Intermediate Tie Beam - Tie Beam in the Middle and Top of a Wall

Since there is no corresponding provision in the earthquake code for this situation, no special definition has been made in the program.

Drawing a beam/tie beam overlapping with walls causes load transfer to be performed twice. This does not result in any change in static calculations other than an increase in weight.

Drawing overlapping walls with different bottom and top elevation values on the same floor means distributing the earthquake forces to the two overlapping walls. This produces incorrect results.

Two types of definitions can be made for this situation:

1) The intermediate tie beam can be considered as a rigid diaphragm and defined as a floor level.

For example:

Floor name: Ground floor lower part, height: 2m

Floor name: Ground floor upper part, floor height: 90 cm, etc.

This approach may result in the building being calculated as less risky than it actually is.

2) Ignoring the intermediate beam/tie beam and (if desired) entering the extra weight of the intermediate tie beam as additional load on walls and above-window tie beams.

In this case, the effective wall height for the wall slenderness calculation is taken as: floor height minus tie beam height above the wall.

It can be considered that Method 1 would calculate the wall compressive safety stress more accurately due to the slenderness ratio calculation (as an engineering approach, not as a definitive judgment). However, it should be noted that the shear stress calculation may deviate from the approach given in the code. As is known, wall compressive strength checks are not used in risk assessment.

It can be considered that Method 2 would provide more appropriate results in terms of shear stresses according to the code.

OUR RECOMMENDATION AND OPINION

As a solution recommendation for this situation: create and save two models according to Method 1 and Method 2 definitions.

Wall compressive strength check reports should be taken from the data file saved according to Method 1.

Wall shear safety stress, risky building performance analysis, and other earthquake-related reports should be taken from the report saved according to Method 2.

It is recommended that the rationale for the procedure performed be explained in the technical report.