System Definition

To the reinforced concrete elements forming the main structural load carrying system, which are produced at factory conditions by using high quality materials, post tensioning is applied after mounting in order to obtain fixed joints transferring moments. By this way, post tensional stresses reserved in elements provides more resistance to the lateral forces such as earthquake.

The system transferred from Japan with know-how and technical sup- port agreements has been successfully applied by ALACALI since 1999.

General Technical Points 

  • Construction of multi-storey buildings with precast technology,
  • No indirect load transmission,
  • No welding risks dependent to the quality of welding or plates (Carbon equivalent < 0.40) used in fitting points,
  • With utilization of high-tech equipments, minimization of workman- ship errors,
  • No corrosion risk,
  • High material quality; Compressive strength of the concrete : C50 – 500 kg/cm2, Yield strength of the post-tensioning cables : 16.000 kg/cm2,
  • Less need for work power at the construction-site: 1/6 (less)
  • Construction period: 1/3 (less)
  • High quality achieved, thanks to manufacturing of the components at the factory conditions,
  • High-tech earthquake resistant structural system developed recently in Japan,
  • Possibility of setting longer structural modulation than convention- al structural systems.

Application Steps

1. Production of Precast Reinforced Elements;
“During the construction of infrastructure at site, C50 columns and beams are produced by fixing post tension channels through the ele- ments in factory. TT slab elements are also produced for obtaining the slabs of ALA-SAWA.”

2. Transportation and Mounting of Columns;
“Elements are transported to construction site. Transported columns are sensitively fixed to the foundations.”

3. Elastomer Joints and The Other Preparations;
“Elastomer joints and the other complementary elements according to know-how are placed to all connection points of columns and beams.”

4. Mounting The Beams and Slabs;
“In order to provide the continuity of the post-tensioning channels through the structure, the produced beams are mounted with ±5 mm. sensitivity. The mounting process of the main system components ends after the slabs are placed.”

5. Preparations for Post-Tensioning;
“The connection points of columns and beams are filled with special non-shrink mortar. The post tensioning cables are driven through the channels.”

6. Post-Tensioning Process;
“Tensioning machine stretches the post-tensioning cables at a cer- tain force to level which is specified at the project and the cables get locked. Since the post-tensioning process is over, the frame becomes a moment transferring frame.”

7. Channel Injection;
“All of the tensioning channels are filled with non-shrink mortar by the computer controlled injection pump after the first and the last ten- sioning points are filled with special mortar.”

8. Concrete Topping;
“On the pre-cast slab elements, that have roughened surfaces and hairpins on them, wire mesh reinforcement is placed. After pouring operation of concrete topping, diaphragm effect is created and the system is completed.”