wit for post-installed rebar - wurth.fi · wit for post-installed rebar beneﬁ ts: • europ 28...

WIT FOR POST-INSTALLED REBAR

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28

POST -INSTALLED REBAR

The guideline specifi es a number of tests in order to qualify products for post-installed rebar applications. These are the performance areas checked by the tests:1. Bond strength in diff erent strengths of concrete.2. Substandard hole cleaning.3. Wet concrete.4. Sustained load and temperature infl uence.5. Freeze-thaw conditions.6. Installation directions.7. Maximum embedment depth.8. Avoidance of air bubbles during injection.9. Durability (corrosion, chemical attack).

If an adhesive meets all assessment criteria, rebar connections carried out with this adhesive can be designed with the bond strength and minimum anchorage length according to EN 1992-1-1as given in the tables below for diff erent Würth injection adhesives.Adhesives (or in conjunction with a certain drilling procedure) which do not fully comply with all assessment criteria can still obtain an approval.• If the bond strength obtained in tests does not fulfi l the specifi ed requirements, then bond strengths lower than those given by EN 1992-1-1 shall be applied. These values are given in the respective approval.

Rebar used as Anchor versus Post-installed Rebar Connections

Tab. 1: Comparison of potential failure modes.

Rebar used as AnchorSituations where the concrete needs to take up tensile load from the anchorage or where reinforcing bars are designed to carry shear loads should be considered as “rebar used as anchors” and designed according to anchor design method such as given e.g. in the guidelines of EOTA and ACI or simplifi ed in this Design Manual. Those guidelines verify all possible failure loads in tension and shear.

Post-installed Rebar ConnectionThe design of the rebar anchorage is performed according to structural concrete design codes, e.g. EN 1992-1-1 or ACI 318. With a given test regime

and a subsequent assessment (EOTA-Technical Report TR 023) it is proven that the load transfer for post-installed reinforcing bars is similar to cast in bars if the stiff ness of the overall load transfer mechanism is similar to the cast-in system. The effi ciency depends on the strength of the adhesive mortar against the concentrated load close to the ribs and on the capacity of load transfer at the interface of the drilled hole.In many cases the bond values of post-installed bars are higher compared to cast in bars due to better performance of the adhesive mortar. But for small edge distance and/or narrow spacing, splitting or spalling forces become decisive due to the low tensile capacity of the concrete.

Rebar used as Anchor Post-installed Rebar Connection

Failure modes in tension Failure modes in shear Failure modes in tension Failure modes in shear

Steel failure of fastener Steel failure of fastener without lever arm

Steel failure of reinforcing bar

Steel failure of fastener with lever arm

Bond failure

Pull-out failure of fastener Concrete pry-out failure Splitting failure

Combined pull-out and concrete failure

Concrete edge failure

Concrete cone failure

Splitting failure

Post-installed rebar anchorage – The assessment criteria of EOTA-Technical Report TR 023

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• If it cannot be shown that the bond strength of reinforcing bars post-installed with a selected product and cast-in reinforcing bars in cracked concrete (w=0.3mm) is similar, then the minimum anchorage length lb,min and the minimum overlap length l0,min shall be increased by a factor 1.5.

Applications

Products tested according to above guideline can be used for applications in non-carbonated concrete C12/15 to C50/60 (EN 206) only, which are also allowed with straight deformed cast-in bars according to (EC2), e.g. those in the following applications: Note to the following Figures: In the Figures no transverse reinforcement is plotted, the transverse reinforcement as required by EC 2 shall be present. The shear transfer between old and new concrete shall be designed according to EC 2.

Fig. 1: Overlap joint for rebar connections.

Fig. 2: End anchoring of slabs or beams.

Fig. 3: Overlap joint at a foundation of a column or wall where the

rebars are stressed in tension.

Fig. 4: Rebar connection for components stressed primarily in

compression. The rebars are stressed in compression.

Fig. 5: Anchoring of reinforcement to cover.

Design Manual 2 (18) JoB-130605-001

WIT fo r po s t - in s ta lled r ebar

If an adhesive meets all assessment criteria, rebar connections carried out with this adhesive can be designed with the bond strength and minimum anchorage length according to EN 1992-1-1as given in the tables below for different Würth injection adhesives. Adhesives (or in conjunction with a certain drilling procedure) which do not fully comply with all assessment criteria can still obtain an approval.

If the bond strength obtained in tests does not fulfil the specified requirements, then bond strengths lower than those

given by EN 1992-1-1 shall be applied. These values are given in the respective approval. If it cannot be shown that the bond strength of reinforcing bars post-installed with a selected product and cast-in

reinforcing bars in cracked concrete (w=0.3mm) is similar, then the minimum anchorage length lb,min and the minimum overlap length l0,min shall be increased by a factor 1.5.

Applications Products tested according to above guideline can be used for applications in non-carbonated concrete C12/15 to C50/60

(EN 206) only, which are also allowed with straight deformed cast-in bars according to (EC2), e.g. those in the following applications: Note to the following Figures: In the Figures no transverse reinforcement is plotted, the transverse reinforcement as required by EC 2 shall be present. The shear transfer between old and new concrete shall be designed according to EC 2.

Fig. 1: Overlap joint for rebar connections

Fig. 2: End anchoring of slabs or beams,



If an adhesive meets all assessment criteria, rebar connections carried out with this adhesive can be designed with the bond strength and minimum anchorage length according to EN 1992-1-1as given in the tables below for different Würth injection adhesives. Adhesives (or in conjunction with a certain drilling procedure) which do not fully comply with all assessment criteria can still obtain an approval.

