Steel Secondary Beam Design Example

For the design of normal floor sub-beams that are hinged to the main frame beams and are not affected by earthquake loads, strength control under floor loads and usability limit conditions under operating 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 situation, according to Table 5.1B in accordance with ÇYTHYE 5.4, calculations are made for the head and body according to the cross-section type.

• Cross section flange;

• Cross-section web;

According to the local buckling limit situation, the width/thickness ratios of the head and body 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 bending 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.

In case of lateral torsional buckling limit characteristic bending moment resistance, M_n is primarily for calculating L_p is computed.

As a result of the control, there is no need to consider the lateral torsional buckling limit situation as per ÇYTHYE 9.2.2(a). In this case, the characteristic bending 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 calculation 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 the analysis result, the relative greatest displacement between the supports,

Deflection control results are checked on the secondary beam report.