TRANSPORT and LIFTING spherical head anchors

Transcription

1 Technical specification head anchors The best way of calculating the lifting anchors is step by step. The following steps are in the correct sequence: Determine the weight of the element. (concrete : +/- 25 kn / m 3 ) Through a right position of the anchors, the same load per anchor can be realized. In the case that one anchor is more heavily loaded than the other anchor, this anchor has to be chosen for this loading. It is better to apply anchors of the same kind per lifting situation. Determine the lifting angle of the hoist cable in relation to the length axle of the. This depends on the adjusting of the length of the hoist cables and the position of then lifting anchors. After determining the lifting angle, the calculation factor follows via the table for the force in the lifting cable. Estimation has to be made of the appeared dynamic forces as a result of the lifting or transport method. Lifting with a stationary crane with a fine hoist possibility reduces these forces, while the forces will be increased enormously when lifting on the building site with a forklift truck. Determine via the table below with which enlargement factor has to be calculated.

2 Dynamic forces During the detaching out of the formwork dynamic forces will arise. The size of the dynamic forces depends on the form of the element, the formwork and the use of additions for the detaching out of the formwork. The table gives some directions for the enlargement factor, which can be used Dα Situation Push factor In a factory with a fixed crane 1,10 to 1,30 Transport with a forklift truck at a flat floor 1,30 to 1,60 At location with a fixed crane 1,30 to 1,50 At location with a drivable crane 1,50 to 1,70 Transport with a dredger at an uneven floor 1,60 to 2,00 Lifting angle α Angle α to concrete ( ) 90 1, , , , ,00 Addition factor in force in the lifting part In extreme cases > 2,00 Directions for stick factors Take account of : Form of the element - Oiled formwork - Taking away the side formwork Stick factors Beam or pillar 1,00 to 1,10 Vertical plate 1,10 to 1,15 Horizontal plate 1,20 to 1,25 Floor plates with cassettes > 2,0 For elements with a difficult form higher factors have to be taken, especially for elements where a vacuum can arise during the taking out, such as with cassette floors. The forces can be a multiple of the weight. The action forces per anchor can be calculated as follows: Action force = weight x lifting angle factor x dynamic factor x stick factor quatity of anchors

3 When the action force of the most heavily loaded lifting is determined the choice of the type of the lifting anchor must be made. By means of the acting forces the type of the Foot -anchor can be determined. With the aid of the added tables can be determined which length of the Foot anchor must be used dependably of the present concrete strength. When lifting in an angle by using Foot-anchors no reduction is needed on the permissible load. For the vertical setting of small elements split reinforcement can be necessary by reason that the pressing force of the lifting hook will lead directly his forces into the concrete. Split reinforcement can be adjusted in the following way. The lifting clutch directly leads the pressing force to the concrete and starts approximately halfway of the recess former. That is why the split reinforcement must be applied. See the drawing. Anchoring of FOOT-anchors If the loading type of thefoot - anchors has been chosen, the length of the anchor has to be determined. Dependably of the form of the element and the strength of the concrete at the first loading, a Foot - anchor has to be chosen, which realizes a larger anchoring force than is calculated as the acting force. The admissible anchoring force is calculated with a safety factor of 2,5. The foot of the anchor obtains the anchoring. At collapsing of the concrete a dish formed foot arises of the Foot -anchor a break out cone with an incline of 1:3. That is why those relatively small anchoring lengths will do. In this technical documentation tables are added, to which in practice most of the situations can be filled in. It is possible to make an exact calculation of the present situation.

4 On request special tables can be made which fulfill the practical situation in the prefab factory or at the building site. If it is possible to divide elements in the groups below, than the following rule of thump can be used.in case of inexperience with the Spherical head anchor system, additional information is always obtainable at CLPT. Type of element Beams Horizontal plates Vertical plates Type of footanchor FOOT- anchors with the standard length per loading type can be used FOOT- anchors with a smaller length than standard can be used. FOOT- anchors with a larger length than standard must be used. Overview of FOOT- anchors lengths Loading class Kg Standard type foot-anchor Often used shortened anchor Often used lenghtened anchor kn x length () kn x length () kn x length () The calculation of the anchoring length can be done with the aid of empiric found formulas, with the VBC-90 or according to the rules of the CUR. When calculating the admissible anchoring force besides the length of the, the present concrete strength is of main importance. Mostly the deforming strength is leading or the concrete strength that is realized at the first loading of the anchors.

5 If there is any doubt about the admissible concrete force or that it is not possible to realize it, additional measurements have to be taken. For instance the concrete force can be enlarged in the location of the Foot- anchor by adjusting isolation material. When you use isolation material, higher temperatures can be reached in the concrete and this gives a quicker force development. The addition of extra reinforcement in the reinforcement nets almost never leads to improvement of the anchoring force. The anchoring force can only increase if the reinforcement is placed around and over the foot of the anchor. The anchoring force of the Foot- anchor is the biggest when the Foot-anchor is placed at a distance to the edge which is 3 times larger than the built in depth so that a complete break out cone can be created. If it is not possible to have an edge distance to all directions of 3 times the built in depth, a better anchoring must be obtained with the aid of a longer Foot- anchor. In the table a situation is described which fulfill as well the edge distances in all directions of 3 times larger than the built in length as well the situation for which the edge distance is limited to 2 directions. With the aid of these tables a good impression can be obtained of what the real admissible force is in situations that are more or less comparable. In case of doubt, please contact CLPT. For vertical plates the possibility that a horizontal break out can occur must be taken into account. Here also the present vertical reinforcement has no effect for the anchoring force. The situation in the figure will become very critical if the thickness of the element is smaller than half the thickness of the chosen Foot-anchor. In this situation please contact CLPT. To enlarge the vertical anchoring a hairpin can be adjusted which falls around the foot. In this situation it is also very helpful to use an eye anchor. With these lifting anchors the anchoring is obtained by a reinforcement hairpin through the eye of the anchor.

