Pretensioning techniques are widely used for beams and slabs in concrete structures due to their ability to efficiently compensate for the reduced tensile strength of concrete through precompression.
The small effect of pretensioning on the bending stiffness coincides with the results previously obtained by Bohannan .
This analysis aims to determine the influence of using different wood species with different mechanical properties for the webs and the effect of pretensioning with unbonded tendons on the strength and bending stiffness of beams.
(v) The pretensioning of the specimens was conducted using threaded bars of Y1100H  steel with a 20 mm diameter, an elastic limit of [f.sub.pk] = 900N/[mm.sup.2], and a tensile strength of [f.sub.pmax,k] = 1100 N/[mm.sup.2].
A hydraulic device has been facilitating the screw tensioning in the company's twin screw extruders and ensuring reproducible installation and pretensioning
. In order to ensure the reliable transmission of the torque, not only special, heavy duty screw shaft materials and an optimum gear geometry are required, but also reliable tightening of the screws in the shaft, according to the company.
With pretensioning each cable, more stability and less simulation time will be achieved.
Most of the proposed optimisation approaches have limitations in determining the optimal pretensioning forces.
Under the combination of the dead load and cable forces, the first estimation of pretensioning cable forces is taken based on the ULM because the computations are less difficult to converge compared to the other iterative methods.
Very high initial stiffness (or joint resistance) due to bolt pretensioning is shown in Figures 4.b to d.
As shown in Figures 4.b to d, the average frictional moment resistance is about 2.16 kNm, 3.71 kNm, and 5.65 kNm for the joints with 5 kN, 10 kN, and 15 kN of pretensioning force per bolt, respectively.
Average maximum resistances of the joints, excluding the partial compression effect, are 10.68 kNm, 10.53 kNm, 10.35 kNm, 10.61 kNm, respectively, for the joint with 0 kN, 5 kN, 10 kN, 15 kN of pretensioning. This result indicates that an influence of pretension in bolt is hardly obvious.
Compressive stresses are induced in prestressed concrete either by pretensioning