How the torque reinforcement is arranged

The torsional reinforcement should be arranged along the outer surface of the torsional member, and the maximum torque position should be at the torsional support of the torsional member (this sentence should be fully understood).

Since pure torsional members are almost non-existent in engineering, in most cases such members are beams, and beams must at least have bending moments due to their own weight.

Under the action of bending moment, the general steel bars will be arranged on the upper surface and lower surface of the beam respectively, and at the same time, the high rectangular beam under the action of large bending moment will be equipped with anti-cracking waist reinforcement on the beam side in order to prevent the side concrete cracking.

In order to facilitate construction, the torsion bars are arranged at the top of the beam, the bottom of the beam and the side of the beam respectively, and theoretically speaking, the arrangement of the torsion tendons should be evenly arranged even if they are only on these four surfaces. However, when the bending reinforcement at the top and bottom of the beam is too large, the possible situation is that the over-reinforced beam is formed because of the configuration of torsion ribs, or it is difficult to construct; Therefore, designers often choose to enlarge the waist tendon as a method of twisting the tendon.

Arrange the waist reinforcement and bending reinforcement.

There is no structure of waist tendons, and they are matched on waist tendons; If there is a structural waist bar and the area is smaller than the area of the torsional longitudinal bar, the excess part is directly assigned to the top and bottom bars without increasing the number and diameter of the waist bar. Therefore, the higher the beam, the more waist reinforcements, and the larger the area of reinforcement next to the tomb of the torsional person who is allocated.

In any case, the anchorage length shall not be less than 250mm. When the length of the straight anchor at the top of the inner column reinforcement and the top of the middle column reinforcement is less than the anchorage length, the right-angle hook can be bent inward or outward for 12d. When the vertical anchorage length of the column wall reinforcement is less than the specified value, it is necessary to add a right-angle hook according to the table in the lower right corner of page 32 or the table in the upper right corner of page 45 of the 101-3 atlas.

The anchorage length of the upper and lower longitudinal bars of the frame beam and the torsional waist bar and the upper longitudinal bar of the non-frame beam is 15d right-angle hook. When the anchorage length is less than or equal to the support length - the protective layer, the anchor can be straightened; When the anchorage length is greater than the support length - the protective layer, the anchorage length should be bent not less than 15d and the horizontal length should not be less than times the anchorage length.

When the cross-sectional height of the beam minus the plate thickness is greater than or equal to 450mm, the torsional reinforcement, that is, the waist bar, needs to be added to the beam.

The lap of the torsional steel bar is LL or LLE (seismic), and its anchorage length and method are the same as the lower longitudinal reinforcement of the frame beam, and the anchorage and lap of the structural steel bar are calculated by 15D, and in 03G101-1, when the web HW of the beam is greater than or equal to (450) mm, the longitudinal structural steel bar must be configured. When the beam width is 350, the diameter of the rib is (8) mm. The tension spacing is (twice the non-encrypted spacing).

The waist bar can be added with a diameter of 10 or 12, and the round steel with a diameter of 10 should be anchored at both ends, and the rebar is not used. Evenly arranged, waist bars are set on the left and right sides of the beam, symmetrical and straight.

Torsional steel bars generally refer to the steel bars arranged on the side of the frame beam when the load on both sides of the frame beam is different and a certain torque is generated on the frame beam. The structural reinforcement and torsional reinforcement are designed by the design institute, and the code of the structural reinforcement is G, and the code of the torsional reinforcement is NThe anchorage length of the structural reinforcement is 15d

The anchorage length of the torsional reinforcement is the same as the anchorage length of the main reinforcement of the beam.

That's what it means, it mainly depends on whether the waist bar is a torsional steel bar or a structural steel bar.

The arrangement is generally 200 spacing from the bottom of the beam upward.

Through-long arrangement, neat arrangement.

Beam net span length + anchorage length on both sides.

Longitudinal reinforcement, stirrups and waist reinforcements.