If the bond strength obtained in tests does not fulfil the specified requirements, then bond strengths lower than those

given by EN 1992-1-1 shall be applied. These values are given in the respective approval. If it cannot be shown that the bond strength of reinforcing bars post-installed with a selected product and cast-in

reinforcing bars in cracked concrete (w=0.3mm) is similar, then the minimum anchorage length lb,min and the minimum overlap length l0,min shall be increased by a factor 1.5.

Applications Products tested according to above guideline can be used for applications in non-carbonated concrete C12/15 to C50/60

(EN 206) only, which are also allowed with straight deformed cast-in bars according to (EC2), e.g. those in the following applications: Note to the following Figures: In the Figures no transverse reinforcement is plotted, the transverse reinforcement as required by EC 2 shall be present. The shear transfer between old and new concrete shall be designed according to EC 2.

Fig. 1: Overlap joint for rebar connections

Fig. 2: End anchoring of slabs or beams,



Fig. 3: Overlap joint at a foundation of a column or wall where the rebars are stressed in tension

Fig. 4: Rebar connection for components stressed primarily in compression. The rebars are stressed in compression

Fig. 5: Anchoring of reinforcement to cover

Anwendungsbilder






Anwendungsbilder






Anwendungsbilder


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a) Reinforcing bars shall be so anchored that the bond forces are safely transmitted to the concrete avoiding longitudinal cracking or spalling. Transverse reinforcement shall be provided if necessary.b) The ultimate bond strength shall be sufficient to prevent bond failure.

The design value of the ultimate bond stress

where:fctd … is the design value of concrete tensile strength according to Tab. 1.η1 … is a coefficient related to the quality of the bond condition and the position of the bar during concreting (details see EN 1992-1-1): η1 = 1.0 when good conditions are obtained and η1 = 0.7 for all other cases and for bars in structural elements built with slip-forms, unless it can be shown that good bond conditions existη2 … is related to the bar diameter: η2 = 1.0 for ∅ ≤ 32 mm η2 = (132 - ∅)/100 for ∅ > 32 mm

Design of Anchorage of longitudinal reinforcement with EN1992-1-1 (EUROCODE 2)

Compressive strength class C12/15 C16/20 C20/25 C25/30 C30/37 C35/45 C40/50 C45/55 C50/60

fck [N/mm2] 12 16 20 25 30 35 40 45 50

fck,cube [N/mm2] 15 20 25 30 37 45 50 55 60

fcm [N/mm2] 20 24 28 33 38 43 48 53 58

fctm [N/mm2] 1.6 1.9 2.2 2.6 2.9 3.2 3.5 3.8 4.1

fctk, 0.05 [N/mm2] 1.1 1.3 1.5 1.8 2.0 2.2 2.5 2.7 2.9

fctk, 0.95 [N/mm2] 2.0 2.5 2.9 3.3 3.8 4.2 4.6 4.9 5.3

fbd [N/mm2] 1.65 1.95 2.25 2.70 3.00 3.30 3.75 4.05 4.35

Tab. 2: Strength characteristics for concrete.

The design value of the bond stress for different adhesives and drilling methods are given below:

Compressive strength class C12/15 C16/20 C20/25 C25/30 C30/37 C35/45 C40/50 C45/55 C50/60

WIT-PE 500

Hammer

drilling and

compressed

air drilling

fbd [N/mm2] 1.65 1.95 2.25 2.70 3.00 3.30 3.75 4.05 4.35

Diamond

drilling

fbd [N/mm2] 1.65 1.95 2.25 2.70 3.00 3.00 3.40 3.70 3.70

WIT-VM 250

Hammer

drilling and

compressed

air drilling

fbd [N/mm2] 1.65 1.95 2.25 2.70 3.00 3.30 3.75 4.05 4.35

Tab. 3: Design values of the bond stress of Würth's WIT adhesives in case of good bond condition.

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Development length is the shortest length needed for reinforcing bar so that the yield strength can induced in the bar.

Reinforced concrete members are often designed using strut and tie models. The forces are represented by trusses and the nodes of these trusses have to connect the forces in such a way that they are in balance: The sum of the concrete compression force, the support force and the steel tensile force equals zero. The node can maintain its function only when the bond between the reinforcing bar and the surrounding concrete is activated and in balance with the horizontal component of the concrete compression strength. The node has to physically provide a certain length over which the rebar can develop stress on its left side. This extension on the left side is called “development length” or “anchorage length”. The length or the space on the left side depends on the method of anchorage: bend, hook or straight.

Development length

Fig. 6: Nodes of trusses.

Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40Cross sectional area of reinforcement

As [mm2] 50.3 78.5 113.1 153.9 201.1 314.2 490.9 615.8 804.2 1256.6

Characteristic yield strength fyk [N/mm2] 500 500 500 500 500 500 500 500 500 500

Partial factor for reinforcing steel

γs 1.15

Design resistance of reinforcement bar

NRd,s [kN] 21.9 34.1 49.2 66.9 87.4 136.6 213.4 267.7 349.7 546.4

Design Bond stress fbd [N/mm2] 2.3 2.1

Development length

lbd [mm] 387 483 580 676 773 966 1208 1353 1546 2100

lbd/∅ 48 48 48 48 48 48 48 48 48 53Tab. 4: Development length for C20/25 and reinforcement bar B500B.


