN 1991-1-1:2004, Acțiuni asupra structurilor. Partea 1-1: Acțiuni generale (+ NA:2006)

P 100-1/2006, Cod de proiectare seismică - Partea I - Prevederi de proiectare pentru clădiri

Cadar I., Clipii T., Tudor A., Beton Armat (ed. II), Ed. Orizonturi Universitare, 2004, ISBN 973-638-176-5

Kiss Z., Oneț T., Proiectarea structurilor de beton armat după SR EN 1992-1, Ed. Abel, 2008, ISBN973114070-0

Mosley W.H., Burgey J.H., Hulse R., Reinforced Concrete Design to Eurocode 2, Sixth Edition, 2007, ISBN:97802305007169780230500716

Nilson A., Darwin D., Dolan Ch., Design of Concrete Structures (13th Ed.), McGraw-Hill Co, 2004, ISBN 0-07-248305-9

Newman J., Choo B. S., Advanced Concrete Technology SET, Ed. Elsevier Science, 2003, ISBN-13:9780750656863

I. DESIGN OF A RC CAST‐IN‐PLACE SLAB

S O OO1. ELEMENTS OF A FLOOR

- STRUCTURAL ELEMENTS WITH STRENGTH ROLE- STRUCTURAL ELEMENTS , WITH STRENGTH ROLE- SLAB AND BEAMS (DISPOSED IN ONE OR TWO DIRECTIONS, WHICH SUPPORTS THESLAB)

NON STRUCTURAL ELEMENTS E G PROTECTIONS- NON-STRUCTURAL ELEMENTS, E.G. PROTECTIONS- FINISHING, FLOORS, ISOLATIONS (ACOUSTIC, HYDRO-), INSULATIONS

GIRDERS (MAIN BEAMS) BEING ALSO IN THE SAME TIME BEAMS OF THE FRAME( )

SECONDARY BEAMS DISPOSED PERPENDICULAR TO THE GIRDERS, BEINGEQUIDISTANT (AS IS MUCH AS IT IS POSSIBLE), THE DISTANCEBETWEEN THEIR AXIS BEINGBETWEEN THEIR AXIS BEING

IN THE CASE OF SLABS REINFORCED IN ONE DIRECTION THE RATIO

IN THE CASE OF SLABS REINFORCED IN ONE DIRECTION, THE RATIOOF A SLAB PANEL RESPECTS THE CONDITION:


1 ELEMENTS OF A FLOOR1. ELEMENTS OF A FLOOR

The cast-in-place floor is a space structure, because, through concrete andt l i f t li k b t th t l t i t dsteel reinforcement a link between the component elements is created.

The computation of a space structure is quite difficult, therefore, in design ist d th l l ti f h t t l l t t l t ki i taccepted the calculation of each structural element separately, taking into

account the load transmission modes, in vertical direction, toward the supports.

I thi it ld b d itt d th t th l b (S) i t d b th dIn this way, it could be admitted that the slab (S) is supported by the secondarybeams (SB), the secondary beams are supported by the girders (G) and columns(C) and the girders together with columns are forming the frame, which transmitsthe loads to the foundations (F) and to the terrainthe loads to the foundations (F) and to the terrain.

S → SB → frame = G + C → F → terrain

The route of the loads specifies the order in which the design of the structural element must be done, i.e.design of the slab, then secondary beams, girders, etc.


S O OO1. ELEMENTS OF A FLOORGirdersSecondary beams

Slab panel

Columns

Detail A

(ope

ning

)

(bay) Transversal sections

girder secondary beam

L

secondary beam

girderDetail A

n x B

L

Girdersecondary beam

Formwork plane



DESIGN PHASESDESIGN PHASES- PRE-DIMENSIONING: choosing the structural elements’ dimensionsaccording to the recommendations, in such a way to correspond also to othercriteria that the strength;g ;

- COMPUTATION OF THE LOADS: determination of the design loads,knowing the structural elements dimensions, the composition of non-structuralelements, destination and location of the construction;

- ESTABLISHING THE STATIC SCHEME FOR DESIGN based on the designf th l tspans of the elements;

- STATIC DESIGN: determining the most unfavourable effects of design loadswhich acting on the admitted static scheme It can be solved by using CADwhich acting on the admitted static scheme. It can be solved by using CADprograms or manually, with approximate methods;



DESIGN PHASESDESIGN PHASES- THE PROPER DESIGN, through following steps:

- finalization of the elements’ cross section, based on the results,from the static calculations and on the used material characteristics;

- computation of the reinforcement area and setting their layout;

- execution drawing, which includes the framework plane andreinforcement layout, reinforcement details and material consumptions( l f th t d i f t)(volume of the concrete and reinforcement).


