Prestressed with both ends of the tension at the same time tension, tension and elongation of double control method, both at the jack up and down pressure, drawing lines, elongation, insert pad and other work together.

Jack in place, the first master cylinder a little oil filled, enable the pedal tight, let prestressed steel strand Bengzhi, in steel wire pull to the specified initial stress sigma 0, stop the amount measured original void and draw a line marking.

Steel strand stretching sequence integrated the following several factors accounting determined: the one to avoid a pull member section is a large eccentric stress state, do not make concrete edge tensile stress; second was computed and compared with the batch tensioning prestress loss value; the third is to minimize the beam body to generate a large camber, to prevent cracking of beams or serious deformation. By comprehensive comparison, the two stage transmission anchor tensioning pull, i.e. T beam concrete strength up to 90%, first of all, tension and anchor n1-n4 of steel strands in the end beam, this four strand duct grouting, and then deposit the beam; in order to reduce the creep of the T beam camber, anchor on the beam at the top of the N5-N7 steel strand awaiting frame beam and tensioning and grouting, then frame beam. The another advantage of the two tensioning process is: pre tensioned pulling a part of the steel wire, lower prestress is applied on the beam, the beam body can bear the weight of load, ahead of the beam in beam removed from production, greatly shorten the pedestal production cycle, accelerate the construction progress.

In the steel strand tension sequence: N2, N3, N1, N4,, N5, N6.

Side beam steel strand tension sequence: N2, N3, N1, N4,, N5, N6,, and N7.

The prestressed steel strand tension force: 0, initial stress and stress control of 0 sigma K (holding 2 minutes anchor). A K pull of the tension control stress (including prestress loss included).

Tensioning construction work order: wear beam, anchorage installation, installation jack and tensioning equipment, Zhang pull, anchorage, removed a jack and a pulling equipment, grouting, the beam storage.