More substantial information is necessary to determine why the contractor wants to create a joint to isolate the lintels horizontally and why the architect agrees (maybe it is based on experience). Not all things done acceptable do not turn strictly on detailed structural analysis. - If this is a typical large one-story commercial or industrial building I can seen the reasons for the agreement.
1. What are the over-all building dimensions (height, width and length).
2. What is the wall panel or open wall spacing and what are the opening heights/locations relative to the wall elevation. I assume (bad word) that the louvers are higher on the wall unless there is floor ventilation/evacuation.
3. What is the wall construction? - materials, thickness, etc.
This is necessary to avoid the myopic analysis similar to the three blind men independently examining an elephant with one hand, no sight and ended up with no agreement.
Unless the building is very small there is always some provision to accept the inevitable movement. I observed a load bearing back wall of a 600' long, 12-14' high commercial/industrial building that had no provision for movement in the wall, but there were 8 man doors (7' high opening) and a continuous 16" deep bond beam/lintel with 4 -#6 bars continuous. Upon investigation, cracks were observed at one edge of each opening. After that, there were cracks at the midpoint of each remaining panel between each of the openings. After the first set of natural cracks, there was another generation of cracks to further subdivide the panels for the temperature and humidity conditions. - There was also on continuous horizontal crack immediately below the continuous bond beam/lintel. The CMUs used were very low shrinkage (less than 1/4 of that allowed for the Type I units at the time) and dry. The architects and engineer lost all further business with the very large client because of the water leakage caused by the 600' horizontal crack - During my 40 years experience in the U.S. and elsewhere, I have seen similar, but far more obvious cases of movement such as long term brick expansion on a 7 story reinforced concrete frame apartment to where the differential movement (concrete shrinkage & brick expansion)it became impossible to open windows for ventilation or emergency access.
You have to look at the big long term picture of the structure, materials and movements that can create problems reflecting back on the professional design. - If not, you may mistakenly identify and elephant for a snake like the blind man.
My comments, as I originally mentioned, were based on the information provided and the information so far really has not been sufficient for more than a quick "boilerplate" solution.
The bottom line is that you probably will not find a specific requirement on continuous steel in bond beams because of the possible detrimental visual maintenance and effects without a structural benefit. IF is is a masonry wall, the purpose of the bond beam generally is to provide a beam that provides a good bearing surface, vertical distribution of the loads into the wall below, resistance to differential movement from lateral loads and still allow horizontal movement of the wall below.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