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Bar

size

Cross sectional areaof reinforcement

Characteristic yield strength of reinforcement B500B

Partial factor for reinforcing steelDesign restistance of reinforcement bar

Design Bond stress

Development length

Minimum anchorage length

Des

ign

load

for

good

bon

d co

nditi

on, C

20/2

5

∅A s

f ykγ s

NRd

,sf bd

l bdl b,

min

Nb,

d

[mm

][m

m2 ]

[N/m

m2 ][k

N]

[N/m

m2 ][m

m]

[kN

]

850

.350

01.

1521

.92.

338

611

67

78

811

1417

20

1078

.550

01.

1534

.12.

348

314

511

1418

2125

28

1211

3.1

500

1.15

49.2

2.3

580

174

1721

2530

3442

1415

3.9

500

1.15

66.9

2.3

676

203

2530

3540

4959

1620

1.1

500

1.15

87.4

2.3

773

232

2834

4045

5768

79

2031

4.2

500

1.15

136.

62.

396

629

042

4957

7185

9911

312

7

2549

0.9

500

1.15

213.

42.

312

0836

271

8810

612

414

115

917

719

421

2

2861

5.8

500

1.15

267.

72.

313

5340

699

119

139

158

178

198

218

238

257

3280

4.2

500

1.15

349.

72.

315

4646

411

313

615

818

120

422

624

927

129

431

733

9

4012

56.6

500

1.15

546.

42.

121

0063

018

220

823

426

028

631

233

836

439

041

644

246

849

452

054

6

Anch

orag

e le

ngth

[mm

]12

013

014

015

020

025

030

035

040

050

060

070

080

090

010

0011

0012

0013

0014

0015

0016

0017

0018

0019

0020

0021

00

WIT

-PE

500

and

WIT

-VM

250

: Des

ign

load

s ve

rsus

anc

hora

ge d

epht

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Basic anchorage length The calculation of the required anchorage length shall take into consideration the type of steel and bond properties of the bars. The basic required anchorage length, lb,rqd, for anchoring the force As ■ σsd in a bar assuming constant bond stress equal to fbd follows from:

Design anchorage lengthThe design anchorage length, lbd, is

α1 = 1.0 for anchorage of straight bars; in case of post-installed rebar application only straight bar possible. α2 = 1.0 for reinforcement bar in compression. α2: 0.7 ≤ 1 - 0.15 (cd - ∅)/∅ ≤ 1.0 for reinforcement bar in tension.

Fig. 7: Values for beams and slabs.

α3 = 1.0 no transverse reinforcement. α4 = 1.0 no welded transverse reinforcement. α5: 0.7 ≤ 1 - 0.04ρ ≤ 1.0 for confi nement by transverse pressure ρ [MPa] along lbd ■ (α2α3α5) ≥ 0.7.

lb,min is the minimum anchorage length if no other limitation is applied: for anchorages in tension

for anchorages in compression

When using WIT-PE 500 with diamond wet drilling multiply the values by 1.5.

Lap or Splice length The design lap length is

α1 = 1.0 for anchorage of straight bars; in case of post-installed rebar application only straight bar possible. α2 = 1.0 for reinforcement bar in compression. α2 0.7 ≤ 1 - 0.15 (cd - ∅)/∅ ≤ 1.0 for reinforcement bar in tension.

α3 = 1.0 no transverse reinforcement.

α5: 0.7 ≤ 1 - 0.04ρ ≤ 1.0 for confi nement by transverse pressure ρ [MPa] along lbd ■ (α2α3α5) ≥ 0.7.

l0,min is the minimum lap length:

When using WIT-PE 500 with diamond wet drilling multiply the values by 1.5.

α6 = 1.0 … 1.5 for infl uence of percentage of lapped bars relative to the total cross-section area according to the following table:

Tab. 5: Values of the coeffi cient.



Basic anchorage length The calculation of the required anchorage length shall take into consideration the type of steel and bond properties of the bars. The basic required anchorage length, lb,rqd, for anchoring the force As.σsd in a bar assuming constant bond stress equal to fbd follows from:

!!,!"# =∅4∙!!"!!"

Design anchorage length The design anchorage length, lbd, is !!" = !! ∙ !! ∙ !! ∙ !! ∙ !! ∙ !!,!"# ≥ !!,!"#

α1 = 1.0 for anchorage of straight bars; in case of post-installed rebar application only straight bar possible.

α2 = 1.0 for reinforcement bar in compression. α2: 0.7 ≤ 1 - 0.15 (cd - ∅)/∅ ≤ 1.0 for reinforcement bar in tension.

Fig. 7: Values for beams and slabs

α3 = 1.0 no transverse reinfordement.

α4 = 1.0 no welded transverse reinforcement. α5: 0.7 ≤ 1 - 0.04ρ ≤ 1.0 for confinement by transverse pressure ρ [MPa] along lbd . (α2α3α5) ≥ 0.7. lb,min is the minimum anchorage length if no other limitation is applied:

!!,!"# ≥ max (0.3 ∙ !!,!"#; 10∅; 100!!) for anchorages in tension

!!,!"# ≥ max (0.6 ∙ !!,!"#; 10∅; 100!!) for anchorages in compression

When using WIT-PE 500 with diamond wet drilling multiply the values by 1.5. Lap or Splice length The design lap length is !! = !! ∙ !! ∙ !! ∙ !! ∙ !! ∙ !!,!"# ≥ !!,!"#

Percentage of lapped bars relative to the total cross-section area

<25% 33% 50% >50%

a6 1.00 1.15 1.40 1.50

Note: Intermediate values may be determined by interpolation


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The minimum coverIn order to transmit bond forces safely and to ensure adequate compaction of the concrete, the minimum cover

should not be less than cmin,b = ∅. Add 5mm if the nominal maximum aggregate size is greater than 32 mm.