2 PRE DIMENSIONING THE ELEMENTS OF THE FLOOR2. PRE-DIMENSIONING THE ELEMENTS OF THE FLOOR

SLAB

IF YES SLAB REINFORCED IN A SINGLE DIRECTION

(Conf. P100-1/2006)

Section a‐ahs

hs = M x 10 mm

l = interaxis



BEAMS

DIMENSION RECOMMENDATIONS

L/(12…15) ‐ girders

HEIGHT

Minimum, hmin

/( 5) g de s

L/20 ‐ secondary beams

L/(8…12) ‐ girdersOptimum, hopt

L/(8…12) girders

L/(12…15) ‐ secondary beams

WIDTH h/b = 1.5 … 3 ‐ rectangular section

b i = 200 mm

WIDTH h/b 1.5 … 3 rectangular section

bmin = 200 mm

h, b = M x 50 mm

L = interaxis



COLUMNS (is chosen)

bCOL = (bG + 5cm) ≥ 350 mm

hCOL ≈ 1,2 bCOL

h, b = M x 50 mm


3 COMPUTATION OF LOADS3. COMPUTATION OF LOADS

ACTION CHARACTERISTICS EXAMPLES

PERMANENTVariation in time is negligible

Self‐weight: structural elements,finishing, etc.

Loads resulted from using of the

VARIABLEVariation in time is important

Loads resulted from using of the buildings (live loads)

Wind

SSnow

ACCIDENTALHigh intensity, reduced time of action

Earthquake

Explosion

Design value of action Partial safety

coefficient

Characteristic value of action



GENERALLY, THESE LOADS CAN BE CONSIDERED UNIFORMLYDISTRIBUTED ON THE SLAB SURFACE AND THERE ARE EXPRESSED INkN/m2.

FOR THE CHARACTERISTIC VALUES k

DESIGN VALUES d



PERMANENT (DEAD) CHARACTERISTIC LOADS : gk( ) gk

‐ SELF‐WEIGHTP ,

- RC SLAB ,

- PLASTER

- FLOOR

,

FLOOR- Asphalt

- Mosaic

,2

,2 2

- Pavement

- Cement concrete lining

,2

,2



SPECIFIC WEIGHTMATERIALS

SPECIFIC WEIGHT ρ [kN/m3]

CONCRETES

R. C. 25.0

FINISHING PLASTERS

C t t 21 0Cement mortar 21.0

Cement‐lime mortar 19.0

Lime or plaster mortar 17.0p



VARIABLE (LIVE) CHARACTERISTIC LOADS: qk( ) qk

‐ IMPOSED LOADSQ ,

- CATEGORIES OF USE ,

- PARTITION WALLS ,

(according to SR EN 1991-1-1:2004)



PERMANENT DESIGN LOADS

VARIABLE DESIGN LOADS

TYPE OF LOADPARTIAL SAFETY FACTOR FOR ACTIONS

TYPE OF LOAD γF

PERMANENT LOADS γg = 1.35

VARIABLE LOADS γq = 1.50



LOAD COMBINATION

- In the design, actions are combined to produce the most unfavorable effectson the structureon the structure

- The combinations are specific for the limit state which is used in design

- Dimensioning and verification of the concrete sections and the reinforcementswill be done in Ultimate Limit State (ULS)

- General form in conf. of CR 0, ch. 4.3 (!):

,1 0, ,


4 STATIC DESIGN OF THE SLAB4. STATIC DESIGN OF THE SLAB

ESTABLISHING THE STATIC SCHEME

- In order to find out the stresses (bending and shear), the slab reinforced in onedirection can be replaced with a 1.0 m wide slab, considered in the short span of thep , pslab panels, this means that on the discharge direction of loads.

‐ From the static point of view, this strip is equivalent with a continues beam.

‐ Supports of the slab are the secondary beams, while the design spans (lc ) of the

continues beam are the clear spans (l0 ) of the slab (clear distance between thecontinues beam are the clear spans (l0 ) of the slab (clear distance between thesecondary beams)

‐ inter‐axis span: lpp

‐ design span, used in static design: lc = l0




-The real slab is replaced with a continues beam having spans of lc and linear

distributed loads of pd x 1 m [kN/m]

Envelope curves

gd,gs/qd,gs = 0,5

gd,gs/qd,gs = 5




-The real slab is replaced with a continues beam having spans of lc and linear

distributed loads of pd x 1 m [kN/m]