6 Welding to the anchors Welding to the anchors (HEAD AND BODY) to for instance the armament web is never allowed. The chose of the material for the anchors in order to obtain the smallest anchor in relation to the highest safety does not allow any welding under normal circumstances. Slabs lifting load data Position of the anchors: Length direction : edge distance 20% of the length. Transverse direction : edge distance 30% of the width. The edge distance is always more than 3 x time the built in depth (*) Built in dept minimum slab thickness 1 0 N/² Concrete strength at first load (kn) 1 5 N/² 2 0 N/² 2 5 N/² > 13.0 > 13.0 > 13.0 > > 13.0 > 13.0 > 13.0 > >25.0 > >25.0 >25.0 >25.0 > >25.0 >25.0 >25.0 > >50.0 >50.0 >50.0 > >50.0 >50.0 >50.0 > >75.0 > >75.0 >75.0 >75.0 > >100.0 > >100.0 > N/² see table next page.

7 (*) For heavy Foot -anchors a minimum edge distance of 500 is applicable Built in dept minimum slab thickness 1 0 N/² Concrete strength at first load (kn) 1 5 N/² 2 0 N/² 2 5 N/² >150.0 > >150.0 > > Basic reinforcement is not required. The slabs should be designed for the transport case. 3 0 N/² Walls and beams load data Position of the anchors: Length direction : edge distance 20% of the length. Transverse direction : edge distance in the middle of the element. Built in dept wall/beam thickness 1 0 N/² Concrete strength at first load (kn) 1 5 N/² 2 0 N/² 2 5 N/² 3 0 N/² > 13.0 > > 13.0 > 13.0 > > 13.0 > 13.0 > 13.0 > 13.0 > > >25.0 > >25.0 >25.0 >25.0 >

8 >50.0 > >50.0 > >50.0 >50.0 >50.0 > >75.0 > >75.0 >75.0 > >100.0 >100.0 > >100.0 >100.0 >100.0 > Façade plates Maximum weight of façade plates, LIFTING ANGLE This table is mentioned for the Foot-anchors as described under the condition that the distance to the edge of the element in 2 directions is more than triple of the built in depth and that the anchor is also the distance between the s must be more than 6 times of the built in depth. The values mentioned in the table are the maximum weights of the elements at a concrete strength of 15 N/². With this the use of an equator as well as a push factor are indicated. see table next page.

9 Built in dept wall / beam thickness Arisen force / anchor kn Max. weight of the element with 2 anchors kn >

10 Maximum weight of façade plates, LIFTING ANGLE < 60 The values mentioned in the table are the maximum weights of the elements at a concrete 35 N/. 60 Built in dept wall / beam thickness Arisen force / anchor kn Max. weight of the element with 2 anchors kn

11 Reinforcement for vertical lifts, wall and beam applications Basic REINFORCEMENT for Lifting anchors under VERTICAL LIFT and a CONCRETE STRENGTH of 15 N / 2. Mesh (**) reinforcement both sides 2 /m (*) (1) Insert stirrup (2) Edge FeB 500 L1 reinforcement FeB 500 not required not required x diam diameter x diam diameter x diam diameter x x diam diameter 16 (*) one layer for minimum wall thickness of 60 (**) Insert stirrup (1), instead of the suggested reinforcement mesh, a comparable amount of reinforcement steel or the combination of a smaller mesh with additional reinforcement bars can also be used L1 a a a a = 125 d/2 d d/2

12 Reinforcement under angled lifts, wall and beam applications REINFORCEMENT under angled lift up to 45 and a CONCRETE STRENGTH of 15 N / 2. Foot anchor Mesh (**) reinforce -ment both sides 2 /m (3) Diagonal lift reinforcement diam. d2 B L 2 (1) insert stirrup FeB 500 L 1 (2) Edge reinforcement a FeB (*) diam x diam diameter diam x diam diameter diam x diam diameter diam x diam diameter diam x diam diameter x diam x diam diameter x diam x diam diameter x x diam x diam diameter 16 (*) One layer for minimum wall thickness of 60 (**) Instead of the suggested reinforcement mesh, a comparable amount of reinforement steel or the combination of smaller mesh with additional reinforcement bars can also be used. (***) The length can be reduced by the use of hook end according to the appropriate standard L2 a a a d/2 d/2 d2 B d

13 Reinforcement for lifting of slabs Load capacity (kn) of the spherical head lifting anchors for lifting of SLABS using the lifting clutch ref 6102 in any chosen direction. L D Basic reinforcement is not required. The slabs should be designed for the transport case. A Built in dept 2 / Anchor length L (*) Min. thickness of the element (D) Edge distance A > Perm. loading in kn concrete strength 15 N/² 25 N/²

14 Reinforcement for lifting with plate anchors 6010 The spherical head PLATE anchor ref 6010 is recoended for all large thin precast slabs. The minimum element thickness results from the anchor length (L) and the required cover (c) for corrosion protection. Reinforcement as indicated in the table must be applied. FeB 500 d a x b L2 L c 6010 Built in depth a x b x t Anchor (L) Reinforcement rebar Feb 500 Perm. loading in kn concrete strength d L2 15 N/² 25 N/² x 70 x xdiam x 70 x xdiam x 90 x xdiam x 90 x xdiam x 90 x xdiam x 90 x xdiam For more technical information, how to calculate the right Spherical anchors and how to build the in and how to use them, CLPT can send you on a simple demand our TECHNICAL DOCUMENTATION