moment loop box...the durability requirements of en1992-1-1. most other connection items in concrete...

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INTRODUCTION 1 - 2

BOX SYSTEM 3

PRODUCT DESCRIPTION 4

DESIGN INFORMATION 5 - 11

PRODUCT TESTING 11

APPLICATION EXAMPLES 12

INSTALLATION GUIDELINE 13 - 15

C O N T E N T S

QUALITY PERFORMANCE

Up to 50% reduction in mortar use

Minimum wall thickness

Highest load capacity

Efficiency

Box installation is not direction dependent

Even distribution of load

Symmetry

Design resistances in every direction

Design fully compliant with EN1992-1-1

Force Transmission

High-quality sheet metal boxes with no loose plastic elements

High strength 1770MPa wire rope

Quality

3DFORCES

*The actual supply might be varied from the original design but it will not affect the quality performance.

M O M E N T

1

www.moment-solutions .com

ADVANTAGES FOR THE DESIGN ENGINEERThe practical, harmonized Moment Loop Box offers an extensive range for all application just from one source.

Casting channels can be kept narrow thanks to the flexibility of the loops.

The widely recognized safety risk due to bending and rebending of projecting rebar is not relevant.

Spring-back wire loop enable the designer to arrange precast concrete elements with flexibility.

ADVANTAGES FOR PRECAST ELEMENT PRODUCEREasily fixed by nailing to the formwork or with magnetic cover.

High strength and specifically design to resist concrete slurry ingress.

Flexible tape covering minimizes the amount of waste when opening the Loop Box.

Long boxes facilitate fast installation and reduces the risk of the boxes moving during vibro-compaction.

Flexible tail anchor is easy to position inside the reinforcing cage.

ADVANTAGES FOR THE ASSEMBLY CREW ON SITEWire loops easily folded out using screwdriver – no troublesome bending of rebar, no time consuming bolting.

No formation of rust as the recess rail and the loop box are galvanized.

No risk of accident due to protruding rebars.

No residual plastic waste.

Profiled edge of the box securely fixes it in the concrete.

Flexible, spring-back loops enable precast panels to be fitted in a gap.

ADVANTAGES FOR THE PURCHASERMoment Loop Box offers a comprehensive, complete program with Moment Single Loop Box, Moment Double Loop Box and Moment Multi Loop Box as well as threaded connections for reinforcement.

Reduced costs for stock holding due to few sizes covering all applications.

Particularly cost effective solution due to modern manufacturing plant.

Easy handling saves erection time and labour.

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2

*Drawings include wall shoes. For further information, please contact our representative.

ECONOMICAL SOLUTIONS WITH MOMENT LOOP BOXRobust steel case - ensures steadiness during nailing and pouring concrete.

Alternative fixing method using reuseable magnetic cover available.

The loops pop up automatically - time saving: no rebending is required.

Flexible wire loops can spring back during setting up - closing a gap can be easily carried out.

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3


Reusable magnetic cover for efficient installation to the formwork

LOOP BOXMoment Loop Box is used for joining together concrete elements. It consists of a sturdy sheet steel rail suitable for building applications, which contains the foldout flexible wire rope connecting loops. Different loop spacing cover all applications. Wall joints, whether butted or corner joints as well as wall-ceiling joints can be manufactured cost effectively, easily and safely. The length of the loop is matched to the profile of the rail to maintain optimum jointing conditions in the casting channel. The rail profile guarantees that the casting channel can be safely and easily filled over the entire height of the storey. A high strength grout with very good flow characteristics must be used for this purpose.

This product can be installed ceveral ways:

The bespoke back cover with magnetic cover benefits to precasters by allowing for quick installation and potential cost saving from repeated use.

NailDouble sided tape

Thermal adhesive or "Hot Glue"Reuseable magnetic cover

Materials:Galvanized, sheet steel boxGalvanized, high tensile steel wire ropeTape cover

Box TypeIndicative Design Resistance (per box)

Tension (kN) In Plane Shear (kN) Out ofPlane Shear (kN)

MLB-S-6-SL 36.3

MLB-D-6-SL 72.6

MLB-M-6-SL-660-160 145.2

49.3

49.3

107.5

5.1

10.3

20.5

*Note: Concrete Grade = 40MPa; Grout Grade = 40MPa; Wall Thickness = 200mm. For all other arrangements, please contact our Technical Team


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MOMENT SINGLE LOOP BOX

Registered trademark and patent pending.