1414

← envelope curves


5 DIMENSIONING OF THE SLAB5. DIMENSIONING OF THE SLAB

CHARACTERISTIC AND DESIGN STRENGTH

CONCRETEQ lit f t i d fi d b th t th l hi h i th h t i tiQuality of concrete is defined by the strength class, which is the characteristic

compressive strength on cylinders

Concrete class is

Design compressive strength of concrete

,

Design compressive strength of concrete

REINFORCEMENT

Design strength of reinforcement



CHARACTERISTIC AND DESIGN STRENGTH



FINALIZING THE THICKNESS OF THE SLAB

Design section of the slab

hs

s s

Reinforcement of the slabpopt (%) for reinforcing with

fyk = 400 … 500 N/mm2 fyk = 300 … 400 N/mm2

In 1 direction 0 25 0 50 0 30 0 60‐ In 1 direction 0,25 … 0,50 0,30 … 0,60

‐ In 2 directions 0,20 … 0,50 0,25 … 0,50




Checking of the chosen thickness (necessary)

MEd ‐ themaximum bending moment from the static design

b 000b = 1000 mm

or μ = f(ω) table , where1 0.5

, in function of popt100




Computation of the necessary slab thickness

where,

/2

∆




Computation of the necessary slab thickness

bond

max , ; , ; 10

bond

durability,

0.1 2

durability

!!!!!!!!! in function of the Exposure Class and Structural class (Ch. 4.4 )∆ 5

, 10 25

hs = M x 10 mm


5. DIMENSIONING OF THE SLAB

FINALIZING THE THICKNESS OF THE SLABFINALIZING THE THICKNESS OF THE SLAB

If

OK, ,

If

RE-CALCULATION OF THE LOADS MOMENTS

FINALIZING THE SLAB THICKNESS

, ,



CALCULATION OF THE REINFORCEMENT AREA

Effective depth:

2



DETAILING RULES – principal reinforcements(SR EN 1992-1-1/ Ch. 9)

, 0.26 0.0013

, 0.04

1 5 2001.5 200 . .80

straight (bound) bars

0.1 2

6

welded bars (welded fabrics)5

ngyt1

ngyt1 in conformity with the N.A.tamas.nagygyorgy; 02.03.2011



DETAILING RULES – principal reinforcements(SR EN 1992-1-1/ Ch. 9)

- At the edge of the slab

, 25% ,

- Perpendicular to the girder , 6/ .

logsgs

lo /4

GP gsgs



DETAILING RULES – secondary reinforcements(SR EN 1992-1-1/ Ch. 9)

= min 20% A= min 20% As

2.5 300 . . ngyt2

ngyt2 in conformity with the N.A.tamas.nagygyorgy; 02.03.2011



DETAILING RULES – welded wire mesh (fabric) reinforcements(SR EN 1992-1-1/ Ch. 9)

- At the edge of the slab

, 50% ,

- Perpendicular to the girder

, , 5/150logsgs

lo /4

GP gsgs


5 DIMENSIONING OF THE SLAB

4.52cm2 3.50cm2

5. DIMENSIONING OF THE SLABSLAB LAY‐OUT – reinforcement with inclined bars

5.58cm2 3.50cm2


5 DIMENSIONING OF THE SLAB5. DIMENSIONING OF THE SLABSLAB LAY‐OUT – reinforcement with straight bars

4.52cm2 3.50cm2

5.58cm2 3.50cm2


5 DIMENSIONING OF THE SLAB5. DIMENSIONING OF THE SLABSLAB LAY‐OUT – reinforcement with welded wire mesh (welded fabric)



CHECKING THE SLAB FOR SHEAR FORCES

Generally, in the case of usual slabs with low thickness, the reinforcement isresulting from the design for bending and reinforcement for shear force is notneeded.needed.

To verify this:

,

, , 100 1/3 0.035 · 3/2 · 1/2 ·

, 0.18/

1200

2.00 0.02

II. DESIGN OF THE SECONDARY BEAM

1. COMPUTATION OF LOADS

s.b.s.b.

s.b

lo sbbG bG

Gs.b

G

B

bsb


1. COMPUTATION OF LOADS

s.b.

s.b

bsblo sbbG bG

G

s.b

G

P , ,

B IT IS THE TOTALLOAD!!!

Q , ,

, , ,


2. STATIC DESIGN OF THE SECONDARY BEAM

ESTABLISHING THE STATIC SCHEMEESTABLISHING THE STATIC SCHEME

‐ The secondary beam will be computed as a continues beam, with design

spans , the supports being the girders.0p , pp g g0,

11


3. DIMENSIONING OF THE SECONDARY BEAM

As1 – Step 2 As1 – Step 2

As2 = the minimum betweens2the reinforcements obtainedfrom the adjacent spans inStep 1 (here from M1 and M2)

As1 ‐ Step 1 As1 ‐ Step 1



FINALIZING THE HEIGHT OF THE SECONDARY BEAMFINALIZING THE HEIGHT OF THE SECONDARY BEAM

Checking the chosen height (necessary)

MEd - maximum bending moment from the static designbsb - from pre-dimensioning

or μ = f(ω) table, where1 0.5

, in function of popt ≈ 1.2 … 1.8100




Computation of the necessary height

,long

/2 stirrcnom

ds

∆




Computation of the necessary heightbond

max , ; , ; 10

bond

!!!!!!!!!!!!!!!!!! in function of the Exposure Class

,

20 …25

durability

and Structural class (Ch. 4.4 )

∆ 10, 10 25

hsb = M x 50 mm and then verification hsb /bsb =1,5 … 3,0 ???

