CONCRETE STRUCTURE

1- Technical Field

Many researches has been done in civil engineering to solve the effect of corrosion on steel reinforcement because of the chemical which adding on the deck slabs during winter to remove the snow from the roads .

Steel-free housing concrete structure slabs is extending to the earl iest research on steel free deck slabs composite bridges by (Mufti) and others. Five bridges were constructed in Canada and all of them were composite bridges. But in this newly system the housing concrete structure slabs is not composite section. That invention is not by accident but the researcher has master degree in the steel- free deck slabs composite bridges and also PhD in steel- free deck slabs composite curved bridges from Faculty Of Engineering Ain Shams University Egypt.

2 - Background Art

Steel tree deck slab composite bridges has been used in five bridges in the Canada and the LindQuist bridge was the longest clear span (3.1 7 m) between the inner edge of two flanges of the girders and the strap was 2.5*5 cm and the thickness of slab was 15 cm at the crown and the girders were steel girders the shear connectors were rivets and straps were steel plate as in the fig ( 1 ) shows the details of that bridge. But in the new system are using in housing concrete structure slabs and all components from concrete section and the slab span 3.6m till 10m as in fig 2-7

The problems in the last art

It was used in bridges only and with composite section and the maximum clear span was 3.1 7 m and with haunches as in figure 1.

. But that invention is semi arched slab with tie from reinforcement steel bars 52. The newly system reached to 10. 1 5 m span as in figure 4. 3- Disclosure of invention

Steel free concrete structure slabs (semi arched slabs). In this newly system 1 use the torsion steel reinforcement( 52) instead of straps and stirrups instead of shear connectors and making minimum curvature and all beams are

reinforcement concrete as in all figure from 2-7. By using the semi arched slab the system becomes arch with tie, in that system the concrete slabs arc resisting the compression only and the ties resisting tension only.

The first model the slab dimension 4.5*4.5 m, span was 4 m clear and the spacing between two ties was 1.25 m and the steel of ties were outside the slab and the slab thickness was 10 cm at the crown. The two ties steel was 5 bars with I cm diameter only and the maximum height of the arch at the crown was 1 0 cm as in figure 2. fhe second model was 5.65 m clear span and maximum curvature 20 cm (arch height) and slab thickness at the crown was 1 5 cm and the steel of two ties were 4 bars with 1 .6 cm diameter for each and the clear spacing between two ties was 1 .6 m and the steel of ties were outside of the slab also as in figure 3.

Third model was 1 0. 15 m clear span and maximum curvature 32 cm and 1 8 cm thickness at the crown and the steel for ties were 6 bars with 1 .6 cm diameter for each and the clear spacing between two ties 1 .75 m and the steel of ties were outside of the slab as in figure 4.

Fourth model was 4.75*4.75 from the outer edge and the maximum curvature was 1 2 cm and the thickness was 10 cm at the crown and ties steel were internal and external of the slab without tie in the middle of slab as in figurc5. That model shows the spacing between external ties were 4m and the internal ties at the corner.

The fi fth model was a project with 12.75* 12.75 m with different curvature from 8 cm till 1 6 cm about the span between the beams, inventor takes also

Different thicknesses with range from 10 to 12 cm in this project i take impeded di fferent ties at the corner and at the middle also as i the figure 6. fhe sixth model was a project also in villa at the last floor with different span also, 4.25*4.25 m and 4. 10* 1 5 m with maximum curvature 10 cm and with thickness 10 cm at the crown and the ties steel were in different position, internal and external and in the corners and mid span as in figure 7. Experimental Work

ΛΙΙ experimental load were taken at the field by using sand or stone to be in secret and nobody believe that invention.

T he first model was loaded by 21 .6 ton (twelve cubic meters sand) the fc of concrete 230 kg/cm ^" . Deflection was 1 .2cm at the mid span of slab between the ties.

The expecting load 4*4% 1 5+.2) = 5.6 ton that mea factor of safety for the slab concrete 21 .6/5.6= 3.85.

The second model was loaded by 6.750 ton (3000 stone* 2.25kg) at the mid span of the model the fc of concrete 250 kg/cm ² . De lection was 1 .6cm at the mid span of slab between the ties. The moment due to load

6.75 *5.65/4=9.53m.t

The expecting moment .35*2*5.65 ² /8 = 2.793 m.t that mean factor of safety for the slab concrete 9.53/2.793= 3.41

The third model was loaded by 10.125 ton (4500 stone*2.25kg= ) the fc of concrete 200 kg/cm ^" . Deflection was 3.2 cm at the mid span of slab between the ties. The moment due to load =10, 125* 10. 15/4= 25.7m.t

The expecting moment .35 *2,25 * 1 0. 15 ² /8 = 10.1 4 that mean factor of safety for the slab concrete 25.7/10. 1 4=2.53

The fourth model was loaded by 6 ton (2660*2.25 kg) the fc of concrete 230 kg/cm ² . Deflection was 1 . 1 cm at the mid span of slab between the ties.

The moment 6*4.25/4= 6.375m.t

The expecting moment .35*4.25*4.25 ^" = 3.36 m.t that mean factor of safety fo the slab concrete 6.375/3.36= 1 .89.

Notice there is no failure at all during loading because the models were inside the building and we should be very careful. All the models stil l exist.

Method of Using

We can use that invention for the concrete structure slab which reducing75% quantity of steel for the slabs (the quantity using 25% from the main quanti ty) 30% for all the concrete structure. It can be use for the village and typical floor for the housing structure. This system is decreasing the demand of steel reinforcement and making its price becomes low.

1 think that invention for the poor people and I promise them that I will do best to make all of them build there houses by lowest coast.

The new in this invention are:

1 - The span becomes from 4 m to 10.15 m clear

2- The thicknesses of different slabs between 10 and 18 cm

3- The curvature between 10 and 32 cm

4- The ties were used internal and external of the slab

5- This system used for the first time in Egypt in housing concrete

structure semi arched slab and making reduction in slab steel till 75% by comparing the solid slab.

6- The different method of using ties was direct and indirect in resisting the tension force.