220

30

50

212

SL

Code SL

6080

100120

MLB-S-6-60MLB-S-6-80MLB-S-6-100MLB-S-6-120

*Offer 5mm wire rope for facade applications.

The Moment Single Loop Box is used for joining together concrete elements. It consists of a sturdy sheet steel box suitable for building applications, which contains the foldout flexible wire rope connecting loops. Wall joints, whether butted or corner joints, as well as wall- ceiling joints can be manufactured cost effectively, easily and safely.

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Materials:Box: Galvanized steelSteel wire rope:High-strength, galvanizedSteel ferrulesCover: Tape 3D

FORCES

22045

50

212

SL

30

Code SL

6080100120

MLB-S-6-60MLB-S-6-80MLB-S-6-100MLB-S-6-120

MOMENT DOUBLE LOOP BOXThe Moment Double Loop Box valid with regular joint as connection of wall-like concrete precast parts. It can transmit forces in all three directions on the connecting joints and consist of a sturdy steel sheet box suitable for building applications which contains the flexible wire rope connecting loops. Wall joints can be manufactured cost effectively, easily and safely. The Moment Double Loop Box enables connection from a thickness of 100 mm.

The selected local mortal fill the joint.

The FDS air tube formwork enables especially fast and effective casting.

For connections in precast part construction with mainly static loads:• Tensile forces• Parallel and vertical transverse forces


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Code SL

6080100120

MLB-M-6-60-l-aMLB-M-6-80-l-aMLB-M-6-100-l-aMLB-M-6-120-l-aMLB-M-6-140-l-a 140

Registered trademark and patent pending.

30

l (350 ~ 300)

SL

a (Min.125)

212

Min.45

MOMENT MULTI LOOP BOXThe multi loop box is intended for precast wall to wall connections. Compared to Single and Double loop boxes, its longer profile requires only minimal time to secure and align to formwork for a wall section. Its specifications such as overall length and number of wire ropes are customizable.

It is used for the construction of prefabricated partition walls and supports as well as wall-wall connections. Filling materials as well as grout can be used as joint filling material. Casting is particularly fast and effective.


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ADVANTAGES FOR DESIGN ENGINEERThe innovative design approach of the Moment Multi Loop Box gives the design engineer complete flexibility to vary the wire spacing, grout and concrete grades as well as the concrete geometry.

ADVANTAGES FOR PRECAST ELEMENT PRODUCERReduced installation time compared with single and double loop boxes.

No additional shear key formwork is necessary.

High strength tape prevents the ingress of concrete slurry in to the box.

More secure connection to the edge formwork means that localised vibro-compaction will not move the box.

ADVANTAGES FOR ASSEMBLY CREW ON SITESignificant reduction in grout volume required reduces the time and cost of on site installation.

Alignment of loops is more controlled than with individual boxes meaning that the placing of the cottering bar is much faster.

WallThickness

Grout Volume (mm3/m)

Single/DoubleLoop Box Multi Loop Box Percentage

Of Grout Saved

150 11000

200 12000

250 13000

5510

6510

7510

49.9%

45.8%

42.2%

Single / Double Loop Box

Multi Loop Box

Less grout used with:

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There are a few additional design considerations to be taken in to account when designing and detailing a joint using a loop box.

STRUCTURAL BEHAVIOUR OF LOOP BOXESThe box creates an indented surface in the precast element, allowing the design to be done as a construction joint in accordance with EN1992-1-1 Section 6.2.5.

TENSIONThe holistic tensile behaviour comes from the interaction between the overlapping wire loops. The cottering/trimmer bar and the joint mortar grout. However, the wire rope itself is often the critical breaking load and the minimum values for this breaking load and the minimum values for this are published in the relevant manufacturing standards.