∆ 10




If

OK, ,

If

RE-CALCULATION OF THE LOADS MOMENTS

FINALIZING THE HEIGHT OF THE SECONDARY BEAM

, ,



DESIGN OF THE REINFORCEMENTS IN SPANDESIGN OF THE REINFORCEMENTS IN SPAN simple reinforced T section

Th ff ti idth f th fl (b ) d d th b d flThe effective width of the flange (beff ), depends on the web and flangedimensions, the type of loading, the span, the support conditions and thetransverse reinforcement.

lThe effective width of the flange (beff ) should be based on the distance l0between points of zero moment.

(B) (B) (B)




beff

,

0 2 0 1 0 2, 0,2 0,1 0 0,2 0

,




T bl th d Table method

/

ω /

22

If μ > μlim re-dimensioning of the section



DETAILING RULESDETAILING RULES(SR EN 1992-1-1/ Ch. 9 and P100/1-2006, Ch.5)

f i i0 26 0 0013 - for non-seismic zones, 0.26 0.0013

- for seismic zones (b = bw)

0 04

, 0.50 0.0013

- according to P100/1-2006

, 0.04

2514

25



DETAILING RULESDETAILING RULES(SR EN 1992-1-1/ Ch. 9 and P100/1-2006, Ch.5)- At the edge of the beam

, 15% ,

- Anchorage of bottom reinforcement at end support

- Anchorage at intermediate supports



DETAILING RULESDETAILING RULES>0.3lo >0.3lo >0.3lo

~10cm ~10cm ~10cm

A B

l≥10d

A B

lbdmin 2ø

2ø8 secondary

min 2ø

lbd min 2ømin 2ø



DETAILING RULESDETAILING RULES

(ch. 8.4.4)1 2 3 4 5 , ,

, /4 /4 ·

·

for anchorages in tension0 3 ; 10 ; 100 for anchorages in tension

for anchorages in compression

, 0.3 , ; 10 ; 100

, 0.6 , ; 10 ; 100



DESIGN OF THE REINFORCEMENTS ON THE SUPPORTSDESIGN OF THE REINFORCEMENTS ON THE SUPPORTS double reinforced rectangular cross section

AAs1 unknown

As2(reinforcement from the span)



DESIGN OF THE REINFORCEMENTS ON THE SUPPORTSDESIGN OF THE REINFORCEMENTS ON THE SUPPORTS double reinforced rectangular cross section

I l l t d 2 2 IT IS THE MINIMUMIs calculated

- If μa > μlim re-dimensioning of the section

2 22 EFFECTIVE AREA !!!

μa μlim g

- If μa < 0 12

- If 0 < μa < μlim , from μa ωa

2

μa μlim μa a

As1 = Aa + As2



DESIGN FOR SHEAR FORCEDESIGN FOR SHEAR FORCEComputation the shear resistance of concrete

100 1/3 0 035 · 3/2 · 1/2 ·

0 18/ 200

, , 100 0.035

, 0.18/ 1200

2.00

0.020.02



DESIGN FOR SHEAR FORCEDESIGN FOR SHEAR FORCE

If minimum shear reinforcement will be provide,

· · , 0.08

, 0.75 1 300

For providing of double-arm stirrups400



DESIGN FOR SHEAR FORCEDESIGN FOR SHEAR FORCE

If is imposed θ = 45o (crack),α = 90o (stirrups)where z ≈ 0,9d

·

choose Asw = n x øsw snec

â and then must be verified if



DESIGN FOR SHEAR FORCEDESIGN FOR SHEAR FORCEDETAILING RULES

T h d til f il To have a ductile failure , ,

0 50.5 1

Where 1 0.6 1250

III. DESIGN OF SLAB DEFLECTION

( )1. DESIGN OF SLAB DEFLECTIONS (Axis VM)

‐ Supports blocked in ZSupports blocked in Z

‐ Permanent loads applied simultaneously

‐ Variable loads applied in chess and/or strips

Design combination in SLS in conformity of CR 0, ch. 4.4:

1,1 ,1 2, ,

Microsoft PowerPoint - Guide RC project ngyt 2013 04 09

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