Concrete cover

Tab. 6: Values of minimum cover, cmin,dur [mm] requirements with regard to durability for reinforcement steel.

The minimum cover of post-installed reinforcing bars depending on drilling method cmin,inst

Drilling method ∅ without drilling aid with drilling aid

WIT-PE 500

Hammer drilling andDiamond drilling

< 25mm 30mm + 0.06lv ≥ 2 ∅ 30mm + 0.02lv ≥ 2 ∅

≥ 25mm 40mm + 0.06lv ≥ 2 ∅ 40mm + 0.02lv ≥ 2 ∅

Compressed airdrilling

< 25mm 50mm + 0.08lv 50mm + 0.02lv≥ 25mm 60mm + 0.08lv 60mm + 0.02lv

WIT-VM 250

Hammer drilling< 25mm 30mm + 0.06lv ≥ 2 ∅ 30mm + 0.02lv ≥ 2 ∅

≥ 25mm 40mm + 0.06lv ≥ 2 ∅ 40mm + 0.02lv ≥ 2 ∅

Compressed airdrilling

< 25mm 50mm + 0.08lv 50mm + 0.02lv≥ 25mm 60mm + 0.08lv 60mm + 0.02lv

Exposure Class

X0 XC1 XC2/XC3 XC4 XD1/XS1 XD2/XS2 XD3/XS3

Stru

ctur

al C

lass

S1 10 10 10 15 20 25 30

S2 10 10 15 20 25 30 35

S3 10 10 20 25 30 35 40

S4 10 15 25 30 35 40 45

S5 15 20 30 35 40 45 50

S6 20 25 35 40 45 50 55

Tab. 7: Minimum Cover depending on drilling method.

The nominal cover

The recommended value for Δcdev = 10mm.

Concrete cover:

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Spacing of bars and lapsThe spacing of bars shall be such that the concrete can be placed and compacted satisfactorily for the development of adequate bond. The clear distance

(horizontal and vertical) between individual parallel bars or horizontal layers of parallel bars should be not less than the max(∅; (dg + 5 mm) or 20mm) where dg is the maximum size of aggregate (8.2; EN1992-1-1:2011-01).



WIT-VM 250

Hammer drilling < 25mm 30mm + 0.06 lv ≥ 2∅ 30mm + 0.02 lv ≥ 2∅

≥ 25mm 40mm + 0.06 lv ≥ 2∅ 40mm + 0.02 lv ≥ 2∅

Compressed air drilling

< 25mm 50mm + 0.08 lv 50mm + 0.02 lv

≥ 25mm 60mm + 0.08 lv 60mm + 0.02 lv Tab. 7: Minimum Cover depending on drilling method

The nominal cover !!"# = !!"# + ∆!!"#

The recommended value for ∆cdev = 10mm. Concrete cover: min ! = max( !!"#; !!"#,!"#$) Spacing of bars and laps The spacing of bars shall be such that the concrete can be placed and compacted satisfactorily for the development of

adequate bond. The clear distance (horizontal and vertical) between individual parallel bars or horizontal layers of parallel bars should be not less than the max(∅; (dg + 5 mm) or 20mm) where dg is the maximum size of aggregate (8.2; EN1992-1-

1:2011-01 .

Fig. 8: Adjacent laps

The spacing between post-installed reinforcing bars shall be greater max(5∅; 50mm), Embedment depth Embedment depth for overlap joints For calculation of the effective embedment depth of overlap joints the concrete cover at end-face of bonded-in rebar c1 shall be considered: !! ≥ !! + !! If the clear distance between the overlapping rebar is greater than 4 Ø the lap length shall be enlarged by the difference between the clear distance and 4 Ø.

Fig. 8: Adjacent laps.

The spacing between post-installed reinforcing bars shall be greater max(5∅; 50mm).

Embedment depthEmbedment depth for overlap jointsFor calculation of the eff ective embedment depth of over-lap joints the concrete cover at end-face of bonded-in rebar c1 shall be considered:

If the clear distance between the overlapping rebar is greater than 4 Ø the lap length shall be enlarged by the diff erence between the clear distance and 4 Ø.

Maximum embedment depth The maximum permissible embedment depth is depending on adhesive, adhesive temperature and the diameter of the rebar:

Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40Adhesive temperature Maximum permissible embedment depth

WIT-PE 500+5°C to +19°C lmax [cm] 130 200≥ 20°C lmax [cm] 200 280

WIT-VM 250 +5°C to +25°C lmax [cm] 100 100 120 140 160 200 200Tab. 8: Maximum approved embedment depth.


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Transverse reinforcementThe requirements of transverse reinforcement in the area of the post-installed rebar connection shall comply with EN 1992-1-1, Section 8.7.4.

Connection jointThe transfer of shear forces between new concrete and existing structure shall be designed according to EN 1992-1-1, Section 6.2.5 “Shear at the interface between concrete cast at diff erent times”.The joints for concreting must be roughened to at least such an extent that aggregate protrude. In case of a carbonated surface of the existing concrete structure the carbonated layer shall be removed in the area of the post-installed rebar connection with a diameter of (Ø + 60mm) prior to the installation of the new rebar. The depth of concrete to be removed shall correspond to at least the minimum concrete cover for the respective environmental conditions in accordance with EN 1992-1-1. The foregoing may be neglected if building components are new and not carbonated and if building components are in dry conditions.

Failure modes and Anchorage lengthIn most cases the reinforcement bars are placed close to the surface of the concrete member to achieve good crack distribution and economical bending capacity. For splices at wide spacing, the bearing capacity of the concrete depends only on the thickness of the concrete cover. At narrow spacing the bearing capacity depends on the spacing and on the thickness of the cover. In the design codes the reduction of bearing capacity of the cover is taken into account by means of multiplying factors for the splice length. Splitting failure is decisive if the radial cracks propagate through the entire cover. Bond failure is caused by pull-out of the bar if the confi nement (concrete cover, transverse reinforcement) is suffi cient to prevent splitting of the concrete cover. EN1992-1-1 controls the failure modes by limiting the α2 value to α2 ≥ 0.7. The spalling of the concrete cover or splitting between bars will be the controlling mode of failure. The value α2 gives an explicit consideration for splitting

and spalling as a function of concrete cover and bar spacing.If α2 is less than 0.7, corresponding to cover dimensions of cd/∅ > 3 or spacing of a/∅ > 6, the cover or spacing is large enough so that splitting cannot occur anymore and pull-out will control. Considering any adhesive for post-installed reinforcing bars with their higher maximum bond strength comparing that of cast-in bars, we would fi nd that maximum value as a limiting value for the increase of the controlling design bond stress. Those values are taken from the relevant anchor approval. Thus, the limitation for bond failure in the code has been replaced by the specifi c design bond stress of the adhesive for the specifi c application conditions.

WIT-PE 500

WIT-VM 250



For the modification of the design for a particular adhesives with its specific design bond strength, the value α2 was adapted

in such a way to create a linear extension of the bond strength function exceeding cd/∅ > 3 or spacing of a/∅ > 6 and calibrated on the basis of tests with the additional limit of a lowest adapted α2 of 0.25. The design values exceeding cd/∅ > 3 or spacing of a/∅ > 6

Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40

Service temperature Maximum design bond strength

WIT-PE 500 ≤ +24°C fbd,ext [N/mm2] 6.0 6.0 5.6 5.6 5.3 4.7 4.4 4.4 4.4 3.4

WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -





Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40



WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -





Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40



WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -





Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40



WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -





Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40



WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -





Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40



WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -





Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40



WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -





Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40



WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -

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For the modifi cation of the design for a particular adhesives with its specifi c design bond strength, the value α2 was adapted in such a way to create a linear extension of the bond strength function exceeding

cd/∅ > 3 or spacing of a/∅ > 6 and calibrated on the basis of tests with the additional limit of a lowest adapted α2 of 0.25.

The design values exceeding cd/∅ > 3 or spacing of a/∅ > 6

Bar size ∅ [mm] 8 10 12 14 16 20 25 28 32 40Service temperature Maximum design bond strength


WIT-VM 250 fbd,ext [N/mm2] 5.3 5.3 5.3 5.3 5.3 5.3 5.3 4.9 4.6 -


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W IT-PE 500: Design loads versus anchorage depth

Barsize

Cros

s se

ctio

nal a

rea

of r

einf

orce

men

t

Char

acte

rist

ic y

ield

str

engt

h of

re

info

rcem

ent B

500B

Part

ial f

acto

r fo

r r

einf

orci

ng s

teel

Des

ign

rest

ista

nce

of

rein

forc

emen

t bar

Des

ign

Bond

str

ess

Dev

elop

men

t len

gth

Min

imum

anc

hora

ge le

ngth

Design load for good bond condition, C20/25

∅ As fykγs NRd,s fbd lbd lb,min Nb,d

[mm] [mm2] [N/mm2] [kN] [N/mm2] [mm] [kN]

8 50.3 500 1.15 21.9 6.0 145 100 15 17 18 20 21

10 78.5 500 1.15 34.1 6.0 181 100 19 21 23 25 26 28

12 113.1 500 1.15 49.2 5.6 233 120 25 27 30 32 42

14 153.9 500 1.15 66.9 5.6 272 140 34 37 49 62

16 201.1 500 1.15 87.4 5.3 328 160 53 67 80

20 314.2 500 1.15 136.6 4.7 463 200 59 74 89 103 118

25 490.9 500 1.15 213.4 4.4 618 250 86 104 121 138 173 207

28 615.8 500 1.15 267.7 4.4 692 280 116 135 155 194 232

32 804.2 500 1.15 349.7 4.4 791 320 155 177 221 265 310

40 1256.6 500 1.15 546.4 3.4 1279 400 171 214 256 299 342 385 427 470 513

Anchorage length [mm] 100 110 120 130 140 150 200 250 300 350 400 500 600 700 800 900 1000 1100 1200 1300

WIT-VM 250: Design loads versus anchorage depth

Barsize

Cros

s se

ctio

nal a

rea

of r

einf

orce

men

t

Char

acte

rist

ic y

ield

str

engt

h of

re

info

rcem

ent B

500B

Part

ial f

acto

r fo

r r

einf

orci

ng s

teel

Des

ign

rest

ista

nce

of

rein

forc

emen

t bar

Des

ign

Bond

str

ess

Dev

elop

men

t len

gth

Min

imum

anc

hora

ge le

ngth




8 50.3 500 1.15 21.9 5.3 164 100 13 15 16 17 19 20

10 78.5 500 1.15 34.1 5.3 205 100 17 18 20 22 23 25 33

12 113.1 500 1.15 49.2 5.3 246 120 24 26 28 30 40

14 153.9 500 1.15 66.9 5.3 287 140 33 35 47 58

16 201.1 500 1.15 87.4 5.3 328 160 53 67 80

20 314.2 500 1.15 136.6 5.3 410 200 67 83 100 117 133

25 490.9 500 1.15 213.4 5.3 513 250 104 125 146 167 208

28 615.8 500 1.15 267.7 4.9 621 280 129 151 172 216 259

32 804.2 500 1.15 349.7 4.6 756 320 162 185 231 277 324

Anchorage length [mm] 100 110 120 130 140 150 200 250 300 350 400 500 600 700

39

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Barsize

Cros

s se

ctio

nal a

rea

of r

einf

orce

men

t

Char

acte

rist

ic y

ield

str

engt

h of

re

info

rcem

ent B

500B

Part

ial f

acto

r fo

r r

einf

orci

ng s

teel

Des

ign

rest

ista

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Des

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8 50.3 500 1.15 21.9 6.0 145 100 15 17 18 20 21

10 78.5 500 1.15 34.1 6.0 181 100 19 21 23 25 26 28

12 113.1 500 1.15 49.2 5.6 233 120 25 27 30 32 42

14 153.9 500 1.15 66.9 5.6 272 140 34 37 49 62

16 201.1 500 1.15 87.4 5.3 328 160 53 67 80

20 314.2 500 1.15 136.6 4.7 463 200 59 74 89 103 118

25 490.9 500 1.15 213.4 4.4 618 250 86 104 121 138 173 207

28 615.8 500 1.15 267.7 4.4 692 280 116 135 155 194 232

32 804.2 500 1.15 349.7 4.4 791 320 155 177 221 265 310

40 1256.6 500 1.15 546.4 3.4 1279 400 171 214 256 299 342 385 427 470 513

Anchorage length [mm] 100 110 120 130 140 150 200 250 300 350 400 500 600 700 800 900 1000 1100 1200 1300

Load Case FireThe bond strength in slabs under fi re has been evaluated in tests and is certifi ed by reports of the Technical University of Brunswik, Germany. The conformity with the German standards is confi rmed in DIBt German national Approval. These documents are downloadable from the Intranet for the diff erent adhesive mortars.

There are two types of design tables corresponding to the basic fi re situations “parallel” and “anchorage or perpendicular”.

In the fi re situation “parallel” the only parameter is the clear distance from the fi re exposed concrete surface to the perimeter of the bar (“clear concrete cover c”). From this parameter, one can directly read the bond strength of the adhesive for specifi c fi re durations.



Load C ase Fire The bond strength in slabs under fire has been evaluated in tests and is certified by reports of the Technical University of

Brunswik, Germany. The conformity with the German standards is confirmed in DIBt German national Approval. These documents are downloadable from the Intranet for the different adhesive mortars. There are two types of design tables corresponding to the basic fire situations “parallel” and “anchorage or perpendicular”.

In the fire situation “parallel” the only parameter is the clear distance from the fire exposed concrete surface to the perimeter of the bar (“clear concrete cover c”). From this parameter, one can directly read the bond strength of the adhesive for specific fire durations.

!!",!!…,!" = !!",!"!… ∙ !! ∙ ∅ ∙ !

In the fire situation “anchorage or perpendicular” the tables directly show the fire resistance as a force [kN] for given diameters, embedment depths and fire durations.

Da müssen wir was englisches draus machen. Strater hat bestimmt die Urtabellen

fi re resistance duration Concrete cover of the post-installed

rebars c

R 30 R 60 R 90 R 120 R 180 R 240

Ultimate bond stress fbd,fi

[N/mm²] [N/mm²] [N/mm²] [N/mm²] [N/mm²] [N/mm²] [mm]

0.32

0.0

0.0 0.0 0.0 0.0

30

0.40 35

0.50 40

0.62 45

0.79 0.31 50

0.95 0.37 55

1.16 0.44 60

1.50 0.53 65


Benefi ts:• Europ

40


Bar size Max. load Anchorage lenght

fi re resistance class

R 30 R60 R90 R 120 R 180

∅ max NRd,fi lv NRd,fi

[mm] [kN] [mm] [kN] [kN] [kN] [kN] [kN]

8 16.2

80 1.7 0.5 0.14 0 0

120 7.5 2.3 1.1 0.6 0.1

170 16.2 9.1 5.3 3.1 1.1

215 16.2 13.2 9.9 3.7

235 16.2 13.4 6.5

255 16.2 10.0

295 16.2

10 25.3

100 5.0 1.5 0.6 0.2 0.0

150 16.0 6.9 3.6 2.2 0.7

195 25.3 16.9 12.1 7.9 2.7

235 25.3 20.9 16.7 8.1

260 25.3 22.2 13.6

275 25.3 16.9

315 25.3

The load case “Fire” is an exceptional load case. Please see the respective standard e.g. EN1991 for load combinations and safety factors. Material factors are assumed to be γM,fi = 1.0.

Corrosion behaviour of post-installed reinforcing barsAccording to the assessment criteria of EOTA-Technical Report TR 023, section 3.3.4 it has to be shown by tests that post installed rebar connections conducted with a particular adhesive provide the same corrosion resistance as cast-in-place rebar. Consequently all Würth adhesives with approval according to TR 023 have been tested.

In the fi re situation “anchorage or perpendicular” the tables directly show the fi re resistance as a force [kN] for given diameters, embedment depths and fi re durations.



Load C ase Fire The bond strength in slabs under fire has been evaluated in tests and is certified by reports of the Technical University of

Brunswik, Germany. The conformity with the German standards is confirmed in DIBt German national Approval. These documents are downloadable from the Intranet for the different adhesive mortars. There are two types of design tables corresponding to the basic fire situations “parallel” and “anchorage or perpendicular”.

In the fire situation “parallel” the only parameter is the clear distance from the fire exposed concrete surface to the perimeter of the bar (“clear concrete cover c”). From this parameter, one can directly read the bond strength of the adhesive for specific fire durations.

!!",!!…,!" = !!",!"!… ∙ !! ∙ ∅ ∙ !

In the fire situation “anchorage or perpendicular” the tables directly show the fire resistance as a force [kN] for given diameters, embedment depths and fire durations.

Da müssen wir was englisches draus machen. Strater hat bestimmt die Urtabellen

41

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EBAR

End support of beam, simply supported

Given information Concrete: C20/25 Steel: B500B Actions: sd = 23.75kN/m, Sd = 50kN Cross section of beam: h x b = 0.5m x 0.3m Eff ective depth of cross section: d = 0.44m Cross section of column: c1 x c2 = 0.6m x 0.6m Clear distance between two columns: 4.5m Eff ective span: leff = 5.0m Exposure Class: XC4 Concrete cover: cnom= 40mm Bending moment at mid span: MEds = 193.95kNm Bottom reinforcement required at mid span: 4 ∅ 20 (=12.6cm2) > As,erf = 11.785cm2

As,max = 0.04 Ac = 60cm2

Shear force at support: VEd = 117.66kN

Examples

5.3.2.2; EN1992-1-1:2011-01

9.2.1.1; EN1992-1-1:2011-01



Examples End support of beam, simply supported

Given information Concrete: C20/25 Steel: B500B Actions: sd = 23.75kN/m, Sd = 50kN Cross section of beam: h x b = 0.5m x 0.3m Effective depth of cross section: d = 0.44m Cross section of column: c1 x c2 = 0.6m x 0.6m Clear distance between two columns: 4.5m Effective span: leff = 5.0m 5.3.2.2; EN1992-1-1:2011-01 Exposure Class: XC4 Concrete cover: cnom= 40mm Bending moment at mid span: MEds = 193.95kNm

Bottom reinforcement required at mid span: 4 ∅ 20 (=12.6cm2) > As,erf = 11.785cm2

As,max = 0.04 Ac = 60cm2 9.2.1.1; EN1992-1-1:2011-01 Shear force at support: VEd = 117.66kN

Bottom reinforcement at Support

Tensile force to be anchored: !! = !!" ∙ !!!

9.2.1.4 (2); EN1992-1-1:2011-01

! = 0.9 ∙ ! = 0.9 ∙ 0.44 = 0.396 6.2.3 (1); EN1992-1-1:2011-01

!! =! cot ! − cot!

2

9.2.1.3 (2); EN1992-1-1:2011-01 6.2.3 (1); EN1992-1-1:2011-01

!! = ! 9.2.1.3 (2); EN1992-1-1:2011-01

!! = !!" ∙!!!=117.660.9

= 130.73!"

450

25

500

VEd = 117.66kN

0.5m x 0.3m

De

E E G

B

esign Manual

WIT for p

xamples

End support of

Given informatConcretSteel: BActions:Cross seEffectiveCross seClear dEffectiveExposurConcretBendingBottom 4 ∅ 20As,max = 0Shear fo

ottom reinforcTensile

post-installe

f beam, simply

tion te: C20/25 500B : sd = 23.75kection of beae depth of croection of coluistance betwee span: leff = 5re Class: XC4te cover: cnom=g moment at mreinforcemen (=12.6cm2) >0.04 Ac = 60corce at suppo

cement at Supforce to be a

450

ed rebar ap

ly supported

N/m, Sd = 50m: h x b = 0.oss section: dumn: c1 x c2 = een two colum

5.0m 4 = 40mm mid span: ME

nt required at > As,erf = 11.7cm2 ort: VEd = 117

pport nchored:

0

0.5m

17

pplication

0kN 5m x 0.3m = 0.44m 0.6m x 0.6mmns: 4.5m

ds = 193.95kN mid span: 85cm2

7.66kN

m x 0.3m

7 (18)

m

Nm

25

VEd

5.3

9.2

9.2

6.29.26.29.2

5

5

= 117.66kN

.2.2; EN1992

.1.1; EN1992

.1.4 (2); EN19

.3 (1); EN199

.1.3 (2); EN19

.3 (1); EN199

.1.3 (2); EN19

500

N

JoB-130

-1-1:2011-01

-1-1:2011-01

992-1-1:2011-

92-1-1:2011-0992-1-1:2011-92-1-1:2011-0992-1-1:2011-

0605-001

-01

1 -01 1 -01

De

E E G

B

esign Manual

WIT for p

xamples

End support of

Given informatConcretSteel: BActions:Cross seEffectiveCross seClear dEffectiveExposurConcretBendingBottom 4 ∅ 20As,max = 0Shear fo

ottom reinforcTensile

post-installe

f beam, simply

tion te: C20/25 500B : sd = 23.75kection of beae depth of croection of coluistance betwee span: leff = 5re Class: XC4te cover: cnom=g moment at mreinforcemen (=12.6cm2) >0.04 Ac = 60corce at suppo

cement at Supforce to be a

450

ed rebar ap

ly supported

N/m, Sd = 50m: h x b = 0.oss section: dumn: c1 x c2 = een two colum

5.0m 4 = 40mm mid span: ME

nt required at > As,erf = 11.7cm2 ort: VEd = 117

pport nchored:

0

0.5m

17

pplication

0kN 5m x 0.3m = 0.44m 0.6m x 0.6mmns: 4.5m

ds = 193.95kN mid span: 85cm2

7.66kN

m x 0.3m

7 (18)

m

Nm

25

VEd

5.3

9.2

9.2

6.29.26.29.2

5

5

= 117.66kN

.2.2; EN1992

.1.1; EN1992

.1.4 (2); EN19

.3 (1); EN199

.1.3 (2); EN19

.3 (1); EN199

.1.3 (2); EN19

500

N

JoB-130

-1-1:2011-01

-1-1:2011-01

992-1-1:2011-

92-1-1:2011-0992-1-1:2011-92-1-1:2011-0992-1-1:2011-

0605-001

-01

1 -01 1 -01


Benefi ts:• Europ

42


Bottom reinforcement at SupportTensile force to be anchored:

Steel section required:

Minimum reinforcement at support:

Decisive As = 300.7mm2; provided 3 ∅ 14 (=461.7mm2)

Minimum spacing between rebar

amin = max(5 ■ 14; 50) = 70mm ≤ 79mm

Basic anchorage length:

Design anchorage length:

α1 = 1.0

α2 = 0.72

0.7 ≤ 1 - 0.15 (cd - ∅)/∅ ≤ 1.0

cd = 39.5mm

α3 = 1.0

α4 = 1.0

α5 = 1.0

lbd controls

9.2.1.4 (2); EN1992-1-1:2011-01

6.2.3 (1); EN1992-1-1:2011-01

9.2.1.3 (2); EN1992-1-1:2011-01

6.2.3 (1); EN1992-1-1:2011-01

9.2.1.3 (2); EN1992-1-1:2011-01

7.3.2 (2); EN1992-1-1:2011-01

9.2.1.4 (1); EN1992-1-1:2011-01

9.3.1.2 (1); EN1992-1-1:2011-01

(slabs only)

8.4.3; EN1992-1-1:2011-01

8.4.3; EN1992-1-1:2011-01

43

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Top reinforcement at SupportMinimum reinforcement at support:As,min,t = 0.15 ■ As,erf = 0.15 ■ 1178.5 = 176.78mm2

Decisive As = 176.8mm2; provided 3 ∅ 10 (=235.5mm2)

Minimum spacing between rebar amin = max(5 ■ 10; 50) = 50mm ≤ 85mm

Embedment depth (considering eff ective span)linst = 100 + 250 = 350mm

9.2.1.2; EN1992-1-1:2011-01

9.2.1.1; EN1992-1-1:2011-01



Steel section required: !!,!"# =!!

!!"!!= !"#.!"

!""!.!"

= 300.7mm2,

Minimum reinforcement at support:

!!,!"# = !! ∙ ! ∙ !!",!"" ∙!!"!!"

= 0.4 ∙ 1.0 ∙ 2.2 ∙ !"###!""

= 63.4mm2 7.3.2 (2); EN1992-1-1:2011-01

As,min = 0.25 . As,erf = 0.25 . 1178.5 = 294.63mm2 9.2.1.4 (1); EN1992-1-1:2011-01

As,min = 0.5 . As,erf = 0.5 . 1178.5 = 589.3mm2 9.3.1.2 (1); EN1992-1-1:2011-01 (slabs only)

Decisive As = 300.7mm2; provided 3 ∅ 14 (=461.7mm2) Minimum spacing between rebar amin = max(5 . 14; 50) = 70mm ≤ 79mm Basic anchorage length: 8.4.3; EN1992-1-1:2011-01

!!,!"# =∅4∙!!"!!"

=144∙130730461.72.25

= 440.45!!

Design anchorage length: 8.4.3; EN1992-1-1:2011-01 !!" = !! ∙ !! ∙ !! ∙ !! ∙ !! ∙ !!,!"# ≥ !!,!"# α1 = 1.0 α2 = 0.72 0.7 ≤ 1 - 0.15 (cd - ∅)/∅ ≤ 1.0 cd = 39.5mm α3 = 1.0 α4 = 1.0 α5 = 1.0 !!" = 0.72 ∙ 440.45 = 318mm !!,!"# ≥ max (0.3 ∙ 440.45; 10 ∙ 14; 100!!) =140mm

lbd controls Embedment depth (considering effective span) linst = 318 + 250 = 568mm Top reinforcement at Support Minimum reinforcement at support: As,min,t = 0.15 . As,erf = 0.15 . 1178.5 = 176.78mm2 9.2.1.2; EN1992-1-1:2011-01

!!,!"# = 0.26 ∙ !!"#!!"

∙ ! ∙ ! = 151mm2 ≤ 176.78mm2 9.2.1.1; EN1992-1-1:2011-01

Decisive As = 176.8mm2; provided 3 ∅ 10 (=235.5mm2) Minimum spacing between rebar amin = max(5 . 10; 50) = 50mm ≤ 85mm

!!,!"# ≥ max (0.3 ∙ 0; 10 ∙ 10; 100!!) =100mm

Embedment depth (considering effective span) linst = 100 + 250 = 350mm

318

100 3 ∅ 10

3 ∅ 14

Embedment depth (considering eff ective span)

linst = 318 + 250 = 568mm

wit for post-installed rebar - wurth.fi · wit for post-installed rebar beneﬁ ts: • europ 28...

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