The in plane of off plane shear loads are transferred across the joint in a similar manner by utilising supplementary reinforcement in accordance with EN1992-4 in the element and a strut and tie mechanism in the grout.

Please note that grout selection could affect the find behaviour of the joint I case of compliance with serviceability limits.

Fig. 1 : Tension loads perpendicular to the joint

Cracking under service loads needs to be controlled within allowable crack widths for your structure to comply with the durability requirements of EN1992-1-1. Most other connection items in concrete limit this movement to 0.10mm but the design resistances provided were all cross checked against the test data that we have to ensure that the design resistances are all lower than the first crack load.

1.

In some cases, additional supplementary rebar might be required to gain additional capacity such as if the wires are very close together or if the concrete panel is very thin. For this we can treat the wire loop as an anchor and provide additional design guidance in accordance with EN1992-4.

The loop box is capable of resisting in plane and off plane shear loads as well and tension.

The tensile loads are transferred in to the element either by anchor theory and calculation of a concrete cone, or via a strut and tie model in to the supplementary reinforcement in the element. The existing mesh or rebar in the panel can be considered to contribute to the supplementary reinforcement requirement, providing it is not being fully utilised to resist other stresses in the element. The same tensile loads are then transferred across in to the adjacent element using strut and tie using a combination of the wire loops and the trimmer/cottering bar as the tie and compression struts within the grout.

2.

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COMBINED LOADINGIf the loopbox is to be subjected to tension, in plane shear and out of plane shear, then the joint can be further optimised by doing a detailed strut and tie analysis to confirm the actual capacity of the joint.

For simple analysis:

+v'sd v2sdv'Rd v2Rd

≤ 1 ∙ 0

FIRE PROTECTIONThis type of steel wire is commonly used in post and pre tensioning concrete, the materials themselves are compliant. For the other parameters such as wire spacing and cover, the relevant fire regulations need to be observed.

IN PLANE SHEARThese type of loads are often critical when designing shear walls to resist against lateral loading due to wind or seismic actions.

In this case the holistic behaviour comes from a compressive strut in the grout/mortar and a tension tie similar to the tensile behaviour of the loops.

OUT OF PLANE SHEARIn this case the existence of the box profile to create a shear key is critical in the formation of the compressive strut in the grout/mortar. Again the tension tie is similar to the tensile behaviour of the loops.

Fig. 2 : Shear load parallel to the joint

Fig. 3 : Shear load perpendicular to the joint

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TESTING

In Plane ShearOut of Plane ShearTension

To ensure that all the variables and tolerances related to precast construction can be accommodated, we have carried out an extensive range of testing to determine the capacity in all the 3 possible load directions:

The wire ropes themselves fully comply with all the relevant international standards and the test regime has been created in such a way that we are able to provide load capacities specific to the wall geometry as well as differing concrete and mortar strength. The wires are pre-galvanised to provide temporary corrosion resistance from casting to panel installation. If the wires become corroded due to excessive exposure, then the worst case wire should be mechanically cleaned to see if there is any excessive pitting or loss of section. If not, then the loops can be safely used without any reduction in performance.

Each engineer should take care to ensure that the required strengths are met and that the loop specified is long enough to ensure buildability of the whole system.

For additional guidance on what levels of surface corrosion would be acceptable, please contact the our technical team and we will gladly provide you with some sample photographs.

LOOP SELECTION FOR LOOP BOX

Loop length required

Loop required is 40 + 10 + 30 = 80mm

if r = 40, g = 20 + u = 60

= r + — + —g u

2 2

Single / Double Loop BoxMulti Loop Box

u

b

gh

r = 0

h

u

bg

rrh h

M O M E N T

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MOMENT LOOP BOX SYSTEM COMPONENTS IN COMBINATIONOf course, it is also possible to use the different Moment Loop Box System components in combination with one another. For example, it is practical to choose a combination of Moment Multi Loop Box and Moment Single Loop Box when buttjoining two wall panels as shown in Fig. 6 and 7. The same can be applied in a similar way to joints between walls and building columns.

APPLICATIONAlthough the loop boxes were originally designed for wall to wall connections, they can be used for securing any 2 pieces of precast concrete together and are commonly used for wall to column connections as well. The flexible steel wire enables a panel to be placed in to position onto vertical starter bars with ease. As the wires come in to contact with each other, they simply bend out of the way before overlapping again to allow the insertion of the trimmer/cottering bar.

Application example Moment Single Loop Box

Fig. 4Butt jointing oftwo walls

Fig. 6Butt jointing oftwo walls

Fig. 5Wall junction

Fig. 7Wall junction

Fig. 8Butt jointing o ftwo walls

Fig. 9Building column-walljunction

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IDENTIFICATION

Single Loop Box- Timber batten (by contractor)

(mm) b1 b2 hMMS >55 55 *)

*) depending on loop length

Double Loop Box- Timber batten (by contractor)

(mm) b1 hMMD >55 - >85

b255 - 85 *)

*) depending on loop length

Fixing to timber formwork:• Nailing• Glueing (adhesive tape, hot glue)

Fixing to steel formwork:• Glueing (adhesive tape, hot glue)• Magnet fixing

TOLERANCESThere are 3 main tolerances when considering the use of a loop box, one is the vertical spacing between the loops, another is the vertical alignment and the final one is the placement of the box relative to the centre of the wall.

The vertical tolerance is dependent of the total overlap of the loops, but making the assumption that the overlap will always be at least 40mm, then the maximum vertical tolerance to ensure that the 45 degree strut can carry loads from one loop to the next will also be 40mm.

The vertical alignment will only be a problem if the trimmer/cottering bar cannot pass through the loops, but a sensible limit to put on this would be +-5 degrees.

The final tolerance is more sensitive if the wall thickness is thinner, so we limit this tolerance to be 3% fo the wall thickness. 3mm for a 100mm wall, 4.5mm for a 150mm wall and 6mm for a 200mm thick wall.

M O M E N T

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Installation tolerances according to the official approvals, recommended also for application as constructive connections

HORIZONTAL VERTICALRegular joint: 20 mm

Minimum joint: 10 mm

Maximum joint: 40 mm

Regular case: Loops aligned axially at the same level

Vertical tolerance: maximum 20 mm

max.20

mm

Note: Welding on MLB-S/D/Mis not permitted!

1 Bar B 500B 12/13mm 3 Bar B 500B 12/13mm

4 Stirrup B 500B, diam. 8mm, anchoring acc. EN1992-1-12 A vertical tolerance of 20mm maximum is permitted.Wire binding of loops is not compulsory

On the construction site:

Precast concrete element with closed MLB-S/D/M.

1. Remove the MLB cover (Tape) from the concrete.

2. Setting up the precast element. All wire loops must protrude perpendicularly to the joint, and after deflection during the setting up they should springback into this position.

3. Insert the reinforcement bar diam. 12 mm and encase the joint with appropriate formwork. Prepare the Grout Mix according to the manufacturers instructions. The maximum groutin height is 3.5 m, or use a hose. Grout mix is free flowing, no additional compaction is required.

4.

1

GROU

TMIX

Installation of additional reinforcement:Additional reinforcement must be installed following the reinforcementdrawing and attached the structural reinforcement.

GROUTINGThe grouting is a critical process to ensure that the joint functions properly. Therefore the contractor must take care to ensure that a shrinkage equalized (non-shrink) grout is used and that it is placed in such a way to eliminate the risk of air voids.

The grout should be flow able to ensure it can fill all the recesses and also be or a strength at least equal to the lower concrete grade of the 2 elements being joined together.

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If it is not possible to nail the box or the rail to the formwork, for instance in the case of steel form works, we have a practical solution at the ready:

When using steel or plastic formworks, it must always be ensured that the surface is smooth and has previously been adequately degreased. Otherwise, the intended Moment Loop Box System components could come loose and shift when pouring the concrete or during the tamping process.

A double-sided adhesive tape is stuck to the tape cover and simply stuck to the de-greased, smooth formwork (steel or plastic). Thermal adhesives (melting glue) can also be used for this purpose (Fig. 9, 10).

AFTER REMOVING THE FORMWORKAfter removing the formwork, the flexible tape cover is easily removed from the appropriate profile (Fig. 11 and 12). The inside of the Moment Loop Box System component is then exposed and the wire rope loops are visible.

CASTING THE JOINTWhen the concrete sections to be joined have been brought into position, a reinforcing rod of ø 12 mm is inserted from above (Fig. 15 and 16).

The wire rope loops can then easily be folded out using an ordinary roofing hammer or a screw driver for example (Fig. 11 and 12). Immediately after folding out, the wire rope loop should stand out roughly perpendicular to the section and also spring back to this position after deflecting. This is important in order to guarantee an adequate and controlled overlap of the opposing wire rope loops.

The weakest point of a channel joint between wall sections is always the channel casting. Channel joints are only able to transmit the specified forces without any problems when the channels have been correctly and completely cast and an appropriate compression of the casting mortar has been ensured.

A concrete with as fine aggregate as possible (largest gravels < 8 mm) must be used for casting in order to completely fill the relatively small channels without forming gravel pockets. The consistency must be adjusted so that the concrete can flow properly into the intermediate spaces. Particular importance should be given to careful compression. For this purpose, a smaller internal vibrator could be used, which is mounted on the top of the assembly bar and vibrates the concrete for an appropriate length of time. In view of the small quantities required to cast the joints on site, it is practical to use ready-mixed casting grouts for this purpose. We recommend the exclusive use of casting mortar, as we have achieved very good overall results.

With the Moment Loop Box System, the wire rope loop is simply latched into the semi-circular recess in the flanges of the box so that the right-angled position is ensured. The individual prefabricated elements are now ready for the final erection on site.

Fig. 9

Fig. 15Moment Single Loop Box

Fig. 16Moment Multi Loop Box

Fig. 10

Fig. 12 Fig. 14Fig. 11 Fig. 13

*Note: As grouting preferences and procedures can vary from one application to another, please contact the our Technical Team for a detailed method statement on how to install and grout up the joint for your project.

M O M E N T

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Worldwide contacts for Leviat:

Notes regarding this catalogue

© Protected by copyright. The construction applications and details provided in this publication are indicative only. In every case, projectworking details should be entrusted to appropriately qualified and experienced persons. Whilst every care has been exercised in the preparationof this publication to ensure that any advice, recommendations or information is accurate, no liability or responsibility of any kind is acceptedby Leviat for inaccuracies or printing errors. Technical and design changes are reserved. With a policy of continuous product development,Leviat reserves the right to modify product design and specification at any time.

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Czech RepublicLeviatBusiness Center ŠafránkovaŠafránkova 1238/1155 00 Praha 5Tel: +420 - 311 - 690 060Email: [email protected]

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FinlandLeviat Vädursgatan 5412 50 Göteborg / SwedenTel: +358 (0)10 6338781Email: [email protected]

GermanyLeviat Liebigstrasse 1440764 LangenfeldTel: +49 - 2173 - 970 - 0Email: [email protected]

ItalyLeviatVia F.lli Bronzetti N° 2824124 BergamoTel: +39 - 035 - 0760711Email: [email protected]

MalaysiaLeviat28 Jalan Anggerik Mokara 31/59Kota Kemuning, 40460 Shah AlamSelangorTel: +603 - 5122 4182Email: [email protected]

NetherlandsLeviatOostermaat 37623 CS BorneTel: +31 - 74 - 267 14 49Email: [email protected]

New ZealandLeviat2/19 Nuttall Drive, Hillsborough,Christchurch 8022Tel: +64 - 3 376 5205Email: [email protected]

NorwayLeviatVestre Svanholmen 54313 SandnesTel: +47 - 51 82 34 00Email: [email protected]

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SwitzerlandLeviatHertistrasse 258304 WallisellenTel: +41 - 44 - 849 78 78Email: [email protected]

United Kingdom LeviatA1/A2 Portland CloseHoughton Regis LU5 5AWTel: +44 - 1582 - 470 300E-Mail: [email protected]

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For countries not listedEmail: [email protected]

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moment loop box...the durability requirements of en1992-1-1. most other connection items in concrete...

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