Steel Secondary Beam Design Example

For design of standard floor secondary beams that are hinged to the main frames and are not affected by seismic loads, strength checks under vertical loads and servicebility limit conditions under vertical loads should be checked.

Steel material: S275 F_y =275 N/mm ² F_u =430 N/mm ²

Cross section: IPE 360

Flexural Strength

Classification of the cross-section for the local buckling limit, according to ÇYTHYE 5.4 Table 5.1B, checks are made for flange and web according to the cross-section type.

• Cross section flange;

• Cross-section web;

According to the local buckling limit, the width/thickness ratios of flange and web parts of the cross-section do not exceed the limit values ​​given in ÇYTHYE Table 5.1B, so IPE 360 is classified as compact.

The characteristic flexural moment strength of the I-section element with double symmetry axes, which is under the strong bending effect of the compact cross-section about its principal axis, M_n, is determined according to ÇYTHYE 9.2.

Firstly, M_n is determined to check L_p in case of lateral torsional buckling limit characteristic.

As a result of the control, there is no need to consider the lateral torsional buckling limit as per ÇYTHYE 9.2.2(a). In this case, the characteristic flexural moment strength becomes equal to the value determined by the yield limit state.

In the secondary beam report, the results are tabulated as follows.

Shear Strength

In double symmetry axis-cross section, as per ÇYTHYE 10.2.1(a)

Shear capacity check is as follows:

Availability Limit State in Beam

Deflection control is done under G+Q load combination as per ÇYTHYE 15.1. It is taken as the displacement limit value (L/240). According to analysis result, the maximum relative displacement between the supports,

Deflection check results are checked on the secondary